Span Spatial Structures Research Articles

Mesh Division Method of Large Span Spatial Structure based on Free-Form Surface

All Free-form architecture has novel and unique shapes, complex and diverse changes, and has become the trend of modern architectural development with its rich shape changes and soft lines. The traditional grid layout method is not applicable to the grid division of free-form surfaces, and how to divide a smooth and beautiful grid is a hot research problem for large-span spatial structures. In response to the above problems, after investigating the current scientific research results at home and abroad, our team proposes a meshing method using the 3D software Rhino platform to solve the problems of uneven meshing of free-form surfaces and low intelligence, and to divide a smooth and beautiful mesh.

Collapse of the spatial double-layer cylinder shell by experimental study

Large span spatial steel structures, such as gymnasiums, exhibition halls, airport terminals, or railway hubs, have developed rapidly over the last four decades. However, the mechanical properties of these structures under complex loads, particularly their seismic performance under severe earthquakes, are not sufficiently understood. During the 2013 M7.0 Lushan earthquake in China, some of the large span spatial structures suffered damage of varying degrees, which necessitates a review of previous seismic designs and theories. This paper investigates the characteristics and rules of the seismic damage of large span spatial structure during the Lushan earthquake and discusses the possible causes of such damage. A shaking table test was conducted with a down-scaled model of a double-layer cylindrical shell structure to obtain the dynamic response of a structure by reasonably arranging the acceleration, velocity and displacement measuring points. The failure pattern and progressive collapse process of the structure under a severe earthquake were investigated. The buckling of members increased with the increment of ground motion, although this effect was not considered in the present code for seismic design for double-layer shell spatial structures. The seismic damage in the test was mainly represented by overall buckling of the upper chord, web member and lower chord, which is the direct reason for the structural collapse during a severe earthquake. The test results indicated that the change in surface curvature of the structure resulting from deformation during a severe earthquake transformed gravitational potential energy into kinetic energy and caused chord members to impact and fracture, thereby inducing progressive collapse of the structure. The findings of this paper provide a basis for the seismic theory and design of large span spatial steel structures. The buckling effect of double-layer cylindrical shell structures, the dynamic amplification effect of the support structures, and the transformation of gravitational potential energy to kinetic energy in particular would be of interest to researchers and designers.

Static properties and stability of super-long span aluminum alloy mega-latticed structures

Two types of aluminum alloy mega-latticed structures were generated through ANSYS to investigate the suitable material and form for super-long span spatial structures. The joint stiffness of the structures was first discussed, and a proper simulation method for the joints was proposed. Subsequently, the analysis of these two structures with spans from 800 m to 1200 m was conducted by emphasizing the peculiar differences with steel ones, based on the mechanical performance and economic indices. Also, the reasons for these differences were analyzed in detail. It was found that both structures had good mechanical performance, but the aluminum alloy structures had much better economic indices for spans greater than 1000 m. The material consumptions of the aluminum alloy structures were 1/3–1/7 of those of the steel structures at spans from 800 m to 1200 m. The aluminum alloy structures are more sensitive to wind but less sensitive to node imperfections than the steel structures. To further explore the applicability of aluminum alloy structures, the static and stability performance of structures with spans of 1600 m and 2000 m were analyzed. This showed that these super-long span structures could have excellent mechanical performance. Finally, four key structural parameters, namely support conditions, sections of the 3D trussed beams, sections of the chord members, and rise-span ratios, were examined. The influences of these parameters were thereby identified, and some reasonable values of these parameters were obtained. This work may provide a reference for the design and application of aluminum alloy mega-latticed structures.

Seismic response of large-span spatial structures under multi-support and multidimensional excitations including rotational components

To achieve rational and precise seismic response predictions of large span spatial structures (LSSSs), the inherent non-uniformity and multidimensionality characteristics of earthquake ground motions should be properly taken into consideration. However, due to the limitations of available earthquake stations to record seismic rotational components, the effects of rocking and torsional earthquake components are commonly neglected in the seismic analyses of LSSSs. In this study, a newly developed method to extract the rocking and torsion components at any point along the area of a deployed dense array from the translational earthquake recordings is applied to obtain the rotational seismic inputs for a LSSS. The numerical model of an actual LSSS, the Dalian International Conference Center (DICC), is developed to study the influences of multi-support and multidimensional excitations on the seismic responses of LSSSs. The numerical results reveal that the non-uniformity and multidimensionality of ground motion input can considerably affect the dynamic response of the DICC. The specific degree of influence on the overall and local structural displacements, deformations and forces are comprehensively investigated and discussed.

