BFRP格栅增强地聚物混凝土三明治墙受压性能

Compression behavior of BFRP grid reinforced geopolymer concrete sandwich insulation wall

为了分析BFRP格栅增强地聚物混凝土三明治保温墙的轴心受压性能与面外偏压性能,分别对6面BFRP格栅增强地聚物混凝土三明治墙、1面BFRP筋地聚物混凝土三明治墙和1面钢筋混凝土三明治墙的受压性能进行试验研究,分析面外偏压荷载的偏心距、长细比、增强材料类型和混凝土类型对三明治墙的破坏形态、荷载-变形曲线、受压承载力和应变发展的影响。基于现有规范中实心墙的轴压和稳定临界力计算公式,提出三明治夹心墙轴压和平面外稳定临界力计算公式,并基于平截面假定和条带法近似计算三明治墙的偏压承载力。研究结果表明:BFRP格栅增强地聚物混凝土三明治墙的轴压力学特性与BFRP筋地聚物混凝土三明治墙的类似,但由于BFRP材料具有较低的弹性模量,二者对混凝土三明治墙轴压承载力的增强作用比普通钢筋的低。当面外偏心距分别为30 mm和90 mm时,高度为2100 mm的BFRP格栅增强地聚物混凝土三明治墙的偏压承载力相比于轴压试件分别降低24.6%和68.8%;高度为3300 mm的BFRP格栅增强地聚物混凝土三明治墙的偏压承载力相比于轴压试件分别降低21.6%和74.3%。当墙体高度从2100 mm增大到3300 mm时,轴压三明治墙体以及面外偏心距分别为30 mm和90 mm的三明治墙体的受压承载力分别降低21.2%,18.1%和35.0%;本文提出的偏压承载力计算方法对小偏压试件有较高的计算精度,而对大偏压试件偏压承载力的计算精度有待进一步提高。

To analyze the axial compression performance and out-of-plane eccentric compression performance of BFRP grid reinforced geopolymer concrete sandwich insulation walls(GCSIWs),six BFRP grid reinforced GCSIWs,one BFRP bar reinforced GCSIW and one steel bar reinforced concrete sandwich wall were tested.The influences of eccentricity of out-of-plane load,slenderness ratio,reinforcement material and concrete types on the failure mode,load-deformation curve,compressive capacity and strain development of sandwich wall were investigated.Based on the existing calculation formulas for the axial compression and critical load of solid wall in the code,the design formulas for the axial compression and out-of-plane stability of sandwich wall were proposed.Finally,based on the assumption of plane section and strip method,the eccentric compression bearing capacity of sandwich wall was approximately calculated.The results show that the mechanical properties of BFRP grid reinforced GCSIW under axial compression are similar to those of BFRP bars reinforced GCSIW.Due to the lower elastic modulus of BFRP material,the enhancement of axial compression capacity of BFRP reinforced on GCSIW is lower than that of steel bar reinforced on concrete sandwich wall.When the out-of-plane eccentricity is 30 mm and 90 mm,the compressive bearing capacities of 2100 mm high are reduced by 24.6%and 68.8%compared with the corresponding axial compression specimens,and those of 3300 mm high BFRP grid reinforced GCSIWs are reduced by 21.6%and 74.3%,respectively.When the height of the wall increases from 2100 mm to 3300 mm,the bearing capacities of the sandwich wall under axial compression,and the sandwich walls with eccentric distance of 30 mm and 90 mm decrease by 21.2%,18.1%and 35.0%,respectively.The proposed calculation method for the eccentric compression bearing capacity has better accuracy for small eccentric compression specimens,while the calculation accuracy for large eccentric compression specimens needs to be further improved.