Flexural behaviour of hollow reinforced concrete continuous beams reinforced with GFRP bars

Hollow sections have been widely used in structures for passing both the electrical and mechanical utilities, they also allow beams to simply cross one another. This paper investigates the flexural behaviour of hollow RC continuous beams reinforced with GFRP bars that symmetrically subjected to two point loading conditions. It depends on both numerical and analytical studies applying one previously validated control beam with solid section and ten other beams having a hollow core. The study also employed ABAQUS to investigate the influence of the hollow core shape, size and location on the flexural response of continuous RC beams. While the numerical model accurately predicted the studied beam response, the analytical study conducted to develop or modify existing equations taking into account the area and position of holes. Consequently, it determined the maximum load and moment at pre-cracking and post-cracking stages of the RC hollow beams. Study results revealed the cracking load; ultimate load and deflection. Results showed that both the numerical and analytical results were close to each other in case of cracking and ultimate loads. In addition, both the solid and hollow beams behaved similarly at the initial stages of loading. Thus, the maximum load of the hollow RC continuous beams decreased by (1.8–32) % based on the shape, size and the location of the hollow core within the beam length. In conclusion, the best location to introduce a hollow core, according to the study, should be within the neutral axis zone of the cross-section of the beam.