Shaking table test and numerical simulation of an isolated cylindrical latticed shell under multiple-support excitations

In order to study the influence of the ground motion spatial effect on the seismic response of large span spatial structures with isolation bearings, a single-layer cylindrical latticed shell scale model with a similarity ratio of 1/10 was constructed. An earthquake simulation shaking table test on the response under multiple-support excitations was performed with the high-position seismic isolation method using high damping rubber (HDR) bearings. Small-amplitude sinusoidal waves and seismic wave records with various spectral characteristics were applied to the model. The dynamic characteristics of the model and the seismic isolation effect on it were analyzed at varying apparent wave velocities, namely infinitely great, 1000 m/s, 500 m/s and 250 m/s. Besides, numerical simulations were carried out by Matlab software. According to the comparison results, the numerical results agreed well with the experimental data. Moreover, the results showed that the latticed shell roof exhibited a translational motion as a rigid body after the installation of the HDR bearings with a much lower natural frequency, higher damping ratio and only 1/2∼1/8 of the acceleration response peak values. Meanwhile, the structural responses and the bearing deformations at the output end of the seismic waves were greatly increased under multiple-support excitations.

Characteristics of Wind Load on Spatial Structures with Typical Shapes due to Aerodynamic Geometrical Parameters and Terrain Type

The characteristics of wind load on large‐span roofs are complicated by their unique geometrical configurations and strong dependence on aerodynamic geometrical parameters and terrain type. However, there is rarely comprehensive research for characteristics of wind load on spatial structures due to aerodynamic geometrical parameters of roofs and terrain type. In this study, first, the effects of geometrical parameters of roofs and terrain type on the wind pressure distribution based on the data obtained from the existing wind tunnel tests were summarized. Then, the wind loads of full‐scale structures were predicted by CFD, and the efficiency of numerical results was further verified by the available wind tunnel tests on spatial structures. Finally, with comparative analyses of the wind pressure distribution of the roofs predicted by CFD under different cases, the effects of shape ratios, especially rise‐span ratio, height‐span ratio, length‐span ratio, and so on, and terrain type on the wind pressure field of typical spatial structures were presented. It can be beneficial to wind‐resistant design of structures and can be provided as reference for aerodynamic design optimum of span spatial structures.

Advances in mechanical properties of coated fabrics in civil engineering

Membrane structures are widely used in large span spatial structures due to excellent mechanical behavior and beautiful forms. Mechanical properties of coated fabrics are an important basis of design, analysis, and construction of membrane structures. This paper gives an overview of the research advances in mechanical properties of coated fabrics. First, the basic mechanical indexes of coated fabrics and corresponding test methods are presented. Then, the existing constitutive relations for coated fabrics are discussed. Finally, the effect of environment and other factors on the mechanical properties of coated fabrics are studied. In addition, the future trends on the mechanical behavior of coated fabrics are given, which can be references for design and analysis of coated fabrics in civil engineering.

Behavior and Construction of Stay Cables in Shiyan Stadium

The construction of stay cable is the key technology problem in large span spatial structures. This paper carried out a study on the construction scheme of stay cables based on the practical project of Shiyan stadium roof. The loss of tensile force caused by the seven steel wring with different construction order is summarized according to the experimental construction, and the tensile force slacken analysis method was used to calculate the stress of construction. Moreover, the loss of tensile force caused by anchor and relaxation is considered too. Then, the control tensile force of construction, which is used to realize the tensile construction one time, is obtained. Results of the engineering test show that the construction process is simplified and he construction scheme is economic under the condition of allowed precision. The method can provide reference for similar projects.

상이한 지반조건을 갖는 아치구조물의 지진응답 분석

Spatial structures have the different dynamic characteristics from general rahmen structures. Therefore, it is necessary to accurately analyze dynamic characteristics and seismic response of spatial structure for seismic design of spatial structure. An arch structure is used as an example structure because it has primary characteristics of spatial structures. Multiple support excitation may be subjected to supports of a spatial structure because ground condition of spatial structures is different. In this study, the response analysis of the arch structure under multiple support excitation and simple support excitation is studied. By means of the pseudo excitation method, the seismic response is analyzed for long span spatial structure. It shows that the structural response is divided into two parts, ground displacement and structural dynamic response due to ground motion excitation. It is known that the seismic response of spatial structure under multiple support excitation and simple support excitation are the different in some case. Therefore, it has to be necessary to analyze the seismic response of spatial structure under multiple support excitation because the spatial structure supports may be different.

Simulation Study on Construction Process of Complex Spatial Steel Structure Based on the Construction Mechanics

The construction process of the large span spatial steel structure was studied by finite element method and the time-varying mechanics. The construction process of complex spatial frame structure was divided into the installation and dismount supporting phase, and each stage was divided into 15 steps in which mainly simulated and analyzed the whole construction process by "life-death" element. The critical control points of each construction step were identified, the stress state, interval value and the maximum stress in the structure of each construction condition were conformed; rod deformation in construction process was analyzed in construction program. The result showed that the large span spatial steel structure construction scheme was numerical simulated and calculated by the method of finite element analysis and the mechanical state, deformation and safety of building structure were predicted accurately during construction.

