Influence of the Shear Cap Size and Stiffness on the Distribution of Shear Forces in Flat Slabs.

Maciej Grabski,Andrzej Ambroziak

doi:10.3390/ma15010188

Abstract

The scope of this paper is to investigate analytically and numerically the influence of shear cap size and stiffness on the distribution of shear forces in flat slabs in a slab–column-connections-reinforced concrete structure. The effect of support (shear cap) stiffness on the calculation of the length of the shear control perimeter according to the available methods is presented. Based on the analysis, the authors indicate in what range of support stiffness the corner concentrations become important in the calculation of the punching resistance. For shear caps with high flexibility ( ≤ 0.5), the concentration of internal forces in the corners does not occur. The authors compare the numerical results obtained from the calculation methods and indicate the correlations, which can be useful guidance for structural designers. In the case of large shear caps, the simplified MC2010 method gives a significantly lower value of the effective control perimeter length compared to more accurate methods. This paper is intended to provide scientists, civil engineers, and designers with guidelines on which factors influence punching shear load capacity of the slab–column connections with shear caps.

Highlights

One of the key issues in the structural design of slab–column structures is a proper determination of the stress state of a nearby slab with a column connection
The scope of this paper is to investigate analytically and numerically the influence of shear cap size and stiffness on the distribution of shear forces in flat slabs in a slab–column-connectionsreinforced concrete structure
The effect of the support size on the calculation of the length of the effective control perimeter according to the available methods is presented and the results obtained are compared

Summary

Introduction

One of the key issues in the structural design of slab–column structures is a proper determination of the stress state of a nearby slab with a column connection. The European EC2 [33] and international MC2010 [34] standards take into account the degree of reinforcement as one of the parameters determining the shear punching resistance of the slab–column connection Despite these differences, all code methods are based on the control perimeter concept. It seems advisable to analyze the available methods to account for the nonuniform distribution of shear forces in the control perimeter in punching resistance calculations for a situation of the shear cap enhancement. This research presents a unique analytical and numerical analysis of the shear cap size and stiffness influence on the distribution of shear forces in flat slabs in slab–columnconnections for reinforced concrete structures. This paper is intended to provide scientists, civil engineers, and designers with guidelines on which factors influence punching shear load capacity of slab–column connections with shear caps

Shear Flow in the Slabs

Performed Analysis

Results of Numerical Analysis

Findings

Conclusions