Дисертації з теми "Timber-framed"

The structural fire resistance of light timber frame walls and floors has traditionally been determined by using standard fire resistance tests to provide a Fire Resistance Rating (FRR). The required FRR was prescribed by building codes and had little relation to likely fire severity. More recently, simple formulae have been used to determine an appropriate FRR given the ventilation parameters of a compartment, the likely fuel load and to a lesser extent the thermal properties of the compartment boundaries. The work described in this thesis determines the validity of these formulae for light timber frame walls and floors and other materials. It is shown that, computer modelling can be used to determine the thermal and structural performance of light timber frame walls and floors exposed to fire. The COMPF-2 program can be used with modification to model compartment fires. The thermal behaviour of cavity walls and floors exposed to fire can be modelled accurately using the TASEF program. The structural behaviour of light timber frame walls and floors exposed to fire can be modelled using a general purpose finite element program, such as ABAQUS. The temperature dependent thermal properties used in the thermal model and the temperature dependent mechanical properties used in the structural model may not be absolutely accurate values, but are effective values that are (modifications of known values within a reasonable range) determined in the calibration process. A simple temperature based failure criterion has been devised for the structural response of light timber frame walls and floors exposed to fires. This study shows that simple time equivalent formulae are not suitable for the prediction of such a complex and variable phenomenon as the response of structures to fire. For accurate prediction of structural response under fire exposure, a more rigorous computer based analysis can be used to give much more reliable results than a simple time equivalent method.

This thesis describes the structural performance of plywood sheathed timber shearwalls exposed to simulated seismic loading and proposes a simple design method. Five full sized three-storey shearwalls were constructed using timber framing and plywood sheathing. The shearwalls were of high aspect ratio and one had large openings. A variety of framing arrangements and hold-down details were used. Each of the shearwalls was instrumented and subjected to reverse cyclic loading representative of the fundamental mode of seismic loading. Construction of the walls and their behaviour under load is described in detail, with an analysis of stiffness, strength, ductility and failure modes. Material properties of the shearwall components were investigated experimentally. A capacity design method is proposed to prevent brittle fracture of the timber and verified by reliability analysis. A proposed method of calculating deflected shapes gives good agreement with test results. The seismic response of multi-storey buildings is investigated. A structural design procedure and suitable detailing for multistorey timber shearwalls incorporating light frame timber construction and plywood sheathing is developed. The procedure is specifically intended for the design of timber shearwalls resisting NZS 4203:1992 seismic loading requirements and meeting NZS 3603:1993 design criteria, but can be adapted to meet other codes of practice. Capacity design methods are incorporated. An example design of a three storey shearwall is included.

Within the UK traditional masonry construction techniques are struggling to deliver the quantity and ecological quality of housing required by an ever increasing UK population. This research employs a case study review of a mainstream mixed timber frame and masonry housing development - Green Street, in order to explore the ecological viability of timber prefabrication as an alternative to the established masonry construction methods currently employed in the majority of British housing. Four houses of each construction type in the Green Street development were outfitted with a number of environmental monitoring sensors for continuous monitoring. In addition the study incorporates fabric testing in the form of air permeability testing, Co-heating analysis, thermography, and a life cycle analysis. Building Use Survey, project management and design team interviews and an industry questionnaire form the final part of the evaluation protocol. The study revealed that heating the timber dwellings ultimately required less energy per degree difference between inside and outside temperatures. During the summer the timber housing displays a greater diurnal temperature swing, while on average the temperature remains consistently lower than the masonry housing. The masonry housing was found to be both more air tight and exhibiting a lower heat loss coefficient, despite that, the performance gap between design and reality for space heating is less in the timber prefabricated housing. The life cycle analysis revealed that the timber walls have a lower impact on climate change. BUS methodology results found that construction type had little to no impact on occupants. The design team review highlighted the need for a greater level of prefabrication in timber housing to increase precision and work around a serious skills shortage. An industry questionnaire suggested that timber construction in the UK can often suffer from poor construction practice, predicated by a gap in specialized knowledge. The research concludes that in this instance, the timber prefabrication technique produced dwellings that perform ecologically on par with their masonry counterparts. In answering the research question, the evidence suggests that at this stage the technique would be better employed on a case by case basis and supported by specialists in timber fabrication, rather than implemented as a blanket alternative for existing masonry construction. Already a number of insights from this research have filtered into industry practice and will continue to better inform both industrial and academic partners in their decisions regarding the use of timber prefabrication in mainstream UK housing.

Construction clients have the position to continuously improve new-built from a life cycle perspective. Furthermore, they can contribute to advancement and improved competition in construction by putting more explicit and distinct requirements and by a willingness to try new, non-local contractors and new construction methods (Statskontoret 2009). Conventional construction is argued to constitute a barrier to change (Dulaimi et al. 2003). Industrialised building, with its off-site characteristics and process-orientation, is seen as a means to attain advancement in construction (e.g. Statskontoret 2009). Industrialised multi-dwelling timber framed (ITF) housing entail all of the identified advantages of industrialisation. Nonetheless, clients are not actively driving change towards industrialised construction (e.g. Engström et al. 2009) and it was indicated that one possible explanation could be that clients are uncertain (Höök 2005). The aim of this thesis is to identify client organisations' uncertainties concerning ITF housing and property, find mechanisms for why they arise and propose measures to manage uncertainty within clients' organisations. The thesis is based on three appended papers and a detached technical report (Levander 2010). Empirical data consist of interviews, economic data, documentation and a questionnaire, they have been collected from in total 27 Swedish client organisations and on 44 ITF properties, and are analysed in two case studies and one field study.The results show that the great majority of client organisations' uncertainties are a matter of equivocality. The mechanisms for the high equivocality are the high complexity and uncertainty in construction in conjunction with the novelty encompassed by ITF housing and property. The current information processing practice within the studied client organisations does not support resolving equivocality.The general conclusion is that ITF housing and property is a radical change seen from clients' perspective and represents novelty in construction technology. Thus, the ITF alternative challenges and goes beyond clients' known frame of reference and thereby causes equivocality. In order to manage and resolve equivocality, client organisations need to enable translation and transfer of frameworks and their activities must constitute challenges to their normal practice. Thus it is proposed that in order to manage uncertainty and equivocality, and thereby contribute to advancements in construction, client organisations need to work with uncertainty management.
Fastighetsägare har i rollen som beställare möjligheten att ständigt förbättra nybyggnation från ett livscykelperspektiv. Dessutom kan de bidra till utveckling och ökad konkurrens inom byggbranschen genom ett tydligare kravställande och med en vilja att prova nya, icke-lokala entreprenörer och nya produktionsmetoder (Statskontoret 2009). Traditionellt byggande hävdas utgöra ett hinder för förändring (Dulaimi et al. 2003). Industriellt byggande, med byggande i fabrik och processorientering, ses som ett sätt att nå framsteg byggandet (ex Stadskontoret 2009). Industriellt byggande av flerbostadshus med trästomme för med sig samtliga fördelar med industriellt byggande. Trots detta är inte beställarna en aktiv kraft (Engström et al. 2009), en möjlig förklaring är att kunderna är osäkra (Höök 2005).Syftet med forskningen är att identifiera fastighetsägarorganisationernas osäkerheter om den industriella träbyggnadsprocessen och om industriellt byggda flerbostadshus med trästomme (ITF-alternativet), hitta mekanismer för varför osäkerheterna uppstår och föreslå åtgärder för att hantera osäkerhet inom kundorganisationer. Avhandlingen bygger på tre bifogade artiklar och en fristående teknisk rapport (Levander 2010). Empiriska data består av intervjuer, ekonomiska data, dokumentation och en enkät som har samlats in från totalt 27 svenska fastighetsägarorganisationer och på 44 ITF fastigheter, och sedan har analyseras inom två fallstudier och en fältstudie.Resultaten visar att kundernas osäkerheter främst är en fråga om tvetydighet (equivocality). Mekanismerna bakom denna är den höga komplexitet och osäkerhet inom byggbranschen generellt, tillsammans med det nya och annorlunda som ITF-alternativet medför. Det nuvarande sättet att hantera information och kommunikation inom de studerade fastighetsägarorganisationerna stödjer inte hantering av tvetydighet.Den allmänna slutsatsen är att ITF-alternativet är en radikal förändring sett ur kundernas perspektiv och representerar nyhet i flera dimensioner. Således går ITF-alternativet utanför kundernas kända referensram och medför därigenom tvetydighet. För att lösa tvetydighet krävs att kundorganisationerna möjliggör överföring av referensramar och aktivt utmanar sina nuvarande arbetssätt. Det föreslås därför att kundorganisationer behöver arbeta med osäkerhetshantering, detta för att kunna hantera och lösa både osäkerhet och tvetydighet, och därigenom bidra till framsteg inom byggandet.
Godkänd; 2010; 20100515 (erilev); LICENTIATSEMINARIUM Ämnesområde: Träbyggnad/Timber Structures Examinator: Professor Lars Stehn, Luleå tekniska universitet Diskutant: Professor Jan Bröchner, Chalmers tekniska högskola Tid: Onsdag den 16 juni 2010 kl 09.00 Plats: F1031, Luleå tekniska universitet

