Space Truss System Research Articles

Experimental and numerical study on static performance of ship lock sector gates

A sector gate is a fundamental type of lock gate. It is designed as a large cantilevered, rotatable space truss structure capable of withstanding bidirectional hydraulic pressures and operating under dynamic water conditions. This makes it prevalent in medium- and large-scale navigation locks. This research examines the structural behavior of a ship lock sector gate using one in-situ test and two numerical models. The sector gate, with an 11.72-m span, consists of a panel beam system, space truss system, boundary column, and floating box. An in-situ test was conducted to obtain the stress and deformation of key components of the sector gate under positive hydraulic head difference conditions during regular operation. A finite element model was established, verified, and a model updating framework incorporating sensitivity analysis based on the Hooke-Jeeves direct search method was established. The updated model was employed to perform an in-depth examination of the gate's mechanical characteristics under extreme conditions of both positive and negative hydraulic head. The findings suggest that the most crucial region is situated at the intersection of the boundary column and the bottom struts. The stress and displacement responses of the components exhibit a positive correlation with water depth, with the struts and truss chords experiencing significant stress. The entire gate demonstrates twisting along the longitudinal axis of the lock chamber, which negatively impacts its ability to seal effectively. These findings provide valuable insights for the design of sector gates, contributing to the safe operation of gates and efficient navigation of waterways.

Uzay Kafes Çatı Sistemlerinde PV Panel yerleşim optimizasyonu ile Maksimum Elektrik Enerjisi Elde Edilmesi

Solar panel is mostly applied in many roof types on buildings. That the angle of solar radiation is different in curved space truss system affects the amount of voltage and current of the solar panels and overall system efficiency. In this study, meteorological information of Isparta city, technical data of various solar panels, intra-year random shadow effect calculations are analyzed. The technic of genetic algorithm is applied, and the process of computerized simulation is performed in order to find the optimal solar panel combination. Based on the simulation results, the highest efficiency will be obtained from the PV panels if PV panels application is made on the curved space truss roof system.

Experimental Characterization of Static Behavior of a New GFRP–Metal Space Truss Deployable Bridge: Comparative Case Study

A new glass fiber-reinforced-polymer (GFRP)–metal box-truss composite girder was developed for use in lightweight deployable vehicular bridges with favorable torsional resistance for large spans. This paper describes the experimental characterization of the static behavior of the latest structure characterized by a closed cross section, with a comparative study on an early version having an open cross section. The structural form of the new structure differed considerably from that of the early version. Nondestructive tests with symmetrical and unsymmetrical static loadings were conducted on a newly fabricated prototype to identify the characteristic flexural and torsional performances of the new structure. Additionally, a comparative evaluation of the experimental behavior in terms of load–displacement and load–strain responses was conducted between the new structure and the early version. Favorable results demonstrated that the new structure enabled satisfactory static performances in terms of deployable bridge applications. The resulting comparisons indicated that the new structure featured a flexural resistance identical to that of the early version. However, the addition of lower plane-truss transverse braces in the new design significantly increased the torsional resistance of the space truss system. The overall torsional rigidity of the new structure approximately corresponded to 2.36 times that of the early version. Moreover, the stress state in the extrusion-type GFRP tubular elements of the space truss system was significantly improved. Compared to the early version, the latest structure is more appropriate for use in the primary load-carrying superstructures of large-span deployable bridges under critical unsymmetrical service loading conditions.

Compression Behavior of Square Pyramid Substructure of Novel Pultruded FRP-Aluminum Space Truss

Abstract To realize lightweight and corrosion resistance, a novel hybrid pultruded fiber-reinforced polymer (PFRP)-aluminum space truss system is proposed, which adopts the pretightened teeth conne...

Static and dynamic behaviour of a hybrid PFRP-aluminium space truss girder: Experimental and numerical study

A novel hybrid pultruded fiber reinforced polymer (FRP)-aluminum space truss system was proposed, aiming to be used as pedestrian bridge or platform in marine areas. A large-scale space truss girder substructure was assembled, and the full-scale static and dynamic tests were separately conducted. The girder’s static behaviour was analysed using three-point bending test, and the girder shows satisfactory bending stiffness contributed by the structural form of space truss. To reveal the girder’s dynamic properties, the output-only modal identification method was used. Some unfavorable dynamic properties such as low natural frequency and the torsion mode as the first order mode shape were observed, which is mainly caused by the unique material properties and structural form. Thereafter, a strategy of adding diagonal bracing at the bottom chord plane to improve dynamic performance was proposed. To accurately predicting the static and dynamic properties, the fine line elements (FLE) model simulating all components’ stiffness of the truss member were built. The simple-link-system (SLS) model was used for comparison. Based on FLE model, parametric analysis was conducted to reveal influences of key parameters. Finally, an efficient design strategy was proposed for this novel hybrid system with combined use of SLS and FLE model.

