Rozprawy doktorskie na temat „RCC BUILDING”

A Construção Civil é um dos setores que mais consomem matérias-primas e também gera resíduos sólidos urbanos. É importante, que se consuma menos matérias-primas e que sejam aproveitados estes resíduos gerados. Uma das propostas para esta situação seria reciclar estes resíduos e transformá-los em agregados e filers, para então usá-los na produção de concretos. Ainda se encontram muitas barreiras para utilização destes agregados e filers em concretos, com e sem função estrutural e, dentre os principais motivos está a dificuldade de se alcançar resistências similares as dos concretos produzidos com matérias-primas naturais. Devido a este fato, foi proposto um estudo para analisar a influência do empacotamento de partículas nos agregados reciclados e ainda verificar a possibilidade de uso do filer de pó do polimento das placas de concreto para revestimento de piso. Inicialmente foram caracterizados dois lotes de agregados reciclados e apenas o de resíduo de concreto (ARC) foi considerado adequado para o estudo. Foram propostos três planejamentos experimentais compostos por mistura simplex com 4 fatores das misturas, contendo além dos agregados, filer e cimento Portland CP-V. Foram realizados estudos sobre as massas unitárias das amostras, para cada um dos planejamentos, considerando toda a faixa granulométrica, e também, amostras sem o material passante pela peneira com abertura de 0,150 mm. A quantidade de água foi determinada pelo consistômetro de Vebe, e a partir deste dado foi calculado o excesso de pasta. Após a obtenção dos corpos de prova, sob vibrocompactação, foi determinado o comportamento da resistência mecânica e da absorção de água. A análise dos resultados mostrou que o melhor empacotamento de partículas dos agregados ocorre na faixa de 42% a 58% de pedrisco. O filer utilizado em grandes quantidades, aumenta significativamente o consumo de água de amassamento e o de excesso de pasta, e por consequência, o aumento da absorção de água e perda de resistência do concreto seco. Entretanto, em quantidades menores que o volume de poros, a inclusão do filer é aceitável, pois não há afastamento das partículas. Conclui-se que, na faixa granulométrica estudada não houve alteração de resistência mecânica, sendo o fator preponderante a concentração de cimento. As resistências à compressão observadas mostram que estes agregados podem ser utilizados na fabricação de artefatos de concreto, como por exemplo, produção de blocos de vedação.<br>Civil Construction is one of the sectors that consumes the rawest materials and also generates municipal solid waste. It is important that less raw materials are consumed and that waste generated is used. One of the proposals for this situation would be to recycle these wastes and turn them into aggregates and filers and then use them in the production of concrete. There are still many barriers to the use of these aggregates and filers in concrete, with and without structural function, and among the main reasons is the difficulty of achieving similar resistance to concrete produced with natural raw materials. Due to this fact, a study was proposed to analyze the influence of the packing of particles in the recycled aggregates and to verify the possibility of using the filter of powder of the polishing of the concrete plates for floor covering. Initially, two batches of recycled aggregates were characterized and only that of concrete residue was considered adequate for the study. Three experimental schedules were proposed, composed of 4 factors of the mixtures, plus the aggregates, filer and Portland cement CP-V. Samples were analyzed for the sample masses, considering the entire grain size range, as well as samples without material passing through the sieve with a 0.150 mm opening. The amount of water was determined by the Vebe consist meter, and from this data, the excess paste was calculated. After the test specimens were obtained, under vibrarocompaction, the behavior of the mechanical resistance and the water absorption were determined. The analysis of the results showed that the best packaging of particles of the aggregates occurs in the range of 42% to 58% of hail. The filer used in large quantities significantly increases the consumption of kneading water and excess paste, and consequently, increased water absorption and loss of strength of dry concrete. However, in smaller amounts than the pore volume, the inclusion of the filer is acceptable, since there is no separation of the particles. It was concluded that in the granulometric range studied, there was no change in mechanical strength, being the preponderant factor the concentration of cement. The observed compressive strengths show that these aggregates can be used in the manufacture of concrete artifacts, such as the production of sealing blocks.

