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Dynamic Characteristics Evaluation of Innovative UHPC Pedestrian Cable Stayed Bridge  [PDF]
Won Jong Chin, Young Jin Kim, Jeong-Rae Cho, Jong Sup Park
Engineering (ENG) , 2012, DOI: 10.4236/eng.2012.412110
Abstract: KICT (Korea Institute of Construction Technology) is conducting a project called “SUPER BRIDGE 200—Development of Low Cost and Long Life Hybrid Cable Stayed Bridge”. This project aims to reduce the construction and main- tenance costs of long-span bridges by 20% and double their lifetime through the exploitation of ultra-high performance concrete (UHPC). This paper presents the design and construction of the first pedestrian cable stayed bridge using UHPC developed by KICT. UHPC, compared to conventional concrete, has not only high compressive and tensile strengths but also high ductility. The UHPC developed at KICT is a steel fiber-reinforced cement compound presenting design compressive strength larger than 180 MPa and design tensile strength exceeding 10 MPa with water-to-binder ratio below 0.24 and admixing of 2 volume percentage of steel fiber. To show the applicability of UHPC to structures, a pedestrian cable stayed bridge (Super Bridge I) exploiting the characteristics of the developed UHPC has been planned, designed and erected at KICT. The dimension of UHPC deck is 2.7 m × 7 m as a precast segment with a typical thickness of deck of only 7 cm. However, harmful crack was observed in the deck at the time of the fabrication of the deck segments. Accordingly, new fabrication method was conceived and applied to prevent cracking of the UHPC slender deck. Four UHPC deck segments were fabricated successfully without any crack. After construction, the dynamic characteristics (natural frequencies and mode shapes) were evaluated through vibration tests since several users felt excess vibration. A vertical tuned mass damper (TMD) was proposed and installed on the parapet of the bridge. The TMD reduces the acceleration by about 30% from 0.0316 g to 0.0244 g when two pedestrians are crossing the bridge.
Conceptual Design of Hybrid Cable-Stayed Bridge with Central Span of 1000 m Using UHPC  [PDF]
Hyejin Yoon, Won Jong Chin, Hee Seok Kim, Moon Seoung Keum, Young Jin Kim
Engineering (ENG) , 2013, DOI: 10.4236/eng.2013.59089
Abstract:

Ultra-high performance concrete (UHPC) is featured by a compressive strength 5 times higher than that of ordinary concrete and by a high durability owing to the control of the chloride penetration speed by its dense structure. The high strength characteristics of UHPC offer numerous advantages like the reduction of the quantities of cables and foundations by the design of a lightweight superstructure in the case of the long-span bridge preserving its structural performance through axial forces and structures governed by compression. This study conducted the conceptual design of a hybrid cable-stayed bridge with central span of 1000 m and exploiting 200 MPa-class UHPC. The economic efficiency of the conceptual design results of the hybrid cable-stayed bridge with central span of 1000 m and of Sutong Bridge, the longest cable-stayed bridge in the world, was analyzed.

