Study in the design and manufacture process of the elastic cable anchor box in steel box girder of Taizhou Bridge

Taizhou Yangtze River Highway Bridge is a large span suspension bridge with three pylons. The elastic cables are installed to connect the steel tower and the steel box girder. The constraints can increase the safety coefficient of the middle saddle, and improve the stress conditions of the middle pylon and decrease the deflection in the middle of the main girder, as well as the longitudinal displacement of the main girder caused by live loads. The anchorage boxes of the elastic cable are installed in the wind fairing outside the vertical web plate of the box girder. Two anchor boxes form a pair and are arranged parallelly. Eight anchor boxes are installed in the bridge. In this paper, the design scheme and the technical difficulties in manufacturing are briefly discussed with the precision control techniques.

The study of temperature effects on steel box girder for Taizhou Bridge

Using the temperature gradient which was proposed by continuously measuring flat steel box girder of Runyang Bridge, temperature effects of flat steel box girder were studied for Taizhou Bridge. With three temperature gradient models （JTG D60--2004 specification, BS5400 specification and the temperature gradient which was proposed in this paper）, the stress of control sections was calculated by finite element program ANSYS. The calculated result indicated that the temperature gradient that was put forward in JTG D60-2004 specification and BS5400 specification for calculating the stress of fiat steel box girder was not suitable to apply to fiat steel box girder. The temperature gradient on flat steel box girder which was proposed in this paper was reasonable.

Stress and noises of steel box girders in Sutong Bridge

Sutong Bridge is a cable-stayed bridge with a main span of 1 088 m. 370 high-precision stress monitoring measured data show that in the process of hoisting the steel box girders,the stress of the main girders is in the fluctuant and complex state and many meteorological factors,such as sunshine radiation,temperature and wind,have important influence on the change of stress of the steel box girders. According to the real-time weather data,the stress data after the process of wavelet denoising from representative measuring points in different weather conditions is picked to establish the stress response brought by meteorological factors with Layered Separation method,thereby basically eliminating the influence of meteorological factors on the stress of main girders,so that accurate and reliable stress data can be got for steel box girders adjustment and cable-tensioned construction control.

Research on overall assembling and welding process of steel box girder tuyere blocks of Taizhou Bridge

This article presents in detail the assembling and welding process technique of the steel box girder tuyere blocks of Taizhou Bridge. The application of this process technique effectively solves the problem of welding stress release in tuyere block assembling and welding without increasing the number of turns of the blocks and overhead welding, thus avoiding possible structural deformation due to excessive accumulation of internal welding stress, greatly reducing the repeated deformation and correction work during assembling and welding, and ensuring the weld seam quality and overall dimensions of tuvere blocks of Taizhou Bridze.

Design of steel box girder for Taizhou Yangtze River Highway Bridge

Taizhou Yangtze River Highway Bridge is the first three-pylon two-span suspension bridge in China. The main girder adopts flat steamline steel closed box girder which has well wind-resistant capability and is technically mature besides beautiful appearance. Straight web plates of the steel box girder in longitudinal direction are proposed in order to ensure the integrity of the steel box girder, and to keep the stress of the steel box girder continuous in the middle pylon, as well as to reduce the gradient of the middle pylon columns. The cross section of the box girder has one box with three cells. Solid-web diaphragm plate with good integrity and high torsional stiffness is adopted. The lifting lugs are utilized in the anchors of suspender cable. In this paper, selection of the cross section of the steel box girder, the general structure design, local structure design and main structure calculation results of Taizhou Yangtze River Bridge are introduced emphatically.

Estimating extreme temperature differences in steel box girder using long-term measurement data

The extreme temperature differences in fiat steel box girder of a cable-stayed bridge were studied.Firstly,by using the long-term measurement data collected by the structural health monitoring system installed on the Runyang Cable-stayed Bridge,the daily variations as well as seasonal ones of measured temperature differences in the box girder cross-section area were summarized.The probability distribution models of temperature differences were further established and the extreme temperature differences were estimated with a return period of 100 years.Finally,the temperature difference models in cross-section area were proposed for bridge thermal design.The results show that horizontal temperature differences in top plate and vertical temperature differences between top plate and bottom plate are considerable.All the positive and negative temperature differences can be described by the weighted sum of two Weibull distributions.The maximum positive and negative horizontal temperature differences in top plate are 10.30 ℃ and -13.80 ℃,respectively.And the maximum positive and negative vertical temperature differences between top plate and bottom plate are 17.30 ℃ and-3.70 ℃,respectively.For bridge thermal design,there are two vertical temperature difference models between top plate and bottom plate,and six horizontal temperature difference models in top plate.

