Liu Guirong, Li Bingchen, Bao Jiasheng, Cheng Shengzhao, Meng Qingxin, Zhao Shunbo
International Joint Research Lab for Eco-Building Materials and Engineering of Henan, North China University of Water Resources and Electric Power, Zhengzhou 450045, China.
China Construction Seventh Engineering Bureau Co., Ltd., Zhengzhou 450004, China.
Polymers (Basel). 2023 Jan 20;15(3):549. doi: 10.3390/polym15030549.
With the wide application of carbon fiber reinforced polymer (CFRP) plate, used for strengthening existed concrete structures, the prestressing technology of CFRP plate is becoming a hot topic, in order to sufficiently develop its high-strength peculiarity. In this paper, a full-scale hollow-section beam with length of 16 m taken from an old bridge which was in service for about 20 years was first examined for existed cracks and repaired by filling epoxy adhesive, and then the beam was strengthened with prestressed CFRP plates. The CFRP plates were tensioned and fixed with flat-plate anchorages at ends and bonded with adhesive on the bottom surface of the beam. The strengthened beam was experimentally studied using a four-point test to measure the concrete strain along the height of the mid-span section and the mid-span deflection. The finite element model of the strengthened beam was verified by the comparison of test results and used for an extending study of parametric analysis considering the effect of the length and amount of CFRP plates. Results indicated that with an increase in the length and amount of CFRP plates, the mid-span deflection of the beam decreases with the increased cracking resistance and bearing capacity, while the ultimate failure mode transfers from the under-reinforcement to the over-reinforcement.
随着用于既有混凝土结构加固的碳纤维增强聚合物（CFRP）板的广泛应用，为充分发挥其高强度特性，CFRP板的预应力技术正成为一个热门话题。本文首先对取自一座服役约20年的旧桥、长度为16m的足尺空心截面梁进行既有裂缝检测，并用环氧胶粘剂进行修复，然后采用预应力CFRP板对该梁进行加固。CFRP板两端采用平板锚具张拉并固定，在梁底面用胶粘剂粘贴。采用四点试验对加固后的梁进行试验研究，测量跨中截面沿高度方向的混凝土应变和跨中挠度。通过试验结果对比验证了加固梁的有限元模型，并用于考虑CFRP板长度和用量影响的参数分析扩展研究。结果表明，随着CFRP板长度和用量的增加，梁的跨中挠度减小，抗裂性和承载力提高，极限破坏模式从少筋破坏转变为超筋破坏。
