哈尔滨西客站轨道层预应力混凝土结构设计

Prestressed concrete structure design for railway floor of Harbin West Railway Station

针对靠近支座处集中荷载大的大跨度预应力混凝土结构设计时摩擦损失大的问题,采用对比分析方法提出无粘结预应力筋与有粘结预应力筋混合配筋、分段张拉梁侧锚固以及直线配筋共3种配筋方案,计算结果表明,无粘结预应力筋与有粘结预应力筋混合配筋和分段张拉梁侧锚固方法大幅度减小了预应力摩擦损失,有效控制结构裂缝和挠度.非预应力筋和预应力筋的面积通过改进名义拉应力控制裂缝宽度的方法计算,预应力强度比视为已知条件,可保证框架梁端混合配筋时预应力强度比满足规范的限值.为满足相对受压区高度限值的要求,在梁截面尺寸不变的前提下,建议采用梁端受压区配置一定数量受压钢筋的方法。

Focus on the problem that the prestressed stress loss due to friction is great,for the reason that the prestressed concrete structures are super long in length and the force is complicated,in the paper,the hybrid reinforcement by both bonded and unbonded strands,the scheme of sectional stretching of the strands and straight bonded strands are proposed to reduce the loss of prestressed stress due to friction.Calculation result shows that the hybrid reinforcement by both bonded and unbonded strands and the scheme of sectional stretching of the strands can reduce prestressed loss,crack width and deflection.In order to determine the area of non-prestressed steel bar and prestressed steel bar,the crack width control method using improved nominal tensile stress is applied.Taking the ratio of prestressed strength as known condition to ensure total reicforcement ratio not exceed the limit.Compression reinforcements are set in compression zones in the ends of beams to meet the requirement relative of the heights equivalent compression zones for taking the dimendions of beams cross sections as constant.