In this Thesis, an intervention system applicable to existing reinforced concrete (RC) framed buildings is presented. The main purpose of the intervention is to improve the seismic behaviour of such buildings using cross-laminated timber (CLT) panels without modifying the original concrete structural system. The intervention proposed can also be implemented to reduce the energy consumption of buildings. Furthermore, the intervention can be partially prefabricated in order to speed up execution and reducing labour costs. The need to intervene on existing concrete buildings to improve their seismic behaviour arises from: a) this type of buildings represents a large percentage of the built heritage of many Countries; b) most of these structures were designed considering vertical loads only. Specifically, the built heritage is often characterised by details and construction techniques that deviate significantly from those required for new structures. Recent earthquakes have shown that, under seismic actions of smaller magnitude than those considered for new buildings, past construction practices frequently involve unforeseen damage or the activation of brittle mechanisms of collapse. The main critical issues of this kind of structure are: the detachment and the collapse of the infills; the failure of the beam-column joints; the shear failure of the concrete elements due to the interaction with the infills; the activation of soft-storey mechanisms as a consequence of torsional motions or concentration of lateral deformations in a single storey. To reduce the seismic vulnerability of these structures, a retrofit solution was proposed. The solution sees the connection of structural CLT panels to the existing RC elements through dissipative steel fasteners. The main goal of this intervention is to improve the in-plane response of the frames. Specifically, two alternative intervention configurations with different levels of invasiveness were studied. With reference to an isolated one-storey one-bay frame, the most invasive configuration, named RC–TP (Reinforced Concrete–Timber Panels), consists in the removal of one or more original masonry wythes and in their replacement with a CLT panel. The panel is inserted into the space originally occupied by the infill and is connected to the RC frame through a timber subframe and metal dowel-type fasteners. The least invasive configuration, named RC–TPext (Reinforced Concrete–external Timber Panels), consists in the arrangement of the CLT panel from the outside without removing the original infill. Vertical cuts at the lateral edges of the masonry infill prevent the infill, which in case of in-plane actions responds as a strut, from transferring additional forces to the columns and causing their collapse in shear. Because in RC–TP the panel is inserted inside the frame, it can also contribute to resist vertical actions if the seismic action damages the structural elements or increases the vertical loads. In addition, the replacement of the masonry infills with CLT panels results in reduced seismic masses and wall thickness. RC–TP has therefore a greater impact on the building and requires more burdensome labours, while RC–TPext leads to shorter execution time and less disturbance to the occupants. In the work presented here, numerical analyses and experimental tests were conducted to investigate the seismic response of existing RC frames both in pre- and post-intervention configurations. Specifically, finite element models comprising bare, masonry-infilled and retrofitted one-storey one-bay frames were subjected to nonlinear static and dynamic analyses by adopting numerical strategies with different levels of refinement. An extensive numerical campaign was devoted to investigating and optimising the behaviour of the intervention system on the basis of several aspects, such as the state of load, the mechanical and geometrical properties of the original system, the presence of weak beam-column joints, and the influence of openings. These analyses enabled the definition of a few “design rules” to guide the implementation of the retrofit system. Through the definition of “simplified” modelling approaches, the intervention system was also applied to entire case-study structures which were subjected to nonlinear static analyses. An analytical approach able to reproduce the response of isolated frames retrofitted with the RC-TP solution was developed to facilitate the pre-design of the intervention. This approach does not require the use of numerical analyses and permits to analyse multiple configurations with small amounts of output data. In the final phase, a set of four full-scale one-storey one-bay frames representative of the Italian heritage were tested by applying in-plane quasi-static cyclic loading up to a collapse condition. The four specimens comprised: a) masonry infilled frame; b) RC–TP retrofit 1; c) RC–TP retrofit 2; d) RC–TPext retrofit 3. The results obtained indicate that the proposed retrofit intervention can be used to significantly improve the seismic behaviour of existing RC frames by increasing both displacement and resistance capacities and by favouring the development of ductile mechanisms of collapse.

This study investigates the monotonic and cyclic response of light-frame wood shear walls with and without openings. Effects of overturning restraint in the form of tie-down anchors and corner segments on light-frame shear walls with and without door and window openings were quantified. While the results are useful to refine a design methodology for shear walls containing openings, they also provide important knowledge that is needed to accurately quantify anchorage requirements for shear wall design, and assess remaining load and ductility capacity of wood frame buildings after earthquakes or hurricanes. Sixteen full-scale wall specimens were tested using monotonic and sequential phased displacement (SPD) patterns. A total of five different wall configurations, five anchorage, and two loading conditions were used. All walls were eight feet (2.4m) high. Straight wall specimens were forty feet (12.2m) long, whereas corner walls measured twelve feet (3.7m) in length. The analysis includes data from a previous investigation in order to further expand the scope of this study. Results reveal that ultimate capacity and stiffness increase with increasing overturning restraint. A shift in failure mode was observed when overturning restraints were omitted. Accumulated damage experienced by the wall specimens tested cyclically was fairly uniform, regardless of the amount of overturning restraint or size of openings present.
Master of Science

This document presents a part of the wide research carried out on modern timber buildings by the timber research group of the University of Trento. In the last five years several experimental and numerical analysis have been performed on crucial structural topics about multistorey timber construction. The efforts have been focused on the traditional light timber framed system (LTF) and on the log-house system (LH). Concerning the LTF, different aspects of the structural behaviour to the lateral load bearing structure such as walls and connection devices were investigated through experimental tests from the single component up to the full-scale building tested on shake table. The goals of these capstone tests, carried out on three-storey buildings, were the investigation of peculiar aspects which especially for the European constructive tradition were not sufficiently discussed. The same layout was follow for the traditional log-house system. In a first step of the research campaign the behaviour of single components (joints, reinforce elements) was tested and analysed in order to form the basis of the second part that was dedicated to the full scale shear walls tests and analysis. The thesis is organized in two main parts. In the opening chapters, after a brief introduction to the constructive system, the seismic behaviour of light timber framed constructions is analysed. The validation of the predictive models and the mechanical characterization of the gypsum fibreboard sheathing material are presented. Different steps of the S.E.R.I.E.S. project are summarized (tests on connection and real scale walls - shake table tests). The aim of the discussion is the deeper understanding of the boundary condition and the reliability of the tests on the single component on the real scale model. In the second part, the mechanical characterization of modern timber log-house building through experimental tests is presented. The strong cooperation among Rubner Haus Company and the timber research group of the University of Trento made possible a detailed experimental campaign organized on two steps. The first is focused on the evaluation of the corner joints proprieties by means of analysis of small portion of walls. The second part deals with the behaviour of full-scale walls with vertical loads in different geometries (corner joints types, length and presence of openings). The two innovative test setup were designed to reproduce the boundary condition of the structural elements of the building, and to minimize the effects of the test pparatus on the results. The outcomes of the tests show a complex interaction between contributions provided by different mechanisms. In the last chapters, a simplified model suitable to predict the overall load displacement curves of the wall is introduced.

This document presents a part of the wide research carried out on modern timber buildings by the timber research group of the University of Trento. In the last five years several experimental and numerical analysis have been performed on crucial structural topics about multistorey timber construction. The efforts have been focused on the traditional light timber framed system (LTF) and on the log-house system (LH). Concerning the LTF, different aspects of the structural behaviour to the lateral load bearing structure such as walls and connection devices were investigated through experimental tests from the single component up to the full-scale building tested on shake table. The goals of these capstone tests, carried out on three-storey buildings, were the investigation of peculiar aspects which especially for the European constructive tradition were not sufficiently discussed. The same layout was follow for the traditional log-house system. In a first step of the research campaign the behaviour of single components (joints, reinforce elements) was tested and analysed in order to form the basis of the second part that was dedicated to the full scale shear walls tests and analysis. The thesis is organized in two main parts. In the opening chapters, after a brief introduction to the constructive system, the seismic behaviour of light timber framed constructions is analysed. The validation of the predictive models and the mechanical characterization of the gypsum fibreboard sheathing material are presented. Different steps of the S.E.R.I.E.S. project are summarized (tests on connection and real scale walls - shake table tests). The aim of the discussion is the deeper understanding of the boundary condition and the reliability of the tests on the single component on the real scale model. In the second part, the mechanical characterization of modern timber log-house building through experimental tests is presented. The strong cooperation among Rubner Haus Company and the timber research group of the University of Trento made possible a detailed experimental campaign organized on two steps. The first is focused on the evaluation of the corner joints proprieties by means of analysis of small portion of walls. The second part deals with the behaviour of full-scale walls with vertical loads in different geometries (corner joints types, length and presence of openings). The two innovative test setup were designed to reproduce the boundary condition of the structural elements of the building, and to minimize the effects of the test pparatus on the results. The outcomes of the tests show a complex interaction between contributions provided by different mechanisms. In the last chapters, a simplified model suitable to predict the overall load displacement curves of the wall is introduced.

This doctoral project aims to contribute to advancement of the research in the field of innovative and resilient timber buildings with high seismic performance and minimum environmental impact in a green and sustainable way. Recent seismic events have raised questions about the adequacy of the current seismic design in code provisions. In modern seismic codes, the performance objectives are expressed in terms of life safety of the occupants and according to capacity design rules a certain damage level of structures is accepted under strong earthquakes. The resultant seismic damages are often difficult and financially prohibitive to repair. In order to significantly reduce structural and non-structural damage and avoid high economic loss, in the last decades research studies focused on the development of low damage design and technologies. In this thesis, seismic design and performance of multi-storey post-tensioned timber framed buildings with different dissipative systems have been investigated in order to develop new low-damage construction systems for high seismic areas. An extensive experimental campaign was performed at the structural laboratory of the University of Basilicata (Italy), in collaboration with the University of Canterbury (New Zealand), considering a three-dimensional, two-third scale, three-storey, post-tensioned glulam timber frame building. Different testing configurations were considered: i) the bare timber frame with post-tensioning only at the beam-column connections (free rocking); ii) the post-tensioned timber frame with dissipative devices at the beam-column and column-foundation connections (dissipative rocking); and iii) the post-tensioned timber frame with dissipative bracing systems at all storey (dissipative bracing). The seismic response of test specimen was investigated through unidirectional shaking table tests under consecutive ground motions at increasing PGA intensities, while the cyclic behaviour of hysteretic dampers was characterized by means of quasi-static tests. In particular, the testing configuration with dissipative bracing, which had not been previously implemented in post-tensioned glulam timber structures, has been deeply investigated in this research. The estimation of equivalent viscous damping has been proposed in order to optimize the displacement-based design procedure for sizing the hysteretic dissipative devices of the bracing systems. The experimental seismic response of the braced model is evaluated in terms of global and local behaviour and nonlinear numerical analysis have been carried out within two different FEM software (Sap 2000 and OpenSees). The comparison of the results obtained from all configurations demonstrated that the dissipative bracing system improved the seismic performance of post-tensioned timber buildings reducing inter-storey drift with full re-centring capability. During all seismic tests no damages were observed to structural elements, only localized breakage of external replaceable devices occurred during the test with strongest earthquake. More than one hundred inelastic cycles were experimentally recorded from dynamic tests before the failure of devices. The reliability of quasi-static testing procedures proposed by current seismic and guidelines codes for type tests and factory production control tests was also investigated. The number of cycles estimated from shaking table tests and non-linear dynamic analyses shows a decreasing trend with the increase of ductility demand in line with American standards testing requirements.