UHPC铺装加固斜拉桥正交异性钢桥面板
Reinforcement of orthotropic steel bridge deck for cable-stayed bridge based on UHPC paving system
 [PDF]

,,张建仁,,,闫燕红,戴理朝,,
- , 2018,
Abstract: 针对正交异性钢桥面板存在的桥面铺装破损及钢桥面疲劳开裂这一系列问题,以长期被该病害困扰的天津海河大桥为研究对象,分析此类病害的分布特征及产生机理;根据病害形成的原因提出采用超高性能混凝土铺装层(UHPC)与钢桥面通过剪力钉形成组合结构的加固方法,并将该方法首次应用于大跨径斜拉桥的加固;基于有限元计算和加固前后实桥比对试验,对UHPC层及桥面板关键部位应力情况进行分析,并连续2年对加固后桥梁的状况进行监测。研究结果表明:桥梁病害产生的主要原因是自身刚度不足,在重载车辆的长期作用下出现疲劳开裂;采用UHPC铺装加固后,钢桥面转变成钢-UHPC组合桥面,可大幅度提高桥面板整体刚度,其受力状态得到明显改善,钢箱梁U肋、横隔板、顶板在标准车荷载下的应力分别降低52.7%、39.2%、28.3%,UHPC铺装加固能有效抑制疲劳裂缝的产生和发展,UHPC材料的抗拉强度能满足活载作用下最大拉应力的要求;在重载交通的运营状况下桥面铺装依旧完好,钢箱梁无新增裂缝。采用UHPC铺装加固正交异性钢桥面板在改善其受力状况方面具备优越性和技术可行性。
The damage of pavement and fatigue cracks are the common problems in orthotropic steel bridge deck. Based on the Haihe Bridge of Tianjin which had been troubled by the disease mentioned above for a long time, the distribution characteristics and the main causes of the disease were analyzed. According to the main causes of the disease, a reinforcement method of using the ultra-high performance concrete (UHPC) was presented, which formed a composite structure with bridge deck by shear studs. The method was firstly applied to the reinforcement of long span cable-stayed bridges. Based on the finite element analysis and the real bridge comparison test before and after the reinforcement of the bridge, the stress situation of the key parts of the UHPC layer and the bridge panel was analyzed. And then the condition of the reinforced bridge was monitored for two years. The results show that the major cause of the bridge diseases was its weak stiffness, the fatigue cracks occur under the long-term action of heavy vehicle. The steel bridge deck changes into composite bridge deck after reinforcement, whose stiffness increases significantly, and the structural force conditions are obviously improved. The stress of the U ribs, the diaphragm and the deck-plate is declined by 52.7%, 39.2% and 28.3% respectively. UHPC pavement reinforcement can effectively inhibit the generation and development of fatigue cracks, and the tensile strength of the UHPC can satisfy the required maximum stress. The monitoring shows that the pavement is still in good condition and the steel box girder has no new cracks under the operating condition of heavy traffic. The reinforcement method of using UHPC pavement to the orthotropic steel bridge deck bridge has superiority and technical feasibility in improving its stress condition
Development of Optimal Structural System for Hybrid Cable-Stayed Bridges Using Ultra High Performance Concrete  [PDF]
Hee Seok Kim, Young Jin Kim, Won Jong Chin, Hyejin Yoon
Engineering (ENG) , 2013, DOI: 10.4236/eng.2013.59086
Abstract:

This study developed an optimal structural system for the hybrid cable-stayed bridge expected to have a durable lifetime of 200 years and of which major structural members are made of ultra high performance concrete (UHPC) with 200 MPa-class compressive strength. This innovative cable-stayed bridge system makes it possible to reduce each of the construction and maintenance costs by 20% compared to the conventional concrete cable-stayed bridge by improving significantly the weight and durability of the bridge. Therefore, detail design is carried out considering a real 800 m cable-stayed bridge and the optimal structure of the hybrid cable-stayed bridge is proposed and verified.

Effect of Cable Degradation on Dynamic Behavior of Cable Stayed Bridges
Journal of Civil Engineering Research , 2013, DOI: 10.5923/j.jce.20130301.04
Abstract: In the present work a cable stayed bridge of fan type arrangement is analysed for static and dynamic load. The analysis is done with all the cables under normal condition, different percentage of corrosion of one cable and the failure of one cable due to excessive corrosion. The analysis is performed using finite element method software MIDAS Civil. The software is validated with simple bridge model. The bridge is analysed for moving load case as per the IRC 6-2000 and also for earthquake load (Time History of El Centro) and for different load combinations. The effect on axial forces in cable, deflection of deck, natural frequency, mode shape of the structure and earthquake response of the Cable Stayed bridge is studied.
Genetic Algorithms-based Optimization of Cable Stayed Bridges  [PDF]
Venkat Lute, Akhil Upadhyay, Krishna Kumar Singh
Journal of Software Engineering and Applications (JSEA) , 2011, DOI: 10.4236/jsea.2011.410066
Abstract: Optimum design of cable stayed bridges depends on number of parameters. Design of Cable stayed bridge satisfying all practical constraints is challenging to the designers. Considering the huge number of design variables and practical constraints, Genetic Algorithms (GA) is most suitable for optimizing the cable stayed bridge. In the present work the optimum design is carried out by taking total material cost of bridge as objective function. During problem formulation most of the practical design variables and constraints are considered. Using genetic algorithms some parametric studies such as effect of geometric nonlinearity, effect of grouping of cables, effect of practical site constraints on tower height and side span, effect of bridge material, effect of cable layout, effect of extra-dosed bridges on optimum relative cost have been presented. Data base is prepared for new designers to estimate the relative cost of bridge.
