Dissertations / Theses on the topic 'RC and masonry'

Masonry is a composite material made of masonry units bonded together with mortar. A large number of historical buildings constructed using masonry can be found all over the world. Little or no seismic loading was considered when they were built. Therefore, masonry structures often need to be retrofitted or strengthened. This research proposed a new strengthening approach using a collar-jointed technique. Namely, the approach is implemented by building another masonry wall parallel to the existing single-leaf wall and bonding the two together using a mortar collar joint. Furthermore, collar-jointed masonry wall construction is also a popular construction system in reality. This thesis considers two different types of collar wall strengthening applications: pre- and post-damaged walls. The results found out that the pre-damaged strengthening could improve the lateral resistance by about 50% while the post-damaged retrofitting can only restore the initial strength. A simplified micro-scale finite element model for fracture in masonry walls was developed. The mortar joints and the brick-mortar interfaces are taken to have zero-thickness. The bricks were modelled as elastic elements while the brick-mortar interfaces were represented using a Mohr-Coulomb failure surface with a tension cut-off and a linear compression cap. One feature of the research was to identify the material parameters for the constitutive model. The material parameters were tuned by minimizing the difference between the experimental and numerical results of a single leaf wall panel. The model was then validated by assigning the parameters to the single-leaf masonry wall as well as to the double-leaf wall to predict its mechanical behaviour. Good agreement with experimental results was found. Furthermore, masonry is also widely used in the form of infill panels within RC frames. Therefore, the collar-jointed technique has also been extended and applied to the infilled RC frame. The numerical results showed that the collar-jointed technique could provide some benefits to the composite structure.

A confined masonry (CM) wall consists of a masonry wall panel surrounded by reinforced concrete (RC) members on its perimeters. Low-rise CM structures are widely used in earthquake-risked (EQ-risked) rural or suburban areas all over the world. Most of these structures fail in shear pattern under lateral EQ loads, and some of them collapse under a severe or even a moderate EQ due to inappropriate design. On the other hand, buildings constructed of RC frames have much better performance in resisting EQs, since their RC members have larger dimensions and heavier reinforcing ratios than those in CM structures. Nonetheless, RC-frame buildings are normally too expensive for most inhabitants in less developed regions. In this study, as an improvement to the conventional CM buildings for EQ resistance and for the sake of post-EQ restoration, a hybrid masonry – RC (HMR) structure, whose working mechanism is different from that of a conventional CM structure, is proposed. The RC members (i.e. “tie beams” and “tie columns”), which function only as confinement in a CM building, will resist most of gravity load and part of lateral EQ load in an HMR structure, while the wall panels will take most of lateral EQ load and part of gravity load. This is achievable by slightly increasing the sizes and reinforcing ratios of RC members in HMR structures. Such buildings will not collapse in the absence of masonry wall panels because the gravity load bearing system is still intact. On the other hand, as the wall panels in the proposed HMR structure will absorb most of the energy induced by lateral EQ load, severe damages will be controlled within the wall panel region, so that only the wall panels need to be replaced instead of rebuilding the whole structure after the EQ event. To investigate the mechanical behaviours of masonry assemblages to be used in HMR structures, a series of experimental tests were conducted. Having established the relevant material properties for HMR structures, finite element (FE) simulation was performed to verify its work mechanism. Prior to applying the FE simulation to HMR structures, the FE technique was first applied to simulate the behaviours of two concrete-brick masonry panels under diagonal compression loading and a CM wall under cyclic lateral loading. The results show a good correlation between the experimental results and the simulated ones. This has validated the feasibility of using the FE software to study the proposed HMR structure. The theoretical simulation results show that in a properly designed HMR wall, depending on the masonry reinforcing details and the boundary conditions of simulated load cases, about 70% of the gravity load imposed on the RC beam will be transferred to the RC columns and more than 80% of the seismic energy (in terms of strain energy) will be absorbed by the masonry panel. Therefore, it is obvious that the proposed HMR structure is very feasible to replace the conventional CM structure in resisting EQ attacks with no risk of collapse.
published_or_final_version
Civil Engineering
Master
Master of Philosophy

