钢箱梁竖向波纹腹板剪力与磁记忆场强关系的试验研究

(1. 西安建筑科技大学 土木工程学院,陕西 西安 710055; 2. 成都基准方中建筑设计有限公司,四川 成都 610021;3. 西安科技大学 建筑与土木工程学院,陕西 西安 710054)

桥梁钢结构; 抗剪性能; 磁记忆检测; 钢箱梁; 波纹钢腹板

Experimental research on the relationship between shear force and magnetic memory field strength of vertical corrugated webs of steel box girder
WANG Wei1, REN Yingzi1,SU Sanqing1, MA Xiaoping1, NIU Xiaobo2,DONG Lining3

(1.School of Civil Engineering, Xi'an Univ. of Arch. & Tech. Xi'an 710055, China;2. Chengdu Benchmark Building Design Co., Ltd., Chengdu 610021, China;3.School of Architecture and Civil Engineering, Xi'an University of Science and Technology, Xi'an 710054, China)

bridge steel structure; shear performance; magnetic memory testing; steel box girder; corrugated steel web

DOI: 10.15986j.1006-7930.2019.03.004

备注

金属磁记忆检测技术是一种新型的无损检测技术,其原理是基于铁磁构件表面产生的漏磁场进行检测.通过Q345qC波纹腹板钢箱梁的四点受弯试验,分析了竖向腹板表面的磁记忆信号沿梁高度方向的变化规律,发现在波纹腹板表面磁记忆信号曲线上,竖向集中力加载位置出现磁记忆场强“波峰”极值,且随着荷载的增大,“波峰”幅值越高,应力集中程度增大; 试件失稳时,磁记忆信号发生正负突变,以此可作为试件失稳时的评判特征; 随着检测线离集中力加载位置越远,“波峰”幅值越低; 随着标定高度的增大,磁记忆信号减小; 沿腹板高度方向区域平均磁记忆信号变化率与腹板高度无关,而主要与两个因素有关:其一是纯弯段或弯剪段区域位置,其二是施加的荷载大小; 弯剪段区域的绝对值随荷载的增加先增大后减小,磁记忆信号平均变化速率存在阈值.

Metal magnetic memory testing is a new nondestructive testing technology based on the magnetic flux leakage field of ferromagnetic components. In the four point bending experiment of Q345qC steel box girder, the variation rule of magnetic recording signal along the beam height direction on the vertical web surface were analyzed. And the relationship curve between magnetic memory signal and loading value were obtained. At the vertical concentrated force loading position, magnetic memory signal curve have a “peak” extreme value, and with the loading increasing, the peak amplitude become bigger, at the same time, the stress concentration increased also. When the steel box girder lose the stability state, magnetic memory signal have a mutations, from positive value change to negative value and vice versa, which may be used as a judgment to diagnose the instability situation for the girder. With the detection line farther away from the concentrated loading position, the wave peak amplitude is decreasing. With the increasing of height calibration, magnetic memory signal decreases. There are two main factors that influence the regional average magnetic memory signal change rate along the height direction of web, one is shear bending or pure bending region and the other is the magnitude of the applied loads, which, but no relate with the height value of web. The absolute value of the change rate of the magnetic memory signal increases initial and then decreases with the increasing of the loading.