Tube Truss Research Articles

Experimental and Design Parametric Study of a Novel Grouted Square Steel Tube Upper Chord–Concrete Composite Floor

A novel composite floor consisting of an upper chord of a grouted square steel tube truss and a lower chord of a reinforced concrete slab is proposed to address existing problems with precast composite floors, such as a complex construction process, high cost, significant resource consumption, and severe environmental pollution. Sixteen-point loading tests were carried out on five simply supported one-way slabs to simulate the stress state of the floor under a uniform load and to investigate the stiffness, cracking moment, load-carrying capacity, and failure mode of the composite floor system. The results showed that the composite floor system exhibited ductile failure, with cracks uniformly distributed at the bottom of the slab; additionally, the grouted steel tube did not experience uplift or out-of-plane buckling, and the truss welds did not fracture, indicating that the composite floor system still had further deformation capacity and load-carrying capacity with satisfactory stress conditions. After unloading, the residual deformation of the composite floor accounted for 28% to 36% of the maximum deflection, demonstrating good deformation recovery ability. The bottom slab thickness and truss height are key parameters that influence the new composite floor, and increasing the two parameters enhances the cracking load, deformation resistance, and flexural capacity of the composite floor, with a significant improvement achieved by increasing the truss height. The floor slab should have a minimum thickness of 60 mm, as required by China’s Code for Design of Concrete Structures, and the truss height-to-span ratio should be 1:30, which meets the deformation and load-carrying requirements of the floor and conforms to the design concept of green buildings.

Research on the Fatigue Performance of Composite Girders with CSW and ST Truss

To study the fatigue performance of a composite girder with corrugated steel web (CSW) and steel tube (ST) truss, based on an engineering object, a test and finite element (FE) analysis were carried out. The fatigue failure mode and the sensitivities of the hot spot stress to the geometric parameters of the composite girder above were studied. The position with the maximum hot spot stress and the fatigue crack position were discussed and determined. Furthermore, a fatigue life evaluation method was discussed. It was found that linear extrapolation was applicable to finding the hot spot stress. The fatigue performance evolution comprised three stages, including initiation, expansion, and failure of the fatigue crack. The fatigue crack initiation stage accounted for about 95.6% of its fatigue life, and the fatigue crack was opening type I. The maximum hot spot stress emerged at the endpoint of the inclined web of CSW (point S). The main reason for the behavior was that the inclined web had a small out-of-plane flexural stiffness but had to bear an out-of-plane bending moment. Moreover, for the same section of the CSW, the hot spot stress on the molding side was less than that on the non-molding side. The hot spot stress exhibited negative correlations with the chord diameter, chord thickness, and bend radius, meanwhile, it had the highest sensitivity to the chord diameter. The existing S-N curves were not suitable to evaluate the fatigue life of the composite girder with CSW and ST truss. Since the intersecting weld between the CSW and the chord was located in longitudinal welded joints, the hot spot stress method suggested adopting the basic fatigue strength of 100 MPa, corresponding to 2,000,000 load cycles. Meanwhile, an empirical calculation model of the S-N curve for the composite girder with CSW and ST truss was created.

Full-Scale Experiment-Based Structural Safety of Membrane Structural Soundproof Tunnels Using Steel Tube Trusses

In this study, the structural performances of membrane structural soundproof tunnels using circular steel tubes are investigated. Full-scale specimens are manufactured for monotonic and cyclic loading tests for snow and wind loads, and their combination. A full-scale experiment is performed to gain insights into the loading test details while considering the effects of membrane tension and the steel tube truss frame. Parametric results show that the soundproof tunnel structures proposed herein satisfy the requirements for structural safety as well as afford a lighter and more aesthetic design.

Experimental study on the flexural performance of concrete-encased square steel tube truss beams

Flexural performance experiments on five concrete-encased square steel tube truss (SSTT) beams were conducted in this paper. The crack patterns, failure modes, vertical load-midspan deflection curves and strain distribution of this type of composite beams were studied. The cracking, yield and ultimate loads were then obtained. The results indicated that the five composite beams had a bending failure, i.e, the lower chords in tension first yielded and a subsequent crushing of concrete followed in the compression zone. Under the vertical loads, the composite beams experienced four stages: the integral, cracking, yielding of steel tubes of lower chords, and the failure stage. Moreover, the steel tubes of the lower chords had a gradual yield during the loading process, whereas as the composite beams reached the ultimate bearing capacity, the steel tubes of the upper chords were still in the elastic state, which showed a linear change with the increasing loads. In addition, the strains across the mid-span section of the composite beams conformed to the plane hypothesis. Based on the test results, the formulae of normal sectional flexural capacity, short-term flexural rigidity and crack width for concrete-encased SSTT beams were proposed, which could be used as a reference in practical engineering.