Effect of Joint Stiffness on Deformation of a Novel Hybrid FRP–Aluminum Space Truss System

To achieve light weight, high load-carrying capacity, and corrosion resistance, a novel hybrid FRP-aluminum space truss system is proposed in detail. An advanced pretightened teeth connection (PTTC) and its combined joint–aluminum bolt–ball connecting system (ABCS) were designed to interconnect pultruded FRP elements. In view of the significant effect of the ABCS on structural deformation, the axial stiffness properties of the ABCS were first investigated through experimental tests and numerical simulations. Then, in establishing a structural calculation model for the hybrid space truss, a new combined-line-elements solution was proposed to simulate the complex axial stiffness variation in the ABCS, to which the traditional Timoshenko beam element cannot be applied. Beam elements with different cross sections were adopted to simulate the FRP truss member and the PTTC. The structural calculation model was verified with a previously published case. The design of a hangar structure using this hybrid space truss system is discussed here. The preliminary design was made using the traditional simple-link-system model, and a comparative calculation was made with the new combined-line-elements model. The results indicated that the structural design of this unique hybrid system under a flexural moment is stiffness-driven rather than strength-driven owing to the low elastic modulus of the materials. The conventional simple-link-system model ignores actual differences in component stiffness and thus is dangerous for structural design. Based on the discussion, a design strategy for the hybrid space truss system is proposed.

Development of sustainable building components utilizing date palm midribs for light wide-span multi-purpose structures for rural communities in Egypt

Date palm midribs are one of the most available and renewable agricultural residues in Egypt. They enjoy a technical heritage that still thrives in the fields of handicrafts, furniture and simple rural huts among the poor rural communities in Egypt. This qualifies them to be developed for contemporary construction that matches the modern lifestyle of the youth. This paper aims to develop low-cost date palm midribs building components for light and sustainable wide-span multi-purpose structures for rural communities. This is achieved firstly by selecting a primary design that respects the natural shape and lightness of the material. The primary design selected was a 12 m span tri-arched space truss system as a semi-form active structure that utilized traditional palm midribs crates techniques such as bundling and friction-based joinery. Secondly, the conceptual design was developed in order to enhance the design ability for mass production, stability, and aesthetic enhancement. Thirdly, an exploratory physical model was built to visualize and develop the practical design of the building components. This process simulated the building sequence and tackled the details of the building components. The physical model showed that the proposed system allowed multiple alterations and high flexibility, showed promising durability and well balanced visual composition with a unique spatial experience that reflect the traditional essence of the material in a modern fashion. The work presented is a part of the undergoing validation process of date palm midribs wide-span building components, to introduce the material a sustainable alternative for the poor rural communities in Egypt.

Steel and glubam hybrid space truss

This paper introduces a new type of hybrid truss system composed of glue laminated bamboo (glubam) for web and upper chord members and steel pipes for lower chords. Several experiments of physical and mechanical properties were carried out on the glubam material for structural design and construction according to timber specifications and codes. A full-scale space truss model with different configurations was constructed and tested under gravity loads. Different failure modes, such as buckling of web chords, shear fracture of bolted connecting joints and yield of bottom steel pipes, were discussed. Analyses of the structural behavior under static load are compared with the experimental results, showing a good agreement. The experimental results validate that the space truss system is of excellent load carrying capacity. If yielding of the lower chord steel pipes can be realized, the system can also have a large plastic deformation under the ultimate loading condition. A prototype structure was successfully designed and constructed as a rain-shed canopy of an office building.

