CFRP-EMD加固灌浆套筒连接装配式桥墩振动台试验

为研究受力筋灌浆套筒连接装配式混凝土桥墩的抗震加固方法，以受力筋灌浆套筒连接装配式混凝土桥墩和灌浆套筒-预应力筋连接装配式混凝土桥墩为研究对象，设计制作了两个1/6缩尺模型，并依据二者的震害特点提出了一种采用碳纤维复合材料-外置金属耗能装置(简称CFRP-EMD)的组合加固方法。选取近断层地震波作为输入，开展了单、双向激励下模型桥墩的振动台试验，从试验现象、基本动力特性、地震响应规律等方面分析了CFRP-EMD对两类装配式混凝土桥墩的加固效果。结果表明：地震作用下两类试件的主要震损包括墩身开裂、墩底接缝开合、接缝混凝土剥落压碎等；附加预应力筋连接可提高构件刚度和自复位能力，降低墩身和接缝的损伤速率和损伤程度；采用CFRP-EMD组合加固能够显著提高震损装配式构件的刚度、抗震变形能力和耗能能力；CFRP-EMD加固后灌浆套筒-预应力筋连接装配式混凝土桥墩的塑性变形更加合理。提出的组合加固设计方法和实施原则可用于装配式混凝土桥墩抗震加固中。

Shaking table test on fabricated pier with grouting sleeve based on CFRP-EMD

To study the seismic reinforcement method of prefabricated concrete pier with grouting sleeve (PCP-GS), this paper takes PCP-GS and PCP with grouting sleeve-prestressed tendon combined connection (PCP-GS-P) as research objects. Two 1/6 scale models of PCP-GS and PCP-GS-P were designed and manufactured. According to the damage characteristics of the two piers, a combined reinforcement method based on carbon fiber reinforced plastic (CFRP) and external metallic dissipater (CFRP-EMD) for the specimens was proposed. The near fault ground motions were selected as input. Shaking table tests for the model piers were carried out under unidirectional and bidirectional excitations. The reinforcement effects of CFRP-EMD on the two specimens were analyzed through test phenomena, basic dynamic characteristics, and seismic response laws. Results show that the main seismic damages of the two specimens were pier body cracking, opening and closing at the joint seam, and spalling or crushing of seam concrete. Compared with PCP-GS, the stiffness and self-reset ability of PCP-GS-P were improved, and the damage velocity and damage degree of the pier body and joint seam were reduced. The CFRP-EMD could effectively increase the stiffness, energy dissipation capacity, and anti-deformation capacity of the damaged fabricated specimens. The plastic deformation of PCP-GS-P strengthened with CFRP-EMD was more reasonable. The proposed design and implementation method can be used as reference for seismic reinforcement of prefabricated concrete piers.