历经荷载历史的混凝土动弯拉特性研究  

Experimental research on dynamic bending-tension behavior of concrete experienced loading histories

作　　者：任晓军[1,2] 孙吉书[1] 窦远明[1] 

机构地区：[1]河北工业大学土木工程学院,天津300401 [2]天津铁道职业技术学院,天津300240

出　　处：《世界地震工程》2015年第2期127-131,共5页World Earthquake Engineering

基　　金：国家自然科学基金资助项目(50878073)

摘　　要：混凝土结构在使用过程中,受到的荷载情况比较复杂,并且不同荷载作用下的应变速率也相差很大,而混凝土动态抗弯拉力学性能在应力历史方面的研究起着重要的作用。因此在对前人研究方法和结果总结的基础上,针对中低强度混凝土被广泛使用的现状,利用MTS加载装置和先进的数据采集仪,采用适当的试件制作方法和加载工艺,当应变速率分别为10-6/s、10-5/s、10-4/s时,对强度为C35的混凝土试件,进行了相应的动态抗弯拉试验,分析了应变速率和应力历史对混凝土动态抗弯拉力学性能和变形性能的影响。试验结果表明:随着应变速率的增大,经历荷载历史后,混凝土的动态抗弯拉强度逐渐增大,同时,混凝土的动态抗弯拉弹性模量也呈增长趋势,峰值应变较直接加载而言,数值变大;混凝土的泊松比受荷载历史和应变速率的影响不大。The load conditions of the concrete structure is very complex in use process, and the strain rates under different load are also vary widely. So, it is very important to research the concrete dynamic bending performance in experience of loading history. Based on the previous research methods and the summary of the results and aiming at the current situation of widely used low strength concrete, we carried out a dynamic bending tensile test on the C35 concrete specimens on the basis of summarizing the previous research results, using the MTS loading devices and advanced data acquisition instrument and adopting the appropriate methods of making specimen and loading process. Dynamic bending tensile experiment was conducted using different strain rates, such as 10-6/s, 10-5/s, 10 -4/s and so on. The influence of strain rates and stress history on dynamic bending performance and deformation performance of the concrete was analyzed. Experimental results show that the dynamical bending strength and elas- tic modulus of concrete increase with increase of strain rates and load histories. Peak value of the strain is larger than that under direct loading. The effect of the strain rate and load histories on Poisson＇ s ratio is not obvious.

关 键 词：混凝土 荷载历史 动态抗弯拉强度 弹性模量 变形特性 

分 类 号：U442.55[建筑科学—桥梁与隧道工程]