Suspen-dome Structures Research Articles

Static and stability analyses of multi-strut type aluminium alloy suspen-dome structure with large opening

By combining the advantages of the multi-strut concept in cable dome structures with aluminum alloy material, a new type of prestressed spatial structure—the multi-strut aluminum alloy suspen-dome with a large opening—has been developed by integrating a lower prestressed support system into an aluminum alloy reticulated shell. The optimal structural configuration was determined by comparing the static, stability, and economic performance of three types of upper chord mesh topologies for this structure. Subsequently, an analysis of the static performance and large-scale parameters affecting the structural stability of the optimal grid topology was conducted. The study explored the influence of structural prestressing, overall shape, and support stiffness—encompassing three categories and seven parameters—on structural stability and material consumption. Additionally, the effects of initial imperfections and load distribution forms on structural stiffness and stability were further examined. Finally, the static properties, stability, and economic indicators of the structure were compared with two other structural systems: the steel suspen-dome and the cable dome. The results indicate that the pentagonal grid topology provides the best structural performance and that the structure is sensitive to cooling effects. Optimal values for key design parameters, such as the rise-span ratio and thickness-span ratio, were identified. Moreover, the economic advantages of the aluminum alloy suspen-dome compensate for its mechanical performance shortcomings compared to the steel suspen-dome. These findings offer innovative solutions and a scientific basis for the selection and stability design of aluminum alloy suspen-dome structures.

Research on the Method of Simplifying Concrete Substructures of Suspen-Dome Prototype Structure in Shaking Table Test Scale Model

This paper proposed and studied the method of simplifying concrete substructures of the suspen-dome prototype structure in shaking table test scale model. Firstly, a method that replaces complex concrete substructures of the suspen-dome prototype structure with steel substructures in shaking table test scale model was proposed. And then, a dynamic integral scale model considering substructures was established. After that, the natural frequencies of the model were obtained by conducting white noise sweep test. Finally, the numerical scaled model was established by ABAQUS software, and the numerical model of the prototype structure was established by Midas/Gen software. The natural frequency, mode shape, and seismic response of the scale model were compared with the prototype structure. It is observed that the natural frequencies of the test scale model were very close to that of the prototype structure after considering the scale ratio, and the scaled model's first five modes were basically consistent with that of the prototype structure. Besides, the difference in acceleration response between the two modes is also small. It is proved that in shaking table test, the method of designing the integral scale model of replacing complex concrete substructures of the prototype structure with steel substructures is accurate and effective. The analysis results provides a reference for researchers and designers to more conveniently establish scaled models of suspen-dome structures in shaking table tests.

Discussion on cable-strut systems of the suspen-dome structures

According to the architectural requirements, the roof structure of a large-span gymnasium adopts the suspen-dome structure. In the scheme selection stage of the pre-stressed cable-strut system at the bottom part of the suspen-dome structure, a Levy-type scheme and a Loop-free scheme are established. The finite element models are established, and the static analysis under the design loads, the whole process analysis of load-displacement, and the dynamic response analysis after accidental cable break are carried out. The architectural expression of the two schemes are discussed. The component material consumption, the structural stiffness, the tension distribution characteristics, and the static bearing capacity of the two schemes are discussed. The failure mode and the progressive collapse resistance of the two schemes after accidental cable break are also discussed. The results show that the Loop-free scheme requires significantly less in terms of component material consumption than the Levy-type scheme. The static failure mode of the two schemes is strength failure, but the Loop-free scheme has greater bearing capacity. The Loop-free scheme has greater structural stiffness, lower cable forces, and uniformly distributed cable forces in each layer, and lower stress on the top reticulated shell members. Neither of the two schemes experience progressive collapse after accidental cable break. Due to the rupture in the loop cable of the Levy-type scheme, the rigidity of the rear region decreases greatly, and the cable force loss is large. On the contrary, internal force redistribution occurs in the Loop-free cable scheme and the cable force loss is not obvious, hence the progressive collapse resistance is better than that of the Levy-type scheme.

Shaking Table Test Research on the Influence of Center-Hung Scoreboard on Natural Vibration Characteristics and Seismic Response of Suspen-Dome Structures