Partial collapses experienced for a steel space truss roof structure induced by ice ponds

This paper presents investigations on the steel space truss roof of an industrial plant collapsed partially after exceptional snowfalls. This low sloped light weight roof structure supported on steel columns of 16.3m height and covering totally 26,080m2 closed area in plan was constructed as Mero type double layer grid steel space truss system having a height of 2m. Also, parapets of 90cm height were placed along the perimeter of the building and siphonic system was used for roof drainage. To find out the main reasons of the partial collapse of the roof structure, a site investigation was conducted and findings were collected, then conformity of the structural members were checked with respect to the current Turkish steel building design codes. The material properties of the primary load carrying members of the roof were scrutinized by performing tensile tests. Finally, it was understood that two unexpected catastrophic collapses were experienced as a consequence of ice ponds that occurred on the edge regions of the roof due to discontinuously heated roof parts by the radiant heaters mounted on the roof structure and the freezing of the siphonic system.

木造スペースフレーム接合部のラグスクリュー引抜き性能に関する研究

As a significant percentage of forestation problems in Japan can be traced to young trees not being properly or selectively culled, their effective utilization contributes to maintain a forest in prime condition. The goal of our research project is to utilize effectively medium and small sized timbers as value added material. Wooden space truss system using those timbers is one important application developed by us. In this paper, pullout performance of lag screw used in joint unit of the truss system is verified through a theory of pull-out properties parallel to the grain, experiments and FEM analysis.

Reinforcement of Steel Tubes with Rings under Compression

Abstract The goal of this study is to reinforce the compression strut ties of space truss systems by increasing the load carrying capacities of them. Therefore, 28 steel bar ties each having 900 mm length and 60.3 mm diameter were reinforced in six different ways and subjected to an axial compression test in the Structure Laboratory of the Civil Engineering department, Faculty of Engineering and Architecture, Selçuk University, Konya, Turkey. The results obtained from tests were examined by making comparisons between the plotted graphics. The applied reinforcement has not increased the buckling load, but it has increased the energy absorption capacity of reinforced bars under yielding and maximum stresses. When the negative effect due to welding is eliminated, a further increase in the energy absorption capacity at the yielding and proportionality limits and an increase in the maximum load carrying capacity can be expected.

Structural Behaviors of Advanced Truss Platform for Effective Road Tunnel Maintenance

This study shows structural behaviors of an innovative space truss typed temporary structure which is effectively used to maintenance and repairs of road tunnels. This evaluated structure has merits to carry out maintenance works of tunnels without blocking cars and transportations. Numerical modeling and analytical testing of the space truss system are investigated by using a commercial engineering program, i.e., ABAQUS 6.5-1, and then it are verified that the truss system takes both structural safety and effective function for maintenances and repairs of road tunnels.

Model updating of LAMOST using RBF neural networks

The development of astronomy needs large telescopes. An accurate Finite Element Model (FEM) of the telescope which represents its real structure is required in dynamics simulation for better reliability. Therefore, we conduct a practical FEM updating method, an iterative algorithm based on Radial Basis Function (RBF) neural networks with hidden variables for Large Sky Area Multi-Object Spectroscopic Telescope (LAMOST). Firstly, build the FEM of LAMOST space truss and balance system. Secondly, discuss the practical selection approaches for the input and output of RBF networks. Only modify big error parameters because of the limited test data. Small error parameters can be gained accurately enough before modeling. The small errors can be seen as noise and are not updated as the hidden variable of neural networks. Uniform design is adopted to get a smaller training sample set, which can reduce computation complexity. Thirdly, after an iterative process, add several uniform points around the last network output, instead of adding only one output point of the network. This improvement can enhance the generalization capability. Finally, a cantilever beam and LAMOST truss simulation results show that the method has good convergence. The balance system of LAMOST is updated using modal test data, which shows that the proposed method is feasible and effective in practice.

Comparison and Research on the Cantilevered Steel Structure Roof of Weinan Hongji Building, Shanxi Province

The substructure of Weinan Hongji building in Shanxi Province is frame shear wall structure, supporting a cantilevered steel roof in the shape of an “official hat”. Two different design proposals were compared between pipe truss structure and steel frame. Space truss system was adopted in the middle large span part. Spatial analysis of the overall model was carried out using Midas730 software and 51types of load combinations were considered. The period, mode, strength and stiffness are compared and the result shows that the option 1 outperforms option 2.

