摘要
为探究钢抱箍的受力特性,保证其设计承载能力满足道路桥梁工程的要求,采用了1∶4缩尺模型,通过3组对比试验研究了螺栓紧箍力、箍身高度及钢-混界面状态对钢抱箍竖向承载能力的影响。结果表明:钢抱箍在螺栓紧箍力下会在加劲板末端发生局部脱空,同时螺栓承压板处的混凝土圆柱也会出现局部压溃,对此可分别采取压注结构胶和设置橡胶垫板的措施进行局部处治;在外荷载作用下钢抱箍的荷载-位移曲线呈现典型的3段式特征:线性增长段、平稳段和下降段,且当外荷载值接近线性增长段末端的起滑点时,钢抱箍有滑移风险;钢抱箍服役时箍身的竖向应力很小,主要承受环向应力,而环向应力呈现两头大中间小的特征,加劲板末端的环向应力突变值较箍身中部均匀应力值增大了5~8倍;箍身未屈服时钢抱箍竖向承载能力随螺栓紧箍力线性增大,在螺栓紧箍力不变的情况下,箍身高度对钢抱箍竖向承载能力的影响较小;当钢-混界面摩擦系数取0.3、螺栓拧紧力矩系数取0.18时,按现有理论公式计算的钢抱箍承载力值与实测值的偏差在5%以内,精度较高且结果偏于安全,但钢-混界面润湿会导致钢抱箍的承载能力降低约18.3%,对此可以通过提高安全系数的方式在设计中予以考虑。
In order to explore the stress characteristics of the steel hoop and ensure its design bearing capacity meets the requirements of road and bridge engineering,a 1∶4 scale model is employed to investigate the influences of the bolt tightening force,hoop body height and state of steel-concrete interface on the vertical bearing capacity of the steel hoop by 3 groups of comparative tests.The result shows that(1)the steel hoop is partially disengaged at the end of the stiffening plate under the force of the bolt hoop,meanwhile the concrete cylinder at the bolt bearing plate is also partially crushed,and the local treatment can be carried out by means of injecting structural adhesive and installing rubber pad;(2)the load-displacement curve of steel stirrup under external load presents 3 typical characteristics of linear growth section,stationary section and descending section,when the external load is close to the starting point of the end of linear growth segment,the steel hoop has the risk of slip;(3)when the steel hoop is put into service,the vertical stress of the hoop body is very small,and the hoop body mainly bears the circumferential stress,the sudden change of circumferential stress at the end of stiffened plate is 5-8 times more than the uniform stress at the middle of hoop;(4)the vertical bearing capacity of steel hoop increases linearly with the bolt tightening force when the hoop is not yield,and the height of hoop has little effect on the vertical bearing capacity of steel hoop when the bolt tightening force is constant;(5)when the friction coefficient of steel-concrete interface is 0.3 and the torque coefficient of bolt tightening is 0.18,the deviation between the bearing capacity of steel hoop calculated by the existing theoretical formula and the measured value is less than 5%,the accuracy is high and the results are safe,but wetting the steel-concrete interface reduces the load-carrying capacity of the steel hoop by about 18.3%,which can be considered in the design by increasing the factor of safety.
作者
古松
吕勇康
顾颖
邓继清
孔超
GU Song;LÜYong-kang;GU Ying;DENG Ji-qing;KONG Chao(School of Civil Engineering and Architecture,Southwest University of Science and Technology,Mianyang Sichuan 621010,China;Yibin Tianyi Lithium Industry Co.,Ltd.,Yibin Sichuan 644200,China;School of Civil Engineering,Southwest Jiaotong University Hope College,Chengdu Sichuan 610400,China)
出处
《公路交通科技》
CAS
CSCD
北大核心
2023年第12期74-81,共8页
Journal of Highway and Transportation Research and Development
基金
国家自然科学基金项目(52108385)
四川省科技计划项目(2022ZYDF083)。
关键词
桥梁工程
设计承载能力
对比试验
钢抱箍
理论公式
bridge engineering
designed bearing capacity
comparative test
steel hoop
theoretical formula
