先张法PC空心板梁桥梁底开裂成因敏感性分析

发布时间：2018-01-26 21:08

本文关键词： 桥梁工程开裂成因先张法PC空心板梁桥主拉应力敏感性分析　出处：《长安大学学报(自然科学版)》2016年06期 　论文类型：期刊论文

【摘要】：为深入研究与探讨先张法PC空心板桥梁底的开裂成因,量化分析多种开裂因素对梁底主拉应力的影响及其敏感性,明确该类桥梁在设计、施工与运营过程中控制梁底开裂现象的侧重点,依托某3×20m的空心板简支梁桥作为工程背景,利用MIDAS FEA中相应的旋转裂缝模型,建立了多梁与单梁有限元模型,多梁结构考虑1片边梁与2片中梁、单梁结构仅考虑中梁单板受力的情况,通过有限元仿真分析预应力钢束偏位、预应力损失、超载、混凝土强度降低、整体温差以及支座脱空等各因素对底板主拉应力的影响,并利用线性回归模型分析比较了各影响因素的开裂敏感性。研究结果表明:各影响因素对先张法PC空心板梁底开裂的敏感性由预应力损失、超载、整体温差、支座脱空、预应力钢束偏位至混凝土强度依次减小;单板受力对梁底受力更加不利,加剧了各影响因素作用下梁底裂缝的产生。所得结论可对已有先张法PC空心板梁桥的开裂分析提供参考依据。
[Abstract]:In order to deeply study and discuss the causes of cracking on the bottom of Zhang Fa PC hollow slab bridge, the influence of various cracking factors on the main tensile stress of the beam bottom and its sensitivity are quantitatively analyzed, and the design of this kind of bridge is made clear. In the course of construction and operation, the key point of controlling the cracking phenomenon of beam bottom depends on a 3 脳 20m hollow slab simply supported beam bridge as the engineering background, and the corresponding rotating crack model in MIDAS FEA is used. The finite element model of multi-beam and single-beam is established. The multi-beam structure considers 1 edge beam and 2 middle beam, and the single beam structure only considers the case of the single slab of the middle beam. The deflection of prestressed steel bundle and the loss of prestressing force are analyzed by finite element simulation. The influence of various factors, such as overloading, concrete strength decreasing, integral temperature difference and pedestal detachment, on the main tensile stress of the bottom slab. The results show that the sensitivity of the influencing factors to the cracking of the first Zhang Fa PC hollow slab beam is caused by the loss of prestress, overload and overall temperature difference. When the support is empty, the deflection of the prestressed steel bundle to the concrete strength decreases in turn. The single slab force is more unfavorable to the beam bottom force, which intensifies the generation of cracks in the beam bottom under the influence of various factors. The conclusions obtained can provide a reference basis for the cracking analysis of Zhang Fa PC hollow slab girder bridge.
【作者单位】：长安大学公路学院;
【基金】：陕西省科技重点项目(2014SZS19-Z02) 陕西省人力资源与社会保障厅项目(110000160004)
【分类号】：U445
【正文快照】： 0引言先张法PC空心板梁桥以其施工简便、自重较轻、受力明确、用材经济等特点,在中国高速公路工程中取得了广泛的应用,但梁底裂缝的出现会对其刚度、承载力以及耐久性能产生不利影响[1-4]。传统桥梁设计中采用的线性杆系与平面理论对混凝土桥梁开裂的研究不够严密且精度较低,

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