Beams non Linear Analysis from Envelope Concept

Resumo

The heterogeneous nature of the Portland cement concrete promotes its irregular mechanical
behavior. Due to the shrinkage deformations, the mass of concrete presents cracks, even before loading. Such
material exhibit non linear performance since the stress level around 30% of its compressive strength, and, in this
way, some researchers developed mathematical models designed to describe that kind of mechanical
phenomenon. A model proposed by Branson, is especially useful to analyze reinforced concrete beams from
beam finite elements resulting, consequently, computational effort economy. It is known that, in some cases, it
may be suitable to carry out continuous beam analysis considering several loading arrangement, culminating
over a bend moments envelope. Preliminary comparative studies made over continuous beam, considering the
bend moments due to full load and bend moments envelope drafted from different load arrangement alternatives
show remarkable differences between these two kinds of analyses versions. The purpose of this work is to report
the nonlinear mechanical performance limit analysis of reinforced concrete continuous beams considering,
include, the bend moments envelope. To accomplish such a subject, a computational code was developed, based
on the finite element approach, applied upon the Branson’s formulation.