Long-span Steel Research Articles

Mechanical Analysis for the Deck Pavement of Long-Span Steel Bridge

The mechanical analysis is applied for the steel box girder bridge with orthotropic plate and pavement by means of Finite Element Method. The interaction between steel bridge and pavement on the long-span steel bridge is evaluated in three calculation stages. The emphasis of the analysis includes the mechanical characteristics and the influential factors of large components(cross diaphragm)and local components (U-shaped ribs). Considering the mechanical changes by the load of heavy-duty vehicles and heavy load with braking, the interfacial shear failure is studied for the main form of damage. In view of this major form of damage, this paper puts forward the corresponding mechanical analysis of the indicators.

Nonlinear Buckling Analysis of Hoisting with Application to Long-Span Steel Truss

Nonlinear buckling analysis method using the finite element with application to Long-Span Steel Truss was studied is this paper. The finite element model of long-span complex steel truss hoisting was established and nonlinear buckling analysis of long-span complex steel truss hoisting for two hoisting points schemes was accomplished. The eigenvalues, eigenvalue buckling modes and nonlinear buckling analysis of two hoisting point’s scheme were analyzed. The results indicate that, the nonlinear buckling analysis method using the finite element is applicable approach to study the hoisting buckling problem, the buckling will be not occurring under hoisting stage only with gravity loads. The force status of long-span complex steel truss is improved under more hoisting point’s scheme and the lateral stability is strengthened.

Performance-Based Fire Resistance Analysis of Long-Span Spatial Steel Structure

The long-span steel structure is usually used for the stadium, exhibition hall, airports, railway stations and other buildings, and these structures often have an intensive staff, stored supplies are relevant to people's livelihood and so on. If these buildings collapse under the fire, it may cause heavy casualties and property losses, so it’s necessary to make a further research on its fire resistance performance. In this paper, make a fire scenario simulation to the Qingdao North Station main station by using fire simulation software FDS, in order to be sure the increased temperature of components. Then calculate stress of components under the most unfavorable fire temperature with finite element software "Midas" to make sure those components which need a fire protection. Finally, according to the analysis results to determine fire protection scheme, reduce unnecessary waste or local protection can not reach the requirements. This method of fire protection in the paper can provide reference for similar projects.

Analysis of Ultimate Load-Bearing Capacity of Long-Span CFST Arch Bridges

In order to study the ultimate load-bearing capacity of the long-span concrete-filled steel tubular (CFST) arch bridge with fly-bird-type, the ANSYS finite element program was used to establish its special model, and to study ultimate load-bearing capacity of this bridge with three different methods. The constitutive relation factors of concrete-filled steel tubular was taken into consideration including confining effect ultimate load coefficients, failure modes, and load-displacement curves of this bridge under different cases. The result indicate that the ultimate load-bearing capacity of the bridge can meet the requirement, all of its failure modes is out-plane, the two methods, linear elastic buckling analysis and only geometric nonlinearity analysis, will over high estimate ultimate load-bearing capacity of this bridge, and linear elastic buckling method cannot reflect real failure mode of this structure. In order to correctly estimate the ultimate load-bearing capacity of the bridge structure, the effect of geometric and material double nonlinearity couldn’t be neglected.

Development and Conceptual Design of Steel Deck Pavement Used Cement/Emulsified-Asphalt/Epoxy Resin Concrete

The objective of this article is to provide a paving project for steel bridge deck based on a new composite bonding system of Cement/emulsified-Asphalt/Epoxy resin (CAE). Reinforced both by Epoxy and emulsified-Asphalt, the cement-based material has reflected good performances, especially rutting deformation at high temperature and adhesive strength with steel blocks, which should be satisfied to long-span steel bridge deck.

Design of Long-Span and Wave-Shaped Steel Canopy Structure of Ningxia Helan Mountain Stadium

Ningxia Helan Mountain stadium the bottom grandstand of which is steel reinforced concrete frame shear wall structure, the top canopy of which is space steel truss structure system. Using SAP2000 (V9.1.6 version) and MIDAS (V7.1.2 version) software, to have an elasticity check analysis to the overrall structure. Discussion the vibration characteristics and seismic performance of the stadium steel canopy; According to computing and analysising the model, taking normative inspect, the consequence show that the structure can meet the bearing capacity, the stress ratio of the majority position are not more than 0.7, and the stress ratio of force greater position are about 0.95. This wave-shaped canopy structure is excellent, is good to the applicability of architectural form, and can be as a reference for the similar stadium.

A Setting Pre-Angle Method in Multi-Steps Construction of Long-Span Steel Structures

Many long-span structures have to be divided into several substructures to manufacture simultaneously and ensemble by multi-steps. Based on the engineering practice that pre-angles can be set at joint nodes between pre-erected and after-erected substructures by inter-node design, this paper proposes that the pre-erected substructures can be analyzed independently with finite element method(FEM) to ensue safety of the semi-complete structure system, and the displacement of joint nodes can server as boundary constraint of after-erected substructures after the rotational components are relaxed, the theoretical basis and solution algorithm is described also. The analysis of a typical case proves that this method make the after-erected substructures facilitated more easily.

