基于空间梁格法的荷载横向分布及超载效应分析

发布时间：2018-01-14 11:24

本文关键词：基于空间梁格法的荷载横向分布及超载效应分析　出处：《长安大学》2015年硕士论文　论文类型：学位论文

【摘要】：为了分析荷载横向分布系数计算各效应的精度问题,本文首先采用板单元模型验证空间梁格模型的准确性,同时提供了各种截面形式的梁格模型其关键效应的空间影响面,将其与单梁模型的纵横向影响线合成的空间影响面进行了比较分析。以公路桥梁通用图中的同种桥宽不同跨径及同种跨径不同桥宽的简支T梁、箱梁、空心板及四等跨连续T梁、箱梁桥为例,给出单梁模型相对空间梁格法各效应的修正系数。结果表明剪力的修正系数相对比较大,弯矩挠度的修正系数比较小。为了明确空间梁格法分析斜桥选用正交网格与斜交网格的问题,本文以30°简支T梁与30°简支箱梁为例,将空间梁格的正交网格、斜交网格与板单元进行对比分析,结果表明:有中横梁时,网格方向与中横梁的设置方向一致;无中横梁时,建议梁格模型建成正交网格。为了分析弹性支撑与刚性支撑对支反力的影响,以简支、连续T梁及箱梁为例,结果表明简支T梁与连续T梁及简支箱梁的差异均在10%以内,而对连续箱梁的差异比较大,在15%左右。通过横隔板的设置情况,探讨了对结构的横向传力情况。为了分析单梁建模及《JTG D60—2004[S]》的估算公式在求解基频中的精度问题,以简支T梁、箱梁、空心板及四等跨连续T梁、箱梁为例,通过与空间梁格法进行对比分析,结果表明各种计算方法相对梁格法的计算结果差异均在10%以内。《JTG D60—2004公路桥涵设计通用规范[S]》规定桥梁整体计算以车道荷载为设计荷载,模糊了桥梁超载标准,车辆荷载对结构产生的效应不明确。本文以公路桥梁通用图中的同种桥宽不同跨径、同种跨径不同桥宽的简支、连续T梁桥为例,采用空间梁格法将汽车荷载标准值与超载车辆荷载效应进行对比分析,结果表明实际运营中经常出现的超载车辆对中小跨径结构产生的最大效应相当于汽车荷载标准值的两倍多,且对边梁的影响大于对中梁的影响,对墩顶负弯矩的影响大于对跨中正弯矩的影响。对于中小跨径的梁桥来说,2~4个超重车足够使其车辆荷载效应达到极值。
[Abstract]:In order to analyze the accuracy of load transverse distribution coefficient calculation, this paper first uses the plate element model to verify the accuracy of the spatial beam model. At the same time, the spatial influence surface of the key effects of the beam lattice model with various cross-section forms is provided. It is compared with the spatial influence surface of the longitudinal and transverse influence lines of the single beam model. The simply supported T beam and box girder with the same bridge width and different span and the same span are used in the general road bridge map. For example, hollow slab, four-span continuous T-beam and box girder bridge, the correction coefficients of single beam model relative to each effect of spatial beam method are given. The results show that the correction coefficient of shear force is relatively large. The correction coefficient of bending moment deflection is small. In order to analyze the problem of selecting orthogonal grid and skew grid for skew bridge by spatial beam method, this paper takes 30 掳simply supported T beam and 30 掳simply supported box girder as examples. The orthogonal grid, skew grid and plate element of spatial girder lattice are compared and analyzed. The results show that the direction of grid is the same as that of middle beam when there is a middle beam. In order to analyze the influence of elastic support and rigid bracing on the support reaction, it is suggested that the girder lattice model be built into an orthogonal grid when there is no middle beam. The simple support, continuous T beam and box girder are taken as examples. The results show that the difference between simply supported T-beam and continuous T-beam and simply supported box girder is less than 10%, but the difference for continuous box girder is about 15%. In order to analyze the modeling of single beam and < JTG D60-2004, the transverse force transfer to the structure is discussed. [The estimation formula of S > is used to solve the accuracy problem of fundamental frequency. Taking simply supported T beam, box girder, hollow slab and four equal span continuous T beam and box girder as examples, the method of space beam is compared and analyzed. The results show that the difference of calculation results between various calculation methods and beam method is less than 10%. < JTG D60-2004 general code for highway bridge and culvert design. [S > > specifies that the design load of the whole bridge is the driveway load, which obscures the overloading standard of the bridge, and the effect of the vehicle load on the structure is not clear. In this paper, the same kind of bridge width and different span in the general drawing of highway bridge are used in this paper. The simple support of the same span and different width of bridge, continuous T-beam bridge as an example, the standard value of vehicle load and the effect of overload vehicle load are compared and analyzed by space beam method. The results show that the maximum effect of overloaded vehicle on medium and small span structure is more than twice of the standard value of vehicle load, and the influence on the side beam is greater than that on the middle beam. The influence on the negative moment of pier top is greater than that on the positive moment of span. For the beam bridge with medium and small span, 2 ~ 4 overweight vehicles are enough to make the vehicle load effect reach the maximum value.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U441.2

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