跨线弯梁桥在超高车辆撞击下的动态响应分析

发布时间：2018-06-17 14:22

本文选题：曲线梁桥 + 超高车辆　；参考：《太原理工大学》2014年硕士论文

【摘要】：随着高速公路的建设和城市道路的进一步发展,道路网中立交桥日益增多。为了使桥梁设计满足路线平面布置的需要及增添城市景观,一般需要采用曲线桥,并且主要采用曲线梁桥的形式。城市立交中曲线梁桥结构也得到了广泛的应用,尤其在立交的匝道设计中应用最广。随着城市道路中曲线梁桥的广泛应用,相应的问题和事故也随之而来。限于匝道桥有限的净空高度,或者错误驾驶,超高车辆撞击跨线桥梁的事故屡见不鲜。因此,开展曲线梁桥在超高车辆撞击下的损伤机理和防护措施具有重要的工程意义。然而,超高车辆撞击曲线梁桥是个极其复杂的动力过程,而且曲线梁桥复杂的“弯扭耦合”作用,导致弯梁桥自身存在很多如曲线梁桥的平面变形问题、主梁腹板开裂问题以及支座脱空等问题还没有很好地解决。用试验方法模拟代价过于昂贵,本文基于高精度有限元软件ABAQUS,讨论了超高车辆撞击曲线梁桥过程中的损伤机理和能量转换方式,并研究了不同支承方式下,曲线梁桥在超高车辆撞击下的弯矩、剪力分布以及支座损伤状况,得出以下结论：一、讨论了不同曲率半径下的曲线梁桥在不同撞击速度下的局部损伤和整体性破坏： (1)曲率半径越小,撞击荷载作用下产生的应力分布越集中,应力峰值越大； (2)曲线梁桥在超高车辆撞击下产生的局部性损伤随着曲率半径的减小而增大,而曲线梁桥的整体损伤主要表现为沿着竖向轴和行车方向的扭转,即“弯扭耦合”的作用效应；二、进行了不同曲率半径下的曲线梁桥在不同撞击速度下的能量转换和模态分析： (1)撞击系统的能量转换方式为撞击动能转化为系统的变性能(弹性应变能和塑性应变能)。 (2)在模态分析中,曲线梁桥的振动集中在X-ROTATION和Z-ROTATION,即“弯扭耦合”效应,印证了结论一的结果；三、讨论了不同多跨超静定曲线梁桥的三种不同支承方式：1)两端点均为“抗扭支承”,中间为“点铰支承”；2)当跨数较多时,梁端点设“抗扭支承”,中间跨设置一个“抗扭支承”,其余都为“点铰支承”；3)为减小扭矩对主梁的作用,梁端设抗扭支承,中间跨设置向外侧的偏心铰支承。并进行了在三种不同支承方式下主梁的受力分析： 1)相对于中间跨设置点铰支座的弯梁桥,中间跨设置了带预偏心的点铰支座的弯梁桥,抗扭增大,在抵抗撞击荷载引起的弯矩时,比不带预偏心的点铰支座处产生的弯矩偏大,这是由于由于预偏心的作用,使得各个支座反力在点铰支座处产生的弯矩偏大； 2)相对于中间跨设置点铰支座(包括带偏心的点铰支座)的弯梁桥,中间跨增设抗扭支座的弯梁桥在撞击力荷载的作用下,支座受到的破坏力更大,主梁变形更严重。为了保证结构受力合理,在工程应用中,应将中间跨设置的抗扭支座尽量隔开设置,以保证该支承区域支座不会发生剪切破坏和错位脱空。
[Abstract]:With the construction of the expressway and the further development of the urban road, the overpass is increasing in the road network. In order to make the bridge design meet the needs of the layout of the route and add the urban landscape, the curve bridge is generally used and the curved bridge is mainly used. The curved bridge structure in the urban vertical intersection has also been widely used. It is especially widely used in the ramp design of the interchange. With the wide application of the curved bridge in the urban road, the corresponding problems and accidents are also followed. The accidents of the flyover with the limited clearance of the ramp bridge, or the wrong driving, are common in the cross line bridges. Injury mechanism and protective measures are of great engineering significance.
However, the super high vehicle impact curve beam bridge is a very complicated dynamic process, and the complex "bending and torsion coupling" effect of the curved beam bridge leads to a lot of curved bridge itself, such as the plane deformation of the curved bridge, the problems of the web cracking of the main beam and the support to be empty are not well solved. Yu Anggui, based on the high precision finite element software ABAQUS, this paper discusses the damage mechanism and energy conversion mode in the process of the super high vehicle impact curve beam bridge, and studies the bending moment, the shear distribution and the damage condition of the support of the curved beam bridge under the impact of the super high vehicle under the different supporting methods.
First, local damage and global failure of curved girder bridges with different curvature radius at different impact velocities are discussed.
(1) the smaller the radius of curvature is, the more concentrated the stress distribution is, the higher the stress peak.
(2) the local damage of the curved bridge under the impact of the ultra high vehicle increases with the decrease of the radius of curvature, and the overall damage of the curved beam bridge is mainly manifested by the torsion coupling along the vertical axis and the driving direction, that is the effect of "bending and torsion coupling".
Two, energy conversion and modal analysis of curved girder bridges with different curvature radius at different impact velocities are carried out.
(1) the energy conversion mode of the impact system is the kinetic energy of impact, which is transformed into the denaturation energy (elastic strain energy and plastic strain energy) of the system.
(2) in modal analysis, the vibration of curved girder bridges is concentrated in X-ROTATION and Z-ROTATION, that is, the effect of "bending torsion coupling", which confirms the conclusion of the conclusion.
Three, the three different supporting methods of different span statically indeterminate curved girder bridges are discussed: 1) both ends are "anti torsion support", and the middle is "point hinge support"; 2) when the span number is more, the end point of the beam is set "anti torsion support", the middle span is set up a "anti torsion support", the rest are "point hinge support" and 3) to reduce the torque to the main beam. The torsion support is installed at the end of the beam, and the eccentric hinge is supported to the outer side of the middle span. The stress analysis of the main girder under three different supporting modes is carried out.
1) the bending beam bridge with a point hinge bearing with pre eccentricity is set in the middle span of a curved beam bridge with a pre eccentricity point hinge support. The bending moment is larger than that of the point hinge support without pre eccentricity. This is due to the effect of pre eccentricity, which makes each support counterforce at the point hinge support. The bending moment is larger.
2) relative to the curved beam bridge with the middle span set point hinge bearing (including the point hinge bearing with eccentric point), the bending beam bridge with the middle span added to the torsion bearing is more destructive under the impact force load, and the main beam is more deformed. In order to ensure the rational structure, the torsional support should be set in the middle span as far as possible in the engineering application. Separate settings to ensure that shear failure and dislocation void will not occur in the bearing area.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U441

【参考文献】