Selection and Arrangement Structure of the Point Support Glass Screen Wall

The selection and arrangement structure is the starting point of glass curtain wall building structure design. On the basis of the structural partition types, the paper discusses the various structural system which be used in engineering in detail. Especially introduces the reasonable layout of the beam system, truss system, framework, arch structure, space truss system, suspension system and so on. Finally, the basic principles and key points of the connection glass curtain wall system structure are also discussed in the paper.

The Construction Process Simulation of a Large-Span Rhombic Space Truss Using FEM Analysis

With the developments of the design theories and the researches, the quantity and the technology of space truss systems in our country have reached the international leading level. In the meantime, the construction methods need to achieve even higher standard. In the article, the rhombic space truss roof of the north station building of Suzhou is selected as the research object. Each step of the sliding and unloading construction is simulated by FEM. The stability and rigidity of the truss are checked in detail. It gives an representative exsample for complicated construction design of large-span space trusses.

Performance of a physical surrogate in the sequential approximate optimization of space trusses

PurposeThe purpose of this paper is to propose physically based varying fidelity surrogates to be used in structural design optimization of space trusses. The main aim is to demonstrate its efficiency in reducing the number of high fidelity (HF) runs in the optimization process.Design/methodology/approachIn this work, surrogate models are built for space truss structures. This study uses functional as well as physical surrogates. In the latter, a grid analogy of the space truss is used thereby reducing drastically the analysis cost. Global and local approaches are considered. The latter will require a globalization scheme (sequential approximate optimization (SAO)) to ensure convergence.FindingsPhysically based surrogates were proposed. Classical techniques, namely Taylor series and kriging, are also implemented for comparison purposes. A parameter study in kriging is necessary to select the best kriging model to be used as surrogate. A test case was considered for optimization and several surrogates were built. The CPU time is reduced when compared with the HF solution, for all surrogate‐based optimization performed. The best result was achieved combining the proposed physical model with additive corrections in a SAO strategy in which C1 continuity was imposed at each trust region center. Some guidance for other engineering applications was given.Originality/valueThis is the first time that physical‐based surrogates for optimum design of space truss systems are used in the SAO framework. Physical surrogates typically exhibit better generalization properties than other surrogates forms, produce faster solutions, and do not suffer from dimensionality curse when used in approximate optimization strategies.

Random Seismic Response Analysis of Leaning-Type Arch Bridge

With an example of steel pipe concrete leaning-type arch bridge, space truss system Finite Element Analysis model is constructed using the Ruiz-Penzien random seismic vibration power spectrum model. The impact of inclined arch rib angle and the number of cross brace between main and stable arch ribs on the seismic internal force response under lateral random seismic excitation is also studied in this research. Research finding shows, the in-plane bending moment of main arch rib gradually increases with increasing stable arch rib angle and cross brace, whereas the out-of-plane bending moment and axial force display a decreasing trend. In general, this indicates that increasing stable arch rib angle and number of cross brace improves the lateral aseismatic performance of leaning-type arch bridge.

Structural Behavior of Connection of Bolt-Jointed Space Truss System Using Steel Node

Structural Behavior of Connection of Bolt-Jointed Space Truss System Using Steel Node

Anchor application in Karatepe andesite rock slope, Izmir—Türkiye

Atatürk's Monument is a steel-constructed building containing a space-truss system, and is the tenth highest monumental construction in the world. Atatürk's mask is installed on this construction. The monument was planned to be built on rocky ground in the old quarry site at Karatepe in İzmir, which has an elevation of 40 m. The steel construction connected to Atatürk's mask was planned to be braced at the andesitic rock slope from three points with different heights. The goal of this study is to determine the most suitable anchor inclination angle. To achieve this goal, two different methods were utilized: (a) kinematic analyses using stereographic projection techniques and (b) numerical analyses considering the stress distribution and lateral and vertical displacements in the andesitic rock slope depending on the variation of the anchor inclination angle. The analyses were conducted in order to confirm the results of the kinematic analyses. The suitable anchor inclination angles obtained from the two different methods were compared, and the results were discussed. The optimum anchor inclination angle obtained from both methods was determined to be 25°. In this state, the anchors are not parallel to the strikes of the discontinuity sets, such as flow band structures, cooling joints and intersection-line formed by the cooling joint sets in andesites. Because the same result was obtained from both methods, it is clear that the stereographic projection methods can be used to determine the suitable anchor inclination angle in jointed rocks.