近爆荷载作用下装配式钢筋混凝土柱抗爆性能及受损加固试验研究

Experimental study on blast resistance performance and damage repair of precast concrete column under close-in explosion

为研究近爆荷载作用下装配式钢筋混凝土(precast concrete,PC)柱的抗爆性能与受损后的加固修复性能,开展了足尺PC柱化爆试验与受损柱加固修复轴压试验研究。共开展了3次化爆试验,获得了PC柱的动力响应与损伤破坏试验数据,分析了PC柱与现浇钢筋混凝土(reinforced concrete,RC)柱试验结果的差异。近爆荷载作用下,PC柱呈现出局部损伤破坏模式,爆心附近混凝土剥落,出现斜裂缝,装配位置的交界面出现贯穿裂缝,锚浆搭接PC柱比灌浆套筒PC柱的损伤更加严重。两种装配形式的PC柱整体上具有与RC柱相近的抗爆性能,但装配界面削弱了PC柱的整体性与抗剪切能力,是PC柱典型的薄弱位置。轴压试验结果表明,分别采用置换混凝土和置换后外包碳纤维增强复合材料(carbon fiber reinforcement polymer,CFRP)布的方式加固受损的两根PC柱,其轴向承载力均超过了同规格未受损柱的试验承载力和设计承载力。

In order to investigate the anti-explosion performance and post-blast performance after reinforcement/repair of precast concrete(PC)columns under close-in explosion,the explosion test of full-scale PC column and axial compression test of repaired blast-induced damage PC column were conducted.The PC columns with the two widely used assembly connections,i.e.,half grout sleeve connection and slurry anchor lap connection,were selected to investigate the effect of connection type on blast resistance and to compare the damage and dynamic response with the reinforced concrete(RC)column of the same specification.The explosion test results show that PC columns had a local damage failure mode.The concrete spalling and oblique cracks occurred near the explosion center and penetrating cracks appeared on the interface of the assembly position.The damage of the anchor slurry lapped PC column was more severe than the grouting sleeve PC column.The PC columns of the two assembly forms had comparable dynamic response and damage characteristics as the RC column in general,but the assembly interface weakened the integrity and shear resistance of the PC column because of its discontinuity.It is the typical weak position of the PC column and should be noticed in design and protection.The axial compression test results show that the axial bearing capacity of the PC column repaired by concrete replacement exceeds 20.8%and 30.6%compared to the undamaged column test value and the calculated value of the same specification respectively.The exceeding proportion of the PC column repaired by concrete replacement and wrapping carbon fiber reinforcement polymer(CFRP)sheet is 38.3%and 49.6%respectively.The results show that it is feasible to reinforce and repair the damaged PC column using the concrete replacement or combining concrete replacement with the wrapping CFRP sheet method,which can meet the requirements of axial bearing capacity.