The center-hung scoreboard is a large electronic display device, that usually has a significant weight and is flexibly suspended from the roof of the gymnasium. The suspen-dome structure is one of the common roof structures of gymnasiums. In order to investigate the effect of the center-hung scoreboard on the natural vibration characteristics and seismic response, including acceleration, displacement, and strain, of the suspen-dome structure and considering that the dynamic behavior of the structure under seismic action can be realistically reflected, a shaking table test was carried out based on the suspen-dome structure of the Gymnasium of the Lanzhou Olympic Sports Center. Firstly, according to the size of the shaking table, a dynamic scale model with a geometric similarity ratio of 1:20 was established. After that, the white noise excitation test and numerical modal analysis were conducted on the models with and without the center-hung scoreboard to compare the two modes’ natural vibration characteristics. Furthermore, the earthquake simulation test was carried out on the models with and without a center-hung scoreboard, and their various seismic responses, including acceleration, displacement, and strain, were compared and analyzed. Finally, the acceleration response and displacement response of the center-hung scoreboard were investigated. The results show that the higher-order natural frequencies of the suspen-dome structure will increase when the center-hung scoreboard is suspended from the roof, and the swing of the center-hung scoreboard will be excited first in the low-order mode. In addition, the various seismic responses, including acceleration, displacement, and strain, of the model with the center-hung scoreboard are all increased compared to the model without the center-hung scoreboard. Meanwhile, the influence of the center-hung scoreboard on the seismic response of the suspen-dome structure decreases from the inner ring to the outer ring of the structure. Moreover, under the action of an earthquake, the acceleration response and displacement response of the center-hung scoreboard are both extremely high. Considering the center-hung scoreboard in the analysis and design stage of the suspen-dome structure is necessary.

On the Collapse Resistance of the Levy Type and the Loop-Free Suspen-Dome Structures After Accidental Failure of Cables

On the Collapse Resistance of the Levy Type and the Loop-Free Suspen-Dome Structures After Accidental Failure of Cables

The tensioning process of ellipsoidal suspen-dome structures with considering the friction of cable-strut joints

The friction between cable and cable-strut joints is a high nonlinear behavior which can cause the loss of cable force and then affect the mechanical behavior of integral structure during the construction and service phase. The ellipsoidal suspen-dome structures have been commonly utilized in practical engineering. Compared to the suspen-dome structures in spherical shape, the prestress loss of hoop cable is very different from the suspen-dome structures in ellipsoidal shape. To quantify the influence of friction force on the cable-strut joints of ellipsoidal suspen-dome structures, an iterative program for quantifying the friction force proposed by authors is integrated with tension compensation method. The influence of form coefficient and the connection stiffness, including axial stiffness and bending stiffness, are systematically investigated. The results indicated that the shape of upper grid structures has significantly influence on the loss of cable force. The friction can reduce the displacement of the whole structure and semi-rigid connection can increase the displacement of the whole structure, and the increase of both will lead to the increase of cable force loss. The friction will reduce the stress of radial rod, while semi-rigid connection will increase the internal force of radial rod. Both of them have little effect on the stress distribution of struts.

Cable Tension Estimation for Suspen-Dome Structures Based on Numerical Method

Suspen-dome structures have been widely adopted due to their superiority over traditional structures. Cable condition is crucial to the safety of suspen-dome structures, especially the magnitude of cable force. However, thus far, investigations on estimating the tension in this type of structure remain lacking. In this study, double-element method was initially developed to simulate cables, and its accuracy was validated. Tension compensation method was adopted to ensure that the cable force is equal to the designed value. Then, transient analysis was conducted based on an actual suspen-dome structure. The dynamic responses derived based on the overall structures and the simplified models were compared, and the reliability of the simplified models was validated. Finally, parametrical analysis was conducted to investigate the influence of support stiffness and cable-bending stiffness on the fundamental frequency of cables. A cable tension estimation program, which was suitable for suspen-dome structures, was updated. Results indicate that vibration method can maintain good accuracy when used in suspen-dome structures.

Influence of Friction on Buckling and Dynamic Behavior of Suspen-Dome Structures

Suspen-dome structures are widely used due to their superiority over traditional structures. The cable condition is crucial for the safety of the overall structures, especially the force in cables. However, to date, no accurate and efficient numerical method can be used for estimating the influence of friction. In this paper, a series of novel numerical methods were proposed and incorporated into a numerical model of the suspen-dome structure. The influence of friction on buckling capacity and dynamic response of suspen-dome structures was analyzed. Results indicated that the dynamic response is significantly influenced by friction. The numerical model that considers friction can be established efficiently in an overall structure model based on general finite element software and can be adopted for dynamic analysis. The buckling capacity can be maximized in the non-sliding condition. The fixation of the hoop cable located in the outer part of the structure has limited influence on the improvement of buckling capacity. For seismic analysis, the varying amplitude of cable force in non-sliding conditions was approximately two times that in sliding conditions.

A Novel Numerical Method for Considering Friction During Pre-stressing Construction of Cable-Supported Structures

Suspen-dome structures are extensively used due to their superiority over traditional structures. The friction between cable and joints may severely influence the distribution of cable force, especially during the pre-stressing construction period. An accurate and efficient numerical method has not yet been developed that can be used for estimating the influence of friction on cable force distribution. Thus, this study proposes an efficient friction element to simulate friction between cable and joint. A flowchart for estimating the value of friction force is introduced. These novel numerical methods were adopted to estimate the influence of friction on cable force distribution. The accuracy and efficiency of these numerical methods were validated through numerical tests.

