轻型组合桥面UHPC层的弯拉静力及疲劳性能试验研究

发布时间：2018-01-12 08:05

本文关键词：轻型组合桥面UHPC层的弯拉静力及疲劳性能试验研究　出处：《湖南大学》2015年硕士论文　论文类型：学位论文

【摘要】：基于现代桥梁和组合结构的发展要求,针对常规正交异性钢桥面的两大难题,湖南大学邵旭东教授提出将配筋UHPC通过抗剪连接件与钢桥面板形成组合结构而协同受力,即钢-UHPC轻型组合桥面系。本文为探究该组合桥面系的横向抗弯性能,对10块钢-UHPC组合简支板进行试验研究及其开裂强度与承载力分析,得出:保护层厚度与截面配筋率对UHPC层开裂荷载影响十分显著,设计时应当将横桥向钢筋置于纵桥向钢筋之上,并适当提高配筋率;当裂缝宽度小于0.2mm时,荷载与最大裂缝宽度关系近似线性。正弯矩作用下,纯弯段裂缝间距几乎与横向钢筋的间距相同;在极限荷载前,荷载与最大裂缝宽度关系近似线性;钢板将纯弯段UHPC最大裂缝宽度有效限制在0.2mm左右。采用弹性分析方法计算UHPC的开裂强度为18.4MPa~32.7MPa,大于实桥荷载作用下UHPC顶面横向拉应力;采用塑性分析方法计算钢-UHPC组合板的抗弯承载力,与试验值吻合较好。本文基于已建的肇庆马房大桥与在建的岳阳洞庭湖二桥均采用了带纵向开口加劲肋的轻型组合桥面,开展了不同配筋率的工字钢梁-UHPC轻型组合梁弯拉疲劳试验研究,得出:该轻型组合梁低、高配筋率的UHPC层静力弯拉开裂强度crf分别为33.2MPa与54.6MPa;当UHPC拉应力幅均为0.49crf~0.15crf时,低、高配筋UHPC层的等效脉动应力分别为14.8MPa、24.3MPa,低、高配筋截面钢-UHPC轻型组合梁分别历经273.4万次、374.0万次弯拉疲劳荷载后,其整体抗弯刚度只稍微减小,UHPC顶面只出现一条细小横向裂缝,说明该轻型组合梁具有良好的抗弯拉疲劳性能;随着截面配筋率的提高,UHPC层的疲劳开裂寿命明显延长,UHPC剩余弯拉强度越大,并且剩余强度与静载强度的比值也越大。本文分别采用Mode code 2010中的推荐公式、基于我国GB50010-2010规范的修正公式与法国UHPFRC-2013规范的推荐公式计算钢-UHPC轻型组合板的裂缝宽度,对比计算结果与试验值可知:基于我国GB50010-2010规范的修正公式可用于预测组合板在负弯矩作用下的开裂荷载,预测值有一定精度且偏安全;对于对于保护层厚较大的组合板,当裂缝宽度小于0.1mm时,可用法国UHPFRC-2013规范的推荐公式的折减计算值来预测负弯矩作用下UHPC顶面的最大裂缝宽度。
[Abstract]:Based on the development requirements of modern bridges and composite structures, there are two difficult problems in conventional orthotropic steel deck. Professor Shao Xudong of Hunan University proposed that reinforced UHPC should be combined with steel bridge panel to form a composite structure. In order to study the transverse bending behavior of the composite deck system, 10 steel-UHPC composite simply supported plates were tested and their cracking strength and bearing capacity were analyzed. It is concluded that the thickness of the protective layer and the ratio of section reinforcement have a significant effect on the cracking load of UHPC layer. The transverse bridge reinforcement should be placed on the longitudinal bridge steel bar and the reinforcement ratio should be increased properly when designing. When the crack width is less than 0.2 mm, the relationship between the load and the maximum crack width is approximately linear. Before the ultimate load, the relationship between the load and the maximum crack width is approximately linear. The maximum crack width of pure bending segment UHPC is effectively limited to about 0.2 mm. The crack strength of UHPC calculated by elastic analysis method is 18.4MPa ~ 32.7 MPA. The transverse tensile stress of the top surface of UHPC is larger than that of the real bridge. The bending capacity of steel-UHPC composite plate is calculated by plastic analysis method. Based on the existing Zhaoqing Mafang Bridge and the Yueyang Dongting Lake Bridge under construction, the light composite deck with longitudinal stiffening rib is adopted in this paper. The bending and tensile fatigue test of I-beam UHPC light composite beam with different reinforcement ratio was carried out, and it was concluded that the light composite beam was low. The static flexural tensile cracking strength (crf) of UHPC layer with high reinforcement ratio was 33.2 MPA and 54.6 MPA, respectively. When the tensile stress amplitude of UHPC is 0.49 CRF 0.15crf, the equivalent pulsating stress of UHPC layer with high reinforcement is 14.8MPa and 24.3MPa, respectively. The overall flexural stiffness of high reinforced steel-UHPC light composite beams is only slightly reduced after two million seven hundred and thirty-four thousand times and 3.74 million times of flexural and tensile fatigue loading respectively. There is only one small transverse crack on the top surface of UHPC, which indicates that the light composite beam has good flexural and tensile fatigue performance. With the increase of section reinforcement ratio, the fatigue cracking life of UHPC layer obviously prolongs the tensile strength of UHPC residual bending. And the ratio of residual strength to static strength is larger. This paper uses the recommended formula of Mode code 2010. The crack width of steel-UHPC light composite plate is calculated based on the modified formula of GB50010-2010 code in China and the recommended formula of UHPFRC-2013 code in France. Comparing the calculated results with the experimental results, it can be seen that the modified formula based on GB50010-2010 code in China can be used to predict the cracking load of composite plates under negative bending moment, and the prediction value has a certain accuracy and is somewhat safe. For the composite plate with larger cover thickness, the crack width is less than 0.1 mm. The maximum crack width of the top surface of UHPC under negative bending moment can be predicted by the reduction calculation value of the recommended formula of UHPFRC-2013 code in France.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U441

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