Single-layer Latticed Shell Structure Research Articles

Experimental Study on Small-Scale Shake Table Testing of Cable-Stiffened Single-Layer Spherical Latticed Shell

The cable-stiffened single-layer latticed shell is an innovative structural design that achieves a perfect balance between lightweight and stability by combining cables and a latticed shell. However, the study on dynamic response and failure mechanism of cable-stiffened single-layer latticed shell under seismic action is still lacking. Therefore, small-scale shaking table tests of two kinds of single-layer spherical latticed shells are carried out; the dynamic response and failure mode of the two shells under sine wave earthquake are investigated by using time history analysis. The conclusions show that the introduction of the prestressed cable plays an important role in improving the seismic performance of the single-layer latticed shell, and the cable-stiffened single-layer latticed shell has better load capacity and seismic performance under earthquake action than the ordinary single-layer latticed shell structure.

Numerical investigation of three-dimensional isolator and mitigation for single-layer lattice shell structure

Three-dimensional (3D) isolators need to have capabilities to support the dead weight of superstructures and mitigate both horizontal and vertical seismic responses of structures. However, the lack of self-centering capability under horizontal loadings and large stiffness under vertical loadings of the 3D isolators might limit their isolation performance in practical engineering. This study presents a novel 3D isolator (hereinafter referred to as DS-SMA-FS) to achieve self-centering capability under horizontal loadings and quasi-zero stiffness under vertical loadings. The self-centering capability is provided by shape memory alloys U-shaped dampers (SMA-UDs), and the quasi-zero stiffness (QZS) property is realized by the negative stiffness of disc spring (DS) isolator and positive stiffness of SMA-UDs. The working mechanism and analytical model of the DS-SMA-FS isolator were developed first. The finite element model of the DS-SMA-FS isolator was furtherly established. Numerical results revealed that DS-SMA-FS can exhibit SC capability under horizontal loadings and QZS property under vertical loadings. Subsequently, single-layer lattice shells were established to explore the isolation performance of the DS-SMA-FS isolator. Structural analysis results indicated that the DS-SMA-FS isolator can prolong the natural vibration periods of the shell and effectively prevent the shells from tri-directional earthquakes.

Seismic protection of a single-layer spherical lattice shell structure using a separated three-dimensional isolation system

Vertical and three-dimensional (3D) isolation systems are emerging control technologies for spatial grid structures in high seismic intensity regions. Recently, multistage vertical isolation bearings (MVIBs) based on prepressed spring devices (PSDs) have been proposed to support the lattice shell and prevent the transfer of vertical ground motion components to the structure. Seismic dampers can be further combined with an MVIB to develop a hybrid bearing with a damping capacity. In this study, the vertical load-carrying and isolation mechanisms underlying the MVIB configuration were investigated in detail. A series of proof-of-concept tests were conducted on a prototype MVIB comprising four identical PSDs to study its actual mechanical behavior. The test results indicated that the MVIB specimen exhibited multilinear elastic behavior with enhanced load resistance. The key parameters of the tested bearing, such as the transition force and isolation stiffness, increased linearly with the number of PSDs. The MVIB model was subsequently refined using ABAQUS to comprehensively understand the mechanical performance of the spring isolator. Following a device-level study, a single-layer spherical lattice shell was used as the research target. The damped MVIBs and friction pendulum bearings were arranged at the roof supports and column bases, respectively, and the stiffness and energy dissipation properties of these isolators were designed. A system-level seismic analysis was conducted using OpenSees to compare the triaxial dynamic responses of the target structure before and after isolation. The results indicated that the separated 3D isolation system achieved its intended design goals and effectively protected the lattice shell structure from tridirectional seismic shaking.

Investigation on Load Path of a Latticed Shell Structure under Localized Fire Based on Member Sensitivity

Thermal expansion of a member can affect structural bearing capacity when one or more members are subjected to fire. To explore the developmental rule of member internal force in latticed shell structure, a computation method of member sensitivity is presented based on the alternate path method. Taking a K8 single-layer latticed shell structure as the analysis object, finite element models are established by ANSYS, applying temperature loads on radial and circumferent ribs, calculating the sensitivity of each member during heating, and exploring the rule of member sensitivity at different temperatures. It is revealed from the numerical results that when one member is in fire, member sensitivity is proportional to temperature and inversely proportional to the distance from the member subjected to fire. Taking the member sensitivity coefficient as an index, the internal force will be transmitted along the member with high sensitivity, the rule of load path and internal force redistribution is given when the latticed shell structure is under elevated temperature.

