节段预制拼装波形钢腹板连续组合箱梁抗弯性能试验研究

EXPERIMENTAL STUDY ON FLEXURAL PERFORMANCE OF PRECAST SEGMENTAL ASSEMBLED CONTINUOUS BOX GIRDER WITH CORRUGATED STEEL WEBS

  • 摘要: 为研究波形钢腹板连续组合箱梁在整体现浇和节段预制拼装施工工艺下抗弯性能的差异,对一片节段预制拼装变截面波形钢腹板连续箱梁和一片相同尺寸的整体式波形钢腹板连续箱梁进行了抗弯性能试验,分析了接缝的存在对节段预制波形钢腹板连续梁不同特征截面上应变的分布、荷载-挠度曲线变化、预应力增量的影响,并对两片梁的破坏形态进行了分析,试验结果表明:加载初期,接缝的存在对试验梁刚度影响较小,两片梁的应变和变形接近。开裂后节段拼装梁节段接缝间的混凝土应变相对整体梁偏小,但接缝处的混凝土应变较大,接缝位置的塑性变形使得内力重分布现象更加明显;整体梁出现典型的弯曲裂缝,而节段拼装梁裂缝数量在整个过程中相对较少,集中出现在节段两侧接缝位置;在塑性阶段,节段梁变形主要发生在接缝位置,梁体变形相对较大,而边跨相对于中跨挠度变化较小。节段拼装梁的预应力筋相比于整体梁发挥了更大的作用,应力增长速率更快,且节段拼装梁有效高度变化小于整体梁。提出了节段预制拼装波形钢腹板连续箱梁抗弯承载力计算公式,且公式计算值与试验结果吻合程度较好。

     

    Abstract: In order to study the difference in flexural performance of continuous composite box girder with corrugated steel webs between under monolithic cast-in-place construction technology and under segmental precast assembled construction technology, a precast segmental continuous box girder with corrugated steel webs and variable cross-section and a monolithic continuous box girder with corrugated steel webs of the same size were tested. The influence of the existence of joints on the strain distribution, the change of load-deflection and prestress increment on different sections of precast segmental continuous girder with corrugated steel webs was analyzed. The failure modes of the two girders were analyzed. The results show that the existence of joints has little influence on the stiffness of the test girder at the initial loading stage, and the strain and deformation of the two girders are similar. The concrete strain between the joints of the segmental assembled girder after cracking is relatively small compared with the monolithic cast girder, but the concrete strain at the joints is relatively large. The plastic deformation of the joints makes the internal force redistribution more obvious. The cracks in the monolithic cast girder are typical bending cracks. The number of cracks in segmental assembled girder is relatively small in the whole process and the distribution range of cracks is mainly in the joints on both sides of segments. In the plastic stage, the deformation of segmental girder mainly occurs at the joints, and the deformation of beam body is relatively large. The deflection of the side span is smaller than that of the middle span. The prestressed reinforcement of the segmental assembled girder plays a greater role than the monolithic cast girder, and the growth rate of the stress is faster. The change of the effective height of the segmental assembled girder is less than that of the monolithic cast girder. The calculation formula of bending capacity of precast segmental assembled continuous box girder with corrugated steel webs is proposed, and the calculated values of the formula are in good agreement with the experimental results.

     

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