点蚀对钢箱梁受力性能的影响研究
发布时间：2018-10-14 16:39
【摘要】：锈蚀是影响钢结构耐久性的重要影响因素之一。本文以工程中应用广泛的中等跨径钢箱梁桥为研究对象,采用理论、试验与数值模拟相结合的方法,分析了点蚀影响下钢梁受力特性,研究了点蚀对钢箱梁腹板屈曲特性和极限承载力的影响。主要研究内容可以分为4个部分:(1)对3根均匀锈蚀和6根点蚀钢梁分别进行了静力加载试验和有限元分析,研究了蚀坑的几何尺寸(大小及深度)和分布对钢梁承载力及破坏形态的影响。结果表明失重率是影响均匀锈蚀钢材材料性能和钢梁承载力的关键因素,但失重率不能全面衡量钢梁的点蚀损伤程度;相同DOP条件下,蚀坑深度越大,极限承载力下降越明显,锈蚀深度是影响点蚀钢梁承载力的关键因素;点蚀钢梁的极限承载力随DOPV的增长而下降,开孔(点蚀)腹板较未开孔腹板刚度下降明显;当DOPV达到一定程度时,会使钢梁腹板提前发生屈曲,这表明点蚀会影响钢梁的失效形式。(2)对四边简支边界条件下点蚀钢梁腹板的剪切屈曲荷载、剪切刚度及抗剪极限承载力进行了研究。研究结果表明DOPA可以较好的描述点蚀影响下初始单板剪切刚度的变化趋势;DOPV可以较好的描述点蚀影响下剪切板弹塑性临界荷载的变化趋势;并提出了点蚀影响下剪切板弹塑性临界荷载的计算公式。(3)基于有限元计算结果对纯剪切作用下工字梁腹板剪切屈曲的计算公式进行了修正,并提出了钢箱梁腹板剪切屈曲系数的计算公式。与有限元结果的相比表明,公式精度较高。对局部锈蚀条件下的钢箱梁腹板进行了有限元研究,研究发现,锈蚀体积损失(DOPV)是影响局部锈蚀箱梁腹板的剪切屈曲强度的关键因素;并得出了基于综合影响系数η的箱梁腹板剪切屈曲强度的计算公式,公式具有很好的适用性。(4)进行了局部锈蚀影响下钢箱梁抗剪极限承载力的试验研究与数值分析,得出了钢箱梁抗剪极限承载力的建议公式。提出了描述点蚀程度的综合影响系数?;基于综合影响系数?得到了点蚀影响下钢箱梁抗剪极限承载力的计算公式,该公式可以较为准确的计算不同点蚀损伤程度下钢箱梁的抗剪极限承载力。
[Abstract]:Corrosion is one of the important factors affecting the durability of steel structures. In this paper, the steel box girder bridge with medium span, which is widely used in engineering, is taken as the research object. The mechanical characteristics of the steel beam under the influence of pitting corrosion are analyzed by the method of combining theory, experiment and numerical simulation. The effect of pitting on the buckling characteristics and ultimate bearing capacity of steel box girder web was studied. The main research contents can be divided into four parts: (1) the static loading test and finite element analysis of three uniform corroded steel beams and six pitting steel beams are carried out. The influence of the geometric size (size and depth) and distribution of the pit on the bearing capacity and failure mode of the steel beam is studied. The results show that the weight loss rate is the key factor affecting the properties of uniformly corroded steel materials and the bearing capacity of steel beams, but the weight loss rate can not comprehensively measure the pitting damage degree of steel beams, and under the same DOP conditions, the greater the depth of corrosion pits, the more obvious the ultimate bearing capacity decreases. The corrosion depth is the key factor affecting the bearing capacity of pitting steel beams, the ultimate bearing capacity of pitting steel beams decreases with the increase of DOPV, and the stiffness of the perforated (pitting) web plate decreases significantly than that of the non-perforated web, and when the DOPV reaches a certain degree, The buckling of the steel beam web will occur in advance, which indicates that the pitting will affect the failure form of the steel beam. (2) the shear buckling load, shear stiffness and ultimate shear bearing capacity of the web plate of the pitting steel beam are studied under the condition of simply supported boundary. The results show that DOPA can well describe the change trend of shear stiffness of initial veneer under pitting corrosion, and DOPV can describe the change trend of critical load of shear plate under pitting effect. A formula for calculating the critical elastic-plastic load of shear plate under pitting corrosion is proposed. (3) based on the results of finite element method, the formula for calculating shear buckling of I-beam web plate under pure shear is modified. A formula for calculating the shear buckling coefficient of steel box girder web is presented. Compared with the finite element results, the formula has higher accuracy. The finite element analysis of the steel box girder web under the condition of local corrosion is carried out. It is found that the corrosion volume loss (DOPV) is the key factor affecting the shear buckling strength of the partially corroded box girder web. The formula for calculating the shear buckling strength of box girder web based on the comprehensive influence coefficient 畏 is obtained. The formula has good applicability. (4) the experimental study and numerical analysis of ultimate shear bearing capacity of steel box girder under the influence of local corrosion are carried out. The suggested formula of ultimate shear bearing capacity of steel box girder is obtained. The comprehensive influence coefficient which describes the pitting corrosion degree is put forward, which is based on the comprehensive influence coefficient? The formula for calculating the ultimate shear capacity of steel box girder under the influence of pitting corrosion is obtained. The formula can accurately calculate the ultimate shear capacity of steel box girder under different pitting damage degree.
