Typescript (photocopy).

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 61-70). Also available via the Internet.

Thesis--Otaniemi. / Thesis statement for v. C. Vol. A has summary in English. Includes bibliographical references.

An analytical investigation was conducted to study the behavior of a bottom flange bearing beam-to girder connection subjected to patch loading. This connection would be useful with deep deck (thickness greater than 3 in.) composite slabs as well as with commonly used deck where floor-to-floor height needs to be minimized. Five girder specimens were loaded until yielding during the initial phase of the research. The analysis section consists of the yield line theory and finite element study that were used to develop a model to predict the collapse loads of the girder sections. These results from the model were then compared to the experimental loads. A design procedure utilizing the proposed model and future work recommendations are then presented. / Master of Science

O objetivo principal deste trabalho é apresentar uma associação dos cálculos elástico e plástico, para análise de lajes-cogumelo. Foram considerados painéis retangulares, com carregamento uniformemente distribuído. O cálculo elástico é utilizado como pré-dimensionamento, fornecendo a razão entre os momentos de vão e permitindo a fixação dos momentos de plastificação negativos. O cálculo plástico é feito através da Teoria das Charneiras Plásticas, que é utilizada na obtenção dos momentos de plastificação, com os quais é feito o dimensionamento. Também se apresentam dois exemplos completos, para comparar os resultados do cálculo elástico com aqueles relativos ao procedimento ora proposto. O cálculo elástico foi feito através do Processo dos Pórticos Equivalentes. Não houve diferença significativa entre os resultados obtidos com os dois processos, para os exemplos considerados. Novas pesquisas são sugeridas para aprimorar o procedimento proposto. / The main aim of this work is to present an association of elastic plate theory and plastic analysis, to beamless slabs (flat slabs and flat plates) analysis. Rectangular panels uniformly loaded were considered. Elastic plate theory is used to predimensioning, determining the relation between positive bending moments and permiting to fix the ultimate negative moments of resistance. Plastic analysis is made by Yield Line Theory, that is used to obtain ultimate moments of resistance, which are used in dimensioning. Two complete examples are also presented, to compare results of elastic plate theory with those relative to proposed proceeding. Elastic calculus is made by Equivalent Frame Method. There was not significant difference between results obtained with the two processes in the considered examples. New researches are suggested in order to perfect proposed proceeding.

O objetivo principal deste trabalho é apresentar uma associação dos cálculos elástico e plástico, para análise de lajes-cogumelo. Foram considerados painéis retangulares, com carregamento uniformemente distribuído. O cálculo elástico é utilizado como pré-dimensionamento, fornecendo a razão entre os momentos de vão e permitindo a fixação dos momentos de plastificação negativos. O cálculo plástico é feito através da Teoria das Charneiras Plásticas, que é utilizada na obtenção dos momentos de plastificação, com os quais é feito o dimensionamento. Também se apresentam dois exemplos completos, para comparar os resultados do cálculo elástico com aqueles relativos ao procedimento ora proposto. O cálculo elástico foi feito através do Processo dos Pórticos Equivalentes. Não houve diferença significativa entre os resultados obtidos com os dois processos, para os exemplos considerados. Novas pesquisas são sugeridas para aprimorar o procedimento proposto. / The main aim of this work is to present an association of elastic plate theory and plastic analysis, to beamless slabs (flat slabs and flat plates) analysis. Rectangular panels uniformly loaded were considered. Elastic plate theory is used to predimensioning, determining the relation between positive bending moments and permiting to fix the ultimate negative moments of resistance. Plastic analysis is made by Yield Line Theory, that is used to obtain ultimate moments of resistance, which are used in dimensioning. Two complete examples are also presented, to compare results of elastic plate theory with those relative to proposed proceeding. Elastic calculus is made by Equivalent Frame Method. There was not significant difference between results obtained with the two processes in the considered examples. New researches are suggested in order to perfect proposed proceeding.