Study on the Mechanical Properties of Irregular Curved Steel Box Girder for City Viaduct

This paper deeply analyses the influence of different local tectonic on stress performance of spatial curved steel box Girder Bridge, using the finite element analysis software to establish space finite element model of this bridge, calculation and analysis were made on the bridge of the strength, stiffness. It has certain reference value for guiding engineering design, have a good foundation for the mechanical properties and stability of linear and nonlinear further study of curved steel box girder.

南京仙新路长江大桥主桥结构设计

南京仙新路长江大桥主桥为跨径1760 m的单跨钢箱梁悬索桥,主缆垂跨比1/9,边跨跨径580 m,边中跨比0.33。该桥上、下游各设1根主缆,单根主缆由169股127∅5.4 mm镀锌铝高强钢丝索股组成,采用PPWS法施工,钢丝标准抗拉强度2100 MPa。吊索与索夹采用销接式结构,跨中设置柔性中央扣索,短吊索设置关节轴承。主索鞍采用宽鞍槽单纵肋铸焊结合构造,散索鞍采用底座式全铸结构。加劲梁采用扁平流线型封闭整体钢箱梁,总宽31.5 m,梁高4 m,顶板与U肋之间采用双面埋弧全熔透焊接。桥塔采用门形混凝土结构,总高277.3 m,其上横梁为预应力混凝土结构,外包N字造型钢结构;桥塔基础采用直径2.8 m钻孔灌注桩。南锚碇采用外径65 m圆形地下连续墙基础;北锚碇采用沉井基础,平面尺寸70 m×50 m,高50 m。对结构进行静力分析及抗风性能理论和试验研究,结果表明:结构强度、刚度均满足规范要求;在加劲梁上设置0.67 m高中央稳定板、两侧风嘴处设置1 m宽水平稳定板后,大桥的颤振、涡振等抗风性能均满足要求,且具备一定的阻尼储备。

主跨330 m高速铁路无砟轨道混合梁斜拉桥设计

研究目的:为满足防洪及通航要求,南玉高铁百合郁江特大桥采用(36+40+64+330+64+40+36)m钢箱-混凝土混合梁斜拉桥跨越郁江。该桥为目前国内在建最大跨度的高速铁路无砟轨道钢箱-混凝土混合梁斜拉桥。本文主要基于百合郁江特大桥的设计与受力特点,通过多种评价方法,探讨在大跨度钢混斜拉桥上铺设无砟轨道适应性,为后续建造同类型无砟轨道桥梁提供理论参考。研究结论:(1)主桥采用钢箱梁与混凝土箱梁,并在钢箱梁顶板上现浇混凝土桥面板,为无砟轨道铺设创造了良好条件,并且能很好地控制后期主梁的收缩徐变变形,提高大跨桥梁对无砟轨道适应性;(2)百合郁江特大桥具有良好的静力性能和刚度条件;(3)主桥将轨道结构高度由725 mm调整为775 mm,分别为底座板和道床板预留了20 mm和30 mm的纠偏量,为后续无砟轨道分级施工和纠偏提供了基础,能更好地将施工与测量误差逐级消除,提高无砟轨道铺设精度;(4)采用多种无砟轨道适应性评价方法对主桥无砟轨道线形进行分析,结论均满足设计要求;(5)该桥的成功实施,为国内外高速铁路无砟轨道桥梁建设提供了宝贵的经验,将进一步推动高速铁路无砟轨道大跨度桥梁的技术发展。

远场爆炸荷载作用下钢箱梁桥的动力响应及毁伤评估

针对大规模爆炸后桥梁结构的毁伤评估问题,以三跨连续钢箱梁为对象,采用计算流体动力学(Computational Fluid Dynamics,CFD)和显式动力学方法,研究了冲击波入射角度与冲击波强度对桥梁结构破坏模式的影响规律,建立了桥梁毁伤程度与冲击波特性之间的映射关系。结果表明:通过CFD数值模拟得到的爆炸荷载可以反映冲击波的绕射和消波效应,可以为桥梁结构的抗爆计算提供可靠的爆炸荷载;桥梁的破坏模式与冲击波入射角有关,而桥梁的毁伤程度与冲击波强度有关;入射角度为0°时,桥梁的迎爆面腹板发生局部屈曲,非迎爆面桥墩发生破坏。

