温度应力对铁路预制装配式空心桥墩壁厚及预应力的影响分析

和(田)若(羌)铁路预制装配式桥墩采用了双柱圆形空心墩的结构形式和预应力钢筋的连接形式.由于线路所在区域昼夜温差大,墩壁内外侧易产生较大的温度应力.本文通过建立实体单元有限元模型,分析温度应力在墩身的分布情况.结果表明:在不同墩柱壁厚设计条件下产生的温度应力差异较大,采用预应力钢筋连接方案时需要施加的消压预应力不同.壁...

Analysis on Influence of Temperature Stress on Wall Thickness and Prestress of Prefabricated Assembly Railway Hollow Pier

The prefabricated assembly pier of Hetian-Ruoqiang railway adopts the structural form of double-column circular hollow pier and the connection form of prestressing steel bars.The railway is located in an area with large temperature difference between day and night,which is easy to generate large temperature stress inside and outside the pier wall.The distribution of temperature stress in the pier was analyzed by establishing the solid element finite element model.The results show that the temperature stress produced under the design conditions of different pier wall thickness is quite different,and the dissipation prestress required to be applied when using the prestressed reinforcement connection scheme is different.For hollow piers with wall thickness of 0.3,0.4 and 0.5 m,4 000,5 000 and 6 000 k N prestress shall be applied to ensure the pier stiffness and produce pressure dissipation effect at the same time.When the pier is affected by the cold wave temperature load,the prestress of hollow pier with wall thickness of 0.3,0.4 and 0.5 m needs to be increased by 6 600,9 000 and 10 800 k N.In the actual project,the reasonable thickness of hollow pier wall shall be selected according to the temperature stress under the design conditions of different wall thickness,combined with the diameter of pier column,the construction technology of prefabricated assembly construction process and prestressed duct construction requirements.And the prefabricated pier of Hetian-Ruoqiang railway finally selects the double-column hollow pier with wall thickness of 0.4 m.