The aim of this research study is to investigate the vulnerability of the building heritage in Gorizia, a town in north-eastern Italy, on the border with Slovenia. This town has not been considered seismic until the year 2003 and then in 2010 it has been classified in a higher seismicity class. For this reason, most of the buildings are not designed to resist seismic action at all and an even lower percentage fulfils the requirements of the current technical standard. Four real existing buildings are analysed as case study buildings, representative of the main structural types that can be found in the town. Two of them are high - rise (11 and 12 storeys) reinforced concrete (RC) framed buildings with a brittle concrete stairwell, designed for gravitational load only and built in the 60’s-70’s. In the last years, a growing attention has been payed to the seismic vulnerability of existing RC framed structures, but this type of buildings, with a core of concrete walls, has been investigated much less, although it is a structural type that is very spread. The other two case studies are masonry buildings built in 1740 and in 1903, respectively. One of the masonry buildings is the city hall of Gorizia, on which many in-situ tests have been performed within a project of the Department of Engineering and Architecture with the Municipality of Gorizia. For both RC buildings, some considerations are made about the influence of the masonry infills on the seismic behaviour of the building and of the numerical model. The vibration periods found with numerical modelling are also compared to the periods evaluated with vibrational measurements. The two numerical models without infills are then analysed with non-linear static and dynamic analyses. The results are processed with a cloud analysis in order to calculate fragility curves of the buildings, that show a very brittle behaviour. The two masonry buildings are analysed also with pushover analysis. For the evaluation of the seismic vulnerability of the analysed buildings, two types of seismic hazard assessments have been considered for the extraction of the seismic inputs: Probabilistic Seismic Hazard Assessment (PSHA) method, by the Italian code response spectra and Neo Deterministic Seismic Hazard Assessment (NDSHA) method, with response spectra of two specific possible scenarios for the town of Gorizia. The physics-based scenarios are calculated for the two faults that are the closest to Gorizia: Idrija and Medea. A comparison is made between the demand given by the seismic inputs defined with the two methods. The importance of using both methods for the design of low-damage retrofitting solutions is highlighted. At last, a theoretical study has been carried out within the present research study in order to find an innovative and effective solution for the retrofit of the RC high-rise brittle buildings. It consists in the application of an exo - or endo - skeleton, with the additional introduction of a sliding system at the base of the RC building, in order to decouple its motion from the ground motion. In this way, the exo- or endo-skeleton can be designed independently from the features of the existing building, that remains undamaged. The characteristics of the exo/endo-skeleton can be calibrated on the seismic input of the site of interest, with the possibility to adapt it to new seismic classifications of the territory.<br>The aim of this research study is to investigate the vulnerability of the building heritage in Gorizia, a town in north-eastern Italy, on the border with Slovenia. This town has not been considered seismic until the year 2003 and then in 2010 it has been classified in a higher seismicity class. For this reason, most of the buildings are not designed to resist seismic action at all and an even lower percentage fulfils the requirements of the current technical standard. Four real existing buildings are analysed as case study buildings, representative of the main structural types that can be found in the town. Two of them are high - rise (11 and 12 storeys) reinforced concrete (RC) framed buildings with a brittle concrete stairwell, designed for gravitational load only and built in the 60’s-70’s. In the last years, a growing attention has been payed to the seismic vulnerability of existing RC framed structures, but this type of buildings, with a core of concrete walls, has been investigated much less, although it is a structural type that is very spread. The other two case studies are masonry buildings built in 1740 and in 1903, respectively. One of the masonry buildings is the city hall of Gorizia, on which many in-situ tests have been performed within a project of the Department of Engineering and Architecture with the Municipality of Gorizia. For both RC buildings, some considerations are made about the influence of the masonry infills on the seismic behaviour of the building and of the numerical model. The vibration periods found with numerical modelling are also compared to the periods evaluated with vibrational measurements. The two numerical models without infills are then analysed with non-linear static and dynamic analyses. The results are processed with a cloud analysis in order to calculate fragility curves of the buildings, that show a very brittle behaviour. The two masonry buildings are analysed also with pushover analysis. For the evaluation of the seismic vulnerability of the analysed buildings, two types of seismic hazard assessments have been considered for the extraction of the seismic inputs: Probabilistic Seismic Hazard Assessment (PSHA) method, by the Italian code response spectra and Neo Deterministic Seismic Hazard Assessment (NDSHA) method, with response spectra of two specific possible scenarios for the town of Gorizia. The physics-based scenarios are calculated for the two faults that are the closest to Gorizia: Idrija and Medea. A comparison is made between the demand given by the seismic inputs defined with the two methods. The importance of using both methods for the design of low-damage retrofitting solutions is highlighted. At last, a theoretical study has been carried out within the present research study in order to find an innovative and effective solution for the retrofit of the RC high-rise brittle buildings. It consists in the application of an exo - or endo - skeleton, with the additional introduction of a sliding system at the base of the RC building, in order to decouple its motion from the ground motion. In this way, the exo- or endo-skeleton can be designed independently from the features of the existing building, that remains undamaged. The characteristics of the exo/endo-skeleton can be calibrated on the seismic input of the site of interest, with the possibility to adapt it to new seismic classifications of the territory.

