Effect of opening on strength characteristics of reinforced concrete dapped ends beams

Abstract

This study is devoted to investigate experimentally the ultimate strength capacity performance of seven dapped ends simply supported reinforced concrete beams with a (length, height, and width) dimension of (1200, 240, and 130) mm, either solid cross section or top/bottom hollow opening/s. One-point load test method results a different crack patterns of multi types of failure with varying intensity. It is found that the beams strength capacity values with openings less than the solid beams by 5-10%, while the deflection values of solid cross section beam contrary increased by 11-30%. Also, for the same location of opening the increase in hollow openings reduce the capacity load by 4.5-10%, but increase the deflection values by 6-12.5%. Finally, the beams with opening located at the compression zone decrease the load capacity and increase the deflection values by 5% than the beams with opening at tension zone. Therefore, this study handed to the civil engineering designer using the dapped ends beams in bridge construction structures under effect of static loads, “for the necessary purposes of installing power supply cable or water pipe, the authors recommended using beams with opening to be located at bottom fiber tension zone”.