Large-span Structures Research Articles

The Use of Serial Structures for Large-Span Frames

The development of engineering and design, the emergence of new materials (steel, concrete, aluminum, etc.) stimulated the emergence of new types of large-span structures. The structures became lighter, this made it possible to increase the size of the overlapping area. The use of large spans is due to the operational and architectural requirements in public buildings (markets, train stations, stadiums, concert and sports halls). In industrial buildings, large spans are subject to technological requirements. The space freed from supports, covered with a large-span structure, gives the building an emotional and plastic expressiveness. The use of large-span structures makes it possible to maximize the bearing qualities of the material and thereby obtain light and economical coatings. Reducing the mass of structures and structures is one of the main trends in construction. Less weight means less material, less material to be mined, processed, transported and installed.

TENSILE FABRIC STRUCTURES. WORLD CONSTRUCTION EXPERIENCE AND PROSPECTS

The article is devoted to tensile fabric architecture. On the examples of the historical world experience in the construction of structures with tensile fabric coverings, the advantages and ways of further propagation of tensile fabric architecture are considered.
 The successful development of architecture in the context of scientific and technological progress is inextricably linked with the use of advanced achievements in various fields of science and technology and, above all, with the use of progressive structural systems and new effective building materials.
 Among modern building structures, the most rational for medium-span structures and the only possible for large-span structures are spatial coating systems. They allow, without a significant increase in labor costs for the manufacture and consumption of materials, in comparison with flat structures, to free the space to be overlapped from intermediate supports. This ensures the versatility of the use of the building, its more intensive operation, slows down its obsolescence, creates the necessary conditions for its adaptation to new functional and technological processes.
 Tensile fabric structures for roofing stand out from the spatial structures. They are economical, less material-intensive, have rich volumetric plastic capabilities and artistic and decorative qualities. Tensile fabric structures are building structures in which the main load-bearing elements mainly flexible (nets, cables, ropes, curved threads from rigid elements, etc.). These elements works exclusively in tension, which makes possible to use fully the load-bearing properties of high-strength materials (mainly steels). Due to the low weight of such structures, it is possible to cover a large space.
 Tensile fabric structures are widely used in construction. They influence the formation of the architecture of large-span structures, they are used in buildings with complex volumetric-spatial solutions, and their plastic qualities enrich the artistic palette of the architect.
 Tensile fabric coverings are successfully used in construction. The combination of steel tension members and modern synthetic materials makes it possible to create unique and effective solutions for both public buildings and industrial or agricultural structures.

DEVELOPMENT OF LARGE-SPAN CONSTRUCTIONS IN THE ARCHITECTURE OF THE MID-19TH AND EARLY 20TH CENTURIES

The article reveals the issues of the development of large-span structures in the architecture of the mid-19th and early 20th centuries. Structural systems used in the construction of these structures are considered and analyzed on the example of the unique objects of the first world exhibitions, as well as large shopping passages. This confirms that the use of large-span structures affects the rapid development of the architecture of unique buildings and structures.

Aerodynamic shape optimization of large-span coal sheds for wind-induced effect mitigation using surrogate models

Large-span coal sheds commonly used in thermal power plants are particularly vulnerable to wind loads, and the aerodynamic performances are largely affected by their external shapes. The search for the best performing shape through an aerodynamic optimization is still of importance for the mitigation of the design wind loads and responses. This study investigated the possibility of using surrogate models combined with genetic algorithm to carry out the aerodynamic shape optimization of large-span roof structures. The approach is applied to tri-centered coal sheds with closed and open gables, respectively. The shape optimization is numerically performed to minimize the vertical displacement of the shed model while subjecting to one normal and two oblique wind directions, 0°, 30° and 45°. The aerodynamic forces acting on coal sheds immersed in turbulent flow are obtained by the CFD simulation with RSM turbulence model, and the results are validated with wind tunnel tests. Kriging model is used to establish a global mapping between design variables and objective function by conducting a set of CFD and structural static response analyses. Results show that the aerodynamic loads and the optimal geometry are sensitive to the selection of gable types and wind directions. The optimal design presents a reasonable performance improvement compared with the near-optimal and original designs. Several compromised designs are finally provided in order to seek a balance between the effects of wind directionality and construction cost.