Numerical and experimental study on loaded suspendome subjected to sudden cable failure

Cables are key components of suspendome structures and usually bear a high level of tension force. Thus, their sudden failure may cause a dramatic vibratory response and disproportionate internal force redistributions. This study investigated the cable failure effect of a 10.8m scaled-down suspendome model during in-service state through numerical simulations and failure tests. The deforming behaviors, internal force redistribution pattern, and oscillatory responses were studied and compared. Results showed that cable failure causes evident oscillations to the rest of the members. However, the suspendome exhibited strong structural stiffness, and no obvious collapse or failure behaviors were observed. Cable sliding occurred at rolling joints, which could influence the internal force redistribution patterns and dynamic effects at cables or strut members around the break region. Cable sliding behaviors reduced tension recovering ability and the dynamic effect at cable segments. Dynamic amplification factor and dynamic coefficient methods were both employed to evaluate the dynamic effect from the cable rupture because of different oscillatory patterns between cable segments and the rest of the members. Dynamic amplification factor was more applicable for shell and strut members, and the safety of cable segments can be evaluated and ensured with the dynamic coefficient method. The suggested values for the two indexes were also derived based on the test data, which could easily be used in the structural design process.

Observer Kalman Filter Identification of Suspen-Dome

A number of Suspen-Dome structures have been built, but there is some difficulty in using experimental data to obtain good modal parameters, especially modal damping. In this paper, an ANSYS numerical simulation of the 35.4 m span Suspen-Dome is presented. Firstly, the natural vibration characteristics of Suspen-Dome and dynamic response under some random forces were obtained. Then the results of the numerical simulation established that 60 modes are sufficient for a reasonable dynamic model. This model is used to represent the Suspen-Dome dynamic behavior, and OKID is then used to try to identify a model from simulated data. A 400-order model generated from OKID is shown to contain the 60 modes from ANSYS and is shown to give good predictions of the dynamic behavior of Suspen-Dome. The results of this paper can confirm that it can be a very efficient tool for the identification of models of Suspen-Dome dynamics.

A novel form analysis method considering pretension process for suspen-dome structures

Suspen-dome is a kind of new prestressed space grid structure which is formed by combing a single-layer reticulated shell and tensegrity system. For the existence of lower flexible cable-strut system, form analysis is crucial for the mechanical performance of suspen-domes. This paper develops a novel form analysis method considering the influence of pretension process for suspen-dome structures. Some definitions of form analysis for suspen-dome structures are first expounded. Then an iterative method is presented for form analysis, and a sequential analysis method is proposed for pretension process simulation. By combining these two methods, a form analysis method considering pretension process is constructed for suspen-dome structures. Two examples are employed to verify the proposed method. Numerical example results show that both the error of nodal coordinates and cable forces can stably converge to set tolerances. According to a scheduled pretension scheme, form analysis results can accurately achieve the expected initial state. Engineering example results show that without considering the influence of pretension process, the form analysis would be error and the final state after all cables tensioned deviates greatly from the expected initial state. However, this can be achieved accurately through the proposed method in this paper.

Influence of member geometric imperfection on geometrically nonlinear buckling and seismic performance of suspen-dome structures

This paper focuses on the effect of member geometric imperfection on nonlinear geometrically buckling and seismic performance of a new style of space steel structure, suspen-dome, which is composed of a reticulated shell and cable-strut system. By supposing the initial curvature of members as half-wave sinusoids, a stiffness equation of imperfect truss elements is derived for the struts, while that of imperfect beam elements is derived for the reticulated shell members. The proposed imperfect elements are implanted into ANSYS finite element program. Three numerical examples are employed to validate the proposed imperfect elements and analysis method. An ellipsoidal suspen-dome of Changzhou gymnasium is taken as an example. The results show that the imperfection value has relatively great influence on the structural stiffness. With the increase of member imperfection, the critical load decreases in a basically linear way. Under different prestress states, the relation curves between the critical load and imperfection are basically parallel. The nonlinear seismic analysis results show that when imperfection is included, the initial state responses are different, namely, the seismic displacement increases while the stress in rods and cables decreases. The proposed imperfection analysis method can be widely used in not only suspen-dome structures, but also other kinds of prestressed space grid structures. In this way, the influence of member imperfection on structural buckling and seismic performance can be estimated.

Structural behavior of the suspen-dome structures and the cable dome structures with sliding cable joints

Sliding cable joints have been developed for the cable dome structures and the suspen-dome structures to reduce the cable pre-stressing loss and obtain a uniform inner force in each hoop cable. However, the relevant investigation is less addressed on the structural behavior of the cable dome structures and the suspen-dome structures with sliding cable joints due to the lack of analysis techniques. In this paper, a closed sliding polygonal cable element was established to analyze the structural behavior of the cable dome structures and the suspen-dome structures with sliding cable joints. The structural behaviors with sliding cable joints were obtained.

