考虑行驶安全的高速路桥过渡段路基防沉降处理措施

在高速路桥工程中,由于工程的复杂性,易引发过渡段路基沉降。为提高路基路面的稳定性,保证行驶安全,需做好相应的防沉降处理措施。通过深入分析桥台台背路堤压实度不够、路面沉陷、路桥的结构沉降量差异及施工技术等路基路面出现沉降的主要原因,结合高速路桥工程的施工特点,提出对应的路基防沉降处理措施,包括科学设立缓和过渡段、提高地基承载力、合理设计挡板长度、压实路基填料等。并依托实际工程,对防沉降处理措施的应用效果进行验证,结果证明,提出的路基防沉降处理措施能够有效减少路基路面沉降,提高行车的安全性。

分析搞好高速路桥工程施工管理的策略

高速公路的建设与发展,说明一个国家的经济发展程度,以及对修路政策的重视态度。俗话说:要想富先修路,我国的高速公路事业发展正在朝着高标准、国际化、科学规范化转变,科学的高速路桥设计,才能给高速施工作业带来良好的施工基础。高速事业中的高速路桥施工管理策略,能给一个工程的成功带来良好的施工开端,从而促使我国的现代化经济建设取得良好的发展空间,进而促使交通发达、经济繁荣,各项社会经济秩序发展全面进行。

浅析高速路桥桥梁墩帽施工工艺

从桥梁结构力学的角度上来说,墩帽是整个结构承上启下的重要部件。因此,需要我们将墩帽施工作为整个桥梁施工中的重点部分来加以对待。结合这一思路,论文以三明泰宁至建宁高速公路为研究案例,针对高速路桥施工中,桥梁墩帽施工工艺的实施要点以及相关的质量控制措施展开了分析与研究。

应用CFG桩加固高速路桥软弱地基的技术探究

阐述介绍CFG桩加固地基的机理,介绍了常规CFG桩基和案例应用CFG桩基的技术特点,并通过案例CFG桩基工程的基底沉降和基底应力测试结果,验证了案例CFG桩基体系在高速路桥软弱地基整固治理上的技术功效,对同类工程应用有技术参考价值。

桥梁墩帽施工工艺在高速路桥施工中的应用

本文针对连霍高速河南段桥梁墩帽施工情况，观察其施工前准备工作，探讨了桥梁墩帽施工工艺在高速路桥施工中的作用，统计分析了施工质量控制要点，使得经验能够应用到更多路桥施工当中，提高施工水平，加强质量保证，提高经济效益与社会效益。

应用CFG桩加固高速路桥软弱地基的技术分析

简单概述了CFG桩的基本概念,并阐述了CFG桩的施工流程和主要施工技术;结合CFG桩作用原理,分析了CFG桩主要质量要求和施工工艺,指出CFG桩施工中的主要质量要点;提出CFG桩施工如常见问题出现的原因及对问题的解决措施,进一步探讨CFG桩的加固处理建议。

双轮驱动,推动多产业创新发展--记山东高速路桥集团股份有限公司

从1948年发展至今,山东路桥股份的建设足迹已经遍布海内外,比如,国内参建了济南黄河公路大桥、南京长江大桥、苏通长江大桥、胶州湾跨海大桥、京沪高速、京台高速等国家重点工程;海外参建了尼泊尔、巴基斯坦、东帝汶、阿尔及利亚、安哥拉、越南、伊拉克、哈萨克斯坦、孟加拉、埃塞俄比亚、马拉维、南苏丹、塞尔维亚等国家的工程项目。

咬合桩在高速路改桥工程中的应用

结合宣城市环城大道下穿芜宣高速的工程实例,阐述了咬合桩这一支护结构在高速路改桥工程中的运用,并提出了相应的计算模式,同时对其施工流程及要点进行了说明,以此为今后同类工程提供借鉴。

崇左至靖西高速公路古龙山大桥利用反力架进行挂篮预压设计与应用

通过对广西崇左至靖西高速公路古龙山大桥连续钢构挂篮采用千斤顶自反力架的加载方法进行挂篮预压试验,文章介绍了正确评价挂篮的强度、刚度和稳定性,验证挂篮的安全性,为挂篮施工和线性控制提供挂篮弹性挠度计算的可靠依据。

论高墩施工技术在高速公路桥梁施工中的应用分析

在路桥事业快速发展的今天,高速路桥工程项目不断增加,相应的施工质量要求越来越高,此时采取有效施工技术显得尤为关键。本文立足高速路桥工程施工现状,重点对高墩施工技术的应用要点进行了探讨,以期为路桥工程施工的相关研究提供一些帮助。