Thesis (MScIng)--Stellenbosch University, 2005.
Some digitised pages may appear illegible due to the condition of the original hard copy.
ENGLISH ABSTRACT: Reinforced concrete (RC) frames with unreinforced masonry infill form the structural system of many buildings and this is also true for South Africa. It is common practice to consider the masonry infill as a non-structural component and therefore it does not contribute to the performance of the Re frame buildings under lateral loading such as earthquake loading. This is done by leaving a sufficient gap between the Re frame and the infill. This ensures that there is no contact between the frame and the infill during an earthquake event. However, it has been suggested that masonry infill can play a significant role in the performance of a Re frame building under lateral loading. The first part of the study focuses on the South African situation. The relevance of shear walls in these Re frame buildings as well as the size of the gap (between frame and infill) left in practice, are investigated. This is done by finite element analysis. The second part of the study focuses on the effects that the infill can have on the global performance of the structure when there is full contact between the Re frames and infill. The effect of openings in the infill to the response of the frame is also investigated. Finite element models of single span Re frames with infill is built and analyzed in order to investigate possible damage to the infill, frame infill interaction and to obtain the non linear stiffness of the frame with infill as a whole. This obtained non linear stiffness can be modelled in Diana as a non linear spring that will be used in the development of a simplified analysis method. The simplified method developed consists of a frame and two such non linear springs, placed diagonally, and which have the same force versus displacement behaviour as the original frame with infill. These single span frames can be added together to model a whole frame. In a first step to generalise the simplified method, various geometries of infills are considered, varying span and height, as well as opening percentage, representing windows and doors of varying total area and positioning. However, in this study a single masonry type, namely solid baked clay bricks set in a general mortar, is considered. To generalise the approach further, other masonry types can be considered in the same way. The use of these springs in a simplified model saves computational time and this means that larger structures can be modelled in Diana to investigate response of'Rf' frame buildings with infill. The work reported in this thesis considers only in-plane action. Out-of-plane-action of the masonry infill has been reported in the literature to be considerable, under the condition that it is sufficiently tied to the frame to prevent mere toppling over, causing life risking hazards in earthquake events. This matter should be studied in continuation of the current research to generalise the simple approach to three dimensions.
AFRIKAANSE OPSOMMING: Gewapende betonrame (GBR-e) met ongewapende messelwerk invulpanele (invul) vorm die strukturele ruggraat van vele geboue en dit geld ook vir geboue in Suid-Afrika. Dit is algemene praktyk om die invulpaneel in sulke geboue as 'n nie-strukturele komponent te beskou. Daarvolgens dra dit nie by tot die gedrag van 'n GBR gebou onderhewig aan 'n aarbewing nie. Dit word bereik deur 'n groot genoeg gaping tussen die betonraam en die invul te los. Die gevolg is dat daar geen kontak tussen die betonraam en die invul plaasvind indien daar 'n aardbewing sou voorkom nie. Dit is egter voorgestel dat invul 'n noemenswaardige rol kan speel in die gedrag van 'n GBR gebou onderwerp aan 'n horisontale las. Die eerste deel van die studie fokus op die Suid-Afrikaanse situasie. Die relavansie van skuifmure in GBR geboue asook die grootte van die gaping (tussen die raam en invul) wat in die praktyk gebruik word, word ondersoek. Dit word gedoen met behulp van eindige element analises. Die tweede deel van die studie fokus op die effek wat invul kan hê op die globale gedrag van 'n struktuur wanneer daar volle kontak tussen die GBR en die invul is. Die effek wat die teenwoordigheid van openinge in die invul kan hê op die gedrag van 'n GBR is ook ondersoek. Eindige element modelle van enkelspan GBR met invul is gemodelleer en geanaliseer om die moontlike skade aan die invul, die interaksie tussen die GBR en die invul asook die nie-lineêre styfheid van die raam en invul as 'n geheel, te ondersoek. Hierdie nielineêre styfheid kan in Diana as 'n nie-lineêre veer gemodelleer word en word gebruik in die ontwikkeling van 'n vereenvoudigde metode. Hierdie vereenvoudigde metode wat ontwikkel is, bestaan uit 'n raam en twee sulke nielineêre vere (diagonaal geplaas). Die raam met vere het dieselfde krag teenoor verplasingsgedrag as die van die oorspronklike raam met invul wat dit voorstel. Hierdie rame kan saamgevoeg word om 'n raam uit 'n gebou as 'n geheel te modelleer. Verskeie invul geometrieë word gebruik in die analises in 'n eerste stap om die vereenvoudigde metode te veralgemeen. Die span en hoogte asook opening persentasie van die invul word gevariëer om vensters en deure van veskeie grootte en posisie voor te stel. In die studie, 'n enkel messelwerk tipe, naamlik solied klei bakstene geset in algemene mortar, word gebruik. Ander messelwerk tipes kan gebruik word om die metode verder te veralgemeen. Die gebruik van die vere in die vereenvoudigde metode spaar berekenings tyd en dit beteken dat groter strukture in Diana gemodelleer kan word om die gedrag van GBR geboue met invul te ondersoek. Die werk gedoen in die tesis neem slegs in-vlak aksie in ag. Literatuurstudie dui daarop dat goeie uit-vlak-aksie van messelwerk invul bestaan, mits dit goed geanker is aan die raam om te verseker dat dit nie kan omval en 'n gevaar vir lewens in 'n aardbewing inhou nie. Dit behoort verder bestudeer te vord in die vervolging van die huidige ondersoek om die vereenvoudige metode na drie dimensies te veralgemeen.