The Basic Differential Equations of Self-Anchored Cable-Stayed Suspension Bridge  [PDF]
Wang Hui-Li,Qin Si-Feng,Zhang Zhe,Huang Cai-Liang,Xu Wen-Jun
Mathematical Problems in Engineering , 2010, DOI: 10.1155/2010/805195
Abstract: The static behavior of self-anchored cable-stayed suspension bridge under vertical load is described with the continuum method. Based on the partition generalized variation principle, considering the compression-bending coupling effect of the main girder and the tower, the large displacement incomplete generalized potential energy functional of three-span self-anchored cable-stayed suspension bridge is established. Then, the basic differential equations of self-anchored cable-stayed suspension bridge are derived through constraint variation. Taking a self-anchored cable-stayed suspension bridge with main span 100?m, for example, the results by the proposed analytic method agree with that of numerical analysis. Therefore, the basic differential equations proposed in this paper could be applied to the preliminary analysis of self-anchored cable-stayed suspension bridge. The equations also provide a theoretical basis to describe the static behavior of this type of bridge. 1. Introduction Sea-crossing bridge projects in the 21st century are facing adverse natural conditions such as deep water foundations, strong winds, and so on. Either suspension bridge or cable-stayed bridge for large span bridge has shown shortcomings and inadequacies [1]. Therefore, the cable-stayed suspension bridge, which combines the advantages of cable-stayed bridge and suspension bridge to make up for their shortcomings, provides a suitable option for long-span bridge, particularly those sea-crossing bridge. There are some cable-stayed suspension bridges in the world, such as Albert Bridge in London, Brooklyn Bridge in New York, and so on [2]. Wujiang Bridge in China, with spans of m is the longest modern cable-stayed suspension bridge. Nagisa Bridge, a single span footbridge in Japan, is a hybrid structure of cable-stayed prestressed concrete bridge and steel suspension bridge. And the schemes of cable-stayed suspension bridge have been proposed many times, such as Turkey Izmit Bridge, Gibraltar Strait Bridge, Lingdingyang Bridge, and so on. However, due to lack of systematic study on such bridge type, the proposals are not implemented. At present, the schemes of cable-stayed suspension bridge just stay in the program design phase, and the proposed schemes all adopt the earth-anchored system with large anchor. Using a self-anchored system could not only save the anchor, but also possess the advantages of cable-stayed suspension bridge. The Jianshe Bridge in Dalian is the first self-anchored cable-stayed suspension bridge in the world [3]. And self-anchored cable-stayed suspension
Extraction of cable forces due to dead loadin cable-stayed bridges under random vehicle loads  [PDF]
Liu Xiaoling, Huang Qiao, Ren Yuan, Fan Yehua, Chen Ping
- , 2015, DOI: 10.3969/j.issn.1003-7985.2015.03.019
Abstract: To extract the cable forces due to dead load in cable-stayed bridges from the monitoring data, the effects of various factors are eliminated step by step by different statistical methods. The information of cable tension sensors recorded by the health monitoring system of Nanjing No.3 Yangtze River Bridge is taken as an example. Temperature effects are eliminated by linear fitting analysis; a 5-level wavelet de-noising method is applied to eliminate the noise signal by the wavelet basis function of DB8. The rest cable force data is tested by the method of extreme-value type-Ⅲ distribution, and the fitted location parameter is selected as the cable force due to dead load. The results show that the cable force has a linear relationship with temperature. Sometimes, the temperature effect is significant. Noise effect accounts for a small percentage, and the vehicle loads effect has twice the temperature effect on the traffic volume in 2007. The calculation results of other stay cables verify the reliability and validity of the proposed method.
