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1.
J. W. Smith 《地震工程与结构动力学》1972,1(4):357-370
This paper presents a method of analysis for the dynamic response of a simply supported beam and slab bridge under the action of a moving vehicle. The bridge is idealized as an orthotropic plate and, in the analysis, is subdivided into a number of finite strips. The vehicle is idealized as a moving sprung mass. Viscous damping is taken into account for both bridge and vehicle. The results show that there is significant variation of response across transverse sections of the bridge. Furthermore the dynamic magnification is considerably greater than that predicted by a more approximate method in which the bridge is idealized as a simple prismatic beam. 相似文献
2.
The dynamic response of single span simply supported bridge decks subjected to the passage of vehicles is examined. A modal analysis approach is adopted that is based upon a finite strip idealization of the deck. The vehicle is modelled as a rigid body supported at two points by a suspension idealization that accounts for the effect of tyre stiffness and the frictional nature of real suspension systems. Results are presented for an orthotropic slab deck and a box girder deck that illustrate the effects of (i) the initial precompression of the suspension system as the vehicle enters the span, (ii) the ratio of the vehicle's natural frequency to that of the bridge deck and (iii) a bridge deck surface profile that is not perfectly horizontal. 相似文献
3.
A new vehicle model and the partial bridge model were used to study the dynamic interaction between an open deck steel truss bridge and a moving freight train. The responses in terms of dynamic stresses in certain critical members in the bridge were generated to predict their fatigue lives by using a reliability-based methodology. 相似文献
4.
Nefize Shaban Alp Caner Ahmet Yakut Aysegul Askan Ali Karimzadeh Naghshineh Arman Domanic Gizem Can 《地震工程与结构动力学》2015,44(6):889-905
Presence of vehicles on a bridge has been observed many times during past earthquakes. Although in practice, the engineers may or may not include the live load contribution to seismic weight in design, current bridge design codes do not specify a certain guideline. A very limited research has been conducted to address this issue from design point of view. The focus of this research is to experimentally assess the effect of a vehicle on the seismic response of a bridge through a large‐scale model. In this scope, a 12‐meter long bridge, having a one lane deck with concrete slab on steel girders, has been shaken under five different ground motions obtained from recent earthquakes that occurred in Turkey, in its transverse direction, both with and without a vehicle on top of the deck. The measured results have indicated that top slab transverse acceleration and bearing displacements can reduce up to 18.7% in presence of a vehicle during seismic tests, which is an indication of reduction in substructure forces. The main reason for the reduction in seismic response of the bridge in the presence of live load can be ascribed to the increase in damping of the system due to mass damper‐like action induced by the vehicle. This beneficial effect cannot be observed in vertical seismic response. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
5.
Single span highway bridges of composite construction are idealized as beams as well as orthotropic plates. A standard HS–20–44 highway vehicle is represented by a planar, two-axle, sprung mass system with frictional device. The response equations are derived in terms of the natural modal co-ordinates of the bridge and of displacement co-ordinates of the vehicle. The road surface irregularities, generally found at the junctions of the approach road and bridge ends, are idealized as a 45° ramp. The maximum impact factors for bending moment and deflection are obtained due to the ramp and in combination with the braking of vehicle for symmetric as well as essentric loading of the vehicle. 相似文献
6.
In this paper the dynamic response of a skew bridge deck has been investigated, treating it as an orthotropic plate and using the finite strip method. Employing the normal mode method, the response of the deck due to a moving force has been calculated. Williams' method has been used to accelerate the convergence of the solution. Numerical work has been done for different skew angles and speed ranges. In this study, the history curves and the maximum amplification spectra for deflection and bending moment are presented. 相似文献
7.
铅阻尼器在自锚式悬索桥横向减震设计中的应用研究 总被引：1，自引：0，他引：1
某自锚式钢桁架悬索桥结构主跨408m,采用双层桥面,2根主缆为空间线形布置。本文根据自锚式悬索桥独特的动力特性,提出在悬索桥主梁与过渡墩、辅助墩之间沿横向设置铅挤压阻尼器的消能减震设计方案,以控制悬索桥的横向地震反应。根据风、行车和地震荷载等各种工况可能引起的支座剪力值,提出了铅挤压阻尼器临界滑移荷载值的确定方法。研究表明,同时采用铅挤压阻尼器和粘滞阻尼器的消能减震技术,可以有效地减小悬索桥的横向地震反应,可供工程实践参考。 相似文献
8.
A method has been developed for the study of the dynamic response of curved bridge decks on the basis of plate equations in polar co-ordinates. A general solution for the forced motion of annular sector plates has been obtained by the method of spectral representation. The specific problem of a moving force on the bridge deck is discussed in detail. A method for obtaining the static response from dynamic analysis is suggested. Numerical results are presented to illustrate the influence of the speed of travel of the force and of the physical parameters of the bridge decks on the deformation. A detailed discussion on the numerical results is also included. 相似文献
9.