This thesis is the result of the industrial PhD carried out in collaboration with Aliva S.r.l. company that develops customized solutions for ventilated facades. The ventilated façade is a multi-layer protective system for the building envelope where the light bearing structure is usually made of aluminium alloy for its property of lightness, durability, corrosion resistance, workability thanks to the extrusion process and eco-sustainability. The scope of this thesis is to investigate the use of aluminium alloys in application fields different from that of the ventilated façade. The use of aluminium alloys in structural engineering is a quite recent activity, because this family of materials is relatively new. Nowadays, after the several research carried out in order to characterize the design of aluminium alloys structures and the publication of Eurocode 9 Design of Aluminium Structures, there are many applications of aluminium alloys in structural engineering. However, there is still a lack of information about the ductility of this material and its use in seismic zones. In fact to date there is no seismic regulations for aluminium alloys applications, only recently in the project for the development of the next generation of structural Eurocodes, it was decided to introduce the aluminium alloys among the new emerging materials for anti-seismic structures. This thesis aims to make a contribution to the study of the possible use of aluminium alloys in seismic areas and intends to study if it can be a competitive solution in the seismic retrofit field. This study is part of the European research project Pro-GET-onE in which the Aliva company is involved together with the university of Bologna and other members. This thesis shows the study and the development of the design of an external structural frame, also called exoskeleton, made of aluminium alloys.

La presenza di tamponamenti in muratura all’interno delle maglie di strutture intelaiate induce, in presenza di azioni laterali, una sostanziale modificazione della risposta globale rispetto a quella dei telai nudi in termini di rigidezza, resistenza e capacità di spostamento. La tesi presenta i risultati di una campagna sperimentale su telai tamponati con diverse tipologie di muratura soggetti a prove di carico cicliche. Successivamente viene proposto un criterio per la modellazione semplificata del comportamento ciclico attraverso un macromodello a puntone diagonale equivalente. Una ulteriore indagine numerica è eseguita per valutare l'entità degli effetti locali dovuti all'interazione fra telaio a tamponamento proponendo un criterio per la loro inclusone nella modellazione a puntone concentrico. Infine viene eseguita una calibrazione del puntone diagonale attraverso un modello a fibre. Tale modellazione è utilizzata per studiare il comportamento nel piano e fuori piano dei pannelli in presenza di azioni sismiche provenienti da qualsiasi direzione.
The presence of infill masonry in RC framed structures substantially modifies of the overall response in presence of seismic actions with respect of bare frames in terms of stiffness, strength and displacement capacity . The thesis presents the results of an experimental campaign on infilled frames with different kinds of masonry subjected to cyclic loading tests. Subsequently, a criterion for the simplified modeling of the cyclic hysteretic behavior through a macromodel equivalent diagonal strut is proposed. A further numerical investigation is carried out to assess the influence of local effects due to the interaction between infill a frame and a criterion for their inclusion when concentric strut models are used is developed. Finally calibration of the equivalent strut by means of a fiber model is performed. This approach is also applied to study the in plane-out of plane behavior of masonry infill panels when in the presence of seismic actions acting in any direction .

