Introduction to steel pylon hoisting of Taizhou Yangtze Bridge

Taizhou Yangtze River Bridge is the first three-pylon two-span suspension bridge in the world. The middle pylon adopts deep water caisson foundation. The superstructure of the middle pylon employs herringbone shape along the bridge, and portal shape in the transverse direction for the first time in China. In this paper, the basic construction procedure, equipment, construction steps, the key construction technologies and methods of steel pylon are introduced.     

Technical research on control of caisson construction for the middle tower foundation of Taizhou Bridge

The real-time informational monitoring system is adopted in the construction of middle tower foundation of Taizhou Bridge for the first time. The geometric state of the caisson, the stress of upstream and downstream anchorage cables, underwater topography, the drag forces of the caisson cutting edge and frictional resistances of the sidewall etc. are monitored in real time. According to the synthesized data analysis and decision-making system, the spatial states of the caisson are adjusted in time to locate and embed the deep water caisson precisely. The offset errors of the caisson are less than 30cm and the vertical errors is 1/363 at the final stage. The control technology for the construction of large caisson under deep water is concluded and would be helpful to the construction of bridge foundation in the future.     

Study in the design and manufacture process ofthe 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.     

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 is 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.     

General design of Sutong Bridge

The main span of Sutong Bridge is a double-pylon, double-plane cable-stayed bridge with steel box girder, which has the world's longest central span of 1,088m within cable-stayed bridges. Overcoming problems caused by severe meteorological conditions, perplexing hydrological conditions, deep buried bedrock and higher navigation level, many new technics and methods were created. The super-long span and stayed cables, super-high towers, as well as super-large foundations in deep water are all world records currently. Keys including structural system, steel box girder, stayed cable, tower, pier, tower foundation, collision avoidance system, wind-resistance, seismic-resistance, structural nonlinear response and structural static stability were presented individually in this paper. It was awarded George-Richardson Medal of International Bridge Conference (IBC) in 2008. The success of Sutong Bridge is the landmark that denotes China from large bridge country to advanced bridge country.     

Key Technical Innovation of Xihoumen Bridge-the longest steel box gird suspension bridge in the world

As the longest steel box gird suspension bridge in the world, Xihoumen Bridge is a cross-sea bridge linking mainland and the Zhoushan islands with the main span of 1650m. All progress from design to construction of the project, some technical question were researched and developed, such as idea of design considering topography condition, making choice of structure considering wind resist, controlling progression of construction considering complex ocean environment, etc. The key technical innovations which have were acquired reach international advance level.     

Vibration mechanism research of large scale and deep water caisson

According to the construction method of Taizhou Bridge, numerical simulation is conducted to analyze the vibration of caisson under wind and water flows to determine the main factors of the caisson vibration. Meanwhile, the localization system of caissons and anchors of Taizhou Bridge is modeled in order to summarize the vibration mechanism of caissons under deep-water and jet-flow condition, and further pertinent vibration-control measures are proposed. The obtained results are well verified in engineer practice, and consequently the safety risk of positioning the caisson during is reduced.     

Design and construction of Sutong Bridge tower

Su-tong Bridge tower with 300.4m is the highest one in the world. The tower anchor area uses the steel-concrete composite structure, its structure and the stress mechanism are complex, So It must be pay more attention to the structure durable issue. The tower with 300 meters is quite sensitive of the environmental factors such as wind and temperature. The safety of tower in construction stage against the wind is important especially. In this paper, the design of composite structure is introduced .The key technologies of tower geometry control and wind resistance in construction stage are analyzed.     

A Study of the system control model of caisson dewatering of the north anchorage of Taizhou Bridge

A caisson foundation is applied to the north anchorage of Taizhou Yangtze River Highway Bridge of which the initial caisson sinking requires dewatering. Since the caisson foundation is quite close to nearby buildings, a system control model is established with source (sink) distribution and intensity being the object function, minimum requirements of settlement and deformation of surroundings caused by dewatering and dynamic water levels during different working procedures being constraints, and the design parameter of pumping wells being the variable, as so to lower the jeopardizing of surrounding buildings, which provides a new method for active control over settlement during dewatering. Such a method of dewatering based on system control model should be of significance for similar projects involving dewatering.     