公铁合建钢混板-桁斜拉桥悬挑式钢锚箱受力特性及结构优化

为研究大跨度公铁合建钢混板-桁斜拉桥主梁悬挑式索梁钢锚箱结构的受力特性及结构优化,以主跨808 m的洪奇沥特大桥钢锚箱为背景,采用仿真分析方法,研究钢锚箱3个设计方案主要板件应力、焊缝应力以及推荐方案锚箱节点的传力特性和锚箱参数对钢锚箱受力的影响。结果表明:锚箱尺寸较大、顶底板加肋方案的主要板件应力最大为300 MPa,小于其他2种方案,且6条焊缝的最大应力和应力不均匀系数较优,因此确定该方案为最终设计方案;索力首先由锚垫板直接向钢锚箱顶、底板和内外腹板较为均匀传递,最终边弦杆底板、内腹板和外腹板分别承担了22.2%,46.4%和31.4%的索力;节点处副桁斜杆、近桥塔侧和远桥塔侧边弦杆、混凝土桥面、节点横梁分别传递约66.71%,9.72%,9.32%,9.68%和4.56%的斜拉索竖向分力;板件应力随顶底板厚度增加而减小,顶底板深入边弦杆长度增加可以降低底板-内腹板焊缝峰值应力,顶底板间距减小可降低内外腹板和顶底板与锚垫板接触区域应力;顶底板厚44 mm、锚箱顶底板深入边弦杆长度1800 mm、顶底板间距660 mm时较为合理。

大跨度铁路桥附属构件对不同宽高比矩形断面涡振性能的影响

在已建成的大跨度鳊鱼洲长江大桥原设计宽高比为6.7∶1的四线铁路桥矩形箱型主梁断面的基础上,通过调整断面宽高比,设计宽高比为4∶1的二线铁路和宽高比为9∶1的六线铁路桥矩形箱梁断面。通过节段模型风洞试验,在0°,±3°和±5°风攻角的均匀来流下,对以上3种常用二线、四线和六线铁路桥矩形箱梁断面与对应相同宽高比纯矩形断面之间的涡振特性关系,以及铁路桥附属构件对不同宽高比矩形断面涡振性能的影响进行研究。结果表明:在宽高比分别为4∶1和6.7∶1的矩形断面上布置铁路桥附属构件能增大断面在负风攻角下的涡振振幅,在-5°风攻角下竖向涡振振幅增大率高达277.5%,但对正风攻角下的涡振响应起到一定的抑制作用,而在宽高比为9∶1的矩形断面布置六线铁路桥附属构件则能明显增大该断面在各风攻角下的涡振振幅,其扭转涡振振幅增大率均在48.3%以上;铁路桥附属构件对矩形断面涡振性能的降低作用随着断面宽高比的增大而提升,针对气动外形较钝的二线和四线铁路桥箱梁,可参考相似宽高比矩形断面涡振特性,并重点考察箱梁在负风攻角下的涡振响应,而针对宽高比较大的六线铁路桥箱梁,由于附属构件影响较大,参考相似宽高比矩形断面涡振特性的意义较小,均应详细研究其在各风攻角下的涡振性能。

武汉青山长江公路大桥宽幅钢箱梁悬臂拼装横向线形匹配技术

武汉青山长江公路大桥主桥为主跨938 m的双塔双索面全飘浮体系斜拉桥,主跨整体式钢箱梁高4.5 m、全宽48 m,采用500 t架梁吊机分节段悬臂拼装架设。钢箱梁悬臂拼装时,架梁吊机站位节段、待架节段由于荷载及约束不同,横截面变形呈现出不同的趋势,线形匹配难度大。为解决该问题,主跨钢箱梁悬臂拼装时选择上、下游分体式架梁吊机,减少架梁吊机自重;经比选选择横桥向27.7 m间距的架梁吊机站位,减小了架梁吊机荷载对横向线形匹配的影响;通过设置顶压装置(由顶压牛腿、支承底座组成),在架梁吊机站位节段、待架节段钢箱梁边腹板处施加1500 kN顶压力,配合少量马板,一次加载完成对接口竖向变形匹配调整。施工后,钢箱梁横向线形匹配精度均满足要求。