Analysis on Out-of-Plane Stability of Large-span Single Space Tube Truss during Hoisting

In order to study the out-of-plane stability of the large-span single space tube truss during lifting, the eigenvalue buckling mode of the truss was calculated by mode analysis in ANSYS, the eigenvalue buckling mode with different combination coefficients was applied to the truss, and the stability bearing capacity was taken as the measurement to conduct the whole process tracking analysis. Finally, the most appropriate eigenvalue buckling mode combination was found as the initial imperfection, and it was applied to a large-span single regular triangle space tube truss and inverted triangle space tube truss to verify its stability during hoisting, respectively. The results show that the combination form of the eigenvalue buckling mode is the most appropriate initial imperfection. When the large-span single regular triangle space tube truss and inverted triangle space tube truss are hoisted, local buckling occurs when the body force is up to 0.30 times and 0.15 times of gravity, respectively, and overall instability occurs when the body force is up to 0.56 times and 0.51 times of gravity, respectively. It can be obviously obtained that the large-span single space tube truss may be destabilized under its own weight during hoisting, local buckling has occurred in some member bars before overall instability, and it is necessary to check the truss stability before hoisting in actual engineering.

Analysis on Flexural Capacity of Square Steel Tube Truss Concrete Beams with Grouted Chords

In this research paper, simulations on five specimens of square steel tube truss concrete beams with grouted chords were conducted by finite element analysis (FEA) software ABAQUS. Comparison of failure modes, vertical load‐deflection curves, and steel tube strain variation with tests was done. The rationality and validity of the FEA models were also verified. On this basis, parameter analysis was carried out, and the influence of concrete strength, steel ratio of upper and lower chords, and spacing of steel tube truss joints on the vertical load‐deflection curves were obtained. From the results of tests and parameter analysis, design formulae of flexural bearing capacity for composite beams were proposed based on the assumption that steel tubes are equivalent to ordinary longitudinal steel bars. Accordingly, the results indicated that the steel tubes of the upper chords in the composite beams cannot get yield for full sections due to the structural requirements; the steel tube of the lower chords will be the first to reach fully yielding and the upper concrete crushed subsequently, showing a failure mode analogous to that of the under‐reinforced concrete beam; the steel ratio of lower chords is the primary factor affecting the flexural capacity of the normal section among the parameters; the calculation from the proposed design formulae for the flexural capacity of normal section is in agreement with the tests and simulations. This research could provide reference for the design of this kind of composite beam.

Performance of concrete-filled steel tube truss girders strength by adding reinforcement

Concrete filled steel tube (CFST) truss girder usually consists of CFST chords and hollow braces. The performance of steel tube truss girders filled with self-compacting concrete was investigated in this study. A total of eight CFST truss girders (Warren-vertical truss) specimens were tested. The main parameters were the concrete compressive strength and adding a reinforced bar in the concrete core of the bottom chord. Two of specimens without reinforcement were suggested as reference specimens. This study shows the load-deflection curves at the midspan, overall deflections, ultimate loads, flexural strength and failure modes of the tested specimens. The Proposed design equation found in the literature was used to predict the flexural strength of CFST trusses. The failure mode includes: weld fracture and shredding around joints and local buckling of the diagonal braces. Results show that the increase of concrete compressive strength caused a slight increase of the CFST truss strength by about (2.8%-10.34%), also the results showed that the best addition to the core concrete of the bottom chord was the circular steel tube compared with the addition of the steel bars.