This thesis has quantified that approximately 68,000 examples of timber-framed buildings, built pre-1850, survive to this day. By mapping their geographic location, it becomes apparent that they are predominantly concentrated in the East and Southeast of England, and to a lesser extent in the West Midlands and Welsh Marches, their distribution showing correlation to the historic availability of building materials, climatic conditions and socio-economic factors. As we aim to improve the energy efficiency of our historic buildings, care must be taken to minimize any negative impacts on the existing building fabric. A balance must be achieved between conservation and improved efficiency to avoid damage to their significance, character and historic fabric. Research to date has focused on the retrofit of solid masonry wall construction, with little investigation into timber-framed buildings. Although guidance on the subject exists, there is minimal academic research to validate the approaches proposed. This thesis aims to begin to address this previously under-researched area. In situ monitoring and digital simulation of five case studies allowed the analysis of current approaches to the retrofit of timber-framed properties. The results suggest that improving airtightness should be prioritised over improvements to the thermal performance of walls. It also indicates that monitoring and simulation should form part of any retrofit decision making process, to ensure the greatest improvements in performance with the minimum loss or risk to historic fabric. Concurrently, the use of interstitial hygrothermal simulation software WUFI®Pro 5.3 was used to simulate proposed replacement panel infill details. Whilst no substantial risk of biological attack has been identified, further physical testing is recommended to corroborate these findings, and simulations should be repeated for specific climates and orientations prior to their use. Together with future research, it is hoped that this thesis will begin to inform guidance that will enable these buildings that have stood for hundreds of years to survive for many more to come.

The research hereinafter describes aims at mechanically characterize the behavior of timber framed buildings, with particular focus on their behaviour in seismic zones. An extensive experimental campaign divided into three phases has been completed in order to achieve this objective. In the first phase tests on the connection between sheating panels and timber studs were conducted. Subsequently the behavior of the connections used for anchoring the walls to the foundation were investigated. In the second stage the full scale timber framed walls were subjected to tests. The walls were realized using different materials and different type of connections to the ground. The results have allowed the study of the individual structural components which constitute an entire building, from the single connector to the entire wall. In order to understand the behavior of the components themselves in a real building, and thus their interaction with each other in case of an earthquake, in the third step a shaking table test of a three-story building has been done. All tests have permitted to collect a wealth of data with which to populate a database to be used both to understand in detail the structural behavior of the timber framed building system and in also to validate the proposed formulations. From the analytical point of view, an equation able to provide the horizontal displacement of a wall subject to a horizontal force has been developed. This equation was then successfully validated by comparing the results with those obtained from laboratory tests. For the execution of the tests have been created procedures and set-up ad hoc, that could be used also in the future to carry out similar tests. An important work has been done to achieve a configuration suitable to test full scale timber framed walls through well controlling the boundary conditions.

The research hereinafter describes aims at mechanically characterize the behavior of timber framed buildings, with particular focus on their behaviour in seismic zones. An extensive experimental campaign divided into three phases has been completed in order to achieve this objective. In the first phase tests on the connection between sheating panels and timber studs were conducted. Subsequently the behavior of the connections used for anchoring the walls to the foundation were investigated. In the second stage the full scale timber framed walls were subjected to tests. The walls were realized using different materials and different type of connections to the ground. The results have allowed the study of the individual structural components which constitute an entire building, from the single connector to the entire wall. In order to understand the behavior of the components themselves in a real building, and thus their interaction with each other in case of an earthquake, in the third step a shaking table test of a three-story building has been done. All tests have permitted to collect a wealth of data with which to populate a database to be used both to understand in detail the structural behavior of the timber framed building system and in also to validate the proposed formulations. From the analytical point of view, an equation able to provide the horizontal displacement of a wall subject to a horizontal force has been developed. This equation was then successfully validated by comparing the results with those obtained from laboratory tests. For the execution of the tests have been created procedures and set-up ad hoc, that could be used also in the future to carry out similar tests. An important work has been done to achieve a configuration suitable to test full scale timber framed walls through well controlling the boundary conditions.

Examined in this study were some physical, mechanical, compositional and durability properties of AAC, its neighboring plasters and jointing adhesive, all of which were produced in Turkey. The compatibility of these materials inside the contemporary wall section and within historic fabric was discussed in terms of their material properties. In addition to the literature survey, laboratory studies were conducted on two types of AAC as G2 and G4, its jointing adhesive and exterior finishing layers as base coat, under coat, finish coat, water repellent finish coat
and some historical traditional construction materials of Anatolia as timber, masonry and infill brick, lime based exterior and interior plasters. The results were evaluated in terms of material properties of AAC, the compatibility of AAC and its complementary elements with each other and with the historic timber framed structures in Anatolia. It was concluded that the use of AAC in repairs of historical structures could be discussed only if the original infill is lost. In addition, its cement-plasters should be avoided from the historic fabric since they introduce salt problems to the structure. In terms of vapor permeability and modulus of elasticity, water repellent finish coat was proper finishing for AAC, and AAC, especially G4, exhibited similarities with historic infill mud brick. Further studies on other compatibility parameters were, however, necessary to decide on the compatibility of AAC with its neighboring materials. Moreover, the integrity of AAC with the historic fabric needed improvement by increasing its pozzolanicity and/or producing a new intermediary repair mortar/plaster.

The Canterbury Earthquakes of 2010-2011, in particular the 4th September 2010 Darfield earthquake and the 22nd February 2011 Christchurch earthquake, produced severe and widespread liquefaction in Christchurch and surrounding areas. The scale of the liquefaction was unprecedented, and caused extensive damage to a variety of man-made structures, including residential houses. Around 20,000 residential houses suffered serious damage as a direct result of the effects of liquefaction, and this resulted in approximately 7000 houses in the worst-hit areas being abandoned. Despite the good performance of light timber-framed houses under the inertial loads of the earthquake, these structures could not withstand the large loads and deformations associated with liquefaction, resulting in significant damage. The key structural component of houses subjected to liquefaction effects was found to be their foundations, as these are in direct contact with the ground. The performance of house foundations directly influenced the performance of the structure as a whole. Because of this, and due to the lack of research in this area, it was decided to investigate the performance of houses and in particular their foundations when subjected to the effects of liquefaction. The data from the inspections of approximately 500 houses conducted by a University of Canterbury summer research team following the 4th September 2010 earthquake in the worst-hit areas of Christchurch were analysed to determine the general performance of residential houses when subjected to high liquefaction loads. This was followed by the detailed inspection of around 170 houses with four different foundation types common to Christchurch and New Zealand: Concrete perimeter with short piers constructed to NZS3604, concrete slab-on-grade also to NZS3604, RibRaft slabs designed by Firth Industries and driven pile foundations. With a focus on foundations, floor levels and slopes were measured, and the damage to all areas of the house and property were recorded. Seven invasive inspections were also conducted on houses being demolished, to examine in more detail the deformation modes and the causes of damage in severely affected houses. The simplified modelling of concrete perimeter sections subjected to a variety of liquefaction-related scenarios was also performed, to examine the comparative performance of foundations built in different periods, and the loads generated under various bearing loss and lateral spreading cases. It was found that the level of foundation damage is directly related to the level of liquefaction experienced, and that foundation damage and liquefaction severity in turn influence the performance of the superstructure. Concrete perimeter foundations were found to have performed most poorly, suffering high local floor slopes and being likely to require foundation repairs even when liquefaction was low enough that no surface ejecta was seen. This was due to their weak, flexible foundation structure, which cannot withstand liquefaction loads without deforming. The vulnerability of concrete perimeter foundations was confirmed through modelling. Slab-on-grade foundations performed better, and were unlikely to require repairs at low levels of liquefaction. Ribraft and piled foundations performed the best, with repairs unlikely up to moderate levels of liquefaction. However, all foundation types were susceptible to significant damage at higher levels of liquefaction, with maximum differential settlements of 474mm, 202mm, 182mm and 250mm found for concrete perimeter, slab-on-grade, ribraft and piled foundations respectively when subjected to significant lateral spreading, the most severe loading scenario caused by liquefaction. It was found through the analysis of the data that the type of exterior wall cladding, either heavy or light, and the number of storeys, did not affect the performance of foundations. This was also shown through modelling for concrete perimeter foundations, and is due to the increased foundation strengths provided for heavily cladded and two-storey houses. Heavy roof claddings were found to increase the demands on foundations, worsening their performance. Pre-1930 concrete perimeter foundations were also found to be very vulnerable to damage under liquefaction loads, due to their weak and brittle construction.

