钢筋混凝土铰支约束梁抗冲击性能试验研究  

Experimental study on impact behavior of hinged RC beams

作　　者：孟一[1] 易伟建[2] 黄方林[1] MENG Yi1, YI Weijian2, HUANG Fanglin1(1. School of Civil Engineering, Central South University, Changsha 410075, China; 2. School of Civil Engineering, Hunan University, Changsha 410082, Chin)

机构地区：[1]中南大学土木工程学院,湖南长沙410075 [2]湖南大学土木工程学院,湖南长沙410082

出　　处：《建筑结构学报》2018年第4期82-90,共9页Journal of Building Structures

基　　金：国家自然科学基金项目(51378504)

摘　　要：为研究钢筋混凝土（RC）框架梁抗冲击特性,取其反弯点间子结构作为试验对象,采用铰支约束边界,对两组试验梁分别进行了落锤冲击加载和静力加载,利用LS-DYNA显式有限元程序对冲击试验进行了数值模拟,并对试验工况进行了扩展分析。结果表明：试验梁在冲击和静力加载下破坏特性差异显著,在冲击加载下,随冲击速度的增加,梁抗冲击特性逐渐由局部破坏所控制,多次冲击加载对梁损伤累积作用明显;在静力加载下,通过梁自身的大变形及开裂抵抗外部荷载,裂缝分布范围广而密集,且发展充分。试验结果和模拟结果均显示,在试验梁纵筋配筋率较低时,增加受拉区纵筋能显著改善RC梁的抗冲击性能,但随着配筋率的提高,梁抗冲击性能逐渐由局部破坏所控制,数值模拟结果表明,配筋率和抗冲击临界垮塌耗能间大致呈抛物线关系,通过与试验梁静力加载失效耗能对比,可以偏保守地取静力加载失效耗能的90%作为试验梁抗冲击垮塌临界耗能,用以评估其抗冲击性能。In order to study the impact resistance behavior of RC beams, a series of static loading tests and drop weight impact tests were carried out on hinged RC beams. Numerical simulations for the impact tests were carried out using LS-DYNA, and then extended parametric studies were conducted. The test results show that： the failure characteristics of the RC beam under impact loading and static loading conditions are evidently different. Under impact loading, local damage governed the impact resistance of the RC beams with increase in the impact velocity ; the damage is also greatly accumulated under repeated impact loading. Under static loading, the RC beams sustain the external loading through large deformation as well as intensive and well-developed cracking. Both the test and simulation results show that： an increase of the longitudinal reinforcement in the tension zone of RC beam can directly improve the impact resistance of the RC beams when longitudinal reinforcement ratio is relatively low. However, with increase in the reinforcement ratio, the impact resistance of the RC beams is gradually governed by local failure. The numerical simulation results show that the relationship between the longitudinal reinforcement ratio and the critical energy dissipation of RC beam follows a parabolic trend. By comparing the static energy dissipation of RC beam and extended numerical results, it is suggested that 90% of the static energy dissipation capacity can be taken as the critical energy dissipation when evaluating the impact resistance of RC beams.

关 键 词：钢筋混凝土梁 低速冲击 落锤试验 抗冲击性能 

分 类 号：TU375.103[建筑科学—结构工程]