摘要
准确掌握不同损伤条件下桥梁结构的动态特性及其变化规律是动态检测法快速检测与准确评价桥梁安全性的前提,而目前对车辆荷载作用下不同损伤开裂混凝土梁桥断裂力学特征的研究成果还很不充分。基于断裂力学理论,以钢筋混凝土简支空心板为研究对象,采用有限元数值模拟方法,对车辆荷载作用下损伤开裂混凝土简支空心板的断裂力学特征进行了研究。基于裂缝穿过空心板底部受力筋的层数确定开裂深度,通过对车辆荷载作用下8 m标准跨径混凝土空心板中部不同开裂深度的计算分析,得到了不同工况下空心板横截面上裂缝附近的J积分值均呈现由两侧向中间先增加后减小的规律,即裂缝附近J积分值的大小与空心板横截面的净高有关,净高越小,J积分值越大,净高越大,J积分值越小,且同一加载方式下,裂缝附近J积分值的大小与空心板横截面的净高有关;在相同加载方式下,裂缝附近的J积分值和裂缝开度随着裂缝深度的增加而呈几何加速度增加,各裂缝尖端的Von Mises应力则近似呈现线性增大;在相同裂缝深度时,加载荷载越大,裂缝附近的J积分值也越大,且J积分值在反映载荷变化时具有较高的敏感性。
As the precondition for rapid detection and accurate evaluation of bridge safety by using the dynamic test method,the dynamic characteristics and its change rules of bridge structure under different damaged conditions must be mastered accurately. However, the researches for fracture mechanical characteristics of concrete girder bridge with different cracks under vehicle loads are inadequate. Taking reinforced concrete simply supported hollow slab as the research object,based on the fracture mechanics theory,the fracture mechanical characteristics of concrete simply supported hollow slab with different crack depths under vehicle load are analyzed by applying the finite element numerical simulation method. The crack depth is determined based on the number of layers of reinforced bars in the bottom of the hollow plate.Through the calculation and analysis of different cracking depths in the middle part of a 8 m standard span concrete hollow slab under vehicle load,it is obtained that( 1) The J integral value on hollow slab cross-section near the cracks under different working conditions firstly increased and then decreased from sides to center along the crack. Namely,the size of the J integral value near the crack associated with the clear height of hollow slab cross-section. The smaller the clear height,the greater the J integral value,and vice versa,and the J integral value associated with the clear height of hollow slab cross-section under the same loading mode.( 2) With the increase of crack depth under the same loading mode,the J integral value and crack opening increased geometrically,while the crack tip Von Mises stress increased approximate linearly.( 3) In the same crack depth,the J integral value near the cracks increased with the increase of vehicle load,and the J integral value is highly sensitive with the change of load.
作者
周术明
颜东煌
ZHOU Shu-ming;YAN Dong-huang(School of Civil Engineering,Changsha University of Science and Technology,Changsha Hunan 410114,China;Hunan City University,Yiyang Hunan 413000,China)
出处
《公路交通科技》
CAS
CSCD
北大核心
2019年第1期94-101,共8页
Journal of Highway and Transportation Research and Development
基金
国家自然科学基金项目(51678068)
长沙理工大学2016年研究生创新性课题项目(CX2016BS02)
关键词
桥梁工程
断裂力学特征
数值计算
混凝土空心板
车辆荷载
bridge engineering
fracture mechanical characteristic
numerical simulation
concrete hollow slab
vehicle load
