外包钢板-高强箍筋约束超高强混凝土剪力墙抗震性能与设计方法研究

In super high-rise buildings, because of the restriction of the concrete strength and axial load ratio, the thickness of the core walls at the base increases exponentially as the structural height increases. To effectively control the core wall thickness of super high-rise structures over 500 meters, a new form of shear walls referred to as high-strength reinforcement-confined ultra-high-strength concrete-filled steel plate (CUHS-CFSP) composite shear walls is proposed. Taking the advantage of each material, the shear wall can sustain higher axial compression with adequate deformation capacity. This project plans to first study the compressive stress-strain relationship of the ultra-high-strength (UHS) concrete confined by both surface plates and high-strength reinforcement, and to establish the constitutive model for the UHS concrete under this dual confinement. Rectangular, T-shaped and L-shaped CUHS-CFSP composite shear walls are then to be tested under cyclic loading, and the effects of the main parameters on the seismic behavior of the shear walls are to be investigated. Based on the test results along with numerical analyses such as finite element analysis, the biaxial bending behavior of the non-planar shear walls and the mechanism of the shear walls with small shear-span ratios are to be studied. On these bases, the design methods for the biaxial moment strengths, shear strengths and spiral reinforcement arrangements are to be established for the CUHS-CFSP composite shear walls. The research achievement will probably promote the improvement of global performance and economy of super high-rise structures.

在超高层结构中，受混凝土强度等级和轴压比的限制，核心筒底部剪力墙厚度随着结构高度的增加近似呈指数增加。为有效控制500m以上超高层结构的核心筒剪力墙厚度，申请人提出了外包钢板-高强箍筋约束超高强混凝土（CUHS-CFSP）组合剪力墙；通过发挥各材料优势，使剪力墙在满足变形能力要求的前提下，能够承担更高的轴压力。本项目首先开展外包钢板和高强箍筋双重约束下的超高强混凝土受压本构关系研究，建立双重约束下的超高强混凝土受压本构模型。在此基础上，开展一字形、T形和L形剪力墙的拟静力加载试验，研究各主要参数对剪力墙抗震性能的影响规律。结合试验结果和有限元等数值方法，研究带翼缘剪力墙的双向压弯受力性能和小剪跨比剪力墙的受力机理，进而建立CUHS-CFSP组合剪力墙的双向压弯承载力计算方法、抗剪承载力计算方法和满足变形需求的箍筋配置方法等。研究成果有望推动超高层结构整体受力性能和综合经济性的提升。

在超高层结构中，受混凝土强度等级和轴压比的限制，核心筒底部剪力墙厚度随着结构高度的增加近似呈指数增加。为有效控制500m以上超高层结构的核心筒剪力墙厚度，申请人提出了外包钢板-螺旋箍筋约束超高强混凝土（CUHS-CFSP）组合剪力墙；通过发挥各材料优势，使剪力墙在满足变形能力要求的前提下，能够承担更高的轴压力。本项目首先开展了CUHS-CFSP组合剪力墙边缘构件的受压性能试验，对内填混凝土抗压强度为112MPa的12个内配螺旋箍筋方钢管超高强混凝土（SCCFST）试件和2个方钢管超高强混凝土（CFST）对比件开展了轴压试验，试验参数包括螺旋箍筋用量、屈服强度以及螺旋箍筋约束区面积与内填混凝土总面积的比值。试验结果表明：内置螺旋箍筋可明显改善方钢管超高强混凝土构件的延性，但对承载力的影响较小。同时开展了SCCFST试件和CFST试件的偏压试验。基于试验结果，建立了外包钢板和螺旋箍筋双重约束下的超高强混凝土的等效单轴应力-应变模型，用于CUHS-CFSP组合剪力墙的纤维单元分析。开展了6个外包钢板-超高强混凝土组合剪力墙试件的拟静力试验，试件参数包括剪力墙的截面形状，外包钢板的连接构造和螺旋箍筋配置情况等。试验结果表明：边缘构件配置螺旋箍筋可显著提高剪力墙的抗震性能；在0.15轴压比下，CUHS-CFSP组合剪力墙的极限位移角可达4.0%。在OpenSees平台上建立了CUHS-CFSP组合剪力墙的纤维模型，对CUHS-CFSP组合剪力墙的压弯受力性能开展了参数分析，建立了CUHS-CFSP组合剪力墙的压弯承载力和极限曲率的计算公式，提出了使剪力墙满足变形能力需求的边缘构件螺旋箍筋配置方法。本项目的研究成果将为CUHS-CFSP组合剪力墙在超高层结构中的推广应用奠定基础，促进超高层结构整体受力性能和综合经济性的提升。