基于运营环境和提升小波变换的桥梁损伤检测研究 总被引：1，自引：0，他引：1
根据损伤桥梁在车辆荷载作用下的动力响应特点,以及提升小波变换对信号突变信息的放大功能,提出了利用桥梁运营荷载作用下加速度响应提升小波变换系数的分布特性对结构损伤进行识别的方法。首先,采集桥梁在行车荷载作用下的加速度响应信号;然后,对加速度响应信号进行提升小波变换,分别利用加速度响应信号、加速度响应信号差,提升小波变换系数空间变化的峰值识别损伤位置;最后,对行车速度、损伤位置、损伤程度和测量噪声对损伤识别效果的影响进行了分析讨论。结果表明：在行车速度8m/s以下、测量噪声不高于5%情况下,利用运营荷载作用下桥梁单点动力响应信号提升小波变换,可以实现桥梁多处损伤的检测和识别。 相似文献
10.
This paper investigates the behavior and the failure mechanism of a double deck bridge constructed in China through nonlinear time history analysis.A parametric study was conducted to evaluate the influence of different structural characteristics on the behavior of the double deck bridge under transverse seismic motions,and to detect the effect of bidirectional loading on the seismic response of this type of bridge.The results showed that some characteristics,such as the variable lateral stiffness,the foundation modelling,and the longitudinal reinforcement ratio of the upper and lower columns of the bridge pier bents have a major impact on the double deck bridge response and its failure mechanism under transverse seismic motions.It was found that the soft story failure mechanism is not unique to the double deck bridge and its occurrence is related to some conditions and structural characteristics of the bridge structure.The analysis also showed that the seismic vulnerability of the double deck bridge under bi-directional loading was severely increased compared to the bridge response under unidirectional transverse loading,and out-of-phase movements were triggered between adjacent girders. 相似文献
11.
The rigid body motions of the bridge deck, along with the impact between the bridge deck and the abutments, were the source of extensive damage on skew highway bridges during the 1971 San Fernando earthquake. In this paper, a model for the rigid body motions of skew bridges is presented and analysed. The focus of the model is the appropriate representation of the impact between the bridge deck and the abutments and the explanation of the inducement of in-plane rotational vibrations of the bridge deck as the result of this impact. A simplified model is briefly described first, and the kinematic mechanism of the problem is explained. Then, the analysis of a more detailed and realistic model follows. This model is applied on a short skew bridge located in Riverside, California. The response of this bridge to several earthquake shakings revealed that the planar rigid body rotations of the deck are induced primarily as a result of the skewness of the deck and the impact between the deck and the abutments. 相似文献
12.
This paper explores dynamic soil–bridge interaction in high speed railway lines. The analysis was conducted using a general and fully three-dimensional multi-body finite element–boundary element model formulated in the time domain to predict vibrations caused by trains passing over the bridge. The vehicle was modelled as a multi-body system, the track and the bridge were modelled using finite elements and the soil was considered as a half-space by the boundary element method. The dynamic response of bridges to vehicle passage is usually studied using moving force and moving mass models. However, the multi-body system allows to consider the quasi-static and dynamic excitation mechanisms. Soil–structure interaction was taken into account by coupling finite elements and boundary elements. The paper presents the results obtained for a simply supported short span bridge in a resonant regime under different soil stiffness conditions. 相似文献
13.
为充分了解板式橡胶支座对斜交连续梁桥地震反应的影响,利用OpenSees软件建立简化的斜交桥计算模型进行时程分析,研究板式橡胶支座摩擦滑移效应,以及支座动摩擦系数、剪切刚度、局部脱空等参数对斜交桥地震反应的影响。结果表明:板式橡胶支座考虑摩擦滑移后,不仅桥面位移和转角显著增大,而且出现残余位移和残余转角;随着支座剪切刚度的增大,桥面位移和转角均明显减小;随着桥墩处支座动摩擦系数的增大,桥面位移、转角均呈增长趋势,然而桥台处支座动摩擦系数的影响与之相反;桥墩处局部支座脱空对斜交桥的影响明显大于桥台支座。 相似文献
14.
R.A.Khan T.K.Datta S.Ahmad 《地震工程与工程振动(英文版)》2005,4(1):83-94
A simplified fragility analysis of fan type cable stayed bridges using Probabilistic Risk Analysis (PRA) procedure is presented for determining their failure probability under random ground motion. Seismic input to the bridge support is considered to be a risk consistent response spectrum which is obtained from a separate analysis. For the response analysis, the bridge deck is modeled as a beam supported on springs at different points. The stiffnesses of the springs are determined by a separate 2D static analysis of cable-tower-deck system. The analysis provides a coupled stiffness matrix for the spring system. A continuum method of analysis using dynamic stiffness is used to determine the dynamic properties of the bridges .The response of the bridge deck is obtained by the response spectrum method of analysis as applied to multidegree of freedom system which duly takes into account the quasi - static component of bridge deck vibration. The fragility analysis includes uncertainties arising due to the variation in ground motion, material property, modeling, method of analysis, ductility factor and damage concentration effect. Probability of failure of the bridge deck is determined by the First Order Second Moment (FOSM) method of reliability. A three span double plane symmetrical fan type cable stayed bridge of total span 689 m, is used as an illustrative example. The fragility curves for the bridge deck failure are obtained under a number of parametric variations. Some of the important conclusions of the study indicate that (i) not only vertical component but also the horizontal component of ground motion has considerable effect on the probability of failure; (ii) ground motion with no time lag between support excitations provides a smaller probability of failure as compared to ground motion with very large time lag between support excitation; and (iii) probability of failure may considerably increase for soft soil condition. 相似文献
15.
