Truss Arch Research Articles

Mechanical Characteristics of Three-Truss Plate-Truss Composite Bridges on High-Speed Railways

This paper presents a study on mechanical behaviors of three-truss plate-truss composite bridges. Both a model test and numerical finite element analysis (FEA) have been conducted. The results indicate that the deck load is allocated to each truss in twice. The first allocation is among the panel points of bottom chord elements (tie beams), and the other through lateral bracings. When the stiffness of each truss (arch) is approximate, the load allocated to middle truss is about two times more than that in edge truss in the first allocation, and the second allocation makes the load tend to approximate among 3 trusses. But the vertical bending moment of bottom chord elements and the axial force of spandrel hangers in middle truss are about twice as that in the edge truss, which should be paid attention to. The results will be useful as references for design of three-truss plate-truss composite bridges.

Out-of-plane elastic buckling behavior of hinged planar truss arch with lateral bracings

This paper is concerned with the out-of-plane elastic buckling behavior of planar truss arch with continuous or discrete lateral bracings. Firstly, planar truss arches with continuous lateral bracings are studied, and a closed form solution of out-of-plane elastic buckling load is obtained theoretically. As for planar truss arches laterally restrained with discrete bracings, two key parameters, namely lateral bracing threshold stiffness and out-of-plane elastic buckling load of an arch segment between two adjacent bracings, are investigated by the finite element method, respectively. Besides, it is found from finite element results that, if the planar truss arch is manufactured by using intersecting joints between web members and chord tubes and is laterally restrained on top chord tubes, the out-of-plane buckling of bottom chord tubes will fully be prohibited. However, the gusset-plate connections between chord tubes and web members cannot prevent the planar truss arch from the out-of-plane buckling due to their weak stiffness, even though the arch is laterally fully restrained on top chord tubes.

Damping Integrated Technology in Three Concentric Circles Stereoscopic Applications on Steel Arch Truss

By the software SAP2000, this article established a 60 m span steel arch three concentric circle space truss model, derived modal characteristics, mastered the dynamic characteristics. By using isolation bearing, viscous dampers[1], shock absorption technology and integrated rear arch truss damping effect. Conclusions show that integrated damping technology, making the earthquake forces effectively reduced.

Assessment of Risks during Large-Span Steel Truss Arch Bridge Construction

Chongqing Chaotianmen Bridge is by far the world's largest three-span continuous half-through double-layer steel truss tied arch bridge. Risk evaluation and risk analysis are made to the bridge during construction period. At the same time, various measures are taken to avoid construction risks and accidents. The principal line of risk controls is clear with reasonable control measures. Chongqing Chaotianmen Bridge was completed and available for traffic on April 29, 2009, its various technical and quality indicators are in accordance with design and specifications.

Research on the Nonlinear Stability of the Steel Spatial Arch Truss with 120m Span and 0.2 Rise-Span Ratio

The elasto-plastic stability analysis on the steel spatial arch truss with 120m span and 0.2 rise-span ratio is carried out with the finite element program ANSYS. In the analyses, two conditions which are the geometric and material nonlinear, double nonlinear under different initial geometric defects are considered. The results show that the instability modes of arch trusses are all asymmetric instability of plane, and that the buckling load and plastic development of the four arch trusses with L/500, L/400, L/300 and L/200 initial geometric defects are decreased with the increase of different initial geometric defects, and that the axial stress of all web members is about the same, but the value of which does not exceed 235Mpa.

Study on Repairing and Strengthening Measures of Reinforced Concrete Truss Arch Bridge

This thesis takes reinforced concrete truss arch bridge---Nanchengzi River Bridge as an example, and adopts bonded steel reinforcement method, section increasing method and deck reinforcement method to reinforce this bridge. It also adopts finite element method to make a calculation and analysis of stress condition of this bridge after reinforcement, and gain the maximum stress value and span deflection of this bridge after reinforcement, so as to provide useful reference for the repairing and reinforcement of this reinforced concrete truss arch bridge.

