Synopsis
This paper presents the results of an experimental study on the shear behaviour of reinforced concrete beams with circular pre-cast web openings. 11 simply supported reinforced concrete beams, with and without web openings located in the shear zone of the beams, were tested using a fourpoint loading procedure. Test variables included size of the web openings, horizontal location of the web openings and shear span to effective depth ratio. The test results showed an almost linear reduction of the ultimate strength of the beams with increasing size of the web openings. The most critical location for the web openings was found to be in the centre of the shear zones where the critical load path directly crosses the web openings. The shear span to effective depth ratio was also found to influence the structural performance and strength of the beams. The results of the experiments are compared with ACI code based predictions.