将再生混凝土填充到高强钢管，可形成力学性能优越的高强钢管再生混凝土结构，符合建筑垃圾资源化和建筑材料高性能化的发展趋势，而目前国内外尚缺乏对该类结构的系统研究。本项目以高强钢管再生混凝土结构为对象，研究其在服役期间承受的长期荷载和多种灾害(如钢管腐蚀、撞击和火灾等）耦合作用下的抗震性能和设计原理，具体包括：1)多种工况（如长期荷载、往复荷载和高温等作用）下高强钢管再生混凝土的钢管-混凝土界面的工作机理；2)多种灾害耦合作用下高强钢管再生混凝土构件的抗震性能和设计方法；3)多种灾害耦合作用下高强钢管再生混凝土柱-组合梁连接节点的抗震性能和设计方法；4)多种灾害耦合作用下高强钢管再生混凝土桁架节点（K形钢管混凝土弦杆-空钢管腹杆连接节点）抗震性能和设计方法。基于项目研究，完成可供工程应用的“高强钢管再生混凝土结构设计指南”，同时也为基于多灾害耦合作用的钢管混凝土结构抗震机理研究提供一种新途径。

A new mechanically advanced composite structures could be invented by filling the recycled-aggregate concrete into high-strength steel tubes, and it can be named as Recycled-aggregate Concrete-Filled High-Strength Steel Tube (RCFHST). The design and application of such new structures are consistent with the general trends of construction waste recycling and high-performance construction material utilization in construction engineering. However, currently, there is a lack of systematic study on the mechanical performance of such structure. This project thus aims at studying the seismic performance and design methods of RCFHST subjected to the coupling effects of multi-hazards (e.g., steel corrosion, impact, and fire, etc.). The major research contents consist of 1) the bond behaviour of high-strength steel and recycle-concrete in the RCFHST structures subjected to the coupling effects of multi-hazards (e.g., the coupling effects of long-term loading, cyclic loading and high temperature, etc.); 2) the seismic performance and design methods of RCFHST members subjected to the coupling effects of multi-hazards; 3) the seismic performance and design methods of RCFHST column to composite beam joints subjected to the coupling effects of multi-hazards; 4) the seismic performance and design methods of RCFHST truss joints (K-joints comprising RCFHST chords and hollow steel webs) subjected to the coupling effects of multi-hazards. Based on the outcomes of the project, a design guide, i.e., Design Guide for Recycled-Concrete-Filled High-Strength Steel Tubes is expected to be drafted, which could be used as the guidance for the engineering applications of RCFHST structures. The outcomes of the project, including the design guide, could also present a new research approach for the seismic performance studies of the conventional concrete-filled steel tubular structures subject to coupled multi-hazards.