Prefabricering av väggelement är en byggmetod under stark framväxt i byggandet av småhus de senaste decennierna. Kostnadseffektiviteten nämns ofta som ett skäl till att prefabricering av småhus har en sådan stor framväxt. Samtidigt har miljö- och klimatfrågan växt och då byggsektorn står för en stor del av Sveriges koldioxidutsläpp krävs det att byggsektorn ställer om till ett allt med hållbart byggande. Detta examensarbete har undersökt denna kostnadseffektivitet och hur och om en går att kombinera med ett hållbart byggande och sedan jämfört detta med platsbyggda väggar i trä. Underlag har tagits fram i samarbete med Skidstahus som producerar prefabricerade väggelement i fabriksmiljö och underlag från Derome Hus AB/ VarbergsHus vad berör småhus i lösvirke. En kostnadsjämförelse av de två byggmetoderna visar att de prefabricerade väggelement som Skidstahus framställer är mer kostnadseffektiva och det beror till stor del på att arbetstiden effektiviseras. Till viss del visar examensarbetet att materialanvändningen även resurs effektiviseras vid Skidstahus produktion och resulterar i mindre spill som därmed gynnar ett hållbart byggande. Andra viktiga aspekter för hållbarhet och livslängd såsom fukt och lufttäthet visar att prefabricerade väggar har utmaningar då skarvar och anslutningar måste vara väl utförda. Samtidigt innebär arbetet i fabriksmiljö att risken för fuktproblem minskar då det ger ett skydd för klimat och väder. Detta är medför även att byggarbetarna får en god och vältempererad arbetsmiljö. Däremot finns frågetecken kring hur byggande med prefabricerade väggelement påverkar miljön i form av transporter i förhållandet till platsbyggda väggar av lösvirke, då transporter till och från fabrik krävs. Utöver detta påverkar byggmetoden hur gestaltning och arkitektur utförs då ett platsbyggt hus i trä enklare går att utföra med valfri gestaltning. Analyserna visar sammanfattningsvis att användandet av prefabricerade väggelement i trä reducerar byggkostnader samtidigt som det kan bidra till ett hållbart byggande. Det krävs dock ytterligare studier för att jämföra den beräknade livslängden på prefabricerade väggar och platsbyggda.
Prefabrication of wood wall elements in construction of villas and terraced houses is a building method undergoing growth in recent decades. Cost efficiency is often cited as a reason why prefabrication has undergone such a large growth. At the same time, the issue of environmental impact and climate change has grown. As the construction sector accounts for a large part of Sweden's carbon dioxide emissions, the construction sector needs to become more sustainable. This thesis has examined this cost-effectiveness and if it is possible to combine with environmental sustainability. To examine this more thoroughly a comparison is made with in site-built timber-framed constructed walls. The thesis has been conducted in collaboration with Skidstahus, which produces prefabricated wall elements in a factory environment, especially for data collection. Information and data have also been collected from Varbergshus / Derome producing houses in site-built timber-framed building. A cost comparison of the building methods shows that the prefabricated wall elements manufactured by Skidstahus are more cost-effective, which can be linked to work efficiency. To some extent, the thesis also shows that material use can be optimized at Skidstahus production and therefore results in less waste, which thus reduces environmental impact. Other important factors for durability and accounted life span is the building method’s ability to handle migration of moisture and airtightness. The thesis shows that prefabricated walls have challenges, as joints and connections must be well designed. At the same time, factory production allows an environment which can reduce risk of migration of moisture as it provides protection for climate and weather impact. Another aspect is that it provides a good and well-tempered work environment for the construction worker. On the other hand, it is questionable whether the use of prefabricated wall elements affects the environment as it may increase the need of transportation in relation to on site-built timber-framed walls, as transport to and from the factory is required. In addition, the prefabricated method could influence how design and architecture is carried out while a wood house made from stick timber is more easily modified. In summary, the analysis show that the use of prefabricated wood wall elements reduces building costs while at the same time it can contribute to environmental sustainability. However, further studies are required to compare the estimated life span of the two compared building methods.

L’étude des bâtiments en terre et bois des agglomérations du Second âge du Fer (IIIe-Ier s. av. n. è.) de Gaule interne (hors littoral méditerranéen) a permis de construire une réflexion autour de deux thématiques de recherche à la fois peu investies et complémentaires. Les nombreux débats concernant la caractérisation de ces habitats agglomérés et leur éventuel statut urbain m’ont amené à développer une approche croisée dans le cadre de ce doctorat. L’objectif a ainsi été de contribuer à une meilleure compréhension du phénomène d’urbanisation et des caractéristiques des agglomérations (oppida et agglomérations ouvertes) à travers une étude fine de l’architecture, permettant de préciser dans quelle mesure les formes architecturales sont révélatrices mais également vectrices de dynamiques socioéconomiques particulières. L’étude technique de 339 bâtiments, provenant de 39 agglomérations, s’est appuyée sur une méthodologie rigoureuse et originale. Celle-ci combine l’analyse des divers types de vestiges architecturaux et des dynamiques taphonomiques intégrant à la fois la documentation archéologique et ethnographique. Si une grande partie de ces constructions est constituée de poteaux plantés, une place privilégiée a été accordée aux architectures en pan de bois et à l’usage de pièces de contreventement obliques. Ces traditions architecturales ont ensuite été intégrées dans une recherche plus globale, considérant à la fois l’organisation spatiale des agglomérations, les usages des bâtiments et les statuts sociaux de leurs occupant·e·s, ainsi que les différences avec l’architecture rurale. Un modèle interprétatif, tenant compte du contexte environnemental et de toute la complexité de ces agglomérations, a ainsi été proposé. Une partie au moins de ces habitats groupés serait caractérisée par la mise en œuvre d’économies et de gestions rationnelles du bois d’œuvre et de la construction, par le développement de réseaux d’artisans ainsi que par des adaptations des modèles architecturaux à l’urbanisme et au degré d’urbanisation
The study of the earthen and wooden buildings of the Late Iron Age agglomerations (3rd-1st century BC) of inner Gaul (except the Mediterranean coast) allows to develop a reflection around two research topics both little invested and complementary. Many debates concerning the characterisation of these grouped settlements and their possible urban status have thus led me to develop an interdisciplinary approach in this PhD. The aim was therefore to contribute to a better understanding of the urbanisation process and of the agglomerations (oppida and open agglomerations) features through a detailed study of architecture, allowing to define how architectural forms reveal and convey particular socio-economic dynamics. The technical study of 339 buildings, from 39 agglomerations, was based on a strict and original methodology: this combines the analysis of various types of architectural remains and taphonomic dynamics integrating both archaeological and ethnographic documentation. While a large part of these constructions is made up of earthfast posts, a significant place was given to timber-framed architecture and the use of diagonal braces. These architectural traditions were then integrated into a more global research, considering at the same time the spatial organisation of agglomerations, the use of buildings and the social status of their inhabitants, as well as the differences between rural architecture and that of grouped settlements. An interpretative model, taking into account the environmental context and all the complexity of Late Iron Age agglomerations, has thus been proposed. At least part of these grouped settlements would be characterised by the development of economies and rational management of timber and construction, craftsmen networks as well as by adaptations of architectural models to urban planning and urbanisation degree

Timber has become more popular as a construction material during recent years. Engineered wood products, such as glued laminated timber and cross-laminated timber, have enabled the construction of multi-storey buildings. Tall buildings with many occupants need to resist a disproportional collapse in case of unexpected exposures, e.g. accidents or terrorism. Structural robustness can improve the collapse resistance of a building. The literature about robustness is comprehensive concerning concrete and steel buildings, but it is rather limited regarding timber. A robust building can mobilise alternative load paths in the structure after the removal of bearing building components. Alternative load paths rely primarily on the connections between components. For timber buildings, few investigations exist to evaluate the alternative load paths after a removal. Analyses usually do not take into account non-linear effects which could influence the capacity of alternative load paths, such as damage of single fasteners, friction,  timber crushing and brittle failure. In particular, the alternative load paths in platform-framed cross-laminated timber buildings are not well understood.  The goals of this thesis are to i) review the concept of robustness in general and determine the state of the art concerning timber buildings in particular, ii) develop a method to analyse the alternative load paths in a platform-framed CLT building taking into account relevant non-linearities, iii) use the method to elicit the alternative load paths in a building after a wall removal, and iv) study the effects of probabilistic variations of model parameters.  The thesis first introduces tall timber buildings and then presents a summary of structural robustness in a collapse resistance framework. The summary includes established analysis methods and specific considerations for timber, whereof a detailed review is provided in Paper I. Paper III additionally provides results of a survey on contemporary practices of professionals around the world concerning robustness.  In the subsequent chapter, the studied 8-storey case building made of platform-framed cross-laminated timber is described including the modelling abstractions. Additionally, the setup of a validation experiment for the modelling approach is described. The following chapter introduces the modelling approach for an alternative load path analysis after a wall removal. The approach is based on the finite element method using the commercial software Abaqus. The deterministic part of the approach includes a non-linear static pushdown analysis of single storeys in a bay and elicits the alternative load paths and their capacity. Finite connector elements in the model substitute single fasteners including their elastic, plastic, damage and rupture behaviour. The 3D models of the walls and floors account for timber crushing, brittle failure and contact friction. A simplified non-linear dynamic model of the entire bay uses the pushdown results as inputs and evaluates the collapse progression among storeys after a sudden element removal. The probabilistic part of the approach models the uncertainty of the input parameters of the dynamic model by varying the parameter values in a Monte Carlo simulation, to evaluate the probability of a collapse.  Paper II applies the approach for a simple pushdown of a single storey and Paper IV applies the pushdown and the dynamic analysis to elicit the alternative load paths after a single wall removal. The thesis shows furthermore the results of a double wall removal in the example building and the results of the Monte Carlo analysis for the single and double wall removal.  For the assumed removals, the developed approach could identify the alternative load paths, determine their capacities and estimate the probability of a collapse under probabilistic variations. The approach might be used to classify various removal scenarios in platform-framed multi-storey cross-laminated timber buildings specifically and predetermine design solutions which could provide a desired level of robustness. The approach might be generalised for multi-storey timber buildings of various construction types.