Analysis and Design of the Accessory Structure under the Large Deformation of a Flexible Roof

An increasing number of large‐span space structures use flexible roofs to achieve a light and splendid architectural effect. When a flexible structural system such as a cable net is applied in a large‐span stadium, the roof will deform significantly under the self‐weight and wind load. Accessory structures of the roof such as catwalks, radial drainage pipes, circular drainage channels, and radial cable trenches need to cooperate with the large deformation of the roof to prevent damage caused by the large deformation of the roof. To thoroughly unveil the analysis and design method of an accessory structure, this paper first carried out the wind tunnel test to determine the wind load of the structure. Then, the gust response factors of each roof area and the dynamic amplification coefficient of the accessory structure considering the roof vibration were determined. Next, circular and radial catwalks were designed based on static analysis. A sliding joint was set in the accessory structure to adapt to the large deformation of the roof. Finally, a time history analysis of the catwalk was carried out to obtain the maximum deformation value of the sliding joint for the safety of the structure. The results demonstrate that the maximum deformation is less than the value given by the design and meets the specification.

ЭТАПЫ И АРХИТЕКТУРНЫЕ СТИЛИ В ПРОЕКТИРОВАНИИ И СТРОИТЕЛЬСТВЕ ОБОЛОЧЕК И ОБОЛОЧЕЧНЫХ КОНСТРУКЦИЙ

In a paper, architectural styles, constructive solutions, information on the history of appearance of structural building materials are briefly set forth and the stages of passion of thin-walled space large-span erections are analyzed. Particular attention is given to establishment of the exact dates in the chronology of appearance of styles, constructive solutions, and in the dates of erection of the first shells of corresponding styles and their authors. Elicit reasons of destructions of some well-known space structures are described and the influence of these destructions and damages for the subsequent designing and building of analogous type is analyzed. It is adduced, in general, positive views of noted architects on the role of shell structures in industrial, public, and civil building at present time. On the basis of the manuscripts published in specialized editions, varieties of points of view of architects to designing space structures are characterized. It was shown that interest of designers and architects in designing of shells in the form of analytically non-given surfaces, polyhedrons, and hipped plate structures is intensively extending. At present, bar metal architecture obtained subsequent development and came to be competitor for reinforcement concrete. In the XXI century, steel net and structural shells are the main means of forming vanguard buildings. Now, architects and structural engineers have wide potential in the selection of form, building material, methods of strength analysis, constructive solutions, styles, and examples of application of large-span thin-walled shell structures. All conclusions of the present work are corroborated by the results of researches containing in 54 references.

Compressive performance of steel-timber composite L-shaped columns under concentric loading

Steel-timber composites (STCs) have emerged in the construction of large-span structures and multistory buildings. In this paper, a novel L-shaped column fabricated using STC (L-STC) was proposed. The L-STC column consisted of equal-leg angle steel and glulam. The angle steel was bonded inside the glulam. Twenty-two L-STC columns were tested under axial compression and compared with four L-shaped glulam columns as control groups. Parameters including wood species, steel ratios and column lengths were considered. The failure modes, stiffness, load-carrying capacity and ductility of the L-STC columns were analyzed. The test results demonstrated that L-STC columns displayed a (near) full composite action. The short L-STC columns failed due to crushing failure while the long L-STC columns failed due to global buckling. The stiffness and load-carrying capacity of the L-STC columns were enhanced by more than 56% and 33%, respectively. Increasing the width of the angle legs was recommended to achieve a higher load-carrying capacity. Furthermore, a finite element analysis was developed and validated. The load distribution on components of the L-STC columns was presented, and restraining effects of the timber on steel were analyzed and discussed. It was found that enhancing the timber grades, column lengths or reducing the steel ratios offered preferable lateral restraint of timber on steel.

The economic feasibility of taking into account the joint work of load-bearing and enclosing elements in large-span wooden spatial structures

Large-span wooden spatial structures in the form of domes, developed in JSC Research Center of Construction under the leadership of A.A. Pogoreltsev, are built in large numbers for roofing various buildings. Such designs have high performance indicators and continue to improve. In 2020 the Manual on accounting for the joint work of the frame and fencing in wooden spatial structures of buildings and structures was developed as an addition to SP 64.13330.2017, containing examples of strength calculation and optimization of rib cross-section dimensions, as well as an example of determining the long-term strength of the shell cladding. These structures, in fact unique, are designed so far in the margin of safety without taking into account the participation of the enclosing part (panels, decking, etc.) in the bearing loads. Taking into account the work of the decking, especially when exposed to asymmetric loads, can lead to material savings. In addition to the above theory of nonlinear shell calculation, the authors have also developed a calculation of composite anisotropic panels operating under complex stress conditions, i.e. under biaxial compression (tension) and shear. The calculation of such structures under both short-term and long-term loads presents certain difficulties and requires the introduction of strength theories and criteria for their description that are unusual for specialists of design organizations.