Advances in Application and Research of Suspendome Structures

The suspendome structure is a new-type of hybrid prestressed spatial structural system which has been developing on the basis of single-layer latticed shell structure and cable dome structure. The wide application prospects of this type of structure have been presented initially since its emergence around ten years ago. Several representative engineering applications of suspendome structures are introduced, and the research status of this structure at home and abroad is summarized. Moreover, further research orientations of suspendome structures are discussed and prospected.

Applicability Study on Method of Stability Analysis for Suspendome Structures

Consistent Mode Imperfections Method based on eigenvalue buckling mode is widely adopted in the stability analysis for the spatial steel structures with initial geometrical imperfections, i.e. latticed shells, thin shells, etc. Taking the new type hybrid structure of suspendome as the analytical object, the applicability of Consistent Mode Imperfections Method is discussed. The effects on structural stability are probed arisen by the factors such as different initial reference loads and different order eigenvalue buckling modes. It is indicated that this stability analysis method can be quite fit for the spatial structures such as latticed shells, while for suspendomes, the initial reference load has a distinct effect upon the analytical result obtained by the stability analysis method. Moreover, it is not always to dominate calculating result when selecting the first order eigenvalue buckling mode as the distributing pattern of initial geometrical imperfections. As a result, some measures should be taken to improve the accuracy in evaluating the stability bearing capacity of the structures with Consistent Mode Imperfections Method based on eigenvalue buckling mode.

Formulation and application of multi-node sliding cable element for the analysis of Suspen-Dome structures

Multi-node sliding cable element was formulated for the analysis of cable structures with cables threading through a number of joints and being able to slide inside them. Tangent stiffness matrix was determined for the element based on uniform strain assumption. The element was implemented in ABAQUS as user defined element and applied in the static and nonlinear stability analysis of a Suspen-Dome structure. The rationality and effectiveness of multi-node sliding cable element for both sliding and non-sliding situations were verified by considering symmetric and asymmetric loads on the Suspen-Dome. The effect of cable sliding on the behaviour of the Suspen-Dome was also discussed.

Sensitivity analyses of cables to suspen-dome structural system

The construction of the cables is a key step for erecting suspen-dome structures. In practical engineering, it is difficult to ensure that the designed pre-stresses of cables have been exactly introduced into the structures in the site; so it is necessary to evaluate the influence of the variation of the pre-stresses on the structural behavior. In the present work, an orthogonal design method was employed to investigate the pre-stressed cables' sensitivity to the suspen-dome system. The investigation was concentrated on a Kiewitt suspen-dome. Parametric studies were carried out to study the sensitivity of the structure's static behavior, dynamic behavior, and buckling loads when the pre-stresses in the cables varied. The investigation indicated that suspen-dome structures are sensitive to the pre-stresses in all cables; and that the sensitivity depended on the location of the cables and the kind of structural behavior. Useful suggestions are given at the end of the paper.

Influence of Gliding Cable Joint on Mechanical Behavior of Suspen-Dome Structures

As a new type of spatial structure system, a suspen-dome structure shows good mechanical behavior, because its cable layers with pre-stress do not only improve the stability and stiffness of the top lattice shell of the structure but also decrease the push-out forces to its hoop beam. There are two kinds of connection forms on the common joints among hoop cable, radial cable and struts. One is continuous gliding cable joint where individual cable can move independently at the same joint, and the other one is no-gliding cable joint (discontinuous cable joint) where different cables at the same joint move in the same direction. These two forms will lead to different structural behavior, such as internal force distribution of cable layers when the structure is subjected to half-span loads. In this paper, frozen-heated method (FHM) is employed to analyze this problem. And, the results obtained show that the first joint form can adjust internal forces and decrease the peak value of internal forces of hoop cables and radial cables, while it has little influence on the mechanical behavior of the top lattice shell of the structure.

Analysis and design of the general and outmost-ring stiffened suspen-dome structures

This paper addresses the analysis and design issues of the suspen-dome structural system. A simple design method for calculating prestress forces in the cables of suspen-dome structures is presented. Emphasis is made in a particular case of the suspen-dome system—the outmost-ring stiffened suspen-dome structure. Nonlinear static, dynamic, and buckling analyses are carried out on the three different types of dome structures. The results show that the tensegric system (cable-strut system) significantly improves the structural properties of the single-layer dome system. The outmost-ring stiffened suspen-dome structure, which has a relatively low construction cost, is as efficient as the general suspen-dome structure under both static and dynamic conditions. The outmost-ring stiffened suspen-dome structure is recommended for cases in which the buckling capacity is not a primary consideration in design.