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为提高桥梁结构抵抗变形的能力,以满足高速铁路迅猛发展对梁结构变形要求的提高,本文提出预应力活性粉末混凝土(RPC)-普通混凝土(NC)叠合梁结构形式,并设计了10根预应力RPC-NC叠合模型梁和1根NC对照梁。试验研究了预应力度、RPC高度、NC等级等因素影响下叠合梁跨中挠度发展特性及计算方法。研究表明:叠合梁跨中挠度发展可分为三个阶段:开裂前弹性阶段;带裂缝工作阶段;普通钢筋屈服后迅速增长阶段。预应力度越高,开裂前弹性段越长,开裂后屈服和强化阶段的刚度下降越快;根据试验值对铁路桥规和混凝土规范中的公式进行修正,修正后的计算结果与试验值吻合良好。
In order to improve the ability of the bridge structure to resist deformation and to meet the requirement of the rapid deformation of the high-speed railway, the present paper proposes a prestressed reactive powder concrete (RPC) -structured concrete (NC) composite beam structure and designs 10 Prestressed RPC-NC Laminated Model Beam and One NC Control Beam. The development and calculation method of midspan deflection of composite beam under the influence of prestressing force, RPC height and NC grade were studied. The research shows that the mid-span deflection of composite beams can be divided into three stages: the pre-cracking elastic stage, the working stage with cracks and the rapid growth stage of ordinary steel after yielding. The higher the prestressing force, the longer the elastic section before cracking, and the faster the stiffness decrease during the yielding and strengthening stages after cracking. According to the experimental values, the formulas in the railway bridge gauge and concrete code are corrected, and the corrected calculation results are consistent with the experimental values good.