Analise de paredes de contenção atraves de metodo unidimensional evolutivo : Marcelo Tacitano / Earth-retaining structures analysis with the evolutionary one-dimensional method

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

The retaining structures, usually of wood, steel or concrete, can be constituted by sheet pile wall, piles with lagging, ?in cast? pile walls and diaphragm walls among others and need to be designed, so that they reach the requirements about functionality, execution, safety and economy an appropriate way. It is possible divide the design methods in three great groups. The Empirical Methods that has been based on results of experimental measures, the Semi-Empirical Methods that admit as loading a diagram of earth pressures for both sides of the wall, in each excavation phase, presupposing the displacements and considering the struts and anchorage as fixed supports and, finally, the Analytical Methods that take into account the characteristics of strength and stiffness of the structure and soil and they make possible the evolutionary calculation of internal efforts (strut forces, bending moments and shear forces) as well as the displacements, so the previous phases are taken indeed into account in the calculations of the following phases. Initially a wide bibliographical revision on the methods of calculation of retaining structures is presented. After that, this work adopts as focus the Winkler?s Model, through One-Dimensional Analytical Method that bases the development of the CEDEVE program (Evolutionary Calculation of Displacements and Efforts in Braced Trenches). This program assimilates the wall as a beam of unitary width, being the soil modeled as springs with linear perfectly elastic-plastic behavior including histeresis. Struts and anchorages, of elastic behavior, with or without initials forces, can be introduced in the structure. The actions on the structure occur by the soil pressures, water pressures and eventually overloads in the soil surface. The calculations are performed in agreement with the excavation phases, leaving the actions (soil pressures) and springs corresponding to the dug soil as well as introducing the struts/anchorages, so that the efforts and displacements happened in the previous phases are properly considered in the calculations of the following phases. The process of cover the trench with earth, when it exists, is also considered. A important differential of the CEDEVE program regarding other similar ones is the possibility of the inclusion of the temperature effects in the calculations of the displacements and efforts, and such thermal effects can be considered on the struts, what promotes the tendency of its stretch, that being impeded partially, generates consequent compression and also in the own retaining wall through gradients that induce bending and, therefore, also influencing on the loads on the struts system. A practical and numerical study is done with the intention of validate and verify the CEDEVE program, firstly testing their results with the program SAP 2000 and, after that, comparing the results generated with several other available programs (SPW2003, DEEP and ESTWIN). The effect of the temperature on the struts, calculated by CEDEVE, is compared with some results of available instrumentations in the consulted bibliography. Besides this, a comparative study with some Empirical and Semi-Empirical Methods was done. In general, it is possible to conclude that the Winkler?s Model used in the modeling of the problem generates satisfactory results and its relationship cost benefit is quite attractive in the analysis of retaining structures

ASSUNTO(S)

earth-retaining structures analise matricial excavation interação solo-estrutura non-linear simulation escavação programação não-linear valas structural matrix analysis soil-structure interaction

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