기하학적 비선형해석을 이용한 비정형 막 구조물의 형상탐색과 인터페이스 기법

막 구조물은 연성의 막에 초기 장력을 주고 외관의 강성을 늘림으로써 외부하중에 안정된 형태를 유지하는 구조물로 두께를 얇게 하여 대공간 구조에 많이 채택된다. 이러한 막 구조는 자유로운 곡선을 표현할 수 있는 특성이 있어, 구조적 형태의 선정은 매우 중요하다. 이에 본 논문에서는 넙스를 기저함수로 하는 비정형 곡면으로 형상을 표현하고, 최적의 곡면 형상 탐색을 위한 대변형 결과값 도출을 위해 기하학적 비선형을 고려한 유한요소해석법을 제안하였다. 또한, 형상 탐색 결과로 나타난 곡면의 형상 근사화의 최소화를 위해 유한 요소망으로 표현된 최종 형상을 다시 넙스로 구현하는 인터페이스 기법을 제안하여, 비정형 막 구조물의 최적 곡면을 표현하였다. The membrane structure maintains stable form by giving initial tension to ductile membrane and increasing the stiffness of exterior that is much adopted in the large span spatial structure by making its thickness thin. This kind of membrane structure has characteristic that can express free-form curve, so the selection of structural form is very important. So, this paper proposes the expression of free-form surface based on NURBS basis function and the finite element method considering geometrical nonlinearity for the deduction of large deformation result. Also, for minimizing the approximation of the surface that is derived from the form-finding result, the interface method that change finite element mesh to NURBS is proposed. So, the optimum surface of free-form membrane is derived.

Study on the Arc-Cable Supported Long Span Spatial Structure of Erdos Dong-Sheng Stadium

This paper has introduced rational arch axis and built finite element models for the analysis of arch axis type selection, based on the retractable roof of Ordos Dong-sheng stadium under actual loads. And the approximation optimum method is used in adjustment of rational arch axis of the stadium's giant arch. At last, this paper supplies some references for this project design.

Applications of Composite Spatial Structure

The application of fiber reinforced polymer (FRP) rebar to large Span Spatial Structure is one of the topics in forward position nationwide and internationally. The properties of FRP rebar, such as high tensile strength, light weight, strong resistance to corrosion and fatigue, material design ability and weight reduction and so on, pave the way to its application to Large Span Spatial Structure. Based on the summary of relevant studies at home and abroad, the applications and research of FRP, such as CFRP poles, Composite Laminated Plate and FRP light roof, rebar to Large Span Spatial Structure are introduced in the paper. Finally, the prospects and some problems needed to further researched are put forward.

Dynamic Instability of Spatial Structures under Typical Wind Flow

The mechanism of dynamic instability of large span spatial structures under high wind speed should be studied carefully, but it has seldom been done before. In this paper, a double-layer cylindrical reticulated shell under a typical wind flow is taken as an example to study the dynamic instability of large span spatial structures under wind flows. The interaction of the shell and the flow is ignored and unsteady wind forces on the shell are obtained from wind tunnel tests. The dynamic instability status of the shell is determined by the Budiansky-Roth criterion. The results show that the double-layer cylindrical reticulated shell will become dynamically instable under high wind speed.

Analyses of Temperature Loads’ and Support Settlements’ Effect on Load Bearing Capacity of Arch-Reticulated Shell Hybrid Steel Structure of Beijing Jiangtai Winter Garden

To large span spatial structures, the displacements and internal forces caused by temperature loads and support settlements cannot be ignored. Beijing Jiangtai winter garden mainly consists of reticulated shell and glass curtain wall. The reticulated shell is composed of 9 spatial arches and other common frames, thus it can be seen as arch-reticulated shell hybrid structure. The two ends of the arches are supported at the top of steel columns and concrete walls separately. The glass curtain wall is fixed to vertical cables. This paper chose eight load cases including temperature loads and support settlements, and used ANSYS to analyze static responses of the structure under such load combinations. The comparative results showed that temperature loads had more effect on the structure’s load bearing capacity than support settlements. And the superiority of hybrid structures was fully embodied in the conclusions of this paper.