简支波形腹板钢箱组合截面与传统截面箱梁桥抗震性能对比分析

为研究波形腹板钢箱-混凝土组合梁桥(CW-SBCCGB)与传统箱梁桥抗震性能的异同,基于截面等效原理,根据某实际工程CW-SBCCGB的单箱截面,等效出波形腹板混凝土箱梁桥(CW-CBGB)和混凝土箱梁桥(CBGB)的单箱截面,再结合动力分析理论和ABAQUS有限元模型对比分析3种截面简支梁桥动力特性和抗震性能的不同。结果表明:3种截面简支梁桥前五阶振型不变,CW-CBGB和CBGB前三阶频率相比于CW-SBCCGB有所下降,但相差不超过1Hz,第四阶及以后频率差异逐渐变大;剪滞效应对CW-SBCCGB和CW-CBGB动力特性影响较大,对CBGB影响较小;在纵桥向+竖桥向和横桥向+竖桥向地震作用下,CW-SBCCGB和CBGB的墩顶位移和跨中位移均大于CW-CBGB结构,CW-SBCCGB主梁跨中截面剪力最小,CW-CBGB跨中截面弯矩最小,说明CW-SBCCGB和CW-CBGB的抗震性能均优于CBGB的抗震性能。

槽形钢箱梁涡振性能及抑振措施试验研究

为提高槽形钢箱梁桥的抗风性能,对槽形钢箱梁的涡振性能及抑振措施进行试验研究。以某人行景观桥槽形钢箱梁为背景,通过主梁节段模型风洞试验,研究+3°、0°、-3°风攻角下均匀流与紊流风场中槽形钢箱梁的涡振性能,分析交替封闭栏杆、将栏杆楔形扶手改为圆形扶手、提高阻尼比等措施的抑振效果。结果表明:原槽形钢箱梁断面涡振性能不满足规范要求,均匀流风场中,3个风攻角下均出现了超限的竖弯涡振,+3°和-3°风攻角下出现了不同程度的扭转涡振,最不利风攻角为-3°;紊流风场中,最不利风攻角下原断面竖弯涡振振幅降低了23%,未见明显扭转涡振;楔形扶手栏杆交替封闭使结构竖弯涡振振幅增大,主梁涡振性能降低;单独改变栏杆扶手形状为圆形对主梁涡振性能影响不大,在此基础上交替封闭栏杆能够有效抑制主梁涡振;提高结构阻尼比能有效抑制主梁涡振,阻尼比为7‰时,主梁竖弯涡振振幅可降至规范限值的一半左右。

波形钢腹板-钢底板组合箱梁耐火极限与设计

研究目的:近年来交通量的增加,由车辆碰撞或易燃物品运输车辆引起的桥梁火灾时有发生,不容忽视。为了解火灾下波形钢腹板-钢底板组合箱梁的火灾响应,采用ANSYS建立三维热-力耦合分析模型,分析火灾下组合箱梁温度场分布状态与抗弯承载力衰变规律,研究不同受火场景对组合箱梁耐火极限的影响,提出抗火设计方法。研究结论:(1)火灾下组合箱梁截面抗弯承载力呈三阶段发展;不同受火范围下跨中挠度随受火时间延长均呈两阶段发展;随着受火长度的增加,组合箱梁挠度增长幅度越大,受火初期受热弯曲效应作用越显著;(2)与抗力准则相比,采用挠度破坏准则判定组合箱梁的耐火极限较安全;(3)在组合箱梁底板增设不同类型的加劲肋形式,均可提高组合箱梁的耐火极限,当加劲肋材料用量相同时,与增设通长加劲肋相比,增设底板局部加劲肋对组合箱梁的耐火极限改善效果更好;(4)本研究成果可为波形钢腹板-钢底板组合箱梁的耐火极限理论分析与抗火设计提供参考。

