南水北调大型渡槽纵梁不均匀挠度对结构的受力影响分析

Effect of Non-Uniform Deflection of Longitudinal Beams on Structure of Large Aqueduct in the South-to-North Water Transfer Project

南水北调中线工程总干渠规模巨大、水头低,沿线大型渡槽设计大量采用多槽一联大跨度预应力钢筋混凝土结构,槽身纵向受力体系由多道纵梁承担,槽身纵向挠度不仅是结构正常运用的一项控制指标,纵梁间的不均匀挠度差对多槽一联的渡槽横向结构的影响也是不能忽视的。纵向结构不均匀挠度差过大,会引起槽身横向结构附加内力过大,甚至引起结构破坏。通过对河北省典型跨河渡槽纵梁不同运行工况的挠度计算,将纵梁间挠度差作为横向计算的初始变位,计算此变位对横向内力的影响。再通过对纵梁预应力的调整,使各种计算工况下纵梁产生挠度对横向结构影响最小,从而达到结构优化的目的。

In the South-to-North Water Transfer Project, the size of the primary channel is huge. Aqueduct design usually is many troughs interconnected with a beam with large span prestressed reinforced concrete structure. The deflection of the longitudinal beams is a control guide for structure＇s operating normally. But non-uniform deflection of the longitudinal beams on the lateral structure cannot be ignored for the transverse structure in the aqueducts. That too large of non-uniform deflection difference of the transverse structure will lead larger additive internal force of aqueduct,which even make the structure destroyed. The deflection of the longitudinal beams of the aqueducts which span the rivers in Hebei Province is calculated under different condition. By adjusting to prestress in longitudinal beams, the effect of the deflection on the transverse structure is reduced to a minimum level. As a result,the structure can get to be optimized.