桥梁装配式防护栏施工质量控制研究

文章以某高速桥梁为例,基于对装配式防护栏质量控制的研究,论述了装配式防护栏施工标准及流程,阐述了结构设计、预埋件生产及加工、钢筋制作、预制浇筑及养护等结构制作要点,并从施工准备及校对、测量放线、吊装准备及构件存放、桥面板安装、防护栏的安装、金属波纹管的安装等方面详细分析了装配式防护栏现场施工控制要点,以供参考。

Influence of pier height on the safety of trains running on high-speed railway bridges during earthquakes

Sudden earthquakes pose a threat to the running safety of trains on high-speed railway bridges,and the stiffness of piers is one of the factors affecting the dynamic response of train-track-bridge system.In this paper,a experiment of a train running on a high-speed railway bridge is performed based on a dynamic experiment system,and the corresponding numerical model is established.The reliability of the numerical model is verified by experiments.Then,the experiment and numerical data are analyzed to reveal the pier height effects on the running safety of trains on bridges.The results show that when the pier height changes,the frequency of the bridge below the 30 m pier height changes greater;the increase of pier height causes the transverse fundamental frequency of the bridge close to that of the train,and the shaking angle and lateral displacement of the train are the largest for bridge with 50 m pier,which increases the risk of derailment;with the pier height increases from 8 m to 50 m,the derailment coefficient obtained by numerical simulations increases by 75% on average,and the spectral intensity obtained by experiments increases by 120% on average,two indicators exhibit logarithmic variation.

Dynamic response limit of high-speed railway bridge under earthquake considering running safety performance of train

Due to the wide railway network and different characteristics of many earthquake zones in China,considering the running safety performance of trains(RSPT)in the design of high-speed railway bridge structures is very necessary.In this study,in order to provide the seismic design and evaluation measure of the bridge structure based on the RSPT,a calculation model of RSPT on bridge under earthquake was established,and the track surface response measure when the derailment coefficient reaches the limit value was calculated by referring to 15 commonly used ground motion(GM)intensity measures.Based on the coefficient of variation of the limit value obtained from multiple GM samples,the optimal measures were selected.Finally,the limit value of bridge seismic response based on RSPT with different train speeds and structural periods was determined.

Review of aerodynamics of high-speed train-bridge system in crosswinds

Serviceability and running safety of the high-speed train on/through a bridge are of major concern in China. Due to the uncertainty chain of the train dynamic analysis in crosswinds originating mainly from the aerodynamic assessment, this paper primarily reviews five meaningful progresses on the aerodynamics of the train-bridge system done by Wind Tunnel Laboratory of Central South University in the past several years. Firstly, the flow around the train and the uncertainty origin of the aerodynamic assessment are described from the fluid mechanism point of view. After a brief introduction of the current aerodynamic assessment methods with their strengths and weaknesses, a new-developed TRAIN-INFRASTRUCTURE rig with the maximum launch speed of 35 m/s is introduced. Then, several benchmark studies are presented, including the statistic results of the characterized geometry parameters of the currently utilized bridge-decks, the aerodynamics of the train, and the aerodynamics of the flat box/truss bridge-decks. Upon compared with the foregoing mentioned benchmarks, this paper highlights the aerodynamic interference of the train-bridge system associated with its physical natures. Finally, a porosity-and orientation-adjustable novel wind barrier with its effects on the aerodynamics of the train-bridge system is discussed.

Beam-track interaction of high-speed railway bridge with ballast track

Based on the construction bridge of Xiamen-Shenzhen high-speed railway(9-32 m simply-supported beam + 6×32 m continuous beam),the pier-beam-track finite element model,where the continuous beam of the ballast track and simply-supported beam are combined with each other,was established.The laws of the track stress,the pier longitudinal stress and the beam-track relative displacement were analyzed.The results show that reducing the longitudinal resistance can effectively reduce the track stress and the pier stress of the continuous beam,and increase the beam-track relative displacement.Increasing the rigid pier stiffness of continuous beam can reduce the track braking stress,increase the pier longitudinal stress and reduce the beam-track relative displacement,Increasing the rigid pier stiffness of simply-supported beam can reduce the track braking stress,the rigid pier longitudinal stress and the beam-track relative displacement.

A computational method for post-construction settlement of high-speed railway bridge pile foundation considering soil creep effect

Based on reasonable assumptions that simplified the calculational model,a simple and practical method was proposed to calculate the post-construction settlement of high-speed railway bridge pile foundation by using the Mesri creep model to describe the soil characteristics and the Mindlin-Geddes method considering pile diameter to calculate the vertical additional stress of pile bottom.A program named CPPS was designed for this method to calculate the post-construction settlement of a high-speed railway bridge pile foundation.The result indicates that the post-construction settlement in 100 years meets the requirements of the engineering specifications,and in the first two decades,the post-construction settlement is about 80% of its total settlement,while the settlement in the rest eighty years tends to be stable.Compared with the measured settlement after laying railway tracks,the calculational result is closed to that of the measured,and the results are conservative with a high computational accuracy.It is noted that the method can be used to calculate the post-construction settlement for the preliminary design of high-speed railway bridge pile foundation.

