Reliability analysis of shear strength of reinforced concrete deep beams using NLFEA: Fid-Bau Portal

Reliability analysis of shear strength of reinforced concrete deep beams using NLFEA

Sanabria Díaz, Rafael A. / Sarmiento Nova, Silvia J. / Teixeira da Silva, Maria C.A. / Mouta Trautwein, Leandro / de Almeida, Luiz C.

Abstract

Highlights • This work investigates the safety level of a deep beam originally designed using the strut-and-tie model. • A methodology is proposed and tested coupling NLFEA and reliability methods for the structural safety assessment. • The probability of failure and the reliability index are obtained using RSM. • A sensitivity analysis is carry out to identify the key parameters for a deep beam reliability assessment.

Abstract Nonlinear finite element analysis (NLFEA) is an important tool for solving deterministic structural problems and predicting the behavior of concrete structures. Nevertheless, inherent uncertainties in structural engineering cannot be considered using deterministic approaches. For that reason, the inclusion of reliability concepts in NLFEA has been a frequent subject in recent investigations. This work aims to study the safety of the design of reinforced concrete deep beams. This is done by coupling the finite element analysis and reliability theory approaches. The assessment of the shear capacity of deep beams involves different phenomenons such as discontinuity regions and size effect. Therefore, this cannot be designed or analyzed by simple calculations. In this study, a simply supported deep beam designed with the strut-and-tie method (STM) is used as an example of structural reliability assessment. The nonlinear analyses were performed in the software ATENA, based on concrete fracture and plasticity theory. For reducing computational effort, the reliability analysis was performed using two different Response Surface Method (RSM) strategies. Uncertainties from concrete properties and geometrical dimensions were considered using probability density functions. As a result, the safety of the deep beam design was expressed in terms of the reliability index $β$ and the probability of failure $P_{f}$ . According to the results obtained, the conclusion was that NLFEA combined with the reliability theory concept can allow an advanced safety assessment of deep beam design.