Analysis on progressive collapse resistance of Zhoukoudian single-layer latticed shell structure

The progressive collapse of the spatial grid structure is the focus and difficulty of the current research. The stability problem of the single-layer latticed shell structure is more prominent due to its low redundancy. In this paper, the dynamic nonlinear analysis of the Zhoukoudian large-span single-layer latticed shell structure is carried out to study its progressive collapse process by the finite element software ABAQUS. The results show that the structure eventually collapse under 7 times the gravity load. The mid-span zone on the left side of the structure is the weak point of the structure where the earliest failure members appear. After the failure members appear for the first time in the structure, the vertical displacement increases faster, and then the failure members develop along the longitudinal and transverse directions of the structure starting from the mid-span zone on the left side, which eventually leads to the failure of the structure.

Seismic Performance Assessment of a Single-Layer Spherical Lattice Shell Structure with Multifunctional Friction Pendulum Bearings

The dynamic responses of spatial lattice shell structures with friction pendulum bearings (FPBs) under multidimensional seismic excitations are complex. In addition, FPBs may experience uplift and separation of the bearing components owing to excessive displacements. In this study, a novel multifunctional FPB (MFPB) with a multi-defense system was developed, and its effectiveness in reducing and controlling the seismic responses of spherical lattice shell structures was evaluated. The proposed MFPB comprises an FPB, superelastic shape-memory alloy cables, and sleeve restrainers. A mechanical model of the MFPB was established, and its isolation and control behaviors were investigated through numerical simulations. Furthermore, the main characteristics and advantages of the isolation system were analyzed. Subsequently, the MFPB system was applied to a single-layer spherical lattice shell structure with surrounding columns. A computational model of the controlled structure was developed using the OpenSees software. Finally, nonlinear time history analyzes were conducted to analyze the seismic performance of controlled and uncontrolled lattice shells. The results demonstrate that the MFPB isolation system can effectively control the structural responses of isolated spatial lattice shell structures under horizontal and vertical seismic excitations and improve their seismic resilience.

Analysis of Stiffening Methods and Effects on Irregular Single-layer Lattice Shell Structures

Local stiffening is often a good solution to mechanical property problems of irregular single-layer lattice shell structures. The effects of three local stiffening methods, namely section enlargement stiffening, planar truss stiffening, and space truss stiffening, on their structural stiffness, strength, and overall stability were analyzed in this study. A practical engineering example showed that these three stiffening methods could effectively reduce the deformation of the lattice shell under vertical and lateral loads, reduce the comprehensive stress ratio, and increase the buckling eigenvalue and ultimate bearing capacity factor. The local space truss stiffening method had the best comprehensive effect. The same stiffening methods were applied to a regular lattice shell and the analysis showed that the stiffening effect on a regular shell is quite different from that on an irregular lattice shell. The three stiffening methods could not reduce its deformation under vertical loading but could reinforce the strength and overall stability of the structure effectively. Proper suggestions are proposed according to the preceding analysis in case a single-layer lattice shell structure cannot meet the demands of the design code.

Static stability behavior of aluminum alloy single-layer spherical latticed shell structure with Temcor joints

In recent years, aluminum alloy single-layer latticed shell has been extensively used in civil and industrial infrastructure. The elasticity modulus of aluminum alloy is low, the rigidity of aluminum joints are weak and the roof load transmission path is different. Therefore, the stability performance of this dome is unique. To clarify the stability performance of aluminum alloy single-layer latticed shell, over 500 aluminum alloy single-layer spherical latticed shells were analyzed with nonlinear finite method. The suggested values of rise/span ratio and initial imperfection were presented. The influencing coefficients of initial imperfection, material nonlinearity and stressed skin effect on stability bearing capacity were obtained. And the structural stability safety coefficient and the approximate calculation formula for stability bearing capacity of aluminum alloy single-layer spherical latticed shell were derived. The influences of joint semi-rigidity were investigated. All the aforementioned results provide a scientific basis for future stability design of aluminum alloy single-layer spherical latticed shell structure.

