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通过模型试验,得到预应力密排框架箱型地铁车站结构在静力荷载作用下的受力特点、破坏特征和构造要求。在极限荷载作用下,两个模型均在顶梁支座处受弯破坏,受拉区钢筋的拉应力达到了屈服强度,受压区混凝土被压坏,结构总体呈现刚架的变形性状,顶梁端部加腋的加强效果对顶梁承载力的提高作用明显;中板出现轴拉裂缝,最终在支座处开裂破坏;两组模型基底反力都呈现跨中小、支座大的分布规律,基础反拱明显。实际工程中,当采用环向预应力束时,应在顶梁和底梁均设置张拉端,控制预应力筋的最小曲率半径,在节点部位加强暗梁和钢筋锚固,将基础适当外挑以调整侧墙下过大的地基反力。
Through the model test, the mechanical characteristics, failure characteristics and structural requirements of the metro station structure under the static load are obtained. Under the action of ultimate load, both of the two models suffered bending failure at the top beam bearing. The tensile stress of the steel bar in the tension zone reached the yield strength, and the concrete in the compression zone was crushed. The overall structure showed the deformation characteristics of the rigid frame, The strengthening effect of the end of the beam plus the axilla significantly enhances the bearing capacity of the top beam; the axial crack occurs in the middle plate and finally cracks and ruptures at the support; the reaction force of the two groups exhibits a large distributional law across the middle and small bearings , The basis of arches obvious. In practical engineering, when using the circumferential prestressing beam, the top and bottom beams shall be provided with tensioning ends to control the minimum radius of curvature of the prestressing tendons, to reinforce the hidden beam and the reinforcing steel anchorage at the node parts, To adjust the side wall under excessive ground reaction.