Construction and alignment control of the middle steel pylon of Taizhou Bridge

In this paper, the general construction procedure of the steel middle pylon is briefly introduced. The alignment control of the pylon is carried out during the whole process of the construction. The control concept is extended to the manufacture stage. The manufacturing alignment errors are strictly controlled in the segments precast process in factory, and the errors are recognized and predicted precisely during the installation stage. The adjusting joints are employed to amend the accumulated errors, which ensure that the steel pylon alignment could satisfy the precision requirements after installation.     

Wind tunnel study of aerodynamic wind loading on middle pylon of Taizhou Bridge

Wind loading on steel pylon will take majority part of the whole wind loading on bridges. In traditional wind-resistance design, wind loading on pylons is determined according to codes, or by using CFD techniques. In this paper, segment sectional model tests are carried out to investigate the wind loading on middle pylon of Taizhou Bridge, which has complicated three-dimensional flow due to its feature of double columns. Through the force measuring tests, aerodynamic force coefficients of every segment of the pylon columns have been obtained. It is found that the tested aerodynamic force coefficients are much smaller than those given by codes. The interference effects of aerodynamic force coefficients between columns of pylon are discussed. The results show that the interference effect is the most evident when the yaw angle is about 30 º from transverse direction. This kind of interference effect can be described as diminutions in transverse aerodynamic force coefficients and magnifications in longitudinal aerodynamic force coefficients of downstream columns.     

preface

<正>On the first issue of Standardization,the earliest journal on standardization published in 1958(now the China Standardization),the first article is titled"Review and future work of iron and steel standardization",indicating the special significance of steel standardization in the history.The ironsteel industry is one of the     

Study on structural system of Sutong Bridge

Sutong Bridge, whose layout is (100+100+300) +1088 + (300+100+100) m,marks the largest span of cable-stayed bridges in the world. The complex natural condition at the bridge site and the strict requirements for resistance of wind and seismic action make it crucial to choose a favorable structural system to assure the function and safety of the bridge. The comparison among several optional structural systems for Sutong bridge is illustrated. After detail analysis is carried out for viscous damper and hydraulic buffer, super liquid viscous damper with additional displacement limitation is designed for the first application in bridge engineering. The parameters for the damper is analyzed and studied and the dampers are installed successfully after required damper tests.     

Synergistic effect of erosion and hydrogen on properties of passive film on 2205 duplex stainless steel

Stainless steels have shown great potential in the application of offshore oil and gas industry.However,the internal surface of stainless steel pipeline may simultaneously suffer erosion from the fluid media inside the pipeline and the damage of hydrogen that is generated from the external activities such as cathodic protection.The synergistic effect of erosion and hydrogen on the properties of passive film on 2205 duplex stainless steel was studied for the first time in a loop system coupled with a hydrogen-charging cell.The components,protective performance and semiconductive structure as well as properties of the passive film under different conditions were investigated using in-situ electrochemical techniques,surface characterization and computational fluid dynamics simulation.The results show that the combination of erosion and hydrogen could greatly thin the passive film,furthermore,the Fe³⁺/Fe²⁺ratio and O₂^-/OH^-ratio in the passive film also decrease dramatically under such a condition.Therefore,the hydration degree of the passive film greatly increases,resulting in an increase in active sites and a decrease in the stability of the passive film.Erosion could destroy the passive film through the impact of sand particles and accelerate the mass transfer process of electrochemical reaction.While hydrogen can not only enhance the charge transfer process,but also make the passive film highly defective.Under the combination of erosion and hydrogen condition,erosion could enhance the hydrogen damage and simultaneously hydrogen could also enhance erosion.Therefore,the synergistic effect of erosion and hydrogen could dramatically change the passive film component,decrease the protective performance,and increase the susceptibility of pitting corrosion of 2205 stainless steel in Cl-containing environment.     