Analysis of the collapse of a precast r.c. industrial building during the 2012 Emilia earthquake, focus on the failure mechanisms in particular on the flexure-shear interactions. Analysis performed by a time history analysis using a FEM model with the software SAP2000. Finally a reconstruction of the collapse on the basis of the numerical data coming from the strength capacity of the elements failed, using formulation for lightly reinforced columns with high shear and bending moment.

Solitamente le tamponature vengono trascurate nella modellazione delle strutture a telaio in cemento armato e solamente il loro contributo in termini di massa viene preso in considerazione, assumendo che la resistenza e la rigidezza delle stesse non influiscano sulla risposta strutturale. Questa pratica è supportata dal fatto che (i) generalmente allo stato limite ultimo le tamponature si considerano completamente danneggiate e, quindi, il loro contributo in termini di rigidezza è trascurabile, mentre (ii) allo stato limite di danno il valore dello spostamento di interpiano, ottenuto trascurando il contributo di rigidezza delle tamponature, può essere considerato a favore di sicurezza. Tuttavia, per edifici di importanza strategica, quali scuole, ospedali, caserme delle forze dell’ordine e dei Vigili del Fuoco, è cruciale preservare le tamponature da qualsiasi danno, anche per terremoti di entità severa, in modo da garantire il normale utilizzo dell’edificio durante la gestione dell’emergenza. Inoltre, questi edifici a volte sono sismicamente protetti con sistemi e dispositivi (smorzatori, isolatori, ecc…) il cui progetto richiede che sia tenuto in considerazione il reale comportamento dinamico della struttura (in termini di frequenze e/o spostamenti e/o velocità). Per questo diventa cruciale modellare accuratamente l’intera struttura, includendo le tamponature, e validare questo modello così ottenuto sulla base dell’evidenza sperimentale. La tipologia delle pareti e le loro procedure costruttive sono fonte di incertezze nella modellazione delle interazioni tra la struttura e gli elementi non strutturali. Quindi, una valutazione sperimentale delle proprietà di rigidezza dei pannelli di tamponatura potrebbe essere molto utile per valutare, all’interno del modello strutturale adottato per il progetto, il contributo in termini di rigidezza fornito alla struttura in c.a. da questi elementi non strutturali. In questa tesi viene presentata una procedura per realizzare modelli globali agli elementi finiti accurati di edifici a telaio in c.a. tamponati, basandosi su risultati ottenuti da analisi modali sperimentali e operative sviluppate rispettivamente su elementi non strutturali e sull’intero edificio. In particolare, sono stati eseguiti test di impatto con martello strumentato su pareti omogenee per identificarne i parametri modali (frequenze e forme modali) e per stimarne le proprietà meccaniche. Dopo di che, le tamponature sono state inserite nel modello strutturale globale agli elementi finiti, i cui parametri modali vengono confrontati con quelli derivanti da analisi modali operative basate su misurazioni di vibrazioni ambientali per valutarne l’accuratezza. In seguito, è stata condotta una campagna sperimentale su tre provini di tamponatura costruiti all’interno del Laboratorio di Prove di Materiali e Strutture della Facoltà di Ingegneria dell’Università Politecnica delle Marche. Questi provini sono stati realizzati con l’intento di riprodurre le caratteristiche di alcune delle tamponature testate in sito e su di essi vengono svolte prove sia dinamiche che statiche. Innanzi tutto, sono stati effettuati test ad impatto con martello strumentato per investigarne il comportamento dinamico fuori dal piano; successivamente sono state svolte prove di spinta laterale per investigare il comportamento statico nel piano dei pannelli soggetti a bassi livelli di forze orizzontali. I risultati sperimentali ottenuti sono stati utilizzati per calibrare modelli agli elementi finiti dei provini al fine di valutare l’esattezza delle proprietà meccaniche delle tamponature stimate in precedenza e secondo diversi approcci.