强受扭损伤箱梁加固后的压弯性能研究

发布时间：2018-07-02 21:16

本文选题：桥梁工程 + 压弯性能　；参考：《公路交通科技》2017年12期

【摘要】：为研究某特大跨双索面混凝土斜拉桥因火灾致强受扭损伤的混凝土箱梁能否修复使用,对强受扭损伤加固后主梁的压弯刚度、扭转刚度及抗弯极限承载力开展了模型试验研究,评估灌浆-锚钢加固对主梁的压弯刚度及扭转刚度的影响。依据常用规范公式对箱梁抗弯极限承载力及正常使用极限状态下的变形、裂缝特征进行验算,评估规范中相应计算公式的适用性,并对加固箱梁在压弯荷载作用下的破坏形态进行对比分析。结果表明:灌浆-锚钢加固能有效地提高弯扭剪复合受力下箱梁的压弯刚度及扭转刚度;在压弯荷载作用下,加固梁的最终破坏形态为箱梁底板拉裂至钢筋屈服破坏,顶板混凝土没有被压溃,腹板锚贴钢板基本无损坏,但顶板锚贴钢板与混凝土界面发生了剥离现象,钢绞线未被拉断;GB50010—2010、JTG D62—2012、ACI318M-05规范均能较为准确地计算箱梁的抗弯极限承载力,ACI318M-05规范计算试验梁在正常使用极限状态下的跨中挠度值与实测值较为接近,基本能反映预应力混凝土箱梁正常使用极限状态下的变形性能;GB50010—2010规范计算试验梁的最大裂缝宽度和裂缝间距与实测值均较为接近,基本能反映预应力混凝土大比例缩尺箱梁的裂缝特性。
[Abstract]:In order to study whether the concrete box girder with strong torsional damage caused by fire can be repaired or used in a long-span double-cable plane concrete cable-stayed bridge, a model test study has been carried out on the compression and bending stiffness, torsional stiffness and ultimate flexural capacity of the main girder strengthened by strong torsional damage. The effect of grouting-anchor steel reinforcement on the bending stiffness and torsional stiffness of the main beam was evaluated. According to the commonly used code formula, the bending ultimate bearing capacity of box girder and the deformation and crack characteristics of box girder under the limit state of normal use are checked and calculated, and the applicability of the corresponding calculation formula in the code is evaluated. The failure modes of the strengthened box girder under the load of compression and bending are compared and analyzed. The results show that grouting and anchor steel reinforcement can effectively improve the bending stiffness and torsional stiffness of the box girder under the combined bending and torsional shear forces, and the ultimate failure mode of the strengthened beam under compression and bending loads is that the bottom plate of the box girder is cracked to the yield of the steel bar. The concrete of roof is not crushed, and the steel plate of web anchor is not damaged, but the interface between the steel plate and concrete is peeled off. The code of JTG D62-2012ACI318M-05 can calculate the ultimate flexural capacity of box girder accurately. ACI318M-05 code can calculate the deflection value of the test beam in the normal service limit state, which is close to the measured value. The deformation performance of prestressed concrete box girder can be basically reflected under the limit state of normal use. The maximum crack width and crack spacing of the test beam calculated in GB50010-2010 code are close to the measured values. It can basically reflect the crack characteristics of prestressed concrete large scale box girder.
【作者单位】：长沙理工大学土木与建筑学院;
【基金】：国家重点基础研究发展规划(九七三计划)项目(2015CB057706) 国家自然科学基金项目(51678068,51678070)
【分类号】：U441;U445.72

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