应力比对钢桥腹板间隙面外变形疲劳性能的影响试验

发布时间：2018-12-26 07:41

【摘要】：为研究应力比对钢桥面外变形疲劳性能的影响,通过足尺疲劳试验对不同应力比循环荷载作用下钢桥腹板间隙典型细节的疲劳裂纹萌生和扩展机理进行研究。采用5个足尺试件开展了疲劳试验,研究了40mm和60mm腹板间隙在不同应力比循环荷载作用下的裂纹萌生和扩展行为,分析了腹板间隙处腹板与竖向加劲肋焊趾细节应力随着循环荷载变化的规律,得到了应力比对该构造细节面外变形疲劳性能的影响。研究结果表明:腹板间隙处腹板与竖向加劲肋焊趾处面外变形疲劳性能受应力比影响较大,疲劳裂纹从焊趾处萌生后远离竖向加劲肋在腹板内扩展;腹板间隙为40mm、应力比小于0.3时,腹板与竖向加劲肋焊趾处的细节疲劳强度为AASHTO规范中D类和Eurocode规范中的71类;应力比大于0.3且小于0.5时,该细节的疲劳强度降为AASHTO规范中E′类和Eurocode规范中的45类;腹板间隙为60mm、应力比小于0.3时,腹板与竖向加劲肋焊趾处的细节疲劳强度为AASHTO规范中C类和Eurocode规范中的100类;应力比大于0.3且小于0.5时,该细节的疲劳强度降为AASHTO规范中D类和Eurocode规范中的80类;腹板与竖向加劲肋焊趾处疲劳裂纹的扩展速率在高应力比的循环荷载作用下较低应力比循环荷载作用下更快;细节疲劳强度随应力比的增加而显著降低,随腹板间隙的增大有一定程度的提高。
[Abstract]:In order to study the effect of stress ratio on the fatigue behavior of steel bridge deck, the fatigue crack initiation and propagation mechanism of the typical details of web clearance of steel bridge under cyclic load with different stress ratios were studied by full-scale fatigue test. Fatigue tests were carried out on five full-scale specimens. The crack initiation and propagation behavior of 40mm and 60mm web gap under different stress ratios under cyclic loading were studied. The variation of the stress of the web and vertical stiffened rib welding toe with cyclic load at the web clearance is analyzed. The effect of stress ratio on the out-of-plane deformation fatigue performance of the structural details is obtained. The results show that the stress ratio affects the fatigue performance of the web and vertical stiffener welded toe, and the fatigue crack propagates far away from the vertical stiffener in the web after the crack initiation from the weld toe. When the web clearance is 40 mm and the stress ratio is less than 0. 3, the fatigue strength of the welded toe between the web and the vertical stiffened rib is class D in AASHTO code and 71 in Eurocode code. When the stress ratio is greater than 0.3 and less than 0.5, the fatigue strength of this detail is reduced to E 'class in AASHTO code and 45 class in Eurocode code. When the web clearance is 60 mm and the stress ratio is less than 0. 3, the fatigue strength of the welded toe between the web and vertical stiffener is class C in AASHTO code and 100 in Eurocode code. When the stress ratio is greater than 0. 3 and less than 0. 5, the fatigue strength of this detail is reduced to class D in AASHTO code and 80 in Eurocode code. The fatigue crack growth rate of web and vertical stiffened rib welding toe is faster under the cyclic load of high stress ratio than under the cyclic load. The detailed fatigue strength decreases significantly with the increase of stress ratio, and increases with the increase of web clearance to a certain extent.
【作者单位】：长安大学公路学院;长安大学公路大型结构安全教育部工程研究中心;
【基金】：国家重点基础研究发展计划(“九七三”计划)项目(2015CB057703) 国家自然科学基金项目(51578073,51078039) 中央高校基本科研业务费专项资金项目(10821153501,310821153401,310821153314)
【分类号】：U448.36

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