Experimental Study On Shear Behavior Of Reinforced Concrete Continuous Beams After Fire

Reinforced Concrete Continuous Beam(RCCB)is an important component that transfers the load of the floor to the column,and plays the role of connecting the column network to form a complete stress and seismic system of the building structure,so it is very important to study the RCCB.After the fire,the RCCB is damaged by fire and cooling,which leads to uneven shrinkage and other complex factors,and may violate the design principle of "strong shear weak bending".It is of great significance to study the shear behavior of RCCB after fire for the identification and repair of RCCB after fire.Nine RCCBs and four simply supported reinforced concrete beams were designed.The temperature rise and fall curves of ISO834 standard were used to raise the temperature of the specimens under constant load,and the shear test under static load was carried out after cooling.The temperature of concrete and reinforcement in reinforced concrete beams,shear capacity after fire,mid span deflection under fire and after fire were collected,and the influence of different test parameters on shear capacity after fire was studied.The results show that the shrinkage of RCCB is not uniform after the fire,resulting in micro cracks in the interior,the decrease of residual shear capacity,ductility and ultimate deflection;the larger the stirrup spacing is,the more obvious the decrease of rigidity of RCCB is,the lower the residual shear capacity is;within a certain range,the greater the protective layer and shear span ratio of RCCB is,the worse the residual shear performance is;The shear capacity of RCCB with water spray cooling is smaller than that with natural cooling;the shear capacity of the single span RCCB with fire is less than that of the double span RCCB with fire;the residual shear capacity of the RCCB after fire is less than that of the reinforced concrete simply supported beam after fire.Figure 85;Table 5;Reference 45...