On site tests to estimate aquifer permeability of drainage area of south caisson anchorage construction of Taizhou Bridge

During the construction of the south caisson anchorage to Taizhou Bridge, the drainage area is located in the lower reaches of the Yangtze River and the permeability of stratums there is considerable. In order to maintain progress and guarantee safety during the sinking of the caisson, water should be drained in the initial period. Subsequently, detailed information about the aquifer permeability is required to make sure that the drainage will proceed successfully, which consequently necessitates the on-site estimation of the aquifer permeability in the drainage area. Therefore, the traditional pumping test and slug test are implemented respectively on site. The comparison of computational results of these two tests indicates that they are consistent overall. Notwithstanding, as slug test can be conduct with portable facilities in a short time and the manipulation is easy and few people need to be involved, the advantages of slug test is conspicuous compared with the traditional pumping test. It could be speculated that slug test will gain a prevalent application in the measurement of aquifer permeability in the future.     

Free Boundary Problems in the Steel Industry

This paper considers two novel free boundary problems that emerge from modelling processes basic to steel manufacture. The first process concerns the spray cooling of hot steel sheet during the process of continuous casting. Here, an important practical consideration is the non-monotonicity of the measured heat transfer from the steel as a function of the steel temperature. In order to understand this phenomenon, a two-phase flow model is written down for the heating and vapourisation of the water spray. This model relies on a microscale analysis of droplet vapourisation and, in a steady state, it reduces to a coupled system of nonlinear ordinary differential equations for the spray temperature and water content. This system predicts the conditions for the existence or otherwise of a free boundary separating the two-phase region from a dry vapour layer close to the steel plate.The thickness of this vapour layer is determined by the solution of a generalised Stefan problem. The second process concerns the macroscopic modelling of pig .iron production in blast furnaces. In the simplest scenario, the blast furnace may be roughly divided into a porous solid region overlaying a hot high pressure gaseous zone. The gas reacts with the solid in a thin “intermediate region“ at the base of the solid region and it is in this intermediate region that the pig iron is produced. A free boundary model is proposed for the location of the intermediate region and its stability is investigated.     

The mechanical response of multi tower continuous span suspension bridge deck pavement based on whole bridge analysis

This paper studied the effect of multiple span suspension structure on the mechanical response of bridge deck pavement, and Finite Element Analysis of stress and strain of pavement according to the bridge floor system features of super-long and high flexibility has been done. Meanwhile, the FEM results were compared with those of the single span suspension structure. Three-stage analytic hierarchy process (ahp) is developed to analyze the mechanical response including whole bridge analysis, partial beams section analysis and orthotropic plate analysis. The most unfavorable load position was determined by the numerical solutions acquired from each stage to study the main mechanical index of multiple span suspension structure. The FEM results showed that the mechanical response numerical solutions by using the three-stage ahp are greater than those by simplified boundary condition, and the force condition of multiple span suspension structure is worse than that of the single span suspension structure.     

Research on the special lifting devices for steel box girders of Sutong Bridge

Su-tong Bridge is a cable stayed bridge with a steel box girder and a main span of 1088 meters. The steel box girder of main-span include five portions: back span large unit, large block of pylon, standard girder, back span closure girder and middle span closure girder. Each back span large unit was fabricated by welding several deck segments together in factory, and was erected by floating crane. Due to the high of navigational clearance of the main bridge, the traditional truss lifting device couldn’t satisfy the requirement of domestic lifting cranes for this kind of lifting height and weight. Hence, a kind of lighter lifting device for the erection of back span large units was accepted for this bridge. In this paper, the design and use of this lifting device is introduced. The upper structure used lifting gantry to install the standard girder segment by cantilever method. Because the bridge’s navigation clearance is high, and the girder segment is wide and heavy, the meteorology and hydrology condition of the bridge district is abominable, and the requirements of long cable girder side pull-in, structure and performance propose high request to the lifting gantry. In this paper, the design and use key point of long cable pull-in angle adjustment device integrate into lifting gantry is introduced.     

Energy conservation research of dehumidification system for main cable anticorrosion of suspension bridge

The necessity of the main cable anticorrosion for suspension bridge is described, operating principles and composition of main cable dehumidification system is analyzed, and an idea using the waste heat of high temperature outlet air of dehumidification system to heat up regeneration air of rotary-type dehumidifier is put forward in this paper. The concrete scheme is to install a heat exchanger on air-out pipeline of Roots blower and air-in pipeline of regeneration electric heater of rotary dehumidifier. Air preheated by the heat exchanger enters regeneration electric heater of rotary-type dehumidifier. Energy conservation of main cable dehumidification system for the Yangtze River highway bridge was calculated, and the results showed that energy conservation rate reached 44%.