Elastic out-of-plane buckling load of circular steel tubular truss arches incorporating shearing effects

For steel tubular truss arches, calculations of sectional rigidity especially the torsional rigidity, as well as the effect of shear deformation on out-of-plane buckling are not available yet. This paper investigates the sectional rigidities of trusses and the out-of-plane buckling loads of pin-ended circular steel tubular truss arches in uniform axial compression and in uniform bending. Firstly the compression rigidity, flexural rigidity, shear rigidity and torsional rigidity of latticed configuration for trusses are deduced. Then the out-of-plane buckling equations for circular monosymmetric arches incorporating the effect of shear deformation are established using a static equilibrium approach. Lastly the closed form solutions for out-of-plane buckling loads of pin-ended circular truss arches in uniform compression and in uniform bending are obtained. It is found that the axial deformation of chord tubes need be taken into account in the derivation of shear rigidity and torsional rigidity of latticed configuration. Due to the curved arch profile, the effect of shear deformation on out-of-plane buckling loads of truss arches is much smaller than that on straight truss columns.

Nonlinear dynamic behavior of steel framed roof structure with self-centering members under extreme transient wind load

Collapse of roof could cause severe economic loss and poses safety risk to residents in the building. This paper presents a nonlinear dynamic analysis of steel framed roof structures with force limiting devices under combined static and transient wind loading. Two types of force limiting devices – one with self-centering behavior and the other exhibiting bilinear-like hysteresis are examined for roof collapse prevention. A nonlinear dynamic analysis that accounts for both material and geometrical nonlinearities was carried out for this simulation study. Two types of steel framed roof structures – a K-series steel joist and an arch truss are selected as the prototype roof frame in this study. It is found that installing force limiting devices at intentionally weakened zone of the prototype steel framed roof structures helps mitigating the displacement demand of the roof frame structure under transient up-lift wind pressure and thus reduce the dynamic collapse risk. Furthermore, the force limiting devices with self-centering behavior minimizes the residual deflection of the roof structures after the wind event.

屋根型単層ラチスシェルの地震荷重伝達能力に限界づけられるトラスアーチ架構の動的挙動と保有耐力評価

The study deals with EP roof type lattice shells with ceiling panels supported by truss arch frames on the both sides. The estimation method based on the elasto-plastic dynamic buckling analyses considering a geometric nonlinearity is proposed to calculate practically the base-shear strength coefficient and the applied seismic lateral and vertical load distributions on the lattice shell and the truss arch frame. As far as the collapsed mechanism is concerned, the member buckling occurs in the both structural elements. The proposed method is practically useful to determine the collapse mechanism and calculate the ultimate lateral strength on the earthquake-proof design for the damage and safety limit earthquakes.

The Dynamic Performance and Stability Analysis of Prestressed Arch-Supported Net Shell Structures

Based on the structural features of net shell and prestressed arch structures, prestressed arch-supported net shell structures have been developed as a new large space structural system. Dynamical performances and stability of a real prestressed arch-supported net shell structure are analyzed in this paper by using ANSYS. The structure vibration frequency and natural conditions are extracted using dynamical modal analysis method. Because of the bigger ratio between the span and the thickness and smaller critical load values, significant stress advanced phenomenon of some truss bars will appear in the influence of construction when prestress cables are introduced to the space structures (especially for the combination of truss arch and net shell). These effects will make link nodes keep certain stress. Literature survey shows that the research on how the residual stress influences the stability of the structure is very still insufficient. Therefore, the overall stability analysis of the prestressed arch-supported net shell structure is very necessary. The result of research shows that the vibration frequency of prestressed arch-supported net shell structures is enhanced continually with the stronger overall stiffness. Vibration models are significantly different for diverse different structure forms. Result of this study also shows that the stress makes the buckling ultimate load of prestressed arch-supported net shell structure be improved markedly and the stability of prestressed arch-supported net shell structure be enhanced. As a result, the overall performance of this new hybrid structure system is better and it has a certain application prospect.

