RELIABILITY ANALYSIS OF COMPOSITE STEEL-CONCRETE SLABS DESIGNED IN ACCORDANCE WITH ABNT NBR 8800:2008

Resumo

This paper presents a study on the reliability of composite steel-concrete slabs designed
according to ABNT NBR 8800:2008 (Design of steel and composite structures for buildings) for
longitudinal shear failure mode. For the calculation of the shear resistance, according to m-k method,
results of bending tests were used. The probabilistic models of the random variables considered in the
analysis were found in the literature, except for the model error variable for longitudinal shear
resistance, which was determined from a base of experimental studies. The reliability indexes were
obtained through the Monte Carlo Simulation (MCS) and the First Order Reliability Method (FORM),
implemented in MATLAB®, for several composite slabs configurations and combinations of actions.
In addition, the influence of geometric parameter variation on reliability was evaluated. Regarding the
partial safety factor for longitudinal shear, the ABNT NBR 8800:2008 recommends that it to be equal
to that determined by the specification used in the bending tests, so a comparison was made between
the safety levels recommended by EUROCODE 4 Part 1-1:2004 (Design of composite steel and
concrete structures) and CSSBI S2:2008 (Criteria for the testing of composite slabs).