Les séismes constituent une source d’aléas importante pour l’étude de la vulnérabilité d’unbâtiment. Le comportement parasismique des bâtiments à ossatures en bois est particulièrementintéressant. Deux familles de structure à ossature en bois peuvent être distinguées : les ossaturesutilisant les produits industriels que sont les panneaux en bois reconstitué servant à contreventerla structure et les connecteurs métalliques, et les ossatures traditionnelles avec remplissage reposantsur des techniques de construction anciennes et dépendantes du contexte local. L’efficacitédu comportement parasismique des bâtiments à ossature en bois traditionnels avec remplissagereste encore peu reconnue en raison du manque de résultats issus des travaux de recherche.Les travaux présentés dans cette thèse visent ainsi à améliorer les connaissances sur le comportementparasismique de cette typologie constructive. Partant de l’hypothèse selon laquellece comportement est gouverné par la réponse des assemblages par connecteurs métalliques, uneapproche multi-échelles, couplant études expérimentales et études numériques est développée.Elle détaille l’analyse à l’échelle 1 de la connexion, en passant par l’échelle 2 des cellules élémentaires,constitutives des murs, par l’échelle 3 des murs de contreventement pour se finaliserà l’échelle 4 du bâtiment dans son ensemble.Sur le plan expérimental, cette approche permet d’une part, de réaliser des études paramétriqueset ainsi d’appréhender l’influence de la réponse de chaque élément (bois, clous, feuillard,remplissage, contreventement, ouvertures) sur le comportement local (échelles 1 et 2) et global(échelles 3 et 4) de la structure. D’autre part, elle permet de fournir une base de données pourla validation des modélisations numériques aux différentes échelles.Sur le plan de la modélisation numérique, cette approche multi-échelles est fondée sur la priseen compte du comportement non-linéaire hystérétique des assemblages à l’échelle supérieure, parl’intermédiaire d’un macro-élément, développé dans la cadre de la méthode des éléments finis.Ainsi, grâce à une modélisation simplifiée (assemblage des macro-éléments), le calcul est rapide,aussi bien à l’échelle du mur qu’à celle du bâtiment, et intègre les phénomènes non-linéaire locaux.Le modèle peut ainsi prédire de manière relativement précise le comportement dynamique de lastructure complète à l’échelle 4, testée sur table vibrante.L’étude présentée dans ce manuscrit fait partie des travaux précurseurs relatifs à l’analysede la vulnérabilité sismique des ossatures bois avec remplissage. Cette étude débouche sur denombreuses perspectives pour l’analyse de cette typologie constructive. Elle confirme que les bâtimentsà ossatures en bois avec remplissage ont un comportement parasismique très performant
The seismic vulnerabilty is an important issue in the design of a building. The seismicresistant behavior of timber-framed structures is particularly relevant. Two types of timberframedstructures can be distinguished : the timber-framed structures using industrial products,such as wood-products panels used to brace the structure or metal fasteners, and traditionaltimber-framed structures included infill made of natuarl materials (earth or stones masonry).The seismic resistant behavior efficiency of traditional structures remains poorly recognizedbecause of the lack of research results on this kind of construction.Therefore, the thesis aims at improving the seismic behavior knowledge of timber-framedmasonry. Based on the assumption that their behavior is driven by the response of the metalfasteners connections, a multi-scale approach is proposed. It couples experimental and numericalstudies. At the scale 1 of the connection, at the scale 2 of the elementary constitutive cell ofwalls, at the scale 3 of structural elements such as shear walls and finally at the scale 4 of theentire building.In regards to the experimental work, this method allows, on the one hand, to perform parametricstudies and to analyze the influence of each element (wood member, nails, steel strip,infill, bracing, openings) on the local behavior (scales 1 and 2) and on the global behavior(scales 3 and 4) of the structure. On the other hand, it allows to provide a database to validatethe numerical modeling at each scale.In regards to the numerical work, this multi-scale approach allows to take into account thehysteretic behavior of joints in the development of a macro-element at the scale 2. Thus, thanksto a simplified finite element modeling (macro-element assembly), the computational cost islimited and it allows to take into account the local phenomena. The model is able to predictrelatively accurately the dynamic behavior at the scale 4 of the building, tested on a shakingtable.The study, presented herein, is one of the pioneer work that deals with the analysis of theseismic vulnerability of timber-framed structures with infill panels. This study provides outlookfor the analysis of this type of buildings. It confirms that the timbered masonry structures havea relevant seismic resistant behavior

Dissertação de mestrado em Structural Analysis of Monuments and Historical Constructions
Ancient heritage is abundant with timber-framed structures that function as strengthening solutions with infill and as independent structural systems. In earthquake areas they have been used as seismic-resistant construction and their good behaviour during seismic events has been documented and observed. However, building typologies like Pombalino buildings in Lisbon have not experienced seismic activity and therefore their behaviour is unknown. Pombalino buildings and others are under risk of failure during seismic events if their mechanical behaviour is not properly quantified and understood. Traditional timber framed walls exhibit nonlinear hysteretic response under in-plane cyclic loading. To better understand their influence in the global response of buildings, it is important to define numerical modelling strategies for this type of constructive element. Therefore, the work presented in this thesis aims at better understanding the mechanical behaviour of timber frame walls based on numerical simulation. The experimental campaign by Poletti (2013) on in-place cyclic testing of traditional half-timbered frames and timber frames at the University of Minho is used as reference. Based on the experimental results, numerical models were developed that capture the cyclic response of traditional timber frame walls including flexural behaviour, pinching and strength degradation. The numerical models were constructed in the finite element software OpenSees with calibrated springs representing nailed connectors found in traditional half lap joints. 2-D nonlinear beam modelling was preferred over 3-D detailed finite element modelling to reduce computational effort. Three distinct timber frame models were developed in order to best capture the experimental response. A correlation was found between model output and experimental results and was used to develop a half-timbered frame model. These models are difficult to control nonlinear behaviour due to multiple hysteretic models that complicate analyses. A parametric study was conducted on both the half-timbered frame and timber frame by varying wall configuration and studying cumulative energy dissipation and the effect of slenderness and load capacity with increasing drift. A macro-model inspired by the macro-modelling of masonry infill walls is proposed at the end of the work as a simplified solution to avoid modelling complexity of traditional timber frames in masonry buildings while maintaining overall mechanical behaviour by concentrating all nonlinearity in the central connection.
O patromónio construído antigo é abundante em estruturas de madeira onde as ligações tradicionais predominan, funcionando como refoço da alvenaria ou como sistemas estruturias independentes. Em regiões sísmicas, as estruturas de madeira tradicionais têm sido utilizadas como construção anti-sísmica e o seu bom comportamento tem sido consttado e documentado. Todavia, tipologias construtivas como os edifícios pombalinos em Lisboa não foram ainda submetidos a eventos sísmicos e portato o seu comportamento em condições reais é desconhecido. Paredes de madeira tradicionais apresentam um comportamento histerético importante quando submetidas a acções cíclicas no plano, sendo importante compreender a sua influência no comportamento global de uma estrutura. Para este efeito será necessário definir estratégias para a modelação numéricas deste tipo de elemento construtivo. Assim, o principal objectivo do trabalho apresentado nesta tese consiste na modelação numéricas de paredes tradicionais sujeitas a acções cíclicas. O trabalho experimental realizado por Poletti (2013) é utilizado como referência pra a acalibração do modelo numérico. Com base nos resultados experimentais, modelos numéricos foram desenvolvidos para descrever a resposta experimental incluindo o comportamento em flexão, “pinching” e degradação da resistência e rigidez. Os modelos numéricos foram desenvolvidos no programa de cálculo Open Sees, sendo calibradas os elementos de mola que foram associadas à ligações tradicionais meia-madeira. Modelos numéricos bidimensionais foram preferidos aos modelos tridimensionais para reduzir o custo computacional. Foram definidos três modelos das paredes ensaiadas de modo a optimizar o ajuste do comportamento ao modelo experimental. Com base no modelo numérico que mais se aproximou dos resultados experimental foi feita uma adaptação para a modelação das paredes de mdeiras tradicionais com enchimento de alvenaria de tijolo. Verificou-se que o controlo do comportamento não linear consiste num problema complexo, principalmente no qe se relaciona com o comportamento histerético. Foi efetuado um estudo paramétrico em termos de geometria em relação às paredes de madeira com e sem preenchimento, sendo definida uma relação entre a rigidez e resistência com a relação altura e largura da parede. Finalmente, definiu-se um modelo simplificado inspirado na macro-modelação de paredes de enchimento em edifícios de betão armado na tentativa de modelar de modo simplificado as paredes de madeira tradicional em edifícios antigos.

The building regulations in Australia and other countries are being reformed from a prescriptive basis of designing fire safety system requirements to a performance basis, which requires the application of engineering principles. Under the prescriptive regulations, fire resistant construction elements were tested using a standard fire resistance test heating regime, which is invariably quite different from the characteristics of real fires. The engineered approach requires the ability to predict the performance of elements of construction that may have different details those tested under the standard heating regime and under different heating regimes. This thesis comprises part of a comprehensive research program undertaken at the Centre for Environmental Safety and Risk Engineering, Victoria University of Technology to develop a comprehensive framework to determine the time dependent probability of failure of timber-framed assemblies subjected to real fires. The objective of the thesis is to determine the structural response of plasterboard-clad, timber framed walls subject to fire and is a key component that is incorporated into the framework to determine the probability of failure of timber-framed assemblies subjected to fire. The structural model simulates dominant phenomena, which have conventionally been ignored in the determination of the structural response of timber-framed walls in fire. The phenomena considered include the degradation in mechanical properties of materials due to thermal effects, non-linear mechanical and geometric effects caused through buckling, partial composite interaction with the plasterboard sheeting, thermal expansion and shrinkage and varied end restraint conditions. These phenomena have been modelled using common frame analysis methods to provide a computationally efficient and robust model. A transient, second-order direct stiffness approach has been utilised, with specific elements devised to consider the partial composite interaction. In conjunction with the development of the model, a comprehensive experimental program has been undertaken, to provide a means of comparison of the model predictions, and to obtain data found to be lacking in the literature. A series of full-scale experiments were conducted on timber framed assemblies under ambient and elevated temperature conditions. The variability, end restraint conditions and contribution of the sheeting were carefully controlled and examined in the experiments. The literature review identified that there was a lack of data detailing the reduction in the modulus of elasticity in compression with temperature. This was considered the most critical mechanical property in determining the time-to-failure of a load bearing timber-framed wall and so a series of experiments was undertaken on short lengths of timber to determine the reduction in the mechanical properties in compression with temperature. The full-scale experiments demonstrated the significance of end restraint and the influence of plasterboard sheeting on the time-to-failure. The full-scale experiments also showed an apparent rapid drop in the apparent stiffness of the timber framing as it approached a mean temperature of approximately 1 OODC through the cross-section. The reduction in the mechanical properties of radiata pine in compression due to elevated temperature exposure was determined directly from tests. It was determined that there was a significant reduction in the mechanical properties in compression of moist timber specimens heated to 70DC, compared with dry specimens. This finding was consistent with results from the full-scale experiments. The structural response model was successfully validated against closed form and finite element solutions and the predictions of the model compared closely with results from a series of full-scale experiments undertaken as part of the research. The deformation induced in the full-scale experiments was irrecoverable and may have been associated with a mechano-sorptive type creep phenomenon, although further research is required to study this phenomenon. This is one several areas requiring future research that has been identified by the author.