An optimum method for latticed shells based on concept of the compression line

To improve the load-carrying capacity latticed shells, an innovative optimum method based on the concept of compression line is proposed in this paper. The basic principle of this method is using the character without moment in compression line. The arc line which forms the contour line of sphere and latticed shell structures is substituted by compression line in this method. Then the latticed shell structures are in the state of compression, and the influence of bending stress reduces greatly. As a result, the load-carrying capacity of the latticed shell structure is increased. Through the geometrical nonlinear analysis of a sunflower-patterned single-layer latticed shell structure with a span of 48m, it is found that the load-carrying capacity of the single-layer latticed shell structure can be improved by 5.48%. Furthermore, the results of 84 structural analyses of single-layer or double-layer sphere and cylinder latticed shell structures show that the optimum method is right and effective. And especially, it is applicable to single-layer latticed shell structure with rise-span ratio 1/5 with the max improvement 6.4% of load-carrying capacity.

Dynamical failure index of single layer Keiwitt latticed shell structures

Based on the double control criterion of displacement and energy, a new index, dynamical damage index, for describing the dynamical damage extent in the single layer latticed shell structure is set up. The calculate method and change law of all kinds of consuming energy under the seismic action in the latticed shell structures are studied. Then the expression of dynamical damage index erected by combining the plastic consuming energy and maximum displacement is present. Moreover, the compare among the three index, dynamical damage index, displacement and plastic bar quantity, is completed by large numbers of parameter analysis in the single latticed shell structures. The results show that the discrepancy of analytical conclusion is distinct among the three index, dynamical damage index, displacement and plastic bar quantity to the latticed shell with local weakening stiffness, and the results of dynamical damage index are more reasonable. The dynamical failure index is in effect for the quantificational analysis of dynamical failure for single layer latticed shells.

Study of the Similarities in Scale Models of a Single-Layer Spherical Lattice Shell Structure under the Effect of Internal Explosion

The similarity of each scale model is verified based on the theory of similarity, deriving the similarity law of internal explosions in a single-layer spherical lattice shell structure via dimensional theory, calculated based on models with scaling coefficients of 1, 0.8, 0.6, 0.4, 0.2, and 0.1. The results show that the shock wave propagation characteristics, the distribution of the overpressure on the inner surface, the maximum dynamic response position, and the position at which the earliest explosion venting occurs are all similar to those of the original model. With the decrease of scaling coefficients, the overpressure peak value of the shock waves of each scale model, and the specific action time of the positive pressure zone, as well as specific impulse are increasingly deviated from the original model values; when the scaling coefficient is 0.1, the maximum relative error between the overpressure peak value at the measurement point and the specific action time of the positive pressure zone as well as the specific impulse and the original model value is 4.9%. Thus, it is feasible to forecast the internal explosion effect of the original structure size model by using the experiment results of the scale model with scaling coefficient λ≥0.1.

Application and design of 3D seismic isolation bearing in lattice shell structure

ABSTRACTA three-dimensional seismic isolation bearing (3DSIB) was introduced. The 3DSIB was designed and applied in a single-layer spherical lattice shell structure with 40 m span by using a SAP2000 software. The original record of the Taft seismic wave was input into the shell structure in X, Y and Z directions, respectively in the model. The effectiveness of the 3DSIB was examined by time history analysis to the shell structural model in the SAP2000. It was shown that the isolated structure with 3DSIBs had better performance compared with the un-isolated structure in terms of the nodal absolute acceleration response as well as member axial force. It was found that the 3DSIB had good isolation function in both horizontal and vertical directions for shell structure under seismic conditions. Furthermore, the influence of horizontal and vertical stiffness of 3DSIB on the structural period, structural member peak axial force and nodal absolute acceleration were analysed. The variation of the structural respo...

