在役空心板桥梁拆除构件室内破坏试验  

In-house destructive test of dismantled component of existing hollow slab bridge

作　　者：渠广镇[1,2] 周广利 黄平明 韩万水[1] 巩文龙[2] 袁阳光 QU Guang-zhen;ZHOU Guang-li;HUANG Ping-ming;HAN Wan-shui;GONG Wen-long;YUAN Yang-guang(School of Highway,Chang'an University,Xi'an 710064,Shaanxi,China;School of Highway,Chang'an University,Xi'an 710064,Shaanxi,China Shandong Transportation Research Institute,Jinan 250012,Shandong,China;School of Civil Engineering,Xi'an University of Architecture and Technology,Xi'an 710055,Shaanxi,China)

机构地区：[1]长安大学公路学院,陕西西安710064 [2]山东省交通科学研究院,山东济南250012 [3]西安建筑科技大学土木工程学院,陕西西安710055

出　　处：《长安大学学报（自然科学版）》2019年第6期57-66,共10页Journal of Chang’an University(Natural Science Edition)

基　　金：国家自然科学基金项目(51878058);山东交通科技创新项目(2016B49);中央高校基本科研业务费专项资金项目(300102218702,310821162008,300102218209,300102218403)

摘　　要：为准确评估服役24年后空心板梁的剩余承载能力,将济青(济南—青岛)高速公路改扩建工程中一空心板梁桥拆除并运回实验室进行破坏试验,对空心板关键位置的静力响应指标,如梁体挠度、钢筋应变、混凝土应变及裂缝发展等进行测试,同时对梁体在主要荷载步下的动力特性进行测试。研究结果表明:空心板跨中挠度-正弯矩曲线呈明显的双折线变化规律,实际塑性转折点对应弯矩值分别为公路-Ⅰ级、汽-超20设计荷载效应的2.50倍及4.09倍;空心板进入塑性阶段主要由部分钢筋率先屈服所引起;破坏试验过程中,空心板中性轴由最初位置上移了6.9 cm,受此影响,距离梁底较高的混凝土压应变呈现先增后减的变化规律;进入塑性阶段前,腹板主裂缝宽度增长相对缓慢且基本在0.3 mm以下,之后裂缝增长明显而跨中弯矩增长很小;就动力特性而言,前期试验中空心板自振频率变化微弱,而进入塑性阶段后,空心板一阶振动频率下降明显,基于模态柔度差可进一步对进入塑性阶段前的空心板损伤程度进行量化;由破坏试验所确定空心板梁实际抗弯承载力为规范计算承载力的1.52倍。In order to accurately assess the residual bearing capacity of the hollow slab beam after 24 years of service,a hollow slab girder bridge of Jiqing Highway Reconstruction Project was demolished and transported to the laboratory for failure test.The key position static response indicators such as beam deflection,steel strain,concrete strain,crack development etc,of the hollow slab were tested during the whole test,and the dynamic characteristics of the beam under the main load step were tested too.The results show that the mid-span vertical displacement-moment curve as an obvious double folding line change.The bending moment corresponding with the actual plastic turning point are 2.5 times and 4.09 times as the design values of two kinds of design vehicle loads,Highway-classⅠand Aubomobile-over 20 respectively.The entering to plastic stage of the hollow slab is mainly caused by the yielding of part of the tensile reinforcements.During the destructive test,the neutral axis of the slab shift up about 6.9 cm from the original location,which induce that the compressive strain of the concrete of the superior border firstly increasing with the loading level and then decreases.Before entering the plastic stage,the width of the main crack of the web increase relatively slowly and is basically below 0.3 mm,and then the crack grow quickly,however the growth of the mid-span bending moment is slow.In terms of dynamic characteristics,the self-vibration frequency of the hollow slab in the preliminary test is weak,and after entering the plastic working stage,the first-order frequency of the hollow slab decrease significantly.Based on the modal flexibility difference,the hollow slab damage before entering the plastic working stage can be further quantified.The actual flexural capacity of the hollow slab beam which determined by the failure test is 1.52 times the normal calculated bearing capacity,12 figs,26 refs.

关 键 词：桥梁工程 在役空心板桥梁 破坏试验 全过程静动力特性 模态柔度差 承载力 

分 类 号：U445.6[建筑科学—桥梁与隧道工程]