预制星形螺箍SRC柱的轴压与反复荷载抗震性能

Axial and Cyclic Loading Tests on the Seismic Performance of Precast SRC Columns Confined with Star Spiral

本文旨在探讨一种创新研发的"复合式螺旋箍筋"用于矩形截面钢骨钢筋混凝土(SRC)柱的可行性及经济效益,共进行了八支实尺寸短柱轴压试验及两支实尺寸长柱反复荷载抗震试验。此种新型的"复合式螺箍"是由一组星形螺箍与一组圆形螺箍共同交织而成的;其中星形螺箍可以有效地束制矩形SRC柱四个角落的混凝土,而圆形螺箍除了可与星形螺箍共同围束混凝土外,亦扮演类似系筋的作用,可以有效地抑制星形螺箍向外扩张变形,进而发挥双重围束混凝土的功能。本文中的复合式螺旋箍筋采用自动化加工制造,有助于降低箍筋绑扎所需的人力及缩短工期,适用于预制工法。试验结果发现,配置复合式螺箍的短柱强度与韧性皆优于配置传统横箍之短柱;两支复合螺箍SRC长柱的反复荷载滞回曲线均相当饱满,在层间变位角高达5.6%弧度下,其强度仍可稳定地维持在高档,柱底部的塑铰区发挥了良好的韧性,显示此种新型的复合螺箍SRC柱具备优越的消能与抗震能力。

A series of full-scale rectangular steel reinforced concrete（SRC） columns confined with a newly innovated multi-spiral cage were tested under monotonic axial compression and cyclic lateral load.The multi-spiral cage is a device of two interwoven spirals including a ＂circular spiral＂ at the center and a ＂star spiral＂ surrounding the perimeter of the column.The innovation of applying the star spiral to the rectangular SRC column is to take its advantage in concrete confinement at the four corners of the rectangular cross-section.The multi-spiral cage can be easily manufactured by automatic processing,which is particularly suitable for the precast construction.The major parameters of this study included the cost effectiveness of the multi-spiral,the axial strength and the seismic resistance of the spirally confined SRC columns.Two full-scale SRC columns were tested under horizontal cyclic loadings.The tested columns were found to be able to sustain a drift angle up to 5.6% radians.As compared to the traditional reinforced concrete column tied with rectangular hoops,the test results revealed that,with significant savings on the consumption of the confinement steel,the SRC columns confined with the multi-spiral cage demonstrated excellent seismic performances in both strength and ductility.