Study on Dynamic Test of a Large Span Steel Truss Pedestrian Bridge

To prevent a long-span steel truss pedestrian bridge vibration problem, finite element model was established by analysis software ANSYS, studies on this pedestrian bridge’s vibration question were carried on by frequent spectrum analysis based on recorded data and modal analysis. It has determined the vibrating level. In addition, the reason for this pedestrian bridge’s vibration has been thoroughly analyzed from the pedestrian and traffic, and had dynamic response analysis of pedestrian bridges under the crowd of pedestrians walking load. Then the main reason which causes the actual vibration characteristic has been found. Thus these both gave the reasonable explanation to the vertical vibration and provided the reference for the similar structure’s dynamic performance research.

Mechanical Characteristics Analysis of Sensitive Parameters of Long-Span Steel Truss Suspension Bridge

In order to study the influences of structure parameters on the structure mechanical characteristics of long-span suspension bridge. The Shiduhe bridge in Hubei Province was taken as the background of this study, The influence on structure line shape and free vibration characteristics of suspension bridge with the change of structure parameters was studied. The results show that main cable stiffness not only has greater effect on the structure shape of long-span suspension bridge, it also has obvious impact on structure free vibration frequency, in addition, the torsion displacement of stiffening girder can be reduced effectively by adding central buckle, it improves structure bending and torsion stiffness significantly, central buckle also can improve free vibration frequency of structure and enhance structure dynamic stability, It shows that the influencing factors of structure static characteristics are restricted by rigidity of main cable, free vibration characteristics are affected by main cable and central buckle, they are not very sensitive to the variations of the parameters of suspender cable, stiffening girder and main tower.

Application of Folded Plate Structure with Flat Truss in Long-Span Steel Roof Structure

Folded plate structure with flat truss is applied in the roof steel structure of the natatorium in Huai’an sports center. In this paper, mechanical analysis on loading case and dynamic characteristics of the roof steel structure is accomplished. Overall stability analysis is also completed by FEM software STRAND7. Analysis results indicate the scheme is in accordance with safety and aesthetic is appropriately designed, which could figure out that bearing capacity and seismic performance of the folded plate structure are satisfactory.

OS15-3-4 Fatigue resistance monitoring and life prediction of a long-span steel bridge

OS15-3-4 Fatigue resistance monitoring and life prediction of a long-span steel bridge

Design of Double Composite Bridges using High Strength Steel

High performance steel for bridges (HSB) which has higher performance in tensile, yield strength, toughness, weldability than common steels has been developed in Korea. HSB800 has a minimum tensile strength of 800MPa. However, design of long-span steel bridges with high strength steels is limited because of buckling and fatigue. In this paper, two concepts of composite and hybrid were utilized to solve the obstacles. Double-composite action in negative moment region was adopted to increase flexural stiffness of composite sections and to enhance buckling problems of steel plates. Combination of steel box girders and double-composite truss girders along the length of the bridges was also utilized to enable the design of longer span bridges. New continuous bridges with more than 100m span length were designed using the proposed concept and HSB. Effectiveness of each combination was discussed to suggest recommendations for the design of composite bridges with high performance steels.

Pavement Rehabilitation Strategy Selection for Steel Suspension Bridges Based on Probabilistic Life-Cycle Cost Analysis

Field inspections on long-span steel suspension bridges in China reveal that the pavements undergo a fast deterioration process attributed to the flexibility of suspension bridges and the heavy traffic loads. Such extensive damage and enormous repair costs call for a cost-effective rehabilitation strategy for these bridges. In this paper, the pavement rehabilitation strategy is investigated for the Runyang Suspension Bridge in China with the aid of the life-cycle cost analysis (LCCA). Three alternatives are compared for their economic efficiency, and both agency costs and user costs are taken into account. To consider the uncertainties that abound in the LCCA, probabilistic analyses are made in which the Latin hypercube method is used to provide samples of random variables. According to the LCCA results, the user costs are a considerable proportion of the total costs so that the selection of rehabilitation strategies is significantly influenced by the user costs. In this regard, the second alternative, the double-layer pavement (guss asphalt plus stone matrix asphalt) is the most cost-effective rehabilitation strategy for the bridge. Additionally, sensitivity analyses show that the traffic growth rates, the discount rate, the work zone duration, and the delay cost rate for passenger cars are the most sensitive variables in the user costs. The methodologies and approaches introduced herein can be easily implemented by practitioners and would be of benefit to pavement rehabilitations for steel suspension bridges.

Design and Construction on the Roof Systems of Guangzhou South Railway Station

The roof structures of Guangzhou South Railway Station are long-span spatial steel structures, The form and structure system are complicated. Prestress cable-arch structure, cable-shell structure and tri-directional truss-string spatial structure are applied. It recommend the construction and design process of roof structure, and also give an analysis of roof structure's working principle on prestress cable-arch structure , cable-shell structure, and the tri-directional truss-string structures. The results show that working stability of the roof structures is good.

