Study of Cyclic Behavior of Confined High-Strength Concrete Moment-Resisting Frames

本报告介绍了约束高强混凝土（HSC）抗弯框架的循环响应的实验信息，沿着与分析方法来评估的故障模式，以及限制HSC框架的极限横向承载力。试验包括6个单跨单层高强混凝土框架，框架由2个200 × 200 mm钢管方柱和1个180 × 300 mm钢管方柱组成。矩形梁由传统的箍限制。所有框架均采用设计强度为80 MPa的高强混凝土，进行了水平荷载和轴向荷载联合循环荷载作用下的试验，试验结果表明，钢管对柱的约束能保证高强混凝土框架在高轴向荷载作用下具有非常稳定的循环性能。由于钢管约束可以将混凝土全部包含在柱内，因此在大变形之前，高强混凝土框架的抗震环不会发生强度突变。它也成为 关于我们 结果表明，采用内加劲肋加固方钢管可以显著提高方钢管的约束效果。具有宽厚比的方钢管（B/t比）为87，并采用内加劲肋进行加固的钢管，其约束效果与B/t比为33，但没有内加劲肋的钢管相同，而前者用钢量仅为55%，本文还提出了一种设计方法，使结构工程师能够简单地评估极限水平荷载和变形能力，受限HSC框架。该方法考虑了方钢管的约束效应，简化了极限承载力的计算过程。承载力和变形能力。理论计算结果与实测结果的对比表明，该设计方法能很好地预测实验结果。此外，所有的测试框架进行了延性的方式，如设计，这意味着所提出的设计方法也使工程师能够可靠地预测的限制HSC框架的破坏模式在设计阶段。少

This report presents experimental information on the cyclic response of confined high-strength concrete (HSC) moment-resisting frames along with an analytical method to evaluate the failure mode as well as the ultimate lateral load capacity of the confined HSC frames. The tests involved six one bay and one-story HSC moment-resisting frames, which consisted of two 200x200mm square columns confined by steel tube and one 180x300mm. rectangular beam confined by conventional hoops. All of the frames were made of HSC with designed strength of 80MPa and were tested under combined cyclical lateral force and constant axial load.Test results have indicated that confinement of the columns by steel tube could ensure very stable cyclic performance to HSC frame even when it was under high axial load. Since confinement by steel tube can contain the whole of concrete in a column, no abrupt strength degradation occurred in the hysterestic loops of the HSC frames till large deformation. It has also beco … More me clear that strengthening the square steel tube with inner stiffener could enhance its' confinement effect significantly. The square steel tube, which had width-to- thickness ratio (B/t ratio) of 87 and was strengthened with inner stiffener, provided the same confinement effect as the steel tube with B/t ratio of 33 but without inner stiffener, while the steel amount of the former is only 55% of the latter.This report also presents a design method enabling structural engineer to simply evaluate the ultimate lateral load and deformation capacity of confined HSC frames. This method involves consideration of confinement effect by the square steel tube and simplification of calculation procedure for the ultimate. load and deformation capacity of confined HSC columns and beams. Comparison between the theoretical and the measured results has indicated that the proposed design method could predict experimental results very well. In addition, all of the test frames performed in a ductile manner as designed, which implies that the proposed design method also enables engineers to reliably predict the failure mode of the confined HSC frames at the stage of design. Less