装配式钢管约束耗能连接节点及其框架结构抗震机理与失效控制

Based on the formulation of "Thirteenth Five-Year Plan" by the Central Committee of Chinese Communist Party, a kind of prefabricated steel tube confined concrete connection joint which has better ductility, energy dissipation and bearing capacity is put forward. The relevant theories including its mechanics model of the frame structure, transmission mechanism on connection interface, plastic hinge forming mechanism, the plastic internal force redistribution regularity, multiple energy damage evolution mechanism, failure mechanism, failure modes under the earthquake will be studied in the project. In order to the study plans，the bond-slip relationship between steel fiber reinforced self-compacting concrete and old concrete, the bond-slip relationship between steel fiber reinforced self-compacting concrete and steel tube, concrete stress-strain relationship under steel tube passive constraints and its finite element model with semi-rigid connection will be set up. Then transfer mechanism and failure modes of prefabricated frame structures will be optimized. Due to the deformation and energy dissipation damage indexes，double parameters performance seismic design theory will be set up systematically. The simplified design methods will be proposed for engineering application. The innovation achievements such as transfer mechanics of prefabricated steel tube confined concrete connection joint and performance seismic design method of its frame structure can provide theories and methods to extend prefabricated frame structure application scopes in seismic region.

本项目围绕“十三五”期间绿色建筑及建筑工业化领域的国家重大需求，提出一种装配式钢管约束延性耗能连接节点，并进行了相关理论研究。本项目拟研究装配式钢管约束耗能连接节点及其框架结构的力学模型、连接界面传力机理、塑性铰形成机制、塑性内力重分布规律和地震作用下多重耗能破坏机制、损伤演化机理、失效模式等科学问题。为此建立钢纤维自密实混凝土与老混凝土和钢管的粘结-滑移关系、钢管被动约束下混凝土应力-应变关系、考虑节点半刚性的钢管约束耗能连接节点及框架结构有限元模型，优化装配式钢管约束耗能框架结构的传力机制和失效模式，系统建立装配式钢管约束耗能框架结构基于变形和耗能双参数损伤指标的性能抗震设计理论，提出方便于工程运用的简化设计方法。取得装配式钢管约束耗能连接节点受力机理和装配式钢管约束耗能框架结构基于性能的抗震设计理论等创新成果，为拓展装配式混凝土框架结构在地震区的适用范围提供系统的理论和方法。

围绕绿色建筑及建筑工业化领域的国家重大需求，提出一种装配式钢管约束延性耗能连接节点，并进行了系列的相关理论研究并提出相应的设计方法。主要研究内容包括：钢纤维自密实混凝土的受压本构关系及其老混凝土粘结抗剪性能研究、橡胶自密实混凝土的力学性能及其与其老混凝土粘结抗剪性能研究、钢纤维-橡胶自密实混凝土的力学性能研究、钢筋与自密实混凝土粘结滑移关系研究、预制装配式钢管约束耗能框架节点滞回试验研究、预制装配式钢管约束耗能框架节点传力机理研究等研究，拓展装配式混凝土框架结构在地震区的适用范围。得到的主要结论如下：.（1）掺入钢纤维能有效提高新老混凝土粘结的抗剪强度；在新老混凝土的粘结做法中沟槽宽度有助于大幅度提高试件的粘结抗剪强度；当槽宽一样时，开一个槽试件比开两个槽的抗剪强度要高；在一定范围内增加植筋率可显著提高试件的抗剪承载力，提出了钢纤维自密实混凝土与老混凝土粘结抗剪设计方法。.（2）掺入橡胶后自密实混凝土的脆性破坏得以改善，具有一定的延性。但橡胶自密实混凝土的流动性随着橡胶掺量的增加而降低，掺入2～4mm橡胶颗粒的流动性最好，掺入橡胶粉的流动性最差，橡胶粒径越小流动性越低。提出橡胶掺量对混凝土的强度影响的预测公式、橡胶混凝土的应力-应变关系预测公式。.（3）自密实混凝土坍落扩展度550-690mm范围内，坍落度在600mm以上时，重复荷载作用后粘结性能相对较为接近，也优于坍落扩展度为550mm时情况，提出钢筋与自密实混凝土的粘结滑移关系。.（4）新型预制装配式钢管约束耗能节点的承载力、耗能能力优于现浇梁柱节点。预制梁与核心区连接段混凝土掺入的钢纤维体积率越大，新型节点的承载力、耗能能力略有提高，P-△曲线刚度和强度退化也较为缓慢。.（5）明确了预制装配式钢管约束耗能节点的斜压杆机制和桁架作用机制，提出新型节点梁端塑性铰抗弯、抗剪的性能化设计方法。