Reinforced concrete frames infilled with unreinforced masonry are commonly used in structures worldwide. The interaction between the frame and the infill panel is usually ignored in engineering practice, and the masonry infill is not considered as a structural element. However, observations made after the occurrence of strong earthquakes have shown that the bare frame and infill-frame behave differently when subjected to in-plane lateral loads. Extensive research has been conducted on the behaviour of infill-frames when laterally loaded. This research focuses on the analysis of infill-frames using the equivalent strut modelling method, whereby an infill-frame is simplified, and the infill panel is replaced by one or more compressive strut elements. A large number of strut models have been proposed in the literature, but recent studies have demonstrated that it is not possible to apply one strut model to all infill-frame structures. It has been found that changing the properties of an infill-frame can also change the geometric properties of struts, namely width, location and number of struts in an equivalent strut model. For this reason, recent studies have proposed a case-specific strut modelling approach. In the current study, a macro script available in the literature that can be used to generate a detailed finite element (FE) model has been applied to construct and analyse a number of infill-frames with different material and geometric properties. Sensitivity analyses on some of these infill-frames have also been conducted by varying the material properties of the infill, and the amount and distribution of vertical loads on the frame. The results of detailed FE analyses, more specifically contours of the compressive principal stresses, have been used to define the geometric properties of the struts of case-specific strut models for each of the infill-frames. Equivalent strut models were then analysed and compared. Further, the proposed strut models were applied to other infill-frames selected for this study; two strut models from the literature were also applied to these infill-frames. It was concluded that the geometric properties of, and the vertical load on an infill-frame can be related to the geometric properties of its equivalent strut model. In contrast, a variation of up to 25% in the masonry material properties did not have a significant effect on the strut properties. It was shown that casespecific strut modelling is a versatile and generic technique that can adequately replicate the highly nonlinear behaviour of infill-frames regardless of their geometric or material properties. By expanding the current research, it is hoped that a rigorous classification of infill-frames and their relevant equivalent strut models can be developed to assist structural engineers in their everyday design tasks.

Subject of the solution master´s thesis is new civil building. It is five floors building with underground floor. The structual system is made by combination of RC frame and loadbearing masonry with monoplane roof. In underground floor is a garage. In First floor is designed for commercial and comunal activities. In next floors there is always 8 flats. Building is located in straight terrain in the development area of new houses in Zlin in area Bartosova.

碩士
國立成功大學
建築學系
106
A nonlinear push-over analytical model for Taiwan’s partially confined masonry in RC frames is re-established in this research, which is based on the existing analytical model and the inductive conclusions of the structural behavior observed in the experiments. By comparing the results of the new analytical model and those of studies at home and abroad, it is observed that theoretical curves and performance points’ strength can effectively reflect experimental results. Furthermore, the determination of both masonry panels’ failure mode and whether shear failure occurred in columns is also accurate.

