论文部分内容阅读
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。
In order to deeply study and explore the cause of cracking of the bottom of prestressed PC hollow slab bridge and quantitatively analyze the influence of various cracking factors on the main tensile stress of the beam bottom and its sensitivity and make it clear that the design, construction and operation of this kind of bridge in the process of controlling the beam Based on a 3 × 20m hollow slab simply supported girder bridge as the engineering background, a finite element model of multi-girder and single girder was established by using the corresponding rotational crack model in MIDAS FEA. The structure of the multi-girder was considered as 1 Beam and two beams, single beam structure only consider the case of central beam veneer stress, finite element simulation analysis prestressing steel strands, prestressing loss, overload, concrete strength reduction, the overall temperature difference and the support off Air and other factors on the impact of the main tensile stress, and the use of linear regression model analysis of the various factors of cracking sensitivity. The results show that the sensitivity of prestressed PC hollow slab to the bottom cracking of prestressed PC hollow slab is affected by the loss of prestressing force, overloading, the overall temperature difference, the emptying of bearing, the deflection of prestressed steel strands and the decreasing of concrete strength. Forced by the force of the beam at the end of the more negative, exacerbated by the impact of various factors under the beam bottom. The conclusion can provide reference for cracking analysis of prestressed PC Hollow Slab Beam Bridge.