The general aim of the research for this thesis was to develop models to predict the performance of fire resistant light-timber framed walls, in relation to requirements of new performance-based building fire regulations being introduced around the world. The performance bases that were adopted in the modelling, were time and probability of failure. The models that were developed for a wide range of wall types, and have been specifically validated for ordinary cavity walls and double framed walls. Validation involved numerical checks for convergence and energy conservation, and the undertaking of eight full scale wall furnace experiments with well controlled conditions. Values of thermal properties of materials in the walls were obtained with simple independent experiments. These experiments helped to clarify appropriate values from the wide ranges which have been previously published. Model predictions were evaluated against results published in the literature. The models comprise specific models for fire severity, heat transfer, structural response and probability of failure. This research has developed the heat transfer model named ADIDRAS, a probability model, and undertaken all linkages of models to produce the time and probability of failure models. A model developed by a colleague, Young, was adopted for the structural response model. The time and probability of failure models can incorporate most fire severity models. In this research, two fire severity models were incorporated; one was the standard fire, and the other was the real fire severity model of Kawagoe and Lie. ADIDRAS, in several respects, is an advance on previous heat transfer models for structures containing cavities. It analyses thermal diffusion with alternating direction implicit finite difference analysis which enhances numerical stability without the loss of computation speed of explicit procedures. It uses the discrete radiation method which enables analysis of radiant heat transfer through smoke and cavities of any shape. Previous models have analysed only cavities without re-entrant corners. It was deduced that when the interfaces between studs and gypsum board on the fire side reach temperatures greater than 400°C, the interfaces open to form gaps due to shrinkage in these materials. These gaps prevent much of the heat transferring directly from gypsum board to the studs, and divert the heat to the cavity by radiation. This diversion explains some anomalies between experimental results and predictions of previously published heat transfer models. It is shown that temperatures in studs are insensitive to the transmissivity of radiant heat in smoke. The structural model and the time of failure model have been applied, to obtain for the first time, relationships between the time of failure and a number of variables including vertical load, elastic modulus of timber, strength of timber, height of wall, size and spacing of studs, initial crookedness of studs and thickness of gypsum board. The time of failure model has established failure, induced by the vaporisation of moisture, is critical for walls that are either higher than walls commonly built (higher than 3.6 metres), or are more heavily loaded than is currently permitted in timber structural engineering codes. It was found that the time of failure is most sensitive to fire temperature, vertical load, elastic modulus of timber in compression, and density and specific heat of timber. It is sensitive also to the thickness and thermal properties of gypsum board, and the sectional dimensions of studs; however, these variables are unlikely to vary much for walls built to specifications in common building construction. It is considered that the probability of failure model is the first theoretically-based reliability model for light-timber framed structures exposed to fire. Several applications of the model have been demonstrated. It was shown that the variabilities of thermal properties of gypsum board and wood are low compared with the large variabilities of mechanical properties inherent in timber. In the applications demonstrated, typical variations of all variables led to a coefficient of variation (Co V) in the time of failure of 0.12 for typical walls subjected to standard (ASI530A) fire. Exposure to a real fire did not significantly affect this CoY. Unlike the standard fire, the real fire did not necessarily lead to collapse. There is much scope for reducing fife resistances of walls without significantly increasing the risk to life.

Dissertação de mestrado em Structural Analysis of Monuments and Historical Constructions
Traditional architecture made of timber-framed masonry (TFM) system is widespread around the world and has already been recognized as a unique cultural heritage to be preserved. These structures have shown a good seismic performance compared to other typologies because their configuration and construction details were constantly updated as soon as the builders addressed the causes of damage mechanisms when earthquakes occurred. Romanian TFM structures can be considered a representative example of this typology also because they experienced several seismic events showing their good earthquake-resistance. Although these buildings are still inhabited nowadays and constructed, no recommendation is provided in the Romanian building code and its structural behavior is not properly characterized and modelled yet. Thus, bearing in mind that the building’s global response depends on many parameters such as TFM walls, floor and roofing system as well as the connections between them, the calibration of shear walls is crucial to define the non-linear behavior under cyclic loading. A simplified modelling strategy was chosen to simulate TFM wall response consisting of an equivalent frame with linear elastic elements and non-linearities lumped at the joints. The present thesis aimed at investigating the seismic performance of Romanian TFM walls and a representative TFM building located originally in Sarbova area, Timis County, but relocated to the National Village Museum “Dimitrie Gusti” in Bucharest, by comparing the numerical results with the measurements taken during the experimental campaign performed at Technical University of Civil Engineering of Bucharest and the in situ dynamic investigation, respectively. The wall numerical model was calibrated by performing the procedure of inverse fitting to obtain a good approximation between the experimental hysteretic curve and the numerical one in terms of initial stiffness, maximum base shear and total dissipated energy. This model was built in the FEM software OpenSees concentrating at the joints a non-linear hysteretic spring per degree of freedom and updating its parameters starting from some experimental tests performed on comparable types of connections. Once the wall response was matched, the Romanian traditional building was modelled by applying the same equivalent frame method, but, in this case, the dynamic properties did not match perfectly to those recorded by ambient vibration tests since microtremors involve the wall in the elastic range while the wall calibration was carried out for its non-linear one. Thus, the model was updated considering an additional contribution of infill since the type of masonry was different from the one infilling the tested wall. Eventually, non-linear static analysis was performed to assess the maximum shear and deformation capacity and predict some local failures at the timber joints. The simplified equivalent frame model shows a good performance in simulating the wall response, but, for the already explained reasons, it was not completely capable of approximating the building dynamic properties. However, this strategy allows to reduce the computational efforts and, at the same time, provide information about the behavior of each connection.
A arquitetura vernacular constituída por paredes madeira com enchimento de alvenaria com estrutura de madeira (TFM) é difundida em todo o mundo e já foi reconhecida como um patrimônio cultural único que precisa de ser preservado. Essas estruturas mostraram um bom desempenho sísmico em comparação com outras tipologias, porque as suas configurações e os seus detalhes constitutivos foram constantemente atualizados assim que os construtores abordaram as causas dos mecanismos de danos quando os terremotos ocorreram. As estruturas TFM Romenas podem ser consideradas um exemplo representativo desta tipologia também porque experimentaram vários eventos sísmicos mostrando a sua boa resistência a sismos. Se bem que estes edifícios ainda sejam habitados hoje em dia e continuem a ser construídos, nenhuma recomendação é fornecida no código de construção romeno e o seu comportamento estrutural ainda não está devidamente caracterizado e modelado. Assim, tendo em conta que a resposta global do edifício depende de muitos parâmetros, tais como paredes TFM, piso e sistema de cobertura, bem como as ligações entre eles, a calibração das paredes de corte é crucial para definir o comportamento não linear sob carga cíclica. Uma estratégia simplificada de modelação foi escolhida para simular a resposta da parede TFM constituída por uma estrutura equivalente com elementos elásticos lineares e não-linearidades concentradas nas ligações. A presente tese tem como objetivo investigar o desempenho sísmico das paredes romenas TFM e de um edifício TFM representativo localizado originalmente na área de Sarbova, no distrito de Timis, mas transferido para o National Village Museum “Dimitrie Gusti” em Bucareste, comparando os resultados numéricos com os resultados obtidos durante a campanha experimental realizada na Universidade Técnica de Engenharia Civil de Bucareste e na investigação dinâmica in situ, respetivamente. O modelo numérico da parede foi calibrado utilizando um procedimento de ajuste inverso para obter uma boa aproximação entre a curva histerética experimental e a curva numérica em termos de rigidez inicial, capacidade máxima e energia total dissipada. Este modelo foi desenvolvido no software a elementos finitos OpenSees, concentrando nas ligações uma mola histerética não linear por grau de liberdade e atualizando os parâmetros a partir de alguns ensaios experimentais existentes realizados em ligações comparáveis. Uma vez que a resposta da parede foi calibrada, o edifício tradicional romeno foi modelado aplicando o mesmo método da estrutura equivalente, mas, neste caso, as propriedades dinâmicas não se ajustaram perfeitamente àquelas obtidas através dos ensaios de vibração ambiental, pois os microtremores envolvem a parede na fase elástica inicial, enquanto a calibração da parede foi realizada para a sua resposta não-linear. Assim, o modelo foi atualizado considerando uma contribuição adicional do preenchimento de alvenaria, uma vez que o tipo de alvenaria foi diferente daquele da parede ensaiada. Após desta calibração, foi realizada uma análise estática não linear para avaliar a capacidade máxima e deformação e prever alguns danos locais nas ligações de madeira. O modelo simplificado equivalente da parede mostra um bom desempenho na simulação da resposta da parede, mas, pelas razões acima explicadas, não foi completamente possível aproximar as propriedades dinâmicas do edifício. No entanto, essa estratégia permite reduzir os esforços computacionais e, ao mesmo tempo, fornecer informações sobre o comportamento de cada ligação.
La tipologia architettonica tradizionale a sistema misto legno-muratura è ampiamente diffusa in ogni parte del mondo. La sua unicità è stata riconosciuta come patrimonio culturale da salvaguardare. Tali edifici hanno dimostrato un buon comportamento sismico se paragonati ad altre tipologie strutturali. La loro configurazione, nonché I loro dettagli costruttivi, si sono costantemente evoluti per opera dei costruttori, non appena questi ultimi hanno compreso le cause dei principali meccanismi di danno che si verificano a seguito di un terremoto. Il sistema misto Rumeno può essere considerato rappresentativo di questa tipologia strutturale, soprattutto perchè il territorio è stato soggetto ad innumerevoli eventi sismici dimostrando la sua capacità resistente. Nonostante molti di questi edifici siano attualmente abitati o in costruzione, non è presente nessuna informazione riguardo la loro progettazione nel codice edilizio Rumeno, inoltre il loro comportamento non è stato ancora propriamente caratterizzato ne modellato numericamente. La risposta globale di un edificio è funzione di diverse variabili tra cui la tecnologia costruttiva di pannelli murari, diaframmi orizzontali, sistema di copertura, nonché del loro grado di connessione. Per questo motivo, la calibrazione del comportamento non lineare delle pareti resistenti soggette a carichi ciclici è di fondamentale importanza per approssimare tale risposta globale. A questo proposito è stata scelta una strategia di modellazione semplificata basata su un telaio equivalente con elementi lineari elastici e non linearità concentrate nelle connessioni. Il lavoro di tesi si rivolge in particolare allo studio del comportamento sismico dei pannelli murari Rumeni a sistema misto legno-muratura e di un edificio rappresentativo localizzato originariamente nell’area di Sarbova, contea di Timis (poi successivamente riassemblato nel Museo Nazionale “Dimitrie Gusti” di Bucarest). Tale ricerca è condotta attraverso la comparazione dei risultati numerici con quelli misurati sperimentalmente nelle prove di laboratorio eseguite su un pannello murario rappresentativo presso il Dipartimento di Ingegneria Civile di Bucarest e i test di identificazione dinamica eseguiti in situ sull’edificio. Il modello numerico relativo alla parete è stato calibrato attraverso una procedura iterativa per ottenere una buona approssimazione tra la curva isteretica ottenuta sperimentalmente e quella numerica, in termini di rigidezza iniziale, forza di taglio massima alla base ed energia totale dissipata. Tale schema è stato realizzato nel software OpenSees modellando molle non lineari per ogni grado di libertà ed aggiornando i relativi parametri che definiscono la risposta isteretica partendo da test sperimentali condotti su connessioni simili. Una volta calibrato il pannello murario, è stato modellato l’edificio con la stessa strategia a telaio equivalente. In questo caso, tuttavia , le proprietà dinamiche non sono risultate perfettamente comparabili con quelle ottenute dall’identificazione dinamica, i muri dell’edificio rispondono in campo lineare elastico, mentre le proprietà delle connessioni sono state calibrate in campo non lineare plastico. Per questo motivo, il modello è stato modificato considerando il contributo di rigidezza aggiuntivo dato da una muratura in mattoni pieni, più rigida di quella presente nelle maglie del telaio testato. Infine, è stata svolta un’analisi non lineare statica al fine di stimare la massima forza alla base, la capacità deformativa del muro nonché alcune rotture locali nelle connessioni. Il modello semplificato a telaio equivalente ha evidenziato un buon grado di approssimazione con la risposta del pannello murario, ma, per le ragioni precedentemente esposte, non è stato in grado di caratterizzare dal punto di vista dinamico l’edificio. Ad ogni modo tale strategia di modellazione permette di ridurre l’onere computazionale e, allo stesso tempo, fornisce informazioni sul comportamento di ogni connessione.