Vertical and Horizontal Seismic Response Analyses of Long-Span and Single-Layer Spherical Lattice Shell Structure

The dynamic characteristics of 80 m single-layer spherical lattice shell structure are analyzed to control its vibration under seismic load. Through the response spectrum curve of current design specification, the analyses for the vertical and horizontal seismic responses of the single-layer spherical lattice shell structure are made by CQC, and the displacement response of the nodes and internal force of the rods unit are calculated respectively. The calculation results show that the vertical and horizontal seismic responses of the long-span lattice shell structure are in great difference, and should be performed in vibration control at the same time, which could provide certain references for the seismic design and vibration control of single-layer spherical lattice shell structure.

Stability Analysis for a Latticed Shell Based on ABAQUS

In this paper, the stability analysis of a single-layer latticed shell structure is presented using ABAQUS, with the geometric nonlinearity considered. The load-displacement curves are calculated according to the elastic and elasto-plastic hypothesis respectively. The ultimate bearing capacity of the structure and its conceivable damage mode are estimated. Finally, the nonlinear stability of this structure is assecced and the further suggstions for improving the structural performance are presented.

The Stability Analysis on the Different Types of Single Layer Latticed Shell

This single-layer spherical reticulated shell has the advantages of reasonable stress,beautiful appearance ,fast construction,is widely applied in practical engineering. Through the static stability analysis of three kinds of single-layer spherical lattice shell structure using ansys, we get them in the uniform deformation under static load, the modal, buckling load. The results show that: The Kiewitt latticed shells displacement is small, structure is stable, better than SchwedLer and lianfang.

Research on Practical Design Method of Single-Layer Lattice Shell Components

There are some limitations on the calculation about effective length factor of the single-layer lattice shell structure`s component by the current specifications. That`s why Euler formula is commonly used to anti-push the effective length in engineering design. In traditional design, one or few components were used to calculate the effective length factor, and the single biggest value is assigned to all components for design. Owing to the coarse method, values of some components` effective length are too large or too small. This paper improved the traditional design method, and used excel in formula programming to calculate effective length factors of all components. Then all factors are assigned to all components for designing by SAP2000. At the end of the article, it explored the difference in this new design method with the traditional design method.

Research on Ultimate Bearing Capacity of Single-Layer Cylinder Latticed Shells Considering the Influence of <i>P-δ</i> Effect

The ultimate bearing capacity of the single-layer cylinder latticed shell structure, calculated without considering the single-member instability(P-δ effect), was not consistent to the actual value of ultimate bearing capacity in practice. The ultimate bearing capacity of the single-layer cylinder latticed shell structure was studied in detail by proposing a method of multi-element simulation, considering the member instability. The value of the ultimate bearing capacity decreased by 1.2% after considering the member instability taking a single-layer latticed shell structure with a 40m span as example. The analysis results show that the value of ultimate bearing capacity is tiny affected for the single-layer cylinder latticed shell structure with a small span and high rise-span ratio

Research on the Influence of the P-δ Effect to Ultimate Bearing Capacity of Single Layer Latticed Shell Structures

The ultimate bearing capacity of the single-layer latticed shell structure, calculated without considering the single-member instability(P-δ effect), was not consistent to the actual value of ultimate bearing capacity in practice. It was studied in detail that the ultimate bearing capacity of the single-layer latticed shell structure considering the member instability by proposing a method of multi-element simulation. The value of the ultimate bearing capacity decreased by 15.6% after considering the member instability taking a single-layer latticed shell structure with a 40m span as example. The analysis results show that the value of ultimate bearing capacity is significantly affected for the single-layer latticed shell structure with a small span and high rise-span ratio

Study on the Static Stability and the Ultimate Bearing Capacity of Vierendeel Latticed Shells

Studies on the static stability and the ultimate bearing capacity of vierendeel latticed shells have been carried out. The buckling modal and the whole course of instability are shown using the Finite Element Method. The ultimate bearing capacity is compared with that of the single-layer latticed shell structure. The results show that the ultimate bearing capacity of the vierendeel latticed shells is 2.87 times more than that of the single-layer lattice shell in the condition of consuming the same steel. The vierendeel latticed shell structure not only has the advantages of concision and transparency like the single layer latticed shell structure, but also has the stability and carrying capacity like double-layer latticed shell structure.

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.