Reinforced concrete frames, infilled with brick/concrete block masonry, are the most common type of structures found in multi-storeyed constructions, especially in developing countries. Usually, the infill walls are considered as non-structural elements even though they alter the lateral stiffness and strength of the frame significantly. Approximately 80% of the structural cost from earthquakes is attributable to damage of infill walls and to consequent damages of doors, windows and other installations. Despite the broad application and economical significance, the infill walls are not included in the analysis because of the design complexity and lack of suitable theory. But in seismic areas, ignoring the infill-frame interaction is not safe because the change in the stiffness and the consequent change in seismic demand of the composite structural system is not negligible. The relevant experimental findings shows a considerable reduction in the response of infilled frames under reverse cyclic loading. This behaviour is caused by the rapid degradation of stiffness, strength, and low energy dissipation capacity resulting from the brittle and sudden damage of the unreinforced masonry infill walls. Though various national/international codes of practice have incorporated some of the research outcomes as design guidelines, there is a need and scope for further refinement. In the initial part of this work, a numerical modelling and linear elastic analysis of masonry infilled RC frames has been done. A multi-storey multi-bay frame infilled with masonry panels, is considered for the study. Both macro modelling and micro modelling strategies are adopted. Seismic loading is considered and an equivalent static analysis as suggested in IS 1893, 2002 is done. The results show that the stiffness of the composite structure is increased due to the obvious confinement effects of infill panels on the bounding frame. A parametric study is conducted to investigate the influence of size and location of openings, presence/absence of infill panels in a particular storey and elevation irregularity in terms of floor height. The results show that the interaction of infill panel changes the seismic response of the composite structure significantly. Presence of openings further changes the seismic behaviour. Increase in openings increases the natural period and introduce newer failure mechanisms. Absence of infill in a particular storey (an elevation irregularity) makes it drift more compared to adjacent storeys. Since the structural irregularities influence the seismic behaviour of a building considerably, we should be cautious while construction and renovation of such buildings in order to take the advantage of increased strength and stiffness obtained by the presence of infill walls. A nonlinear dynamic analysis of masonry infilled RC frames is presented next. Material non linearity is considered for the finite element modelling of both masonry and concrete. Concrete damage plasticity model is employed to capture the degradation in stiffness under reverse cyclic loading. A parametric study by varying the same parameters as considered in the linear analysis is conducted. It is seen that the fundamental period calculation of infilled frames by conventional empirical formulae needs to be revisited for a better understanding of the real seismic behaviour of the infilled frames. Enhancement in the lateral stiffness due to the presence of infill panel attracts larger force and causes damage to the composite system during seismic loading. Elevation irregularities included absence of infill panels in a particular storey. Soft storey shows a tendency for the adjacent columns to fail in shear, due to the large drift compared to other storeys. The interstorey drift ratios of soft storeys are found to be larger than the limiting values. However this model could not capture the separation at the interfaces and related failure mechanisms. To improve the nonlinear model, a contact surface at the interface is considered for a qualitative analysis. A one bay one storey infilled frame is selected. The material characteristics were kept the same as those used in the nonlinear model. Contact surface at the interface was given hard contact property with pressure-overclosure relations and suitable values of friction at the interface. This model could simulate the compressive diagonal strut formation and the switching of this compressive strut to the opposite diagonal under reverse cyclic loading. It showed an indication of corner crushing and diagonal cracking failure modes. The frame with central opening showed stress accumulation near the corners of opening. Next, the micro modelling strategy for masonry suggested by Lourenco is studied. This interface element can be used at the masonry panel-concrete frame interface as well as at the expanded masonry block to block interface. Cap plasticity model (modified Drucker – Prager model for geological materials) can be used to describe the behaviour of masonry (in terms of interface cracking, slipping, shearing) under earthquake loading. The blocks can be defined as elastic material with a potential crack at the centre. However, further experimental investigation is needed to calibrate this model. It is required to make use of the beneficial effects and improve upon the ill-effects of the presence of infills. To conclude, infill panels are inevitable for functional aspects such as division of space and envelope for the building. Using the lateral stiffness, strength contribution and energy dissipation capacity, use of infill panels is proposed to be a wiser solution for reducing the seismic vulnerability of multi-storey buildings.

碩士
國立成功大學
建築學系碩博士班
96
Slender unreinforced masonry (URM) walls can easily be found in typical RC school buildings in Taiwan, in-filled between RC frames and doors or windows due to the need for opening. Since the walls are only 60~100cm wide with a slenderness ratio more than 1 and lack of vertical boundary members, they are usually damaged by flexural bending in earthquakes. Based on the failing behavior investigated from in-site tests and the concept from former researches, an analytical model for flexural cracking and ultimate strength of slender URM walls is established in this thesis. From the observation in in-site tests for existing school buildings, it is found that when the slender URM wall is subjected to lateral loading comes from the top slab, horizontal flexural cracks appears along its top and bottom edges at once due to lack of tensile capacity. However, with sufficient vertical confinement by RC boundary frame, an inclined strut can form between the top and bottom compressive zones and provide lateral resistance by arching action. In the analytical model, the lateral resistance is derived from equilibrium of the couple by eccentric resultant compression at the top and bottom compressive zones and the moment resulted from lateral load. By assuming the wall is nearly rigid between cracked sections, the strain and depth of compressive zone can be derived geometrically. A stress-strain relationship for masonry is then employed to calculate the compressive stress and resultant compression. The lateral load-drift curve can be obtained by repeating the calculation for any given drift and the maximum load in the curve means the flexural ultimate strength of the wall. The model shows that analytical flexural ultimate strength of URM walls is proportional to its uniaxial compressive strength and almost inversely proportional to the slenderness ratio. The effect by simultaneously applied axial loading is also considered in this model. It appears that the analytical flexural strength increases slightly with the increase of initial axial loading less than about 60% of the ultimate axial strength but decreased rapidly after axial loading exceeds the range. Determination of analytical failure mode by introducing an existing model for shear strength is presented in the thesis as well. Comparison with experimental results shows that the analytical flexural strength and load-drift curves are conservative and reasonable.