Experimental Study of Self-Compacted Concrete-Filled Steel Tube (CFST) Truss Girders

Concrete filled steel tube one of the most important modern innovations in the world. This paper studies the performance of steel tube truss girders filled with self-compacting concrete. Four CFST truss girders specimens tested. The first novelty in this research was using square tubes to made truss girder; the main parameters were bottom chord concrete compressive grade and reinforce steel bar is embedded in the bottom chord (second novelty). One bar with a nominal diameter 16 mm was used to reinforce the concrete in the bottom chord while keeping the concrete in the top chord without reinforced. This paper shows the load-displacement curves at the mid-span, deflections along the span, peak loads, flexural strength, and failure modes of the tested specimens. The design equation was used to predict the flexural strength of CFST truss specimens. Results show that the flexural strength increased with increasing the concrete grade from 29.23MPa to 48.41MPa by about 4.5% and increased by about 10.27% when using reinforce steel bar embedded the concrete in the bottom chord.

Seismic Response Investigation and Nonlinear Numerical Analysis of Cold-Formed Thin-Walled Steel Tube Truss Shear Walls

In order to satisfy the requirements of seismic capacity of cold-formed thin-walled steel structure in low- and multi-rise buildings, an innovative cold-formed thin-walled steel tube truss (CFSTT) shear wall sheathed with both-side oriented strand board (OSB) was proposed in this paper. Five full-scale specimens of CFSTT shear walls which composed of square cold-formed thin-walled steel tubes, tracks, galvanized V-shaped connectors and OSB panels were tested under low-cyclic loading. The seismic performance of CFSTT shear wall was evaluated in terms of hysteretic behavior, envelop curves, ductility and energy dissipation, etc. Then, a practical nonlinear simplified analysis method of CFSTT shear walls under low-cyclic reversed lateral loading was proposed based on the principle of equivalent tie rod model. The double- and four-limb lattice studs were also simplified as single steel tubes. Besides, a pivot modeling approach was suggested to stimulate the sheathing-to-frame connection. Subsequently, the finite element models of CFSTT shear walls were established based on this simplified method and verified by the experimental data. Numerical and experimental results indicated that CFSTT shear walls exhibited excellent seismic performance, and the accuracy of the simplified of lattice stud was verified. Furthermore, the simplified method proposed in this paper will highly facilitate conducting the nonlinear analysis for shear walls.

Predictive Analytics of In‐Service Bridge Structural Performance from SHM Data Mining Perspective: A Case Study

In‐service bridge structural performance analysis and prediction are usually complicated and challenging because of many unknown and uncertain factors. Contrary to the traditional structural appearance inspections and load tests, structural health monitoring (SHM) can provide a perspective for online analysis, prediction, and early warning. So far, SHM has been widely used in many bridge structures, and a lot of bridge SHM data have also been collected. However, the existing studies usually focus on some independent and unsystematic analysis methods, which are hard to use widely in engineering applications to reveal the overall structural performance. This study focuses on the structural performance analysis and prediction of the highway in‐service bridge. The dynamic problems in bridge SHM are pointed out firstly, followed by a detailed analysis about the characteristics of bridge SHM data. With the consideration of different characteristics, three targeted analysis methods are proposed. An urban concrete‐filled steel tube (CFST) truss girder bridge (opened to traffic in 1995) is also presented, which once experienced some prominent vibration problems. The bridge SHM system is designed and stalled after several appearance inspections, load tests, and some reinforcement measures. The data mining methods proposed (distribution function, association analysis, and time‐series analysis) are employed for the analysis and prediction of structural response and deterioration extent. This study can provide some references for maintenance and management and can also build a foundation for further online analysis and early warning.

Seismic response evaluation and design of CTSTT shear walls with openings

Nowadays, cold-formed thin-walled steel tube truss (CTSTT) shear walls are popularly used in engineering practice because of their superiority in light weight, convenient construction and good ductility. However, little attention to the seismic response of the CTSTT shear walls has been paid. This paper aims to investigate the effect of wall openings on seismic behavior of cold-formed thin-walled steel tube truss (CTSTT) shear walls. Five full-scale specimens of CTSTT shear walls sheathed with double-sided oriented strand board (OSB) panels and one full-scale specimen of CTSTT skeleton were tested under vertical axial compression combining lateral low-cyclic load. The parameters, including the type and layout of openings, stressed skin diaphragm as well as opening rate, were estimated in the quasi-static tests. The seismic performance of CTSTT shear wall was evaluated in terms of shear capacity, rigidity, ductility and energy dissipation, etc. Moreover, a simplified empirical formula for predicting the shear capacity of CTSTT shear wall with opening was proposed and verified by the experimental data. The test results indicated that the CTSTT shear wall with double-sided OSB panels exhibited admirable rigidity, good ductility and excellent energy dissipation properties. The shear capacity of CTSTT shear wall decreased by wall opening setting, while seismic behavior of the type of wall could be improved by using four-limb studs within the vicinity of opening. These experimental and analytical studies would improve the application of the CTSTT shear walls in engineering practice.