During the 1979 Imperial Valley earthquake, an array of 26 strong-motion accelerometers produced records for the Meloland Road Overpass, a two-span reinforced concrete bridge structure located only 0.5 km away from the causative fault for this earthquake event. This paper describes the application of a new system identification methodology to the array of strong-motion measurements, in order to assess seismic response characteristics of this bridge. Results of this application show that (1) linear models provide an excellent fit to the measured motions of the bridge, despite the fact that it was subjected to very strong shaking; (2) the transverse response of the structure is controlled by its abutment motions, with no significant dynamic amplification in the deck; and (3) the vertical response of the bridge deck at the midlength of its spans is dominated by a single vertical translational mode whereas, above the central pier, the deck's vertical response is most affected by the vertical motions of the pier base and by torsion of the deck. Also, systematic estimates of modal damping ratios and qualitative assessments of states of stress developed in the bridge during the earthquake are provided. 相似文献
16.
天兴洲公铁两用斜拉桥主梁纵向列车制动振动反应分析 总被引：1，自引：0，他引：1
本文对天兴洲公铁两用斜拉桥主梁纵向列车制动的振动反应进行了研究。天兴洲大桥是目前在建的世界上跨度最大的公铁两用斜拉桥,由于具有四线铁路,其主梁在列车制动及行车移动荷载作用下会沿纵向产生大幅振动,因此对其列车制动及行车移动荷载反应进行研究尤为必要。文中,首先根据车辆动力学的原理建立了列车制动动力学模型,获得了列车制动力纵向荷载及在制动过程中列车行走所产生的竖向荷载,并建立制动力传递有限元模型,应用有限元分析软件来获取钢轨上制动力及列车行走时引起的桥梁结构节点上的作用力时程。最后对天兴洲公铁两用斜拉桥主梁纵向列车制动及行车移动荷载的振动反应进行了仿真分析,发现了其主梁纵向列车制动反应具有位移大且速度极小的特点。 相似文献
17.
5跨连续中承式钢管混凝土拱桥抗震性能分析 总被引：12，自引：0，他引：12
钢管混凝土拱桥由于桥型优美在城市桥梁中得到广泛应用,对某正在设计的5跨连续巾承式钢管混凝土拱桥进行了动力特性和抗震性能分析,根据该桥的结构特点,建立了’该桥的空间有限元分析模型,计算桥梁的自振特性,基于反应谱方法计算了该桥在横向、纵向水平地震反应,计算结果表明：该桥拱肋的面外刚度相对较小,在桥梁振动中首先出现拱肋的面外振动;桥梁的竖向振动表现为拱肋与桥面的整体竖向振动,其基频明显比拱肋面外振动大;主拱肋的轴力由横桥向地震动控制,其他内力由纵桥向地震动控制;地震作用对弯矩的影响较大,故主拱的内力计算应考虑地震力的影响;在设计计算中除常规关键点应作为控制点外,内外拱连接处也应作为控制点。计算结果已为该桥的抗震设计提供了参考。 相似文献
18.
本文根据某自锚式悬索桥独特的动力特性,分别提出了在悬索桥主梁与主塔之间沿纵向设置粘滞阻尼器和铅挤压阻尼器的消能减震设计方案,来控制悬索桥的纵向地震反应。研究表明,采用以上2种消能减震技术,可以有效地减小悬索桥的纵向地震反应。本文研究结果可供工程实践参考。 相似文献
19.
The problem of spatial dynamic response of a suspension bridge to the passage of trains of concentrated forces with random values is considered. The arrival of forces at the bridge is assumed to constitute a Poisson process of events. Such an excitation process is an appropriate model of vehicular traffic loads acting on the bridge. The bridge is idealized by a single-span thin-walled beam underslung to two cables. The response of the bridge in the space-time domain is described by a coupled system of non-linear, integro-differential equations. The dynamic influence functions of vertical and horizontal deflections at each cross-section point are obtained for the linear case. Cumulants and probability density functions of response are determined. Numerical methods have been used to develop a computer-oriented algorithm aimed at the numerical solution of the problem. As examples, numerical results for a particular bridge with some practical load cases are presented and illustrated by graphs. 相似文献
20.
This study proposes a new identification algorithm about the admittance function, which can estimate the full set of six aerodynamic admittance functions considering cross power spectral density functions about the forces and the turbulence components. The method was first numerically validated through Monte Carlo simulations, and then adopted to estimate the aerodynamic admittance of a streamlined bridge deck. The identification method was further validated through a comparison between the numerical calculation and wind tunnel tests on a moving bridge section. 相似文献