斜拉桥锚拉板足尺模型疲劳试验
Fatigue Test of Full-scale Model of Tensile Anchor Plate in Cable-stayed Bridge
 [PDF]

王连华,丁秉昊,李立峰
- , 2016,
Abstract: 为研究斜拉桥钢主梁与锚拉板采用对接焊形成的“上”字形索梁锚固结构的疲劳性能,进行了锚拉板足尺模型疲劳试验。通过全桥有限元分析确定了疲劳试验的模型设计;综合对比多种疲劳荷载计算方法,确定了试验的疲劳荷载;考虑平均应力对疲劳荷载的影响,确定了疲劳荷载的最大、最小峰值。结果表明:足尺模型历经300万次疲劳加载后,各部位均未发现疲劳裂纹,应力测试结果与有限元分析值吻合良好;“上”字形索梁锚固结构的疲劳性能满足工程要求。
In order to study the fatigue property of special??shaped anchorage structure of a cable beam which connects steel girder of cable-stayed bridge with tensile anchor plate using butt welding, the fatigue test of full-scale model of tensile anchor plate was carried out. Through the finite element analysis of whole bridge, the model design of the fatigue test was determined. Several fatigue load calculation methods were comprehensively compared, and the fatigue load was determined. At the same time, considering the influence of mean stress on fatigue load, the upper and lower peak value of fatigue load were determined. The results show that after 3 million times of loading cycles, there was no fatigue crack on the weld parts of the full-scale model, and the stress values of fatigue test and those of finite element analysis matches well. The fatigue property of the special-shaped structure meets the engineering requirements
Optimal Sensor Placement for Stay Cable Damage Identification of Cable-Stayed Bridge under Uncertainty  [PDF]
Li-Qun Hou,Xue-Feng Zhao,Rui-Cong Han,Chun-Cheng Liu
International Journal of Distributed Sensor Networks , 2013, DOI: 10.1155/2013/361594
Abstract: Large cable-stayed bridges utilize hundreds of stay cables. Thus, placing a sensor on every stay cable of bridges for stay cable damage identification (SCDI) is costly and, in most cases, not necessary. Optimal sensor placement is a significant and critical issue for SCDI. This paper proposes the criteria for sensor quantity and location optimization for SCDI on the basis of the concept of damage identification reliability index (DIRI) under uncertainty. Random elimination (RE) algorithm and heuristic random elimination (HRE) algorithm are proposed to solve the sensor quantity optimization calculation problem. Multistage global optimization (MGO) algorithm is also proposed to solve the sensor location optimization calculation problem. A case study is conducted to evaluate and verify the criteria and algorithms. Results indicate that the HRE algorithm can provide better solution with less elapsed time than the RE algorithm can in some cases, and the MGO algorithm can meet the multistage criterion for sensor location optimization and give a satisfying optimized solution. Theoretical analysis and case study results confirm that the criteria are reasonable and suitable for optimal sensor placement for SCDI. The proposed algorithms are effective and efficient for practical optimization calculation. 1. Introduction In recent years, bridge health monitoring system (BHMS) has been developed rapidly and widely used in large bridges, especially in cable-stayed bridges. Sensors, which are required to monitor the structural status and influential environmental parameters, are the most important foundation of BHMS. Since the project budget of BHMS is always limited, how to optimally place the limited sensors in a large bridge in order to obtain the best data for parameter and damage identification is a challenging task. Research activities in the last few years have been focused on the design and optimization of sensor placement. Some latest representative studies are presented as follows. Kim et al. [1–3] presented a design of autonomous smart sensor nodes to monitor tendons and girders in prestressed concrete (PSC) bridges and a design of hybrid acceleration-impedance sensor nodes on Imote2-platform for damage monitoring in steel girder connections. Ho et al. [4] presented a type of solar-powered, multiscale, vibration-impedance sensor node on Imote2 platform for hybrid structural health monitoring (SHM) in cable-stayed bridge. Yi et al. [5] attempted to explore the sensitive range of the Fiber Bragg Grating (FBG) sensor and proposed an optimal placement for FBG
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