高约束高强混凝土结构抗震性能及其设计理论和方法研究

For the brittleness of high strength concrete (HSC) and the smaller confinement pressure to concrete (especially high-strength concrete) in our country’s structure, the highly confined concrete is proposed in this project, in which the high-strength steel and FRP bars will be set as the stirrups to impose high confinement on high-strength concrete. Based on the experimental study, theory analysis and the numerical simulation, the confining effect and mechanical property of highly confined high-strength concrete, and the influence of confinement pressure on the behavior of highly confined HSC under concentric load will be researched systematically; the method of calculating confinement pressure, the damage criterion and constitutive model of highly confined HSC are to be established; and the quantized index of high confinement for confined concrete will be proposed. Also the seismic performance research of highly confined HSC columns will be carried on, in which the relationship between confinement pressure and ductility of columns is analyzed; the restoring force model and the characteristic parameters of the columns are to be proposed; based on the ductility demand of columns, the limits of axial compression ratio and the minimum confining reinforcement characteristic values of highly confined HSC columns at different levels of seismic are present, and the shear capacity model and expression are to be established;. At last, the seismic performance of the frame structure with highly confined HSC columns is to be researched systematically, and the performance based seismic evaluation and design method are to be put forward. The achievement of the project will promote the application of the high-strength materials in china, and will provide the theoretic basis for the design of frame structure with highly confined HSC columns.

针对高强混凝土的脆性及目前我国结构中对混凝土（特别是高强混凝土）的约束力一般均较小的现状，提出高约束高强混凝土的概念，拟采用高强钢筋、FRP筋作箍筋对高强混凝土施加高约束。通过试验研究、理论分析和数值模拟，研究高约束高强混凝土的约束效果及力学性能，分析约束力大小对其轴压性能的影响，建立箍筋约束力的计算方法及高约束高强混凝土受压破坏准则和应力-应变本构模型，提出高约束混凝土的量化指标；研究高约束高强混凝土压弯构件的抗震性能及构件延性性能与约束力的关系，建立其恢复力模型及特征参数的计算公式，提出满足构件有限延性的轴压比限值和配箍水平限值，建立该类构件在塑性铰出现后依据延性需求确定其抗震受剪承载力的计算公式和设计方法；研究高约束高强混凝土柱框架结构的抗震性能，建立该类框架结构基于性能的抗震设计和评估方法。研究成果为高强材料的进一步推广应用提供技术支撑。

针对高强混凝土的脆性及目前我国结构中对混凝土（特别是高强混凝土）的约束力一般均较小的现状，提出高约束高强混凝土的概念，采用高强钢筋作箍筋对高强混凝土施加高约束。.通过31根高强箍筋约束高强混凝土棱柱体试件的轴心受压试验，对约束高清混凝土的应力-应变本构关系进行了研究。结果表明，采用高强箍筋约束是防止高强混凝土应力-应变曲线陡然下降的有效措施；箍筋间距较小、强度较高、形式较复杂的约束混凝土试件，具有较高的箍筋侧向约束力，其应力－应变曲线的下降段较为平缓，显示出良好的延性性能。在试验的基础上，提出一种适合于高强箍筋约束高强混凝土轴心受压的应力－应变关系本构模型，并结合试验结果与国内外几种典型本构模型进行对比，结果表明该模型与试验曲线吻合较好。. 通过10个高强箍筋约束高强混凝土柱在高轴压比下的低周反复水平加载试验，研究该类构件的破坏过程、破坏形态、滞回曲线和延性性能，分析箍筋的应力及其强度发挥水平，并与普通强度箍筋的约束效果进行对比。结果表明，在高轴压比下，该类型柱的滞回曲线仍呈稳定丰满的梭形，具有较好的延性性能、耗能能力和较强的抗倒塌能力，即密配高强箍筋是保证高强混凝土框架柱在高轴压比下具有良好延性性能以及提高其轴压比限值的有效措施。分析了轴压比、箍筋间距以及配箍率对其骨架曲线的影响，给出了HSC柱4个特征点——开裂点、屈服点、峰值点和极限点所对应荷载及位移的计算方法，建立了高强箍筋约束高强混凝土柱四折线荷载-位移骨架曲线简化模型。结合国内外大量试验数据，建立高强箍筋约束高强混凝土柱的极限位移角、延性系数与轴压比、配箍特征值、保护层面积及纵筋配筋率之间的关系；提出考虑轴压力水平的该类型柱中高强约束箍筋的计算公式以及在不同抗震等级下柱箍筋加密区的最小配箍特征值。.研究成果为高强材料的进一步推广应用提供技术支撑。