Thesis (M.A.Sc.)--University of Ottawa, 2007. / Copyright date: 2008. Includes bibliographies.

Death of firefighters due to structural collapse has been on the rise for the past few years, and has not gone unnoticed by the research and firefighting branches of the industry. However, the modes for improving this situation by both are very different. While firefighters depend on experience for detection, research organizations have invested in developing new technology to detect signs of structural collapse. Thus far neither effort has led to any improvement in the current circumstances. In order to bridge this gap, members of the fire-safety community need to more thoroughly understand the reasons for structural collapse due to fire. Through research and analysis, a case study manual analyzing structural steel failures due to fire was developed. This manual contains analysis of the actual mode of failure for the cases chosen, as well as analysis of alternative situations for each case that may have led to different outcomes. The goal of this manual is to aid in the teaching and practice of structural steel collapse due to fire as a supplement to current knowledge.

Reinforced concrete buildings may be vulnerable to progressive collapse due to a lack of continuous reinforcement. Progressive collapse is an extreme form of collapse that is disproportionate to the originating cause. Such collapses cause not only significant damage to buildings, but also greater loss of life and injuries. Carbon fiber reinforced polymer (CFRP) may be used to retrofit existing reinforced concrete beams and provide the missing continuity needed to resist progressive collapse. This research focuses on retrofitting the beams in a reinforced concrete building to provide sufficient continuity to reach catenary action. The catenary action may allow the beam to carry vertical loads at large displacements if a supporting column were removed. The CFRP can provide continuity through the negative moment reinforcement or through the positive moment reinforcement. The research was broken into three major components. Anchorage tests form the design basis of the CFRP retrofit and ensure that the capacity of the retrofit can be accurately predicted. Continuity tests determine if the CFRP retrofit is capable of providing continuity and if the retrofit will allow the beam to reach catenary action and sustain a load representing resistance to progressive collapse. The analysis model forms a set of equations for catenary action so the results can be applied to reinforced concrete beams in general. Forty anchorage tests, eight continuity tests, and one analysis model were constructed and evaluated. The anchorage tests found that carbon fiber anchors enabled improved utilization of the tensile capacity of a CFRP sheet and improved the efficiency of material usage in CFRP retrofits. The continuity tests found that beams without continuous reinforcement can reach catenary action (depending on design details) and a CFRP retrofit, if designed correctly (placed in locations that do not cause rebar fracture before catenary), may be able to reduce vulnerability to progressive collapse. The analysis model was able to accurately predict the load-deflection behavior of a reinforced concrete beam in catenary action. The overall conclusion is that a CFRP retrofit can reduce vulnerability to progressive collapse in reinforced concrete buildings. / text

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Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

Thesis (PhD (Civil Engineering))--Stellenbosch University, 1986. / ENGLISH ABSTRACT: This dissertation presents the development process of a wind damage and disaster management support model for South Africa. Several aspects of wind damage are analysed. The impact of wind disasters on human habitat is highlighted by providing selected data of loss due to such events. This is followed by a comprehensive review of relevant research, carried out locally and internationally. The role and relevance of wind loading codification is discussed. The factors influencing wind damage are identified and their applicability to South African conditions is evaluated. An outline of a database of wind damage in South Africa which has been developed during the course of the project is presented. Selected statistics derived from this database are presented. A probabilistic model for assessing wind damage in South Africa is proposed. The model is based on the spatial principle of occurrence of strong wind events. A 'first approximation' division of the country into zones where various types of wind events occur and the characteristics of their generic footprints (i.e. distribution of wind speeds) are developed. The risk model procedure also takes the distribution of wealth, and the vulnerability of the built environment into account. / AFRIKAANSE OPSOMMING: Hierdie verhandeling bied die ontwikkelingsproses vir 'n hulpmodel vir windskade en rampbestuur vir Suid-Afrika aan. Verskeie aspekte van windskade word ontleed. Die invloed van windskade op woongebiede word beklemtoon deur die aanbieding van geselekteerde data oor relevante plaaslike en internasionale navorsing. Die rol en toepaslikheid van windbelasting in ontwerpkodes word bespreek. Die faktore wat windskade beinvloed, word geidentifiseer en die aanwendbaarheid onder Suid-Afrikaanse omstandighede word beoordeel. 'n Beskrywing van n databasis vir windskade in Suid'-Afrika, wat tydens die projek saamgestel is, word aangebied. Sekere statistiek wat uit die databasis afgelei is, word voorgelê. n Statistiese model vir die beraming van windskade in Suid-Afrika word voorgestel. Die model is gebaseer op die ruimtelike beginsel van voorkoms van sterk-wind-gebeurlikhede. 'n "Eerste benadering" - indeling van die land in streke waar verskillende soorte windgebeurlikhede voorkom en hulle karakteristieke kenmerke (bv. verspreiding van windspoed) is ontwikkel. Die werkwyse vir die risikomodel neem die verdeling van rykdom en die kwesbaarheid van die beboude omgewing in ag.