【学位授予单位】：江苏科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U448.213;U441
本文编号：2271017
[Abstract]:Corrosion is one of the important factors affecting the durability of steel structures. In this paper, the steel box girder bridge with medium span, which is widely used in engineering, is taken as the research object. The mechanical characteristics of the steel beam under the influence of pitting corrosion are analyzed by the method of combining theory, experiment and numerical simulation. The effect of pitting on the buckling characteristics and ultimate bearing capacity of steel box girder web was studied. The main research contents can be divided into four parts: (1) the static loading test and finite element analysis of three uniform corroded steel beams and six pitting steel beams are carried out. The influence of the geometric size (size and depth) and distribution of the pit on the bearing capacity and failure mode of the steel beam is studied. The results show that the weight loss rate is the key factor affecting the properties of uniformly corroded steel materials and the bearing capacity of steel beams, but the weight loss rate can not comprehensively measure the pitting damage degree of steel beams, and under the same DOP conditions, the greater the depth of corrosion pits, the more obvious the ultimate bearing capacity decreases. The corrosion depth is the key factor affecting the bearing capacity of pitting steel beams, the ultimate bearing capacity of pitting steel beams decreases with the increase of DOPV, and the stiffness of the perforated (pitting) web plate decreases significantly than that of the non-perforated web, and when the DOPV reaches a certain degree, The buckling of the steel beam web will occur in advance, which indicates that the pitting will affect the failure form of the steel beam. (2) the shear buckling load, shear stiffness and ultimate shear bearing capacity of the web plate of the pitting steel beam are studied under the condition of simply supported boundary. The results show that DOPA can well describe the change trend of shear stiffness of initial veneer under pitting corrosion, and DOPV can describe the change trend of critical load of shear plate under pitting effect. A formula for calculating the critical elastic-plastic load of shear plate under pitting corrosion is proposed. (3) based on the results of finite element method, the formula for calculating shear buckling of I-beam web plate under pure shear is modified. A formula for calculating the shear buckling coefficient of steel box girder web is presented. Compared with the finite element results, the formula has higher accuracy. The finite element analysis of the steel box girder web under the condition of local corrosion is carried out. It is found that the corrosion volume loss (DOPV) is the key factor affecting the shear buckling strength of the partially corroded box girder web. The formula for calculating the shear buckling strength of box girder web based on the comprehensive influence coefficient 畏 is obtained. The formula has good applicability. (4) the experimental study and numerical analysis of ultimate shear bearing capacity of steel box girder under the influence of local corrosion are carried out. The suggested formula of ultimate shear bearing capacity of steel box girder is obtained. The comprehensive influence coefficient which describes the pitting corrosion degree is put forward, which is based on the comprehensive influence coefficient? The formula for calculating the ultimate shear capacity of steel box girder under the influence of pitting corrosion is obtained. The formula can accurately calculate the ultimate shear capacity of steel box girder under different pitting damage degree.
【学位授予单位】：江苏科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U448.213;U441
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