黄土沟谷地区格构式高墩偏位及受力性能分析

Deflection and Mechanical Behavior Analysis of Lattice High Pier in Loess Gully Area

黄土沟谷地区格构式高墩在施工以及使用过程中,由于受到不同因素的影响,其墩身可能会产生一定的偏位。为研究其偏位对墩身受力以及损伤性能的影响,以河沟大桥4#高墩为研究对象,利用有限元软件Midas Civil和ABAQUS研究分析了高墩在最不利荷载状态下墩顶的最大偏位值以及偏位后的墩身的受力性能和损伤性能。研究结果表明:最不利荷载作用下墩顶最大偏位为35 cm;当墩顶偏位最大时,墩顶水平推力小于混凝土破坏时的水平推力临界值,此时,墩身受压侧混凝土压应力之比与墩体受拉侧钢筋拉应力之比均小于规范允许上限值,墩身混凝土未发生完全破坏;在墩顶最大偏位位移下,墩身受拉损伤因子相比墩身受压损伤因子较大,墩身受拉损伤比较严重。可见黄土沟谷地区格构式高墩施工应控制墩顶偏位,降低对墩体承载力的消弱。

During the construction and use of lattice type high piers in loess gully area,the piers may produce certain deflection due to the influence of different factors.In order to study the influence of the deflection on the force and damage performance of the pier body,the 4#high pier of the river trench bridge was taken as the research object,the finite element software Midas Civil and ABAQUS were used to study and analyze the maximum deflection value of the pier top under the most unfavorable load condition and the force and damage performance of the pier body after the deflection.The research results show that:the maximum deflection of the pier top under the most unfavorable load is 35 cm.When the maximum deviation of the pier top,the pier top horizontal thrust is less than the critical value of the horizontal thrust when the concrete damage,at this time,the ratio of the compressive stress of the concrete on the compressive side of the pier body and the tensile stress of the reinforcement on the tensile side of the pier body are less than the upper limit allowed by the code,the concrete of the pier body is not completely damaged.Under the maximum deviation displacement of the pier top,the tensile damage factor of the pier body is larger than the compressive damage factor of the pier body,and the tensile damage of the pier body is more serious.It is concluded that construction of lattice high piers in loess gully areas should control the top deflection to reduce the weakening of pier bearing capacity.