The Best PhD Thesis in the Faculties of Architecture, Arts, Business & Economics, Education, Law and Social Sciences (University of Hong Kong), Li Ka Shing Prize, 2005-2006. / published_or_final_version / abstract / Real Estate and Construction / Doctoral / Doctor of Philosophy

A special problem in many reinforced concrete structures built in the 1970s and earlier is the lack of continuity between elements. Continuity is a characteristic of structures essential to preventing collapse. Therefore, in extreme loading conditions such as loss of a column support due to terrorist attack or if earthquake or other extreme actions occur, the structures could be vulnerable to collapse. The study reported here focused on two structural discontinuities in existing reinforced concrete structures, discontinuity in bottom reinforcement in beams (horizontal discontinuity) and poorly detailed lap splices in columns (vertical discontinuity). The objective of this study was to develop rehabilitation methods using CFRP to provide continuity of reinforcement in existing structures. To develop the rehabilitation methods, two separate experimental studies were conducted using beam and column specimens. CFRP materials were applied to the bottom or side face of a beam and anchored using CFRP anchors or U-wraps to provide horizontal continuity in bottom reinforcement and tested under dynamic loading. After CFRP rehabilitation, the ductility of the bottom reinforcement and large rotational capacity of the beam were realized. CFRP materials were also applied to the lap splice region in square and rectangular columns which exhibited a brittle splice failure as-built. After rehabilitating the columns using CFRP jackets and anchors, the failure mode changed from a brittle splice failure to yield of column reinforcement, and the strength and deformation capacity were improved under both monotonic and cyclic loading. Based on the results of beam and column tests, design guidelines for CFRP rehabilitation were proposed. Horizontal and vertical continuities can be provided through the use of CFRP for rehabilitating existing reinforced concrete structures that were designed prior to the introduction of codes that require continuous reinforcement along members and between adjacent members. The vulnerability of such structures to collapse can be reduced through rehabilitation. / text

Procurando conhecer o grau de deterioração precoce das estruturas de concreto armado dos edifícios residenciais da Região Metropolitana da Cidade do Recife, Estado de Pernambuco, este trabalho visa, utilizando um método de quantificação dos danos e o uso de ensaios, avaliar as patologias das estruturas estudadas. Estudou-se três edifícios residenciais (ER), com semelhante padrão de construção, idades construtivas aproximadas e inseridos em diferentes classes de agressividade ambiental. Foi realizada inspeção visual e ensaios em amostras dos pilares, vigas, lajes e reservatório inferior do subsolo dos três edifícios. Após análise dos três edifícios, verificou-se que o caso ER 1, localizado em classe ambiental de agressividade forte (III), a mais agredida pelo meio ambiente, e o estudo de caso ER 2, localizado a uma distância significativa da orla marinha em Classe de Agressividade Ambiental II, apresentaram grau de deterioração media (GD) de 36,98 e 31,23 respectivamente, com recomendação para inspeção periódica e intervenção a médio prazo. Já o estudo de caso ER 3, que está localizado dentro da uma classe de agressividade forte (III), em orla marinha, porém com barreiras de proteção que evitam a incidência direta da névoa salina, encontra-se com alto grau de deterioração (GD = 103,94), sugerindo uma intervenção imediata com riscos de colapso / This work aims to evaluate the pathology of residential buildings structures located at the Metropolitan Region of Recife, Brazil using the quantification of damages to measure the degree of early deterioration of reinforced concrete. Three residential buildings (RB) with similar construction standards were studied. All buildings have approximate age and are inserted into environmental aggressiveness distinct. A visual inspection took place as well as a laboratorial sample analysis of their pillars, beams and underground water reservatories. It was verified that the RB1 case, located at a high environmental aggressiveness class (III), and the RB2 case, located significatively far from the sea and classified with a moderate environmental aggressiveness class (II), both presented a medium degree of deterioration (GDE). For both buildings it is suggested a periodic inspection recommendation and a medium term intervention (GD 1 = 36,98 ; GD 2 = 31,23). The third case (RB3), located at a high environmental aggressiveness class (III) and seafront with protection barriers, presented a high degree of deterioration (GD 3=103,94). It is suggested for RB3 an immediate intervention with collapse risks