Cyclic test and numerical analytical assessment of cold-formed thin-walled steel shear walls using tube truss

Cold-formed thin-walled steel tube truss (CFSTT) shear walls are gradually used in some engineering practice (i.e. residence, supermarket, school etc.) owing to their superiorities such as light weight, better ductility and easy construction. However, little attention to the seismic behavior and parametric influence of the CFSTT shear walls has been paid. In this paper, a series of cyclic tests and numerical analysis were conducted to investigate structural performance of the CFSTT shear walls. Five full-scale CFSTT shear walls sheathed with double-side oriented strand board (OSB) panels and one pure CFSTT skeleton wall were tested under constant axial compression combining lateral cyclic load. Failure pattern, horizontal load versus displacement relationship and ductility of the test specimens were analyzed and assessed. The experimental data showed that the CFSTT shear walls behaved good hysteretic behavior, ductility and energy dissipation. Following this, a nonlinear finite element (FE) analysis modeling of the type of cold-formed shear wall was developed, and the accuracy of the FE models was verified by experimental data. Parametric studies were conducted to explore the effect of X-shaped bracing number, OSB panel thickness, sheathing type, etc. on the shear bearing capacities and elastic stiffness of the CFSTT shear walls. The results indicated that the shear bearing capacity and elastic stiffness of the CFSTT shear wall were obviously affected by number of X-shaped bracing, four-limb lattice stud, thickness of OSB panel and the type of sheathing. The experimental and analytical results may promote the design and application for CFSTT shear walls in engineering practice.

Experimental behavior and analysis of prestressed concrete-filled steel tube (CFT) truss girders

Prestressed concrete-filled steel tube (CFT) truss girders usually consist of CFT chords, hollow steel tube braces, and high-strength prestressing strands. This paper investigates the behavior of prestressed CFT truss girders by conducting both experimental tests and finite element analyses. Experimental tests on five prestressed CFT truss girders are first conducted. The test parameters are the prestress level and shear span-to-depth ratio. Results from the experimental tests indicate that: (i) the initial flexural stiffness and flexural strength of prestressed CFT truss girders increase as the prestress level or shear-span-to-depth ratio increases, and (ii) the failure modes of prestressed CFT truss girders are influenced by the prestress level and shear span-to-depth ratio. Finite element models, which were developed previously by the authors for CFT truss girders, are then modified to predict the behavior of prestressed CFT truss girders. Comparisons with experimental load-deformation responses indicate that the developed finite element models can reasonably predict the behavior of prestressed CFT truss girders.

Finite Element Analysis of Prestressed Concrete-Filled Square Steel Tube Truss

Prestressed concrete-filled square steel tube truss is the kind of truss whose upper chords and lower chords are respectively concrete-filled square steel tube and prestressed square steel tube. Four truss models as square steel tube truss, concrete-filled square steel tube truss, prestressed square steel tube truss and prestressed concrete-filled square steel tube truss were analysed by ANSYS, each of those truss models’ span has three variations. The result shows that the bar sections’ strength of square steel tube truss and concrete-filled square steel tube truss are far from reaching their design strength when the allowable values of deflection has reachedl//400. Unlike the cases described above, when the bar sections’ strength of prestressed square steel tube truss and prestressed concrete-filled square steel tube truss has reached their design strength, their load-bearing capacity is 1 or 1.5 times higher than those cases above and their deflection has not reached the allowable values.