Experimental Study on Cast-Steel Joints for Nantong Sports Exhibition Center

Cast-steel joints characterized in strong adaptability are widely applied in various long span spatial structures. At present, there is no national design specification available on cast-steel joints. Therefore, it is quite a necessity to conduct full-scale test or model test on cast-steel joints suffering complicated forces. This Paper has, taking Nantong Sports Exhibition Center as an example, conducted the experimental study of some important joints, and compared with elastic-plastic nonlinear finite element analysis result. According to the result, the fracture morphology of joints, stress distribution and bearing capacity of joints obtained from the elastic-plastic nonlinear finite element analysis are consistent with those of measured result, proving that the analysis theory applied in engineering design is basically suitable for the actual working condition of cast-steel joints and the joints are sufficiently safe.

Static and Buckling Behavior of a Beam with Changeable Boundaries

A structure with “changeable boundaries”, changed from construction stage to service stage, is a new design idea used in long span spatial structures. The inner force distribution will be more reasonable and the structure self-weight will be lighter, if the idea is adopted. Adoption of the idea enables the inner force distribution of the structure changing from the construction stage to the service stage. Although the time of the inner force changing is much short, it has a significant influence on the loading behavior and the construction cost of the structure. As an example, a simple beam with different boundaries (unchangeable and changeable), under uniformly distributed lateral loads, is analyzed in this paper. Through static analysis, the loading behavior of the beam under three different boundaries, including simple support, fixed support and changeable boundary, is compared. The linear buckling behavior of the beam with changeable boundaries is also investigated. The critical equilibrium equation is derived subsequently for computing the critical stability load. A new computation method for the beam with changeable boundaries is proposed.

Finite element model updating for large span spatial steel structure considering uncertainties

In order to establish the baseline finite element model for structural health monitoring, a new method of model updating was proposed after analyzing the uncertainties of measured data and the error of finite element model. In the new method, the finite element model was replaced by the multi-output support vector regression machine (MSVR). The interval variables of the measured frequency were sampled by Latin hypercube sampling method. The samples of frequency were regarded as the inputs of the trained MSVR. The outputs of MSVR were the target values of design parameters. The steel structure of National Aquatic Center for Beijing Olympic Games was introduced as a case for finite element model updating. The results show that the proposed method can avoid solving the problem of complicated calculation. Both the estimated values and associated uncertainties of the structure parameters can be obtained by the method. The static and dynamic characteristics of the updated finite element model are in good agreement with the measured data.

A New Frequency Domain Method for Wind Response Analysis of Spatial Lattice Structures with Mode Compensation

The large span spatial lattice structures have many natural frequencies in a narrow frequency range, the conventional frequency domain method is difficult to contain all significant contribution modes. Through numerical examples, it is found that some high order modes are likely to be overlooked because of their higher positions of modal order, in spite of their significance to wind response. According to the contributions of modes to strain energy of system, the paper presented an efficient method to compensate the errors owing to missing out some significant high order modes. The effectiveness of the proposed method is verified through a numerical analysis of the wind responses of a spherical dome. At last, a simplified method of wind vibration coefficient is present for design of practical projects.

The role of cables in large span spatial structures: introduction of recent space structures with cables in Japan

The use of cables as structural members in large-span spatial structures is increasing. One reason for this is that from an architectural design perspective, these cables are light and provide an expanded impression of space, while smoothly curving cables create soft outlines. A second reason is that from a structural design perspective, these cables provide for the well-defined transmission of forces and rational layout of members in a structural system where members can be arranged so as to make the best use of their individual material properties. Cables are used in a variety of ways. In cable structures they are used as tensile members, and they help control member stress and deformation of frame structures. They enable systems to be constructed for balancing entire structural frames, and by applying tension to these cables, structural members can be made resistant to compression. This paper reports, by introducing several fine examples constructed recently in Japan, on the role of cables in typical applications where they are used to control frame structure deformation and structural member stress, or to form systems that balance entire structural frames. In the Miyagi General Gymnasium, which was completed in April 1997, horizontal thrust generated at the base of the continuous gable frames forming the large ridge roof is absorbed by tie cables. The cables are laid out on planar gable frames at each end of the roof, and the thrust is transmitted to the gables through planar bracing frames attached to the lower edge of the roof. In this design, cables not only form the system, they also actively control member stresses as a result of the tension applied to them. This system provides the structure with a self-balancing space for the entire structural frame. In the Saitama Arena, which is due to be completed in March 2000, one edge of the roof (160 m) is supported by a 130 m beam–string–structure employing cables to control deformation in structural frames and stress in the members. This is achieved by applying a tension of 3000 tons to the cables, matching the typical load applied to cables used in bridges. This system also provides the arena with a dynamic atmosphere of tension. The Sapporo Dome, due to be completed in March 2001, employs a non-conventional design in which the edge-ring of the dome is cut along an arc and a 90 m span bridge girder is inserted to link the cut ends of the ring to form a partially open structure. This turns the open dome into a dynamically closed structure by introducing tension into cables arranged within the girder.