Near-fault directivity pulse-like ground motion effect on high-speed railway bridge

The vehicle-track-bridge(VTB)element was used to investigate how a high-speed railway bridge reacted when it was subjected to near-fault directivity pulse-like ground motions.Based on the PEER NAG Strong Ground Motion Database,the spatial analysis model of a vehicle-bridge system was developed,the VTB element was derived to simulate the interaction of train and bridge,and the elasto-plastic seismic responses of the bridge were calculated.The calculation results show that girder and pier top displacement,and bending moment of the pier base increase subjected to near-fault directivity pulse-like ground motion compared to far-field earthquakes,and the greater deformation responses in near-fault shaking are associated with fewer reversed cycles of loading.The hysteretic characteristics of the pier subjected to a near-fault directivity pulse-like earthquake should be explicitly expressed as the bending moment-rotation relationship of the pier base,which is characterized by the centrally strengthened hysteretic cycles at some point of the loading time-history curve.The results show that there is an amplification of the vertical deflection in the girder's mid-span owing to the high vertical ground motion.In light of these findings,the effect of the vertical ground motion should be used to adjust the unconservative amplification constant 2/3 of the vertical-to-horizontal peak ground motion ratio in the seismic design of bridge.

Long-term settlement prediction of high-speed railway bridge pile foundation

The process and characteristics of loading on high-speed railway bridge pile foundation were firstly obtained by means of field research and analysis,and the corresponding loading function was presented.One-dimensional consolidation equation of elastic multilayered soils was then established with single drainage or double drainages under multilevel loading.Moreover,the formulas for calculating effective stress and settlement were derived from the Laplace numerical inversion transform.The three-dimensional composite analysis method of bridge pile group was improved,where the actual load conditions of pile foundation could be simulated,and the consolidation characteristics of soil layers beneath pile were also taken into account.Eventually,a corresponding program named LTPGS was developed to improve the calculation efficiency.The comparison between long-term settlement obtained from the proposed method and the in-situ measurements of pile foundation was illustrated,and a close agreement is obtained.The error between computed and measured results is less than 1 mm,and it gradually reduces with time.It is shown that the proposed method can effectively simulate the long-term settlement of pile foundation and program LTPGS can provide a reliable estimation.

Structure and behavior of floor system of two super high-speed railway Changjiang composite bridges

Wuhan Tianxingzhou Changjiang (WTC) Bridge and Nanjing Dashengguan Changjiang (NDC) Bridge are two super high-speed railway 3-trusses composite bridges. This is the first time of using three trusses in such large bridges in the world. These two types of railway floor systems of the two bridges have never been used in China before. The problem how to conform the deformations and stress levels of the railway floor system of WTC Bridge was studied. After finite element analysis and comparison,the plan of arranging one expansion stringer every two panels in railway floor system were proposed and good effect was obtained. Because of the application of three trusses,the allocation of the loads acted on the deck in three trusses is different and varies in different places of NDC Bridge. This problem was studied by model experiment and 3D finite element analysis. The results of 3D FEM analysis coincide with the model test results. The allocation rule of the loads acting on the deck in three trusses was presented. Because of the application of monolithic decks,the stiffness and structural integrity of NDC Bridge are high.

Influence of interface crack on dynamic characteristics of CRTSⅢslab ballastless track on bridge

The damage of the self-compacting concrete in CRTSⅢslab ballastless track on bridge will lead to a partial void of the track slab,which will affect the comfort and safety of the train and the durability of the track slab and bridge structure.In order to study the impact of the interface crack on the dynamic response of CRTSⅢballastless track system on bridge,based on the principle of multi-body dynamics theory and ANSYS+SIMPACK co-simulation,the spatial model of vehicle-track-bridge integration considering the longitudinal stiffness of supports,the track structure and interlayer contact characteristics were established.The dynamic characteristics of the system under different conditions of the width,length and position of the interface crack were analysed,and the limited values of the length and width of the cracks at the track slab edge were proposed.The results show that when the self-compacting concrete does not completely void along the transverse direction of the track slab,the crack has little effect on the dynamic characteristics of the vehicle-track-bridge system.However,when the self-compacting concrete is completely hollowed out along the transverse direction of the track slab,the dynamic amplitudes of the system increase.When the crack length is 1.6 m,the wheel load reduction rate reaches 0.769,which exceeds the limit value and threatens the safety of train operation.The vertical acceleration of the track slab increases by 250.1%,which affects the service life of the track system under the train speed of 200 km/h.