Effect of Large Openings on the Behavior of Reinforced Concrete Continuous Deep Beams under Static and Repeated Load

Mohammed R Khalaf,Ali Hussein A Al-Ahmed,M Karkush,M Fattah,D Choudhury

doi:10.1051/e3sconf/202131803012

Abstract

This paper aims to investigate the behavior of the existence of large openings on reinforced concrete continuous deep beams (RCCDBs) under static and limited cycles of repeated load. The experimental work included testing seven RCCDBs. One of these beams was solid subjected to static load, while the other beams having external shear spans, internal shear spans, and mid-span openings subjected to static and fifteen cycles of repeated loading. The range of the repeated loading was varied between a lower level and an upper level, equal to 30 and 70 percent, respectively, of the ultimate load of the beam subjected to static load. All test specimens were tested under five-point bending. For beams with large openings, 160×160 mm (which represents 40% of the overall depth of the section) openings were created symmetrically at various locations. Experimental results showed that the maximum ultimate loads of beams with large openings were decreased by about 36% for beams with large openings locating at interior shear spans compared to a solid beam. However, the maximum reduction in ultimate load of the beam with a large opening subjected to repeated load was about 6%.

Highlights

In structural engineering experience, reinforced concrete continuous deep beam (RCCDB) is a subject of great interest [1,2,3]
When beams CDB-R-EO, CDB-R-IO, and CDBR-MO compared to beams CDB-M-EO, CDB-M-IO, and CDB-M-MO, the percentages increase in mid-span deflection were about 18, 5, and 18%, respectively at the same load level of ultimate load of beams under repeated load
Large openings in RCCBD lead to a decrease in the ultimate load and an increase in mid-span deflection

Summary

Introduction

In structural engineering experience, reinforced concrete continuous deep beam (RCCDB) is a subject of great interest [1,2,3]. Extensive theoretical and experimental studies of supported deep beams with or without openings over the years, well-established approaches for serviceability design under static loads have developed. Experimental investigations on the behavior of RCCDBs with large openings under five-point load have been carried out on continuous deep beams having large symmetrical openings subjected to static and limited cycles of repeated load. The RCCDBs with openings were tested under static and repeated load. Beam CDB-Solid was tested under static load only. Normal weight concrete with cylindrical compressive strength of about 23 MPa was prPoRduOcD edUfCorEcDasBtiY ngAthNe A teU stTsO peDciEmSeK ns.STThUeDyEieNldTstVreEsR s SION and ultimate strength for steel reinforcement were 510 MPa and 625 MPa, respectively, for bar diameter of 6 mm and 650 MPa and 730 MPa, respectively, for a bar diameter of 12 mm

Ø 6 mm

Findings

Conclusions