Nonlinear Finite Element Analysis of Beam String Structure

Beam string structure (BSS), which is a new kind of semi-rigid hybrid system, composed of arch, strut and string, has been developed rapidly in long-span steel structures in recent years. Based on the principle of virtual work and Updated Lagrange, the formulas of geometric nonlinear F.E.M. for spatial beam element, cable element and truss element are derived respectively in this paper. Taking the one-way BSS model of the steel roof in Guangzhou International Convention and Exhibition Center as a computational example by using both linear and nonlinear analysis method, the analytical results show that it is appropriate when adopting the straight truss element with two joints and equivalent elastic modulus to simulate the cable element with small sag. Although the linear analysis can meet the requirement of practical engineering due to its weak nonlinearity of BSS, the nonlinear method is also important to improve the precision theoretically. The conclusions obtained may be helpful for the designers in similar projects.

Research on the Unloading Process of Long-Span Steel Roof and the Design of Temporary Bracing Structure

Unloading is a complicated process that the load-carrying condition of main structure is gradually transferred and the internal force is redistributed, and so the exact numerical simulation applied on the unloading process is crucially important. The steel roof composed of the space tubular truss with the long-span and cantilevered structure for the Helan Shan stadium at Yinchuan city in Ningxia Hui autonomous region is taken as an analytical example and the finite element analysis software SAP2000 is used to simulate the unloading process during the steel construction. The computational model is established and the simulation method is provided for investigating the detailed unloading process of steel roof. The load-carrying characteristic of every bracing point acquired by the numerical simulation analysis is applied to analyze and evaluate the structural performance under two different comparable unloading cases and then an optimized unloading scheme is achieved from these two cases. The deformation of steel roof and stress ratio of steel member at each different unloading step during the whole unloading process are presented. Ultimately, based on the preferable unloading scheme, the temporary bracing structure is designed by using the maximum reaction of bracing points when unloading.

Long-Span Shallow Steel Arches Subjected to Fire Loading

This paper considers the thermo-elastic behaviour of shallow steel arches of long span, which are deployed in large roofing applications such as airport terminals, during a fire. The analysis of shallow arches requires recourse to geometrically non-linear analysis, which is further complicated by the nature of the thermal loading which may occur under a fire and of the degradation of the material properties of steel during a fire. A general technique based on the principle of virtual work is developed, and the analysis results in a formulation in closed form, which includes the stiffness of a tie between the supports of an arch and the supporting columns. It illustrates that these long span structural arch roofing elements are stressed at a low enough level to, in general, preclude considering inelastic effects during a typical fire, so that the simplifying assumptions of elastic behaviour are valid. Guidance is suggested for preliminary design purposes.

Mitigating Epistemic Uncertainty in Structural Identification: Case Study for a Long-Span Steel Arch Bridge

Characterization of constructed civil-engineering systems through structural identification (St-Id) has gained increasing attention in recent years due to its potential to enable more effective infrastructure asset management and performance-based engineering. Although there have been recent advances that mitigate the challenges posed by aleatory (random) uncertainty, there are many remaining challenges associated with epistemic (bias) uncertainty that often have a more critical impact on the reliability of St-Id (especially with applications to constructed systems). The objective of this paper is to illustrate various sources of epistemic uncertainty and describe mitigation approaches by detailing the St-Id of a long-span steel arch bridge. This application includes a priori modeling, ambient vibration monitoring, data processing, feature extraction, and finite-element (FE) model correlation. Following a description of the St-Id, the impact of various modeling uncertainties on the calibrated FE model is ...

Numerical Study of Dynamic Response of Steel Deck Pavement under Traveling Random Vehicle Load

The steel deck pavement on long-span steel bridges is subjected to the heavy impact load imposed by the passage of millions of trucks during the several decades of its service life, and severe premature failures of steel deck pavement have appeared, especially the cracking. The irregularity of the pavement surface was simulated according to the power spectrum density function, and the random load was calculated according to the vehicle vibrating equation. Finite Element Method was used to build the vehicle-pavement coupling model. The effects of vehicle speed on the dynamic response of pavement were studied. Research results have proved that the maximum transversal tensile stress related to the cracking firstly increases and then decreases with the increase of vehicle speed.

A Double-Parameter K~J Fracture Criterion for Epoxy Asphalt Concrete

The epoxy asphalt concrete is extensively used as paving material for long-span steel bridges in China. But mode I crack, which is most prominent cracking pattern for the pavement, often appears on the pavement surface. Therefore, the stress intensity factor K and J-integral were adopted to analyze fracture properties of single-edge notched three-point bending beams. The influence of temperature on the two parameters was studied. The analyses indicate epoxy asphalt concrete exhibits ductile fracture property at 5~25°C and brittle fracture property at -15~5°C. It is also found that fracture property of epoxy asphalt concrete is better than other kinds of bituminous concrete. Finally, a double-parameter K~J fracture criterion is founded for the epoxy asphalt concrete and provides basis for anti-cracking design and repair of cracks of the pavement.