基于裂缝分布特征的桥梁损伤评价与计算方法研究

发布时间：2018-01-08 11:40

本文关键词：基于裂缝分布特征的桥梁损伤评价与计算方法研究　出处：《河北工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：钢筋混凝土是目前桥梁中应用最为广泛的材料,但随着运营时间的不断推移,在多种因素的影响下,既有钢筋混凝土桥梁经常会出现各种损伤,其中裂缝是最主要的表现形式之一。为确保结构的安全性,对裂缝这一主要病害特征开展研究,继而对结构的损伤状况和承载能力作出评价具有极为重要的理论价值和现实意义。本文首先归纳了钢筋混凝土裂缝的分类及成因,介绍了X-FEM裂缝损伤扩展有限元理论及在ABAQUS软件中的应用。而后以简支梁和连续梁为研究对象,在前人二维模型的基础上,建立了更为真实的三维实体损伤模型,据此分别研究了受弯竖向裂缝、受剪斜裂缝、裂缝数量以及混凝土配筋量、钢筋形状、是否带初始微裂缝等多种工况下结构的损伤状况和承载能力,获得主要结论如下:(1)有无初始微裂缝的简支梁,在相同荷载作用下后期产生的裂缝在高度和宽度上较为相近,钢筋应力也无太大差异,说明有无初始微裂缝对结构损伤影响较小。同时发现,在三维模型中局部裂缝开裂位置处的钢筋要比两边的钢筋损伤要大,这一点在二维模型中无法体现。(2)相同简支梁在单条初始裂缝的情况下,以裂缝高度为指标的无筋梁、少筋梁、适筋梁和超筋梁的损伤呈明显递减的趋势,且不配置钢筋与配筋量较少时,混凝土的损伤状况均较为严重,而超筋梁存在发生突然破坏的潜在风险。多条裂缝的计算结果与单条裂缝一致。(3)在斜裂缝处,钢筋弯起后与弯起前相比,其应力值削减近一倍,同时裂缝长度亦明显缩减,说明在支座附近处将钢筋弯起是一种降低结构损伤、抑制斜裂缝扩展的有效方法。(4)对相同载荷作用下的连续梁而言,相比仅正裂缝存在的情况,斜裂缝和正裂缝的同时出现,由于梁内部应力的重新分布,正裂缝的开展反而相对缓慢,裂缝高度变低,受弯区的损伤亦减轻。
[Abstract]:Reinforced concrete bridge is currently the most widely used material for the application, but with the continued operation time, under the influence of various factors, existing reinforced concrete bridge will often appear all sorts of damage, crack is one of the most important form. In order to ensure the safety of the structure, to carry out research on the main diseases of crack then the characteristics, structural damage and bearing capacity evaluation has extremely important theoretical value and practical significance. This paper summarizes the classification and causes of concrete cracks, introduces the application of the extended finite element theory and ABAQUS software X-FEM. Then the crack damage of the simply supported beam and continuous beam as the research object, in the based on the two-dimensional model, a three-dimensional damage model is true, according to respectively study the flexural vertical cracks, shear crack, crack number and Reinforced concrete, reinforced with initial shape, whether micro cracks under conditions such as structural damage and bearing capacity, the main conclusions are as follows: (1) beams with no initial micro cracks, cracks in the later stage under the same load in height and width are similar, the steel stress is not so there is no big difference, that the initial micro cracks on the structure damage influence. At the same time, the reinforced local cracking position of 3D model than reinforced damage on both sides of the larger, this point in the 2D model can not reflect the. (2) the same beam in a single initial crack under the condition of the fracture height as an indicator of the beams, reinforced beam, reinforced Liang Hechao beam damage showed a decreasing trend, and the allocation of less reinforcement and reinforcement, damage of concrete are more serious, and there are sudden destruction over reinforced beam The potential risk of cracks. The calculation results are consistent with a single crack. (3) in the oblique cracks, bending up and bend than before, the stress value cut nearly doubled, while crack length is also significantly reduced, in the vicinity of the bearing steel bend is a structure for reducing loss injury, effective method to suppress the oblique crack propagation. (4) of the continuous beam under the same load, there is only compared to the cracks, cracks and cracks at the same time, due to the re distribution of internal stress of the beam, is the development of cracks but relatively slow crack height low, bending the injury was alleviated.

【学位授予单位】：河北工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U446

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