Bielas e tirantes

Advances in Reliability Analysis of Strut-and-Tie Models Applied in Reinforced Concrete Structures based on Experimental Results
J.C. PANTOJA
Professor, Universidade Federal Fluminense, Rio de Janeiro-UFF, Brazil

L.E. VAZ
Professor, Universidade Federal Fluminense, Rio de Janeiro-UFF, Brazil

L.F. MARTHA
Professor, Pontifícia Universidade Católica do Rio de Janeiro-PUC Rio, Brazil

J.N. LIMA
Professor, Centro Universitário de Brasília, Brasília-UNICEUB, Brazil

ABSTRACT: This paper shows a methodology for reliability analysis of reinforced concrete structures applying the strut-and-tie models based on experimental results. FORM and Crude Monte Carlo formulations are used to calculate the reliability index and probability of failure of modes, considering both safety and ductile behavior of the strut-and-tie model. A large number of experimental results obtained by others researches are used for calibration of model uncertainties factors applied during reliability analysis. An example of design of a deep beam using reliability analysis for validation of safety and ductility aspects is presented. 1. INTRODUCTION Some provisions in ACI 318-05 have applied strut-and-tie concepts in the design of deep beams. Using these concepts, the designer is capable of predicting the load capacity of many types of deep beams. However, experimental results demonstrate that the actual behavior of a reinforced concrete component and its prediction using ACI code are quite different. Collins and Kuchma (1999) showed experimentally that ACI code overestimated the shear capacity of reinforced concrete deep beams having large sections and small reinforced ratios. Therefore, it is necessary to investigate possible ways to surpass these difficulties. The main objective of this paper is to present a reliability criterion for analysis and design of deep beams using the strut-and-tie model. This approach permits that all kind of uncertainties present in problems of structural