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

• Published in: Engineering structures 2020-01, Vol.203, p.109760, Article 109760
• Main Authors: Sanabria Díaz, Rafael A., Sarmiento Nova, Silvia J., Teixeira da Silva, Maria C.A., Mouta Trautwein, Leandro, de Almeida, Luiz C.
• Format: Article
• Language: English
• Subjects: Computer applications; Concrete; Concrete structures; Concrete technology; Deep beams; Design; Finite element analysis; Finite element method; Finite elements; Mathematical analysis; Nonlinear analysis; Occupational safety; Probability density functions; Reinforced concrete; Reliability; Reliability analysis; Reliability engineering; Response surface methodology; Safety; Shear; Shear strength; Size effects; Software reliability; Structural engineering; Structural reliability; Strut and tie models; Uncertainty
• ISSN: 0141-0296; 1873-7323
• DOI: 10.1016/j.engstruct.2019.109760

•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. 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 Pf. 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.