薄壁U形钢板加固受火后钢筋混凝土梁受力性能研究

发布时间：2018-12-21 20:31

【摘要】：采用外套薄壁U形钢板、内灌无收缩灌浆料加固受火后钢筋混凝土梁,该加固技术能有效避免灌浆材料脱落,具有长效的加固功能。为验证该加固方法的有效性,进行了14根混凝土梁的静载试验,研究了U形钢板厚度和受火时间对加固RC梁受弯性能的影响,以及U形钢板厚度和剪跨比对加固RC梁受剪性能的影响。借鉴常温下组合梁承载力的计算方法,给出了薄壁U形钢板加固受火后RC梁受弯和受剪承载力的计算公式。结果表明:受火1.0、1.5 h后混凝土梁的受弯承载力分别降低了9.4%、10.4%,剪跨比为1.74、2.58的混凝土梁受火1.5 h后受剪承载力分别降低了19.5%、10.6%。薄壁U形钢板加固受火后RC梁的受弯、受剪承载力相比未受火RC梁分别提高了127.4%~151.7%、21.3%~56.7%。在薄壁U形钢板内侧和上翼缘焊接角钢形成的内隔环能保证薄壁U形钢板和混凝土共同工作,加固后试件可作为完全剪切连接的组合梁。加固试件发生受弯破坏时内隔环承受的纵向剪力较大,而发生受剪破坏时内隔环承受的纵向剪力较小。
[Abstract]:The reinforced concrete beam after fire was strengthened with thin-walled U-shaped steel plate with internal grouting without shrinkage. The reinforcement technology can effectively avoid the fall off of grouting material and has the function of long-term reinforcement. In order to verify the effectiveness of the reinforcement method, the static load tests of 14 concrete beams were carried out, and the effects of the thickness of U-shaped steel plate and the time of fire on the flexural behavior of the strengthened RC beams were studied. And the effect of U-shaped steel plate thickness and shear span ratio on shear behavior of strengthened RC beams. With reference to the calculation method of the bearing capacity of composite beams at room temperature, the formulas for calculating the flexural and shear bearing capacity of RC beams strengthened by thin-walled U-shaped steel plates after fire are given. The results show that the flexural bearing capacity of concrete beams decreases by 9.4% and 10.4, respectively, and the shear bearing capacity of concrete beams with shear span ratio of 1.74 ~ 2.58 decreases by 19.5% after 1.5 h of fire, respectively. 10.6. The shear capacity of RC beams strengthened with thin-walled U-shaped steel plate is 127.4% higher than that of unburned RC beams. The inner isolation ring formed in the inner and upper flange of thin-walled U-shaped steel plate can ensure the joint work of thin-walled U-shaped steel plate and concrete. The reinforced specimen can be used as a composite beam with complete shear connection. The longitudinal shear force of the inner ring is larger when the specimen is subjected to bending failure, but the longitudinal shear force of the inner diaphragm ring is smaller when the shear failure occurs.
【作者单位】：华侨大学土木工程学院;
【基金】：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(ZQNYX204)
【分类号】：TU375.1

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