建筑结构学报2017，Vol.38Issue(3)：58-66,9.DOI:10.14006/j.jzjgxb.2017.03.006
薄壁U形钢板加固受火后钢筋混凝土梁受力性能研究
Mechanical performance of reinforced concrete beams after fire and strengthened with thin-walled U-shaped steel plate
摘要
Abstract
Reinforced concrete (RC) beams after fire can be strengthened by installing external thin-walled U-shaped steel plate and filling non-shrinkage grouting material inside.It has the advantages of effectively avoiding the shedding of the grouting materials to ensure a long-term reinforcement effect.In order to verify the effectiveness of the reinforcement method,the static loading tests of 14 concrete beams were carried out.The effects of U-shaped steel plate thickness and fire exposure time on the bending performance of strengthened RC beams,and the effects of U-shaped steel plate thickness and shear span ratio on the shear performance of strengthened RC beams were investigated.The calculation formulas for the flexural strength and the shear strength of the strengthened beams were developed by referring to the calculation formulas for the capacity of composite beams at ambient temperature.The results show that the flexural strength of concrete beam decreases by 9.4％ and 10.4％ after experiencing fire for 1.0 h and 1.5 h,respectively.After experiencing fire for 1.5 h,the shear strength of concrete beam with the shear span ratio 1.74 and 2.58 decreases by 19.5％ and 10.6％,respectively.The flexural strength and the shear strength of concrete beams firstly exposed to fire and then strengthened with thin-walled U-shaped steel plate is about 127.4％-151.7％ and 21.3％-56.7％ of that without fire,respectively.The spaced ring formed by welding angle steel in the inner side and above the flange of thin-walled U-shaped steel plate can ensure the U-shaped steel plate and concrete work together.The strengthened specimens can be seen as full shear connection composite beams.The longitudinal shear force of the spaced ring is larger when the flexural failure occurs in the strengthened beams,and is smaller when the shear failure occurs in the strengthened beams.关键词
混凝土梁/薄壁U形钢板/加固/火灾后/静力试验/受力性能Key words
concrete beam/thin-walled U-shaped steel plate/strengthening/after fire/static test/mechanical performance分类
建筑与水利引用本文复制引用
徐玉野,郑顺盈,董毓利,罗漪..薄壁U形钢板加固受火后钢筋混凝土梁受力性能研究[J].建筑结构学报,2017,38(3):58-66,9.基金项目
国家自然科学基金项目(51578255),福建省科技计划重点项目(2014Y0033),华侨大学中青年教师科研提升计划(ZQN-YX204). （51578255）