The Research on the Nonlinear Stability of the Steel Spatial Arch Truss with 120m

In this paper, the elastic stability and elasto-plastic stability analysis on the steel spatial arch truss with 120m span and 0.2 rise-span ratio is carried out with the finite element program ANSYS. In the analyses, three conditions which are the geometric ,the geometric and material nonlinear, double nonlinear under different initial geometric defects are considered. The results show that the instability mode of arch trusses are all asymmetric instability of plane, and that the buckling load of considering double nonlinear is 13.84% that of considering geometry nonlinear, and that the coupling effect of geometry nonlinear and material nonlinear has accelerated reducing the stiffness of structure and bearing stable capacity ,and that the ratio for the buckling load of the four arch trusses with L/500, L/400, L/300 and L/200 initial geometric defects is 1.0: 0.927: 0.904: 0.87: 0.804, and that load-displacement process curves of feature node are the same change for the structures under different initial geometric defects.

Study on Model Experiment of Long-Span Steel Truss Arch Bridge

This paper based on the structural characteristics of thin-wall steel truss of JiuJiang Yangtze River Bridge, designs a distorted model that thickness ratio is 1/10 and the length ratio is 1/40.Through the static test model, the cross-section stress of hangers chord, diagonal and the deflection of corresponding test point is tested, and the result is compared with numerical simulation result. It shows that the result of the test and numerical simulation satisfy the similar relations, thus verifying that the design of scale model is reasonable and correct.

Static and Dynamic Test Detection of Steel Tube Truss Arch Bridge

Static and dynamic test of 85m span half-through steel tube concrete truss arch were in. Follow contents were determined in the static test:control section deflection of steel tube concrete arch rib under test load;deck control section deflection and strain measuring in test load;deflection and strain measuring of suspender beam;strain test of suspender;crack observation of beam in loading. The deflection and strain measuring point of deck control section were on the beam. The content of dynamic load test :the measuring of impact coefficient、natural frequency and cable tension by frequency methods. Finally, operational situation of bridge was estimated.

Analysis on Stability and Ultimate Bearing Capacity of Steel Truss Arch Bridge

Based on the secondary development of ANSYS, a through-type steel truss arch bridge is modeled, and the most unfavorable position of live load for each concerning location of the bridge is determined by using the influence lines program self-developed with parametric language. Linear elastic stability analysis of the whole bridge is firstly conducted, and followed by calculating the ultimate bearing capacity of the bridge with the consideration of geometrical and material nonlinearity of structure. By analyzing the buckling modes and safety coefficients of two types of stability problems, and comparing the linear elastic and nonlinear stability analysis results, the first type stability analysis, as a non-conservative method, is found to be suitable for ideal structures; the second stability analysis is found to be completely different from the first stability analysis, with different buckling mode and lower stability coefficient. Therefore, it can be concluded that the ultimate carrying capacity of structures should be determined based on the second stability analysis.

Relocating A Local Landmark

As part of a first-of-its-kind agreement in Pennsylvania, a county and a township partnered to relocate the century-old Keller’s Covered Bridge, a single-span Burr arch truss structure listed in the National Register of Historic Places. While the local landmark continues to serve vehicular traffic in a new location, it has been replaced in its original setting with a contemporary bridge that can handle increased traffic volumes and meet modern safety standards.

Structural Analysis and Load Test of a Nineteenth-Century Iron Bowstring Arch-Truss Bridge

A structural study examines the oldest remaining metal bridge in the Commonwealth of Virginia, a wrought-iron bowstring arch truss, designed and manufactured by the King Iron Bridge Company. Finite-element analysis is used to evaluate the interaction between the arch and truss, and the results are compared with field measurements from a live-load test. The study reveals that diagonal truss elements decrease arch bending by distributing concentrated vertical loads along the arch toward the abutments in a way consistent with that of modern network arch bridges. When the truss diagonals are absent, the vertical bridge-deck deflection is doubled. Underslung portal frames provide lateral stiffness to the arch, an innovation that accommodates a shallow arch profile conducive to transportation and erection.

