高墩大跨连续刚构桥的稳定性分析

Analysis of Stability of Long-span Continuous Rigid Frame Bridge with High Pier

研究目的:西部地区及偏远地区受地形条件的限制,修建公路时常需要跨越河流、沟谷等复杂地形,因此高墩大跨连续刚沟桥的修建日益增多,其墩高也由原来的几十米提升到了上百米的高度,随着墩高的增大、跨径的增长,对该类桥型稳定性问题的研究就显得尤为重要。研究结论:本文以山西省某(90+168+90)m高墩大跨连续刚构桥为工程背景,分别进行了高墩自体稳定性分析、施工阶段最大悬臂状态稳定性分析以及成桥阶段稳定性分析。通过计算可知:(1)高墩自体稳定性分析中,温度效应对高墩稳定性的影响较小;(2)施工阶段最大悬臂阶段的稳定性分析中,各向风荷载中顺桥向的风荷载对结构的稳定性最为不利;(3)成桥阶段的稳定性分析中,当车道荷载和人群荷载的均布力布置于中跨时对成桥的稳定性最为不利,风荷载对成桥阶段的稳定性影响较小,而温度效应对稳定性的影响则不可忽略;(4)该桥在施工过程中以及成桥阶段均具有良好的稳定性,计算分析过程对实际工程中高墩大跨连续刚构桥梁的稳定性分析具有一定的参考价值。

Research purposes： The highway in western China or the remote region needs to cross over rivers and valleys and passes the regions with complex terrains due to the limitation of topographical condition. For this reason, the long - span continuous rigid frame bridge with high pier becomes more and more and the height of the bridge increases from several decameters to hundreds of meters. With increases of the pier height and the span length, the research on the stability of such kind of bridge is becoming more and more important. Research conclusions：Taking the long- span continuous rigid frame bridge with （90 ＋ 168 ＋ 90） m high pier in Shanxi province as the engineering background, the basic principle related to the structure stability is discussed and the stability of the high pier, the stability of the longest cantilever during construction and the stability in complete stage of the bridge are analyzed. From the calculation results it can be seen that for the bridge presented in this paper, the temperature effect has a little influence on the high pier stability, the wind load along the bridge axial direction has the most negative impact on the structure stability in the construction stage of the longest cantilever, and during the complete stage of the bridge, the lane load and the load of the crowded people set on the middle span has the most negative impact on the bridge stability. Furthermore, wind has a little influence and the influence of the temperature effect can be ignored in this stage. The calculation results also show this bridge has a good stability during its construction process and in the complete stage of bridge. The calculation and analysis processes presented in this paper can provide the reference to the similar works.