<br>Infill walls are commonly disregarded in the modelling of reinforced concrete (r.c.) frame structures and only their contribution in terms of mass is taken into account assuming that resistance and stiffness do not affect the structural response. This practice is supported by the fact that (i) at ultimate limit state infill walls are usually considered to be completely damaged, so that their contribution is negligible in terms of stiffness, while (ii) at the damage limitation limit state the value of the interstorey drift, obtained by neglecting the infill walls stiffness contribution, is commonly considered to be conservative. However, for strategic buildings, such as schools, hospitals, police and fire stations, it is crucial to preserve the infill walls from any damage, even for severe earthquake, in order to guarantee the building occupancy during the emergency management. Furthermore, these buildings are sometimes seismically protected with system and devices (dampers, isolators, etc…) whose design requires the real dynamic behaviour of the structure (in terms of frequencies and/or displacements and/or velocities) to be considered. To this purpose, it becomes crucial to accurately model the entire structure, including infill walls, and to validate this model on the basis of experimental evidences. The wall typology and the construction procedures are source of uncertainties in modelling interactions between structural and non-structural components. Thus, an experimental evaluation of the stiffness properties of the wall infill panel could be very useful to assess the stiffening contribution added by the infill masonry walls to the concrete frame in the structural model adopted for the design. In this thesis is presented a procedure for developing accurate global finite element (f.e.) models of infilled r.c. frame buildings based on results of experimental an operational modal analysis of non-structural components and of the whole buildings. In particular, impact load tests with an instrumented hammer are performed on homogeneous wall panels to identify the modal parameters (frequency and mode shapes) and to estimate the mechanical properties of the masonry walls. Afterwards, the infill walls are included in the f.e. structural model, whose modal parameters are compared with those derived with operational modal analysis based on ambient vibration measurements. Furthermore, an experimental campaign on three specimens of infill masonry walls built in the Laboratory of Materials and Structures of the Faculty of Engineering at the Università Politecnica delle Marche is conducted. These specimens are built with the target to reproduce the features of some of the in situ investigated infill walls and are tested both dynamically and statically. First of all, impact load tests with an instrumented hammer are performed to investigate the out of plane dynamic behaviour of these walls; then, lateral load tests are carried out to investigate the in plane static behaviour of the panel under low level of lateral forces. The experimental results obtained are used to calibrate f.e. models of the specimens with the aim to evaluate the reliability of the masonry mechanical properties estimated through different approaches.

