Failure mechanism and strategies for analyzing the one-way shear strength and punching capacity in one-way slabs under combinations of concentrated loads

Abstract

Bridge slabs present a particular behavior in shear since both failures as a beam over a certain effective shear width as the punching shear can occur in these elements when subjected to concentrated loads. In this aspect, it is observed that most studies that address the topic have investigated the problem through reduced-scale tests with slabs subjected to only one partially distributed or concentrated load close to the support. However, this type of approach may not adequately represent aspects such as the size effect existing in thicker slabs and the superposition of stresses caused by the combination of concentrated loads on bridge slabs. For this reason, this study proposes to investigate the one-way shear and punching shear capacity of thicker slabs when subjected to combinations of concentrated loads, a situation most representative of stresses in bridges. To achieve this, we first intend to validate a numerical modeling strategy, based on the finite element method, to represent: (i) large-thickness one-way slabs greater than 50 cm, which presented shear failure with a significant size effect, ( ii) large-thickness flat slabs that failed due to punching or two-way shear and (iii) one-way slabs subjected to single concentrated loads with different shear failure mechanisms. Subsequently, after validating the modeling strategy to represent the different shear failure mechanisms and the size effect in these structures, we intend to (i) explore the level of accuracy of the proposed modeling strategy to represent the few tests available in the literature that deal with the combination of concentrated loads on one-way slabs and (ii) investigate the effect of parameters such as the position, spacing, and number of wheels from the design truck on the shear strength of the slabs. With this, the aim is to develop a database of numerical results that will be used to calibrate analytical approaches to verify the one-way shear strength and punching capacity for one-way slabs subjected to combinations of concentrated loads. In other words, the study intends to use advanced numerical simulation tools to support the development of practical recommendations for checking the resistance to shear force and punching of bridges. Furthermore, this project aims to subsidize improvements in the research infrastructure of the Faculty of Engineering of Ilha Solteira (UNESP/FEIS) and promote the training of human resources in this institution's postgraduate programs. (AU)