钢筋浆锚搭接连接高温后性能试验研究

Experimental research on connection performance of restraint grouting-anchoring overlap-joint of steel bar after high temperature

为了研究高温后钢筋浆锚搭接连接的受力性能,采用恒温后自然冷却的方式,对18个钢筋浆锚搭接连接试件进行了高温后单向加载试验。钢筋直径有12 mm、14 mm、16 mm等3种,试件采用了1.0基本锚固长度(la),设置常温、200℃、300℃、400℃、500℃和600℃等6种不同温度。获得了不同温度不同钢筋直径试件的破坏形态、试件荷载-位移曲线、极限荷载随温度变化关系。试验结果表明:常温下,具有1.0倍基本锚固长度的钢筋浆锚搭接连接试件,钢筋断于外部,连接性能可靠;300℃以下高温作用后,极限承载力稍有增加,400℃至600℃高温后,极限承载力出现下降;常温至500℃高温后,钢筋断于外部,600℃高温后,12 mm试件钢筋断于内部,16 mm试件发生粘结滑移破坏,破坏曲线呈现出延性特征。

In order to investigate the mechanical properties of restraint grouting-anchoring overlap-joint of steel bars after high temperature,18 specimens were tested under the uniaxial loading after high temperature by means of natural cooling after the constant temperature.The diameter of steel bar is 12 mm,14 mm and 16 mm.The specimen adopts 1.0 basic anchoring length and is set at six different temperatures:normal temperature,200℃,300℃,400℃,500℃and 600℃.The failure modes,load-displacement curves and the relationship between ultimate load and temperature of specimens with different temperatures and different steel bar diameters are obtained.Experimental results indicate that the restraint grouting-anchoring overlap-joint of steel bar with 1.0 times the basic anchoring length is broken outside,thus the connection performance is reliable at normal temperature.The ultimate bearing capacity slightly increases after the high temperature below 300℃,and decreases after the high temperature from 400℃to 600℃.After normal temperature to high temperature of 500℃,the steel bar of joint is broken outside,after high temperature of 600℃,the steel bar of 12 mm specimen is broken inside,and the bond slip failure occurs on 16mm specimen,and the failure curve shows ductile characteristics.