Este trabalho apresenta uma associação dos cálculos elástico e plástico, para lajes retangulares com carga uniforme e uma borda livre. O cálculo elástico é usado para pré-dimensionamento, na determinação dos momentos negativos e da razão dos momentos positivos nas duas direções. Esses momentos fletores são obtidos através de funções aproximadoras, determinadas a partir de tabelas. Após compatibilização dos momentos elásticos, são adotados os momentos de plastificação negativos, sendo os positivos obtidos através da teoria das chameiras plásticas, que é utilizada também no cálculo do comprimento das barras sobre os apoios. Conhecidas as armaduras, os momentos elásticos são novamente utilizados na verificação das flechas. Nos exemplos são comparadas as armaduras do cálculo elástico com as obtidas através do cálculo plástico, no qual se pôde constatar a economia deste último em relação ao primeiro. / This work presents an association of elastic and plastic analysis, for rectangular slabs with uniform load and a free edge. The elatic theory is used to estimate the negative moments and the relation between positive moments in the two directions. These bending moments are obtained from approached functions, based on tables. After compatibilization of elastic moments, the negative plastic moments are adopted and the positive moments are obtained from yield line theory, which will be used again in the calculation of the lenght of the bars over the supports. Once the reinforcements are known, the elastic moments are used again for checking the deflexions. In the examples, the results of elastic plate theory are compared with those obtained by plastic analysis, where it is possible to evidence the economy of the later over the former.

Throughout the United States accelerated bridge construction is becoming increasingly popular to meet growing transportation demands while keeping construction time and costs to a minimum. This research focuses on eliminating the need to form full-depth concrete bridge deck overhangs, accelerating the construction of concrete bridge decks, by using full-depth precast prestressed concrete deck panels. Full-depth precast overhang panels in combination with cast-in-place (CIP) reinforced concrete are experimentally and analytically investigated to assess the structural performance. Experimental loaddeformation behavior for factored AASHTO LRFD design load limits is examined followed by the collapse capacity of the panel-to-panel seam that exists in the system. Adequate strength and stiffness of the proposed full-depth panels deem the design safe for implementation for the Rock Creek Bridge in Fort Worth, Texas. New failure theories are derived for interior and exterior bridge deck spans as present code-based predictions provide poor estimates of the ultimate capacity. A compound shear-flexure failure occurs at interior bays between the CIP topping and stay-in-place (SIP) panel. Overhang failure loads are characterized as a mixed failure of flexure on the loaded panel and shear at the panel-to-panel seam. Based on these results design recommendations are presented to optimize the reinforcing steel layout used in concrete bridge decks.

Este trabalho apresenta uma associação dos cálculos elástico e plástico, para lajes retangulares com carga uniforme e uma borda livre. O cálculo elástico é usado para pré-dimensionamento, na determinação dos momentos negativos e da razão dos momentos positivos nas duas direções. Esses momentos fletores são obtidos através de funções aproximadoras, determinadas a partir de tabelas. Após compatibilização dos momentos elásticos, são adotados os momentos de plastificação negativos, sendo os positivos obtidos através da teoria das chameiras plásticas, que é utilizada também no cálculo do comprimento das barras sobre os apoios. Conhecidas as armaduras, os momentos elásticos são novamente utilizados na verificação das flechas. Nos exemplos são comparadas as armaduras do cálculo elástico com as obtidas através do cálculo plástico, no qual se pôde constatar a economia deste último em relação ao primeiro. / This work presents an association of elastic and plastic analysis, for rectangular slabs with uniform load and a free edge. The elatic theory is used to estimate the negative moments and the relation between positive moments in the two directions. These bending moments are obtained from approached functions, based on tables. After compatibilization of elastic moments, the negative plastic moments are adopted and the positive moments are obtained from yield line theory, which will be used again in the calculation of the lenght of the bars over the supports. Once the reinforcements are known, the elastic moments are used again for checking the deflexions. In the examples, the results of elastic plate theory are compared with those obtained by plastic analysis, where it is possible to evidence the economy of the later over the former.

Three full-scale experimental tests were conducted to investigate the strength and stiffness of weak-axis moment end-plate connections. Each test consisted of two girders connected to a column web with four-bolt extended moment end-plates. Two tests were conducted with bare steel. One test included a composite concrete slab that confined the top extension of the end-plate. Finite element models of the tests were created with the commercial software SAP2000. A simplified modeling procedure was developed to overcome the contact problems between the end-plates and column web, and between the bolts and holes in the end-plates and web. The simplified modeling procedure accurately predicted the experimental elastic stiffness, in the form of column web rotations, of the connections. Yield line theory was used to investigate the plastic strength of the column web. Several yield line patterns were examined. Analytical plastic moment strengths were very conservative when compared to the observed behavior of the column web. The experimental stiffness of the test with the concrete slab confining the top extension of the end-plate was compared to the stiffness of a similar test without a slab. The slab increased the elastic stiffness of the connection; however, after the concrete began cracking and crushing around the connection, the stiffness was greatly decreased. / Master of Science