波形腹板钢箱-混凝土组合梁横向内力计算与分析

为精确分析波形腹板钢箱-混凝土组合梁(SBCCGCW)的横向内力,考虑波形钢腹板特性和箱梁的畸变效应,利用框架分析法推导SBCCGCW的横向弯矩计算公式;通过两座实桥横向弯矩的有限元和实测结果对所提公式的正确性进行验证;对SBCCGCW横向内力的影响因素进行研究,并根据有限元分析结果提出SBCCGCW横向内力的简化计算公式。结果表明:利用所提公式获取的横向弯矩值与有限元结果和实测结果吻合较好,误差在10%以内;横隔板会大幅度减少荷载作用点处的横向弯矩;宽高比、混凝土顶板厚度、荷载作用位置对混凝土顶板横向弯矩的影响较大,钢底板厚度变化对混凝土顶板横向弯矩的影响较小。研究成果可为SBCCGCW的横向内力计算与分析提供参考。

大跨PK断面钢箱梁斜拉桥涡振性能及优化措施研究

红莲大桥主桥为主跨580 m的双塔斜拉桥,中跨主梁采用PK断面钢箱梁,该类主梁断面易发生涡振,需对其涡振性能及抑振措施进行研究。基于该桥有限元动力特性分析结果,制作PK断面钢箱梁1∶60缩尺比节段模型进行测振风洞试验,研究桥梁原始设计断面主梁的涡振性能,讨论增加结构阻尼比(增加至0.010和0.027)措施的涡振抑振效果,并对增设稳定板、水平导流板、部分封闭桥面栏杆等不同气动优化措施及组合对主梁涡振性能的影响进行分析。结果表明:原始设计PK断面钢箱梁的涡振振幅明显超过规范限值;增大结构阻尼比虽然可以有效抑制涡振响应,但阻尼比增加至0.027时竖弯涡振振幅仍然显著;在桥面检修栏杆上缘外挑1.6 m宽水平导流板可将涡振振幅降低到可忽略的水平;采用在检修栏杆上缘外挑1.1 m宽水平导流板、优化桥面燃气管道位置、调整防撞护栏下部封闭高度为0.42 m,或移除检修道栏杆底座、错列布置封闭检修道栏杆和防撞护栏等组合措施,虽不足以完全抑制涡振的发生,但可将涡振振幅控制至明显小于规范限值。

大跨度钢箱梁斜拉桥顶推施工中的关键技术研究

大跨度钢箱梁斜拉桥在跨越河流、峡谷等地形复杂地区时具有独特的优势,是现代桥梁工程的重要类型。文章以大跨度钢箱梁斜拉桥顶推施工为研究对象,以四川某大跨度桥梁工程施工数据为背景,讨论了临时墩布置位置的优化分析、顶推过程中钢箱梁斜拉桥竖向位移及支承处横肋和纵肋板件厚度对梁体局部受力的影响。研究结果表明,在实际施工中梁体向下倾斜居多,最大的竖向位移达392.08 mm;当支承处横肋厚度为0.016 m时,横肋的应力减小到200 MPa以下,适当设置横肋可以有效减小横肋自身的应力,提高结构的稳定性和安全性。该研究成果对提升斜拉桥施工水平、推动交通建设具有一定的指导意义和实践价值。

公铁混合布置大跨度斜拉桥主梁断面形式研究--以赣江公铁大桥西支主桥设计为例

以赣江公铁两用大桥西支主桥设计为例,研究一种适应上层8车道公路、下层对称双线铁路+4车道公路混合布置的主梁断面形式。提出带挑臂双索面箱桁组合断面、带挑臂单索面箱桁组合断面、矩形箱桁组合断面、矩形钢桁梁断面4种主梁断面方案,采用有限元软件分析各方案静动力性能及受力特点,综合考虑方案构造特点、技术指标、工程数量、公铁运营安全、景观效果等,确定该桥选用带挑臂双索面箱桁组合断面。该桥斜拉索最大索力16000 kN,锚固在下层钢箱梁两侧,通过有限元实体分析对锚拉板和钢锚箱式两种索梁锚固形式进行比选研究,钢锚箱形式受力合理、应力水平低、经济性好,设计采用钢锚箱形式。带挑臂双索面箱桁组合断面桥面空间布置合理、下层公铁行车干扰小、梁端竖向变形最小、经济性好,是一种适应公铁混合布置大跨度斜拉桥主梁断面形式。