碩士
國立成功大學
建築學系碩博士班
98
Data collection is an important work in the earthquake reconnaissance. However, major issues were found in the damage data collected from the past earthquakes. Different damage evaluation standards and data formats were used by different inspectors, causing the difficulty and misunderstanding in using these data. Therefore, this thesis is aimed at improving the post-earthquake damage evaluation procedure. Firstly, several current damage evaluation standards were reviewed. A new damage evaluation procedure was then presented based on the review. The presented procedure was validated by the comparison with 3 in-situ test specimens. The positions of damage conditions on the push over curves and the drift ratio corresponding to each damage state were discussed. The ability to distinguish moderate damage states of the procedure was also verified by using the data of 10 school buildings damaged during recent earthquakes. Twelve professionals with different backgrounds were asked to evaluate the damage state of the buildings with both their subjective judgments and the presented procedure. The damage states determined by using the presented procedure showed less dispersion and stricter result than the subjective judgments. The procedure results between professionals from different back grounds also showed less difference. The procedure was then compared with current procedure used by the Construction and Planning Agency; the results from the two procedures showed good agreement. Finally, the presented procedure was applied to an existing databank for school buildings damaged during the Chi-Chi earthquake to revise the damage state. The relationships between the revised damage state and structural factors, including adjacent building condition, building orientation, and column density, were studied. Typical school buildings that had adjacent buildings facing them with the strong axis showed lighter damage state than those that had no adjacent buildings or adjacent buildings facing with the weak axis. The building orientation also showed clear relationship with the damage state in this earthquake. Buildings with the longitudinal axis along the E-W and NW-SE directions had heavier damage than buildings lie in the N-S direction. The relationship between the column density and the damage state was reasonable; the column density decreased as the damage state became heavier.

碩士
國立成功大學
建築學系碩博士班
94
In Taiwan, many people live in RC buildings that were constructed with un-reinfroced infilled masonry walls in RC frames. The existing seismic assessment for such structures usually emphasizes only on in-plane capacity of the infilled walls. However, the damage reports for earthquakes tell that sometimes the infilled masonry walls collapse at out-of-plane direction before they can contribute in-plane capacity. In this thesis, failing behavior of infilled masonry walls and interaction between the walls and RC boundary frames when they were subjected to out-of-plane loading were investigated from results of in-site tests. Analytical models were developed for estimating out-of-plane cracking and ultimate strength and displacement of the infilled masonry walls. From 2 in-site tests, it is found that when the infilled masonry walls were subjected to out-of-plane concentrated loading, the top and bottom of walls bended and cracks happened at the tensile side. Out-of-plane displacement measured show that after the cracking happened, region between top and bottom cracks remained rigid, therefore the walls behave like 2-force members with hinges at both ends. The analytical model assumes that infilled masonry walls are subjected to only concentrated loading. The cracking strength and displacement can be calculated simply by material and geometric properties, while the ultimate strength and displacement are developed by strut model. The ratio of height to thickness and compressive strength of brick piers are found to be main factors of the out-of-plane ultimate strength. Analytical P-Δ curves of infilled masonry walls are compared with the experimental ones. Analytical model presented in this thesis shows conservative but better prediction than other analytical models. It shows that the analytical model presented in this thesis is reasonable and applicable.

碩士
國立成功大學
建築學系
103
This study tested two specimens: An in-filled masonry panel with a door opening in a reinforced concrete (RC) frame called specimen ID, and a bare RC frame called specimen BF. To reuse the RC frame of specimen ID, we removed the panels after the test. Both specimens were tested under lateral cyclic loading and constant vertical force. Test results show that the panels and columns of specimen ID separated soon after the loading started. The panels were failed in bed-joint sliding. Flexural cracks appeared at both ends of the columns; however, they were not seriously damaged. The columns of specimen BF exhibited double curvature deformation, and failed in flexural mode at maximum load. Comparison between the two specimens shows that the in-filled masonry panels increased the strength and the stiffness if the frame and did not affect the failure mode of the columns. The capacity curves of the columns and panels were calculated independently, and then superposed to get the analytical curve of the whole frame. Comparison with the test result shows that using modified FEMA356 model with the axial force distributed by the axial stiffness ratio to the columns and panels can provide a reasonable estimation.

