Abstract
To investigate the residual shear capacity of post-fire bolted side-plated (BSP) reinforced concrete (RC) beams with different depths of steel plate and types of anchor adhesive, i.e., magnesium oxychloride cement (MOC) and HIT-RE500, a control beam and five BSP beams were fabricated, of which two were exposed to fire in accordance with ISO834 temperature curve. Four-point bending shear tests were conducted to investigate the influence of elevated temperature on the failure mode, cracking load, shear capacity, stiffness, ductility and strain development, etc. The shear capacities of RC beams were found to be improved significantly by using the BSP technique. However, the stiffness of BSP beams was seriously degraded after exposed to fire, but the reduction in shear capacity was negligible, whereas the ductility and the strain of longitudinal reinforcement were obviously increased. Thus, the failure-mode was changed from shear failure to flexural failure. Regarding the adhesive mortar used for bolt anchorage, magnesium oxychloride cement (MOC) achieved higher shear capacity and better ductility but lower stiffness for BSP beams compared with HIT-RE500. Additionally, increasing the depth of bolted steel plates effectively improved the shear performance of BSP beams. In the tests, uneven relative slips were observed on the plate-RC interface due to the shear deformation of bolt shafts and the plates’ tensile principal stress perpendicular to the main diagonal crack, which proved the deformation lag of the bolted steel plates with respect to the RC beam. The outcomes of this study provide a better understanding on the shear performance of BSP beams at room temperatures and at fire conditions.
Highlights
Comprehensive methods can be employed to increase the bear capacity of reinforced concrete (RC) structures, such as structural retrofitting [1,2,3,4] and the use of high-performance materials [5,6,7,8,9,10,11,12,13,14,15]
The letter “P” and the following number represent the depth of steel plates in decimeters, the letter “B” and the subsequent number represent the bolt spacing in decimeters, while the letters “magnesium oxychloride cement (MOC)” means the bolted side-plating (BSP) beams were anchored by MOC adhesive mortar and “T” indicates the specimens were tested after being exposed to fire
The shear performance of BSP beams and their post-fire performance have been investigated based on four-point-bending shear tests after exposure to fires
Summary
Comprehensive methods can be employed to increase the bear capacity of reinforced concrete (RC) structures, such as structural retrofitting [1,2,3,4] and the use of high-performance materials [5,6,7,8,9,10,11,12,13,14,15]. Li et al [34,35,36,37,38,39,40] conducted comprehensive experimental, numerical and theoretical studies on the BSP technique, and found that the flexural strength, shear strength, stiffness and ductility of RC beams could be effectively improved. Most existing studies are focused on the flexural performance of BSP beams, studies on the shear behaviour are still limited: Barnes et al [41] compared the shear strengthening effect of fixing steel plates to the side faces of RC beams by using adhesive bonding or bolting. The letter “P” and the following number represent the depth of steel plates in decimeters, the letter “B” and the subsequent number represent the bolt spacing in decimeters, while the letters “MOC” means the BSP beams were anchored by MOC adhesive mortar and “T” indicates the specimens were tested after being exposed to fire. The number and the horizon spacing of the anchor bolts decreased in the pure bending zone, because in this area, both the transfer of shear and longitudinal stress between the bolted steel plates and the RC beams were fairly low, fewer anchor bolts were needed
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