Dissertação de mestrado em Structural Analysis of Monuments and Historical Construction
Historical timber-framed structures can be found all over the world since ancient times, being able to observe a variety of procedures and construction systems which is adapted to each zone according to the materials and available knowledge. Recent earthquakes have highlighted the good anti-seismic behavior of this structural typology. Likewise, its antiquity has also evidenced a good structural capacity. The case of Pombalino Buildings are born from the need to build an anti-seismic constructive system after the earthquake of Lisbon 1755 which destroyed most part of the city. The present thesis seeks to complement the study of these buildings due to the uncertainty related to their seismic behavior since up to date there has not yet been an earthquake registered in Lisbon since 1755. The work presented in this thesis seeks a better understanding of the mechanical behavior of Pombalino structures based on finite element modelling on OpenSees program. The experimental campaign of Gonçalves (2015) is used as reference and centered on the experimental results, the developed models were calibrated. A sensitive analysis was carried out in order to determine the variants that affected the behavior of the cyclic curve and also to elaborate an adequate calibration process. Finally a macro-model was elaborated from the floorplans of an existing building and using the properties of the calibrated model, the mechanical behavior and seismic performance of the building was reproduced.
Estruturas históricas de madeira podem ser encontradas em todo o mundo, podendo ser observada uma variedade de procedimentos e sistemas construtivos adaptados à cada zona segundo os materiais e o conhecimento disponível. Sismos recentes destacaram o bom comportamento anti-sísmico de tipologia estrutural, embora ESTA sua antiguidade têm evidenciado que é bom partilha estrutural. Os recentes sismos têm destacado o bom comportamento anti-sísmico desta tipologia estrutural. Além disso, sua antiguidade também evidenciou um bom comportamento estrutural. O caso dos edifícios Pombalinos nasce da necessidade de reconstruir adotando um sistema construtivo antisísmico após o terramoto de Lisboa de 1755, que destruiu grande parte da cidade. A presente dissertação pretende complementar o estudo destes edifícios devido à incerteza relacionada com seu comportamento sísmico já que até a data ainda não se teve um terramoto registado em Lisboa desde 1755. Este assunto tem sido estudado na última decada por diferentes autores e várias campanhas experimentais e numéricas de forma a reproduzir e compreender o comportamento sísmico desta tipologia de estruturas. O trabalho apresentado nesta tese procura um melhor entendimento do comportamento mecânico das estruturas Pombalinas baseando-se em elementos finitos. A campanha experimental de Gonçalves (2015) foi utilizada como referência, em particular os resultados experimentais pelos quais os modelos numéricos foram calibrados. Uma análise de sensibilidade foi feita de modo de avaliar as variantes que afectam o comportamento da curva cíclica e também calibrar o modelo. Finalmente um macro-modelo foi aplicado num edifício existente com base nas propriedades dos modelos já calibrados, os comportamentos mecânico e sísmico do edifício foram reproduzidos.
Estructuras históricas en madera pueden ser reconocidas alrededor de todo el mundo, pudiendo observar una variedad de procedimientos y sistemas constructivos adaptados a cada zona según los materiales y conocimiento disponible. Terremotos recientes han resaltado el buen comportamiento antisísmico de esta tipología estructural. Asimismo su antigüedad también ha evidenciado un buen compartamiento estructural. El caso de los edificios Pombalino nace de la necesidad de construir un sistema constructivo antisísmico después del terremoto de Lisboa de 1755, que destruyó gran parte de la ciudad. La presente tesis pretende complementar el estudio de estos edificios debido a la incertidumbre relacionada con su comportamiento sísmico ya que hasta la fecha todavía no se ha habido un terremoto registrado en Lisboa desde 1755. Este asunto ha sido estudiado desde hace un par de años por investigadores y campañas experimentales que se han realizado buscando reproducir y comprender el comportamiento sísmico de estas estructuras. El trabajo presentado en esta tesis busca un mejor entendimiento del comportamiento mecánico de las estructuras Pombalino basándose en elementos numéricos finitos. La campaña experimental de Gonçalves (2015) se utiliza como referencia y centrándose en los resultados experimentales, modelos numéricos fueron calibrados. Un exhaustivo análisis sensitivo fue llevado a cabo de modo de determinar las variantes que afectan el comportamiento de la curva cíclica y también calibrar el modelo. Finalmente un macro-modelo fue elaborado desde la planimetría de un edificio existente y usando las propiedades de los modelos ya calibrados, el comportamiento mecánico y comportamiento sísmico del edificio fue reproducido.

Windstorms are one of the major causes of severe damage to houses and other infrastructure. Damage investigations indicate that the roof is the most vulnerable part of a timber-framed house, and that failures take place at inter component connections; hence there is a need to study the load sharing and structural response of these timber-framed house structural systems to assess their performance. Contemporary houses in many parts of Australia are brick veneer structures with metal or tile clad roofs that are built to National Construction Code of Australia's design specifications. Full-scale tests were carried out on a representative part of a brick veneer contemporary house to assess the loading effects on roof to wall connections and load sharing. Tests were conducted for each stage of construction: bare frame followed by the installation of roof battens and cladding, wall lining, ceiling, etc. These construction stages were used to assess the contribution of the structural and lining (i.e. ceiling, ceiling cornice and wall lining) elements to the load sharing and response of the timber-framed house structure to wind loading. Results show that the vertical load sharing of the timber-framed house through the roof to wall connection depends on the stiffness of the roof to wall connection and the truss location (i.e. whether located at the end or middle). The contribution of the lining elements to the vertical load sharing is about 15% to 20%. In addition, individual component tests were conducted on the roof to wall framing anchor (i.e. triple grip and truss grip) connections to examine their structural response to loading. This study also showed that construction defects in roof to wall connections influence the design uplift capacity. Two missing nails out of ten in the hand nailed triple grip connection (i.e. one nail from the truss and other one from the top plate) reduces the design uplift capacity by about 40 % of the "Ideal" hand nailed triple grip connection. Finite element models were also developed for part of the timber framed house and roof to wall connections (i.e. triple grip and truss grip connections) using ABAQUS finite element software. Results obtained from the finite element models were compared with the experimental tests, showing good agreement. This finite element model can be used to predict the roof to wall connection response and truss hold-down force variation with a range of construction defects and truss bay configurations. The overall outcomes can be used to evaluate house structure vulnerability to wind loading, and to improve the design and standards of timber-framed houses.