Apesar de ser uma grande geradora de impactos ambientais devido ao grande consumo de matéria-prima e da grande geração de resíduos, a Construção Civil é reconhecida como uma das mais importantes atividades para o desenvolvimento econômico e social do país. Nos países desenvolvidos, a geração de RCD nas obras de demolição entre os anos de 1994 a 1999 variava entre 32 e 99 ton/ano. O que não difere muito do Brasil, que em 2005, através de pesquisas em 11 Municípios, observou-se uma geração de resíduos com média de 59% também, provenientes de obras de reforma, ampliação e demolição. O Município de Petrolina localizado em pleno sertão Pernambucano, atualmente, tem uma população de 268.339 habitantes e ainda não possui um sistema de gerenciamento de RCD, conforme preceitua a Resolução n. 307 do CONAMA (2002). Visando contribuir com o estudo desta problemática, a presente dissertação realiza um diagnóstico dos RCD do Município verificando sua potencialidade de reciclabilidade. A pesquisa constitui de um trabalho de campo de natureza exploratória e descritiva que visa identificar os materiais descartados pela indústria da construção civil de 10(dez) empresas geradoras de RCD, bem como identificar, para efeito de estudos de impacto ambiental, 11(onze) pontos de deposição irregular de RCD e a possível reutilização desses materiais. Os resultados demonstraram que 91,2% dos materiais são resíduos classe A, com potencial de reciclabilidade, tendo em vista os descartes de materiais cerâmicos representar no total da amostra 45,5% de todo o material observado, seguido de argamassas com (23,6%), de concreto (14,1%) e da areia (8,0%), ficando os 8,8% restantes destinados ao descartes de plásticos, gesso e madeira. Apesar da falta de uma destinação adequada, tanto as empresas quanto o Poder Público do referido município, tentam se adequar ao que determina a Resolução 307, em especial, no que se refere ao beneficiamento dos RCD, implantando uma usina de reciclagem no aterro remediado Raso da Catarina, proporcionando assim, emprego e renda à população. Esta pesquisa também propõe ações futuras que poderão colaborar na realização de estudos de viabilidade técnica utilizando agregados de RCD na produção de agregados para pavimentação, confecção de blocos sem função estrutural, peças para o meio fio, entre outros, beneficiando a população e o Município de Petrolina<br>Besides the fact that it is the cause of some environmental impact due to the great consumption of raw material and generation of residues, construction engineering is recognized as one amongst the most important activities that contributes to the economic and social development of our country. Within underdevelopment countries the generation of CDW (Construction and Demolition waste) in demolition works between the years 94-99 varied from 32 to 99 tons/year. CDW in Brazil is not different. In 2005, a research carried in 11 municipalities showed that the medium CDW was 59% as well. The municipality of Petrolina is located in the arid backlands of the state Pernambuco, the current population is 268,339 and still doesnt own a system for management of the CDW as required in the resolution 307 of CONAMA(2002) (National Council for Environmental Issues). Willing to contribute to the solving of this problem, the present dissertation brings a survey of variability of CDW in the municipality of Petrolina and verifies its recycling potential. The research is based on exploratory and descriptive field work and aims to identify the varied waste material discarded through the work of ten civil engineering companies and also to identify 11(eleven) points of irregular discard and the possible re-use of the discarded material. Results show that 91, 2% of residues are class A, waste with recycling potential. 45, 5% of the waste is ceramic, 23, 6% is mortar, 14, 1% is concrete and 8% is sand. The other 8, 8% are discard of wood, plastic and plaster. Despite the lack of place for disposal, private and governmental companies try to adjust themselves to what is required in resolution 307, specially regarding to recycling of CDW.There have been implemented a recycling industry in a disposal area called Raso da Catarina therefore providing jobs for the population. The present work of study also suggests some future action that may collaborate in studies for the use of CDW aggregates for paving, blocks with non-structural function and pieces for sidewalk, benefitting population and municipality as a whole

With the outlook of improving seismic vulnerability assessment for the city of Bishkek (Kyrgyzstan), the global dynamic behaviour of four nine-storey r.c. large-panel buildings in elastic regime is studied. The four buildings were built during the Soviet era within a serial production system. Since they all belong to the same series, they have very similar geometries both in plan and in height. Firstly, ambient vibration measurements are performed in the four buildings. The data analysis composed of discrete Fourier transform, modal analysis (frequency domain decomposition) and deconvolution interferometry, yields the modal characteristics and an estimate of the linear impulse response function for the structures of the four buildings. Then, finite element models are set up for all four buildings and the results of the numerical modal analysis are compared with the experimental ones. The numerical models are finally calibrated considering the first three global modes and their results match the experimental ones with an error of less then 20%.