矩形空心墩变形能力及塑性铰区约束箍筋用量

为研究空心截面桥墩的变形能力和塑性铰区约束箍筋用量,整理了71个矩形空心墩的抗震拟静力试验数据,总结了不同破坏形态下空心墩的变形能力和现有规范对保证空心墩延性抗震能力的可靠性,基于多元线性回归分析和相关分析讨论了影响空心墩变形能力的主要因素,基于Caltrans规范给出了矩形空心墩塑性铰区约束箍筋用量计算公式.研究发现:Caltrans规范和ACI规范对保证矩形空心墩的弯曲破坏形态和延性变形能力具有较高的可靠性,中国JTG/T B02-01-2008规范偏于不安全.矩形空心墩变形能力主要与塑性铰区配箍、纵筋配筋、壁厚和轴压比等因素有关,随箍筋、纵筋配筋和壁厚增加而增加,随轴压比增加而减少.

Deformation Capacity and Amount of Confining Reinforcement in Potential Plastic Hinge Regions of Rectangular Hollow Bridge Piers

Quasi-static test results of 71 rectangular hollow bridge piers were collected to study the deformation capacity and amount of confining reinforcement in the potential plastic hinge region of the bridge piers. The deformation capacity of the hollow bridge piers with different failure modes were analyzed, and current codes provisions for the amount of confining reinforcement in hollow bridge piers were evaluated. Then, main factors influencing the deformation capacity of the piers were discussed based on multiple linear regression analysis and correlation analysis. At last, design equations based on Caltrans code of required confining reinforcement for rectangular hollow bridge piers were proposed. It is found that both the Caltrans and ACI codes show great reliability for the flexural failure mode and deformation capacity of the hollow bridge piers while the Chinese JTG/T B02 -- 01-- 2008 code is unsafe. Also, the deformation capacity of the hollow bridge piers increases with the increase of the transverse reinforcement, longitudinal reinforcement, and web width, and decreases with the increase of the axial load ratio.