EXPERIMENTAL STUDY OF SHEAR BEHAVIOR OF SHALLOW WIDE BEAMS

Abstract

Shallow wide beams are considered a simple solution to avoid architectural constrains in the design of buildings. Using shallow wide beams also gives time saving in construction due to simplicity of formwork and reinforcement placement that means more economy can be achieved, so that engineers prefer using it. The ECP 203-2007 requires that the applied shear strength in the shallow wide beams be less than the concrete shear strength without any shear reinforcement contribution, and the shear strength provided by concrete for shallow wide beams equals two thirds of the concrete shear strength of shallow projected beams. Consequently, large cross-sectional areas of the concrete shall be provided for these members to resist shear demands, which seem uneconomic conservative design provisions. The above-mentioned requirements by the Egyptian Code were not found in most recognized international codes or standards. The objective of the research was to study the influence of specific parameters on the shear behavior of shallow wide beams, and to determine the contribution of web shear reinforcement to shear strength. The studied parameters are volumetric ratio of vertical stirrups, concrete compressive strength, and specimen width. The experimental program consisted of fifteen simply supported reinforced concrete shallow wide beams subjected to two concentrated loads to examine the above-mentioned parameters. A comparison between the observed shear capacities of beams and the calculated values using ECP 203-2007, ACI 318-11, and CSA A23.3-04 shear provisions was also presented in the research. Based on the results of the current experimental program, it is recommended that the ECP 203 code is to consider the contribution of steel shear reinforcement (vertical stirrups) in the calculation of shear strength of shallow wide beams.