矩形高强钢管混凝土柱抗震性能及FRP增强机理研究

Rectangular concrete-filled steel tubular (CFT) columns using high-strength steel and concrete (fy≥460MPa，fc≥60MPa) offer the benefit of high bearing capacity; however, they are susceptible to local buckling of steel tubes which lead to the decrease of ductility under earthquake. Fiber reinforced polymer (FRP) can effectively restrain the outward buckling of steel tubes and strengthen the seismic performance of high-strength CFT columns. The project focuses on the seismic performance of high-strength CFT columns and the strengthening mechanism using FRP. Firstly, FRP-high-strength steel plates/tubes will be tested under static and cyclic load to investigate the buckling property and the performance degradation mechanism. The theoretical model will be proposed to account for the cooperative work, failure of FRP and buckling restrained mechanism based on the tests. Secondly, the project will conduct the tests on the (FRP confined) high-strength CFT columns under cyclic load. The influence rule of various parameters on the seismic performance and the strengthening mechanism of FRP confined CFT columns will be detailed investigated. Finally, the detailed finite element models will be established taking the cooperative work mechanism, failure of FRP and the restrained buckling into account. The design recommendation on the seismic performance of FRP confined high-strength CFT columns will be given. The study results of this project will help to strengthen the seismic performance of rectangular high-strength CFT columns using FRP more scientifically and reasonably, which have an important theoretical significance and application value of engineering.

矩形高强钢管混凝土柱（fy≥460MPa，fc≥60MPa）强度高，但是其钢管易受屈曲影响而导致地震下延性降低。纤维增强复合材料（FRP）可以有效约束高强钢管混凝土柱中钢管向外屈曲，从而增强其抗震性能。本项目针对矩形高强钢管混凝土柱的抗震性能及FRP约束增强机理进行研究。首先，通过FRP-高强钢板/管静力及低周往复荷载试验，研究其约束屈曲及低周往复荷载下的受力性能退化机理，并建立考虑协同工作、FRP失效及约束屈曲的理论模型；其次，通过矩形高强钢管混凝土柱及FRP增强后低周往复试验，分析不同参数对其抗震性能的影响规律，研究FRP对抗震性能的增强机理；最后，构建考虑FRP、钢及混凝土三者在往复荷载作用下协同工作及破坏、约束屈曲的精细化模型，并建立FRP增强矩形高强钢管混凝土柱抗震性能设计方法。项目研究成果有助于科学合理地利用FRP增强矩形高强钢管混凝土柱抗震性能，具有重要的理论意义和应用价值。

矩形高强钢管混凝土柱（fy≥460MPa，fc≥60MPa）强度高，但是其钢管易受屈曲影响而导致在地震下延性降低，无法充分发挥其优势。纤维增强复合材料（FRP）轻质高强，可以有效约束高强钢管混凝土柱的钢管向外屈曲，从而增强其抗震性能。本项目针对矩形高强钢管混凝土柱的抗震性能及FRP约束增强机理进行研究。首先，通过对照FRP-钢板静力和循环拉伸荷载的试验结果，揭示了循环拉伸荷载下两种材料整体性能的退化机理，明确了FRP与钢板在循环荷载下的协同工作机理，并提出了FRP-钢板的理论恢复力计算模型。在此基础上，对FRP约束矩形高强钢管混凝土柱的抗震性能进行了系统研究，分别对矩形高强钢管混凝土柱和FRP约束矩形高强钢管混凝土柱进行了水平往复荷载作用下的拟静力试验，研究了FRP层数、约束方式、轴压比等参数对试件抗震性能的影响规律和FRP对抗震性能的增强机理。最后，建立了考虑FRP、钢及混凝土三者在往复荷载作用下协同工作及破坏、约束屈曲的精细化模型，研究了更多参数对抗震性能的影响，并提出了适用于FRP约束矩形高强钢管混凝土柱的滞回曲线理论模型。本项目成果为FRP约束矩形高强钢管混凝土柱在实际工程中的运用提供了理论依据和设计方法，具有重要的应用价值。