碩士
國立成功大學
建築學系
104
Four full-scale masonry panels in RC frames were tested to investigate the influence of openings and type of masonry panel on in-plane seismic behavior. Test parameters of specimens were construction method and opening condition. Confined masonry panels failed in diagonal tension, and infilled masonry panels failed in bed-joint sliding. Columns of specimens without opening failed in shear, and columns of specimen with openings were flexural behavior. Behavior of both columns and panels, interaction between column and panel are affected by opening condition and construction method. The maximum strength and initial stiffness is higher for confined specimens and specimens without opening, and the maximum displacement has opposite trend. The experimental results were compared with FEMA 356 and Chen’s model. The capacity curves of panels were superposed on the ones of columns. The results show the distribution of axial force and behavior of columns affect the estimation of maximum strength.

碩士
國立成功大學
建築學系碩博士班
101
ABSTRACT Earthquake damage is a major issue for buildings in Taiwan. However, Different damage evaluation standards and data formats were used by different inspectors, causing misunderstandings in processing damage evaluation of buildings. Therefore, this thesis is aimed at improving and validating a damage evaluation procedure for RC and confined masonry buildings established in former research. The evaluation procedure is a simple check list consists of non-structural component damage, structural components (beam/column/wall) damage, and residual drift. The overall damage state is determined by the severest damage condition checked. Following the former research, questionnaires to professionals are used to study how the evaluation procedure is capable of discriminating moderate damage states. Professionals including architects, structural engineers, and researchers were asked to observe damaged building examples with provided pictures and fill the evaluation form, but determine the overall damage state according to their subjective judgment. Another damage state is determined by the author in accordance with the filled form. The accuracy and applicability of the evaluation procedure is then studied by comparing the form-determined damage state and the subjectively judged result. RC building examples with RC walls were added in this research. An internet-based questionnaire platform is established to reduce the paperwork and enlarge the number of evaluators. A lecture on earthquake damage for the evaluators was performed to study the effect of training in advance of damage evaluation. The questionnaire result shows that the form-determined and subjectively judged damage states are close, and the form-determined one is lightly stricter. The form-determined damage states shows less difference between professionals from different back grounds than the subjectively judged ones. However, the training in advance of the damage evaluation shows little effect on the result. A few building examples has larger dispersion in the form-determined damage states than in the subjectively judged ones. The questionnaire answers for these buildings were thoroughly examined. Most of the errors are found to come from the misunderstanding of the evaluators, such as mistaken crack width and misidentification for member types. Since the errors did not come from the procedure itself, the evaluation procedure is not majorly modified, only the division for residual story drift is changed to correspond with the damage evaluation procedure by the Construction and Planning Agency. A blank space is also added for recording special damage condition that is not covered in the check list. The modified evaluation procedure is then validated by comparing with in-situ pushover tests of school buildings and shaking table tests of one-third scale RC building specimens. It is found that the divisions between damage states in the in-situ specimens are usually showed at larger drift than in the shaking table specimens. The main reason is the lack of crack width and residual drift data in the in-situ tests. The evaluation procedure by the Construction and Planning Agency is also used to evaluate the specimens. Good agreement is found in the results from both procedures. Keywords: earthquake damage, damage evaluation, reinforced concrete, confined masonry

碩士
國立成功大學
建築學系
105
This paper presents the results of in-plane loading tests for in-filled masonry panels with eccentric openings. The specimens included two full-scale masonry panels with eccentric door and window openings, respectively. An additional specimen with a door opening was retrofitted using a new method. All specimens were tested under a combination of constant vertical loading and cyclic lateral loading with controlled displacement. The experimental results showed that diagonal cracks occurred on all specimens, but the locations of the cracks were affected by the windowsills. Diagonal cracks occurred on retrofitted specimen in the two directions due to the constraint of retrofit elements. The independent column with door openings exhibited flexure-shear failure, and the adjoining column failed in shear. Due to the increased of shear capacity on the columns for the retrofitted specimen, shear failure occurred earlier then did ID-e-1.8. The columns with window openings exhibited shear failure due to short-column effect. Specimen IW-e-1.8 showed a much higher maximum strength but lower deformation capacity than that of ID-e-1.8. While the retrofitted specimen ID-e-1.8R showed a much higher maximum strength and displacement but lower stiffness than those of ID-e-1.8. When analyzing with Chen’s model, if the suggested axial load distribution and column analyzing method were used, the analytical curves would be similar to but slightly underestimated comparing to the experimental curves. All of the specimens met the criteria except for specimen ID-e-1.8R, which its failure mode of the columns is different from the actual circumstances. The FEMA 356 model cannot be used to evaluate the strength contribution of the panels, and is thus not applicable to this study. SPOCC can be used to analyze the behavior of bare frames accurately estimate maximum strength and displacement.