Dynamic Elasto-Plastic Analysis on the Steel Spatial Arch Truss with 60m Span and 0.1 Rise-Span Ratio

In this paper, the elasto-plastic dynamic analysis on the steel spatial arch truss with 60m span and 0.1 rise-span ratio is carried out under earthquake wave with SAP2000. In the analyses, the geometric and material nonlinear effects are considered at the same time based on the plastic-hinge theory. Under the action of EL wave with the peak increasing gradually, its elasto-plastic dynamic responses have been obtained. The results show that its failure mode under the earthquake action is elasto-plastic dynamic buckling; that its critical peak acceleration of EL earthquake wave when applied in horizontally direction is 678gal, and is 624gal when applied in vertically direction; The ratio of its maximal node horizontal and its structural height is 1/961, and its displacement ductility coefficient is 1.14 and the ratio of its bars with plastic hinge appearing when buckling is 2.15% when EL-Centro waves applied on structure in X direction; The ratio of its maximal node vertical and its structural span is 1/660, and its displacement ductility coefficient is 1.17 and the ratio of its bars with plastic hinge appearing when buckling is 6.09% when EL-Centro waves applied in Z direction.

The Seismic Dynamic Response on the Steel Spatial Arch Truss with 60 m Span and 0.4 Rise-Span Ratio

In this paper, the elasto-plastic dynamic analysis on the steel spatial arch truss with 60 m span and 0.4 rise-span ratio is carried out under earthquake wave with SAP2000. In the analyses, the geometric and material nonlinear effects are considered at the same time based on the plastic-hinge theory. Under the action of EL wave with the peak increasing gradually, its elasto-plastic dynamic responses have been obtained. The results show that its failure mode under the earthquake action is elasto-plastic dynamic buckling; that its critical peak acceleration of EL earthquake wave when applied in horizontal direction is 808.5 gal, and is 789.0 gal when applied in vertical direction; The ratio of its maximal node horizontal displacement and its structural height is 1/259, and its displacement ductility coefficient is 1.071; The ratio of its maximal node vertical displacement and its structural span is 1/736, and its displacement ductility coefficient is 1.105.

Mechanical Behavior of the Shear Studs on Composite Deck of Steel Arch Bridge

Shear studs are critical important connectors in steel and concrete composite structures, and they will subjected to longitudinal shear force and transverse shear force, and as well as the tensile force under the applied loads. The mechanical behaviors of the studs are very complicated. In this paper, the spatial finite element model of Xinshiji Bridge, a steel truss arch bridge, was established, and the mechanical responses of the studs under various load cased were analyzed. The calculation results show that the shear forces of the studs under the dead loads are very small due to the structural characteristics of the bridge and the construction sequence of the bridge decks. Thermal effects, especially the effect due to temperature difference, are the key factors for the design of the studs in region near the ends of the bridge decks.

Dynamic Elasto-Plastic Analysis on the Steel Spatial Arch Truss with 30m Span and 0.2 Rise-Span Ratio

In this paper, the elasto-plastic dynamic analysis on the steel spatial arch truss with 30m span and 0.2 rise-span ratio is carried out under earthquake action with SAP2000. In the analyses, the geometric and material nonlinear effects are considered at the same time based on the plastic-hinge theory. Under the action of EL wave with the peak increasing gradually, its elasto-plastic dynamic responses have been obtained. The results show that its failure mode under the earthquake action is elasto-plastic dynamic buckling; that its critical peak acceleration of EL earthquake wave when applied in X direction is 654gal, and is 1108gal when applied in Z direction; The ratio of its maximal node horizontal displacement and its structural height is 1/102, and its displacement ductility coefficient is 4.215 and the ratio of its bars with plastic hinge appearing when buckling is 15.54% when EL-Centro waves applied on structure in X direction; The ratio of its maximal node vertical displacement and its structural span is 1/994, and its displacement ductility coefficient is 1.338 and the ratio of its bars with plastic hinge appearing when buckling is 11.66% when EL-Centro waves applied in Z direction.