Cyclic Testing of an Unbonded Pre-tensioned Bridge Column with Rocking Detail: Footing Specimen 02

The seismic performance of the precast system was evaluated with quasi-static tests of two column-footing sub-assemblies. In this column-to-footing sub-assembly, a ductile fiber-reinforced concrete (HyFRC) was used to fill the steel rocking detail and the region immediately above it. This column also contained a steel dowel bar that extended down from the body of the column into the footing.

The column-to-spread-footing subassembly had a cantilever height of 60 in. and a column diameter of 20 in (42% scale). The specimen was subjected to a constant axial Load of 159 kips and a quasi-static displacement history based on the NEHRP recommendations for precast structural walls.

The lateral displacement history consisted of ten four-cycle sets. Each set had target peak values of 1.2X, 1.44X, 1.44X, and 0.48X, where X is the maximum target drift from the previous set. The maximum target drift of the first set was selected so that the column would remain elastic throughout the duration of the first four cycles (X = 0.167 in.).

本研究通过2个柱-基础子装配体的拟静力试验，对预制结构体系的抗震性能开展了评价。在该柱-基础子装配体中，采用延性纤维增强混凝土（HyFRC）填充钢摇摆构造及其紧邻的上方区域。该柱还设置了一根从柱身向下延伸至基础的钢传力杆。
该柱-独立扩展基础子试件的悬臂高度为60英寸，柱直径为20英寸，缩尺比例为42%。试验试件承受了159千磅力（kips）的恒定轴向荷载，以及基于美国国家地震灾害减轻计划（NEHRP）针对预制结构墙体制定的拟静力位移加载制度。
该横向位移加载制度包含10组四循环加载工况。每组加载的目标峰值依次为1.2X、1.44X、1.44X和0.48X，其中X为前一组加载的最大目标位移值。首组加载的最大目标位移被设定为使柱在前四个加载循环全程保持弹性状态（X=0.167英寸）。