碩士
國立成功大學
建築學系
105
Two full-scale confined masonry (CM) panels in RC frames were tested under lateral cyclic load and constant vertical force simultaneously to expore the influence of opening type of masonry panel on in-plane seismic behavior. Test parameters of specimens were opening condition. Thus, two types of openings are proposed：eccentric door and window opening. The test results show that the specimens had asymmetric behavior under cyclic loading. Both masonry panels failed in bed-joint sliding when the loading was pushing. Adjoining columns of specimens failed in shear, and independent columns of specimens failed in shear after they exhibited flexural strength. The windowsill here did not show to affect the panel behavior, but precipitated short-column effect to the frame and inhibited the deformation capacity. Comparing with prevailing analytical models, Chuang’s model can conservatively forecast the envelope curve after appropriately modification and Chen’s model overestimated the contribution of panels apparently whatever the distribution of axial force and behavior of columns.

The issue of the influence of masonry infills within RC frames structures have been widely investigated in the last decades by several researchers. The large interest addressed to this topic depends on the actual observation that when in presence of seismic events the response of framed structures is strongly conditioned by the interaction with the infills, which however are considered as non-structural elements and not included in the models. The influence of masonry infills in structural response is so much relevant to affect not only the overall strength and the stiffness but it may radically change the possible collapse mechanisms of the structural complex under the effect of strong ground motions. Infills panels may thus have a beneficial effect on the structural response, being able in some cases to supply the lack of resistance of structures to lateral actions, or an adverse contribution inducing unexpected and dangerous non ductile collapse mechanisms. However the studies carried out on this topic have demonstrated that, independently from the beneficial or adverse contribution of masonry infills on structural response, their presence cannot be neglected in structural modelling both in design and verification phases. As more deeply discussed in this thesis, several modelling approaches have been developed to represent infill-frame interaction, going from refined nonlinear FEM approaches to simplified equivalent strut models. Especially the use of equivalent braced strut approach is pointed out in this work because of its simplicity in and the low computational effort required, which make this technique a predictive tool that is particularly attractive to perform complex nonlinear analyses of large buildings. As base reference of the modelling techniques developed in this thesis a large experimental campaign has been carried out and is presented in Chapter 2. The experimental investigation dealt with the cyclic behaviour of RC frame infilled with different kinds of masonry among the most employed in the worldwide building traditions. The results of this experimental campaign have been fundamental not only to enlarge the experimental knowledge but also for the further processes of calibration and comparison of the proposed models and predictive strategies. The research topics followed in this work regarded 3 fundamental aspects of the infill-frame interaction problem. The first is the calibration of the equivalent strut model, being able to overcome the difficulties in identification of the hysteretic parameters required by the models available in literature. The model makes use of a hysteretic “pivot” law needing few mechanical parameters for the identification and based on geometric rules rather than analytical. The study has shown that despite the simplicity of the model, it is able to provide an adequate accuracy to represent the cyclic hysteretic response of infilled frames. A second topic investigated in this thesis regarded the issue of the local interaction between infills and RC members. The panels are in fact able to attract a large portion of the lateral actions during earthquakes that can be however supported by the frame members if the latter have an adequate transversal reinforcing. The equivalent strut approach is unable to provide information about the additional shear demand arising on beams and column ends, therefore the study was addressed to fill this predictive lack. This was provided by means of a deep parametric study associated with the results of a detailed nonlinear FE analysis. This allowed to define abcorrelation between a geometrical-mechanical parameter identifying the infilled frame system and the shear demand on the beam and column critical end sections. The last topic was developed during a visiting period at University of California - San Diego and regarded the updating of the equivalent strut model able to predict simultaneously the in plane – out of plane response of an infilled frame and the reciprocal damaging in when seismic events occur. The equivalent struts have been modelled by means of fiber elements with distributed plasticity, able to reproduce the arching mechanism developed by the masonry panels confined by the RC frames in presence of out of plane actions. An identification procedure for the definition of an interacting in plane – out of plane model has been developed and validated on experimental basis.