钢管混凝土边框钢纤维混凝土中高剪力墙受弯承载力计算方法

Calculation method for bending capacity of steel fiber reinforced concrete mid-rise shear wall with concrete-filled steel tubular columns

为改善中高剪力墙的抗震性能,提出钢管混凝土边框钢纤维混凝土剪力墙。通过8个剪跨比为1.5的钢管混凝土边框钢纤维混凝土中高剪力墙和1个剪跨比为1.5的钢管混凝土边框混凝土中高剪力墙的低周反复加载试验,研究钢管混凝土边框钢纤维混凝土中高剪力墙的受力机理及破坏模式,分析钢纤维体积率、钢纤维掺加高度、混凝土强度和轴压比对其抗震性能的影响。结果表明:钢管混凝土边框钢纤维混凝土中高剪力墙的破坏模式为弯曲破坏;墙体裂缝主要为典型的弯剪裂缝,钢纤维可有效限制剪力墙裂缝宽度,改善裂缝形态;随着钢纤维体积率和钢纤维掺加高度的增大,剪力墙受弯承载力、延性和耗能能力明显提高;其他参数相同的条件下,钢纤维体积率为0.5%、1.0%和1.5%剪力墙受弯承载力较未掺钢纤维剪力墙的分别提高了8.8%、14.2%和21.8%;随着混凝土强度和轴压比的提高,剪力墙受弯承载力和耗能能力明显提高,但延性降低;其他参数相同的条件下,钢纤维混凝土强度等级为C60、C80剪力墙的受弯承载力较C40剪力墙的分别提高了21.9%和39.7%;轴压比为0.2剪力墙的受弯承载力较轴压比0.1剪力墙的提高了13.5%。基于剪力墙受弯破坏特点,明确钢管和钢纤维对剪力墙受弯承载力的贡献,建立钢管混凝土边框钢纤维混凝土中高剪力墙受弯承载力计算方法,计算值与试验值偏差基本控制在10%以内,吻合较好。

In order to improve the seismic behavior of mid-rise shear wall,the steel fiber reinforced concrete shear wall with concrete-filled steel tube columns was proposed.By testing eight steel fiber reinforced concrete mid-rise shear walls with concrete-filled steel tubular columns with a shear span ratio 1.5 and one reinforced concrete mid-rise shear walls with concrete-filled steel tubular columns with a shear span ratio 1.5 under reversed cyclic loading,the mechanical characteristics and failure mode of the considered shear walls were investigated.The effects of key factors,such as the volume fraction of steel fibers,the depth of steel fiber reinforced concrete layer,the concrete strength and the axial compression ratio,on the seismic behavior of the shear walls were studied.The results show that the fundamental failure mode of steel fiber reinforced concrete mid-rise shear walls with concrete-filled steel tubular columns is bending failure.All the specimens mainly exhibit a typical bending-shear cracking pattern during the testing process,and the steel fiber can effectively control the crack width and improve the distribution shape of cracks.The bending capacity,ductility and energy dissipation capacity are obviously improved with the increase in the volume fraction of steel fibers or the depth of steel fiber reinforced concrete layer.Compared with the shear wall without steel fibers,the bending capacities of the walls with steel fibers of a volume fraction of 0.5%,1.0%and 1.5%increase by 8.8%、14.2%and 21.8%,respectively.The bending capacity and energy dissipation capacity of the shear walls increase obviously with the increace of concrete strength or the axial compression ratio,whereas the ductility decreases with the increace of concrete strength or the axial compression ratio.Compared with the shear wall with a concrete strength of C40,the bending capacities of the shear walls with concrete strengths of C60 and C80 increase by 21.9%and 39.7%,respectively.Compared with the shear wall with an axial compression ratio of 0.1,the bending capacities of the shear wall with an axial compression ratio of 0.2 increase by 13.5%.Finally,the calculation method for the bending capacity of steel fiber reinforced concrete mid-rise shear walls with concrete-filled steel tubular columns was developed based on the characteristics of bending failure,which defined the contributions of steel tube and steel fibers.The deviation between the calculated values and the test values is within 10%,and the calculation results are in good agreement with the test results.