Optimum Location of Outrigger-belt Truss in Tall Buildings Based on Maximization of the Belt Truss Strain Energy

A B S T R A C T In this paper, based on maximizing the outrigger-belt truss system’s strain energy, a methodology for determining the optimum location of an outrigger-belt truss system is presented. Tall building structures with combined systems of framed tube, shear core and outrigger-belt truss system are modeled using continuum approach. In this approach, the framed tube system is modeled as a cantilevered beam with box cross section. The effect of outrigger-belt truss and shear core system on framed tube’s response under lateral loading is modeled by a rotational spring at the outrigger-belt truss location. Optimum location of this spring is obtained when energy absorbed by the spring is maximized. For this purpose, first derivative of the energy equation with respect to spring location as measured from base of the structure, is set to zero. Optimum location for outrigger-belt truss system is calculated for three types of lateral loadings, i.e. uniformly and triangularly distributed loads along structure’s height, and concentrated load at top of the structure. Accuracy of the proposed method is verified through numerical examples. The results show that the proposed method is reasonably accurate.

The Implosion Performance Analysis of the Tube Truss Roof Based on Measured Defects

In order to analyze the mechanical properties of the steel truss roof burst in the case of defective within, the use of non-linear display dynamic finite element analysis software ANSYS / LS-DYNA to study the different effects of different random defect structure. The measured defect data is obtained by a construction tube truss roof structure .To accord to the random sampling method, defects randomly distributed and the parametric statistical information is to establish. Defect structure antiknock performance is derived, considering the tube truss structure roofing layer, and unconsidering the two simulation models for pipe truss structure roofing layer, and taking into account the rod defects affect the dynamic characteristics of tube truss structure to explosivesposition, explosives equivalent parameters by analyzing and comparing the different parameters of the explosion of the power of the tube truss structure response. Roof layer, the location of the explosion, explosives equivalent with tube truss structure antiknock performance relationship and the weak position of the structure is determined to ensure that the building security to provide a theoretical basis . The results show that the tube truss structure system when the explosion shock wave loads, its dynamic response is a very complex process, the role of the explosion shock wave loading, pipe truss the plastic development process and the structure of the internal location of the explosion, explosivesweight, defects, and consider whether the the roofing layer has relationship.

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.

Behaviour of Composite Beam of CFST Truss with Diagonal Web Members

This paper presents the results of an experimental program for a novel composite beam of concrete-filled steel tube (CFST) truss with diagonal web members. This paper investigated the static performance and failure modes of the composite beam. Load-deformation relationships and deflection regulation of the test beam were obtained and its performance was evaluated in terms of its stiffness and bearing capacity. The strain distribution within critical components was also analyzed. The experimental results showed that the composite beam of CFST truss with diagonal web members has high strength and ductility performance. It markedly improves the stiffness and strength of the composite beam of CFST truss with straight web members

Behaviour of Composite Beam of CFST Truss with Diagonal Web Members

This paper presents the results of an experimental program for a novel composite beam of concrete-filled steel tube (CFST) truss with diagonal web members. This paper investigated the static performance and failure modes of the composite beam. Load-deformation relationships and deflection regulation of the test beam were obtained and its performance was evaluated in terms of its stiffness and bearing capacity. The strain distribution within critical components was also analyzed. The experimental results showed that the composite beam of CFST truss with diagonal web members has high strength and ductility performance. It markedly improves the stiffness and strength of the composite beam of CFST truss with straight web members

Finite Element Analysis on Static Performance on Combined Truss with Rectangular Steel Tube and Concrete-Filled Steel Tube

Finite element analysis on three trusses was carried out in order to study the performance of combined truss with steel tube and concrete filled steel tube. The first specimen was a RHS truss, the second one was a combined truss with steel tube and concrete filled steel tube, and the third one was a concrete-filled steel tube truss. The results show that the finite element model can reflect the static performance of combined truss and can carry out the affective parameters analysis, which can offer theory evidence for engineering application of combined truss. The damage of three trusses was all due to the joint failure and the failure mode was all punishing shearing failure, but the concrete filled changed by the failure place of joints. The bearing capacity of three trusses was controlled by the jionts and the strength and stiffness of jionts were increased by the concrete filled in the chord, therefore the bearing capacity of trusses was increased while the deformation of trusses was decreased. In combined truss with steel tube and concrete filled steel tube, the concrete-filled steel tube joints can improve the bearing capacity and the steel tube joint can satisfy the requirements of deformation, which have obvious advantages in the engineering application.