Dissertação de Mestrado Integrado em Engenharia Civil apresentada à Faculdade de Ciências e Tecnologia
Timber is natural and recyclable, presents a high strength-to-weight ratio, requires less energy at production than other traditional structural materials and allows a high level of prefabrication. The development of engineered wood products, such as, glulam contributed to an increasing utilization of timber solutions in different types of structures. In the design of timber structures, a special attention must be paid to the connections. The semi-rigid behaviour of moment-resisting connections leads to an interaction between the stiffness of the connection and the design of the structural members.Despite structural optimization is not commonly used in Civil Engineering design practice, the use of optimisation techniques in the design of timber structures constitutes an effective way to obtain economical, structurally efficient and sustainable solutions. Therefore, an integrated analysis and optimization numerical model was developed as a tool to assist in the design of glue laminated timber frames with semi-rigid connections. The optimization problem is formulated as the minimization of a single objective function (cost of the structure) subjected to a set of constraints related to strength and service criteria defined according to Eurocode 5 provisions. The design variables are the cross-sectional sizes of main structural members (beams and columns) and secondary structural members (purlins and bracing members), stiffness of beam-column connection and number of building’s frames. The structural analysis considers the relevant actions and effects (linear and nonlinear). The use of a genetic algorithm allows solving the optimization problem considering discrete design variables.The features and capabilities of the developed algorithm are illustrated by numerical examples concerning the optimisation of real-sized timber frames.
A madeira é um material natural e reciclável, apresenta uma elevada relação resistência-peso, requer menor energia na produção do que outros materiais estruturais tradicionais e permite um elevado nível de pré-fabricação. O desenvolvimento de produtos derivados da madeira como o glulam tem contribuído para a crescente utilização de soluções em madeira para diferentes tipos de estruturas. No projeto de estruturas de madeira deve prestar-se especial atenção ao comportamento das ligações. O comportamento semirrígido das ligações resistentes a momentos origina uma dependência entre a rigidez da ligação e o dimensionamento dos elementos estruturais.Apesar de a otimização estrutural não ser habitualmente utilizada na prática da Engenharia Civil, o uso de técnicas de otimização no projeto de estruturas de madeira constitui uma forma eficaz de obter soluções económicas, estruturalmente eficientes e sustentáveis. Deste modo, desenvolveu-se um modelo numérico integrado de análise e otimização como ferramenta de apoio ao projeto de estruturas porticadas de madeira lamelada colada considerando o comportamento semirrígido das ligações viga-pilar. O problema de otimização é formulado como a minimização de uma função objetivo (custo da estrutura) sujeita a um conjunto de restrições de modo a verificar critérios de resistência e utilização definidos de acordo com as disposições do Eurocódigo 5. As variáveis de decisão consideradas são as dimensões das secções transversais dos elementos estruturais principais (vigas e pilares) e secundários (madres e elementos de contraventamento), a rigidez das ligações viga-pilar e o número de pórticos do edifício. Na análise estrutural consideram-se os efeitos (lineares e não lineares) e ações relevantes. O recurso a um algoritmo genético permite resolver o problema de otimização considerando variáveis de decisão discretas. As características e capacidades do modelo numérico desenvolvido são ilustradas através da resolução de exemplos de aplicação relativos à otimização de pórticos de madeira de dimensões reais.

La tesi di dottorato ha come oggetto il patrimonio architettonico rappresentato dalle cosiddette case baraccate, la cui tecnica costruttiva, definita alla fine del XVIII secolo dal governo borbonico, ha rappresentato il modello per la ricostruzione post-terremoto di diverse città italiane nell’arco di tempo compreso tra il 1783 ed il 1908. In tali costruzioni la concezione della struttura portante, rappresentata da una gabbia ligne immersa nelle pareti murarie perimetrali ed interne, è il risultato di una “memoria sismica” basata su una tradizione costruttiva pregressa e su intuizioni e conoscenze scientifiche la cui fondatezza è stata per lo più verificata solo da un punto di vista empirico. In questo senso la ricerca ha avuto come obiettivo principale quello di valutare l’efficienza sismica del sistema costruttivo in esame attraverso la definizione di uno specifico modello meccanico di analisi. In aggiunta, la ricerca si è interessata all’analisi e descrizione degli aspetti costruttivi, tipologici e morfologici, che caratterizzano la tecnica baraccata, riscontrati in alcuni esempi ancora esistenti sul territorio calabrese. Uno degli edifici più emblematici di questa tecnica costruttiva, il palazzo vescovile di Mileto (VV), è stato analizzato in dettaglio ed ha rappresentato l’oggetto di analisi del modello meccanico sviluppato. In relazione agli ambiti di ricerca sopra descritti, la tesi è struttura in tre parti, in ciascuna della quale la tecnica antisismica baraccata è stata indagata da un diverso punto di vista: Analisi storico-costruttiva La prima parte della tesi, di carattere introduttivo, indaga la genesi e la diffusione della tecnica costruttiva in relazione ad esempi analoghi, presenti nei territori ad alto rischio sismico dell’Italia e più in generale del mondo. Le peculiarità del sistema costruttivo sono indagate da un punto di vista qualitativo, individuando i principi antisismici che lo contraddistinguono. Accanto a questa attività di “ricostruzione storica” della tecnica costruttiva, la prima parte della tesi contiene anche un’indagine sul patrimonio esistente volta a documentare l’esistenza e lo stato di conservazione di costruzioni baraccati ancora esistenti, alcune delle quali scoperte “ex-novo” a seguito di una campagna di indagini in-situ in diversi centri calabresi. Analisi meccanica Nella parte centrale della tesi, invece, viene descritto il modello meccanico definito per l’analisi di sistemi baraccati. L’obiettivo è stato quello di tradurre in un linguaggio scientifico moderno le intuizioni empiriche che caratterizzano la configurazione strutturale delle case baraccate. Attraverso un’analisi meccanica multiscala, è stata definita una metodologia di modellazione semplificata per descrivere i complessi fenomeni meccanici che caratterizzano il comportamento sismico delle strutture miste in legno e muratura. In particolare, in una prima fase è stata condotta un’analisi micro-meccanica su una parete baraccata, già oggetto di test sperimentali al Laboratorio CNR-Ivalsa di Trento nel 2013, che ha permesso la calibratura dei parametri meccanici che caratterizzano gli elementi della parete (telaio ligneo, connessioni, muratura). Successivamente, l’approccio di analisi semplificata chiamato a Telaio equivalente (EFM – Equivalente Frame Method), largamente diffusa in letteratura per lo studio di strutture murarie, è stato implementato per l’analisi sismica di un intero edificio baraccato. Caso studio L’ultima parte della tesi, infine, si è interessata dello studio di un caso emblematico di casa baraccata sette-ottocentesca. In particolare, il palazzo vescovile di Mileto (VV), dato il suo enorme valore storico, costruttivo e culturale, è stato scelto come oggetto di uno studio specifico, finalizzato all’applicazione e validazione del modello meccanico definito. Parallelamente all’analisi sismica, è stata condotta una dettagliata analisi costruttiva del palazzo, il cui pessimo stato conservativo ha consentito di rilevare dettagliatamente le soluzioni costruttive originarie. In aggiunta, al fine di evitare la completa perdita del palazzo vescovile, interessato negli ultimi anni ad estesi crolli e numerosi atti vandalici, la tesi si è interessata alla ricostruzione delle vicende amministrative degli ultimi decenni relative al bene. Tali ricerche fanno parte un’attività di recupero, materiale e culturale, promossa dal Dipartimento di Architettura di Roma TRE, che ha recentemente consentito l’avvio di una procedura di apposizione del vincolo architettonico sul palazzo, che dovrebbe dare l’avvio alla sua definitiva salvaguardia e valorizzazione.
The doctoral dissertation concerns about architectural heritage represented by the so-called “Baraccato” houses. The most ancient Baraccato structural system was defined by the Bourbon Government in the late 18th century and it represented the anti-seismic model for the reconstruction of several italian cities between 1783 and 1908. In such constructions the load-bearing system, composed by a timber-framed masonry infill, is the result of a "seismic memory" based on a experience and pratical knowledge whose scientific validity has been mostly verified only from an empirical point of view. For this reason, the main scope of the thesis was to assess the seismic efficiency of the constructive system by defining a specific mechanical model. In addition, the research deals with the analysis and description of the typological and morphological aspects that characterize the Baraccato houses found in some examples still existing in Calabria, a region in the South of Italy. One of the most emblematic buildings of this construction technique, the Episcopal Palace of Mileto, was analyzed in detail and has been the object of analysis of the mechanical model proposed. With reference to the research areas of interest described above, the thesis consists of three main parts: Historical and constructive analysis The first part explores the genesis and spread of the Baraccato technique with regard to similar examples, widespread in the territories of high seismic risk of Italy and more generally in the world. The research shows the constructive characteristic of the Baraccato building, identifying the anti-seismic quality. In addition to the "historical reconstruction" of the Baraccato technique, the first part of the thesis contains the results of a survey on existing heritage aimed at evaluating the extent of Baraccato heritage in different centres of Calabria and its conservation status. Mechanical analysis In the central part of the thesis, the mechanical model proposed for the analysis of the most ancient Baraccato system is shown. The aim was to translate the empirical intuitions that characterize the structural configuration of the Baraccato buildings with a modern scientific language. Through a multiscale mechanical analysis, a simplified modeling methodology has been defined to describe the complex mechanical phenomena that characterize the seismic behaviour of mixed wood and masonry structures. As a matter of fact, in a first phase a micro-mechanical analysis was carried out on a single Baraccato wall, already undergoing experimental tests at the CNR-Ivalsa Laboratory of Trento in 2013, which allowed the calibration of the mechanical parameters that characterize the wall elements, like wooden frame, connections and masonry. Subsequently, the simplified analysis approach, called EFM (Equivalent Frame Method), widely used in the literature for the study of masonry structures, has been implemented for the seismic analysis of an entire Baraccato building. Case study The last part of the thesis concerns about the study of an emblematic case of eighteenth-century Baraccato house. In particular, the Bishop palace of Mileto (South Italy), because of its enormous historical, cultural and constructive value, was chosen as the subject of a specific study, aimed at application and validation of mechanical model defined. In addition, the poor state of conservation of the building has allowed to detect the original construction solutions, providing a rare testimony of the original Baraccato technique. As a matter of fact, in order to avoid the complete loss of the Bishop's Palace, affected by several collapses and acts of vandalism in the last few years, the thesis contains the results of a recovery activity, material and cultural life, promoted by the Architecture Department of Rome Tre University, which has recently led to the beginning of a procedure for affixing the architectural constraint on the Palace, which should guarantee its definitive preservation and enhancement.