Experimental research on the bearing capacity of RC beam during heating and cooling process under pre-loading
In order to study the change of bearing capacity of reinforced concrete beams after fire in service,7 reinforced concrete(RC)beams were tested under high temperature and loading.The temperature in the beam,the ultimate bending moment,and the ultimate deflection of the beams were tested at 250 ℃,450 ℃ and 650 ℃.The influences of temperature and cooling mode on the bearing capacity of preloaded beam were analyzed.The results show that,under the pre-loading 39％ultimate bending moment,with the increase of heating temperature,the ultimate bending moment of the naturally cooled beam decreased to 96.45％,93.41％and 91.38％of that of the beam at room temperature.The ultimate bending moment of the beam cooled by water spray gradually decreases to 96.45％,95.69％and 94.68％of the beam at room temperature.When the ultimate bending moment in middle span of the beam is reached,the deflections of heated beams increase gradually with the increase of temperature,and the deflections of naturally cooling beams are 10.03 mm,16.11 mm and 22.32 mm respectively after being subjected to 250 ℃,450 ℃ and 650 ℃.The deflection of the water spraying cooling beam are 15.89 mm,16.63 mm and 17.43 mm respectively.The higher the temperature the preloaded beam is subjected to,the more their bearing capacity decreased.
pre-loadingheating and cooling processRC beamsmechanical properties
万方数据
维普
