全干式预应力拼接柱节点单向偏压试验研究

Experimental Research on Fully-Dry Connections of Prestressed Concrete Columns Under Unidirectional Eccentric Compression

预应力拼装框架结构体系是一种全干式连接的装配式结构体系,深入研究预应力拼装柱节点的力学性能对推动该体系的发展具有重要意义。通过低周往复加载试验研究了三种预应力钢棒拼装柱节点的力学性能,分别选取无黏结预应力钢棒拼装柱节点(UBPC)、有黏结预应力钢棒拼装柱节点(BPC)以及纵筋和无黏结预应力钢棒拼装柱节点(RUBPC)三种节点形式,开展了单向偏压作用下的拟静力试验。试验结果表明,三种节点均具有较好的延性,当加载位移幅值达到弹塑性层间位移角限值1/50时,各试件的最大承载力均在极限承载力的85%以上;UBPC和BPC通过柱底黏接面的张开可有效减轻预制柱构件的损伤程度,但其最大承载力较RUBPC降低了15%~20%;UBPC和BPC的耗能能力弱于RUBPC,但其具有较好的自复位特性和更小的残余变形;预应力钢棒在试验加载过程中均处于弹性变形阶段,当加载至试件破坏时,RUBPC和UBPC中预应力钢棒的初始预加拉力下降了12%左右;相比较而言,BPC较UBPC具有更好的极限承载能力和耗能性能。

It is of great significance to perform the mechanical properties of connections of pre-stressed concrete columns for promoting the development of pre-stressed concrete frame structure which is a typical kind of assembled structure with fully-dry connections. In this paper, the mechanical properties of three kinds of connections of pre-stressed concrete columns were studied through quasi-static connection of loading tests. The quasi-static tests on the connection of unbonded pre-stressed concrete column(UBPC), bonded pre-stressed concrete column(BPC), and the connection between longitudinal rebar and unbonded pre-stressed concrete column(RUBPC) were carried out under unidirectional eccentric compression. The experimental results demonstrated a better ductility for the three connections. When the deformation of the columns reached 1/50 which was the elastic-plastic inter-story drift of RC frame structure, the maximum bearing capacity was still more than 85% of the ultimate bearing capacity for each specimen. For UBPC and BPC, the damage of precast column was effectively reduced due to the opening of the bonding surface at column bottom, while their ultimate bearing capacity was 15%~20% lower than that of RUBPC. In addition, the energy dissipation of UBPC and BPC was less than that of RUBPC. When Compared with RUBPC, UBPC and BPC presented better re-centering capacity and smaller residual deformation. Moreover, the steel rods remained elastic during tests for all the specimens, and their initial tensile forces in RUBPC and UBPC were decreased by 12% when the specimens were destroyed. Compared with UBPC, the BPC presented a larger bearing force and a better energy dissipation.