Doctoral Thesis
DOI
https://doi.org/10.11606/T.18.2001.tde-18072006-151221
Document
Author
Full name
Edgar Bacarji
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Carlos, 2001
Supervisor
Committee
Venturini, Wilson Sergio (President)
Noronha, Marcos Aurelio Marques
Proenca, Sergio Persival Baroncini
Ribeiro, Gabriel de Oliveira
Savassi, Walter
Title in Portuguese
Aplicação do método dos elementos de contorno à análise de pavimentos de edifícios
Keywords in Portuguese
análise de pavimentos de edifícios
elementos de contorno
Abstract in Portuguese
Title in English
Application of the boundary element method to slab floor analysis
Keywords in English
and concrete slab floor
boundary elements
physical nonlinearities
Abstract in English
This work deals with a formulation of the boundary element method applied to slab floor analysis with special emphasis concrete flat slabs exhibiting physical non-linearities. In this formulation normal and shear components of the stress tensor are taken into account to capture more accurately the ultimate strength of the structural element. The boundary element formulation in the context of Reissners plate bending theory is initially studied. Then, the formulation is extended to deal with combinations of plate elements with other elements such as beams and columns and also to incorporate internal support effects, for which full contact is assumed over small areas. The plate-beam and plate-column interaction model is based on a combination with the finite element method. Thus, this model allows an accurate evaluation of the internal forces along the plate-linear element interfaces and also over its vicinity. The presence of possible initial moment fields is also taken into account, which enables us to consider physical non-linear behaviours. The solution of the nonlinear system of algebraic equations is based on an iterative algorithm with constant matrix. In order to obtain a better modelling of the reinforced concrete slabs, the stress integrals along the thickness are performed with an appropriate gauss scheme; the reinforcement contribution is computed by considering concentrated effects at its geometric centre. Thus, the concrete degradation and the steel yielding can be independently evaluated. To represent the concrete behaviour the Mazars damage model has been adopted, while the steel material is governed by a uniaxial elastoplastic criterion with isotropic hardening. After the initial cracking of the concrete the shear stresses are properly transferred to the shear reinforcement using the Mörsch truss concept. The accuracy of the proposed formulation is illustrated by the analysing some practical examples. The results obtained are compared with experimental results and other numerical technique solutions