Coaction of Wind and Rain Effects on Large-Span Hyperbolic Roofs

Rainfall is often accompanied by strong winds. The large-span roof structure has a low height, its surrounding turbulence is high, and the wind speed changes greatly. The effects of coaction of wind and rain on the roofs cannot be ignored. Wind-driven rain (WDR) is an oblique movement phenomenon of raindrops generated by wind flow. Four types of hyperbolic roofs, that is, square, rectangular, circular, and elliptical, are selected as the objective to study the wind-driven rain by CFD simulation. Effects of wind direction, wind speed, and rainfall intensity on the WDR are analyzed. Pressure distribution of four types of hyperbolic roofs under coaction of wind and rain is obtained. The results are compared with those from the wind action only. The roofs are partitioned to obtain the coaction of wind and rain pressure of the four large-span hyperbolic roofs with different shapes under the most unfavorable working conditions. The results show that the average pressure coefficient of the roof surface increases with the increase of wind speed and rainfall intensity. The reference value of the average pressure coefficient of wind-driven rain on the surface of the roof is given, which provides a reference basis for the design of wind-driven rain on similar hyperbolic roofs.

Assessment on the Progressive Collapse Resistance of a Long-Span Curved Spatial Grid Structure with Main Trusses

The progressive collapse resistance of the terminal building of Zhongchuan Airport in Lanzhou, China was studied, which is a long-span curved spatial grid structure with main trusses. Firstly, the finite element model was built using MSC. Marc software adopting the fiber model based on material. Secondly, an improved method of zoned concept judgment and sensitivity analysis was proposed to determine the key components. Thirdly, the initial failure components were removed individually based on the alternate load path method (AP method). The responses of remaining structure were calculated using nonlinear dynamic analysis method. Lastly, the influences brought by the cross-sectional sizes of grid members were investigated through conducting parametric analysis. According to the results, the proposed selection method can avoid omitting the key components. The structural responses are significant when removing the concrete filled steel tubular (CFST) column SC14 directly supporting the front middle part of the roof, with a maximum vertical displacement of 10 m at cantilever end, which should be focused on for this kind of large-span spatial structure. In addition, the tensile strength and cross-sectional area of the upper and lower chords should be increased by 20% to enhance the progressive collapse resistance of the structure, and the changes of axial compression ratios of the columns supporting the roof have little effects.

A Study on Nonlinear Dynamic Response of the Large-Span Roof Structure with Suspended Substructure

Nowadays, it is common to see large public buildings, e.g., stadiums, with some equipment or substructure suspended from the center of the roof. These substructures will tend to be larger and heavier the more gear is needed, which may have negative impacts on the dynamic performance of the roof structures. In this paper, to explore the dynamic response of a large-span roof structure with a suspended substructure, a real structure model is simplified into a two-degrees-of-freedom system. The essential consideration of nonlinear vibration is elaborated in the equations of motions. Approximate analytical solutions for free and forced vibrations are derived using perturbation methods, while numerical analysis is carried out to validate the solutions. The ratio of linear to nonlinear amplitude is proposed to represent the nonlinear effect of the primary structure, and the nonlinear effect, varying with structural parameters of frequency ratio, mass ratio, excitation ratio, and external force to the primary structure, is investigated. It is shown that internal resonance occurs when the structural frequency ratio is close to 1:2 and that secondary resonance takes place due to certain external excitations; internal resonance and secondary resonance will magnify the amplitude of the primary structure during vibration. Finally, a case of a designed practical dome with a suspended substructure is studied to verify the outcomes from the above research. According to these findings, some design proposals for this type of structure are provided.

Evaluation of the efficiency of aerodynamic dampers based on preliminary numerical modeling

The article is devoted to the issues of ensuring the stability of large-span bridge structures by means of their aerodynamic damping. Aerodynamic damping allows you to change the nature of the wind flow around structures or their individual elements, which can significantly reduce the loads that cause the occurrence of various aeroelastic phenomena. Aerodynamic damping devices (fairings, deflectors) are based on the phenomenon of changes in the circulation of the wind flow around the structure, the purpose of their use, as a rule, is to disrupt regular vortex formation. The main problem when using these devices is the lack of recommendations for their selection and the need for costly experimental studies to assess their effectiveness for each specific bridge. One of the ways to reduce the time and cost of research is preliminary numerical modeling in specialized software systems. Within the framework of this study, the most common types of aerodynamic dampers have been analyzed, and typical designs of large-span beam bridges have been selected. For the selected structures, a preliminary numerical simulation was carried out in a two-dimensional formulation. Based on the results obtained, the most effective designs of deflectors and fairings were determined.

Parametric modeling compressed ellipsoid of rotation as the analytic surface

The article deals with the shaping of the analytical surface in the form of a compressed ellipsoid of rotation. In the process of research, the principle of the golden section was applied, an ellipsoid of rotation with optimal parameters for the design of a large-span unique building of the exhibition complex was obtained. To solve the problem of choosing a rational analytical surface in the Lira-CAD software package, three variants of constructive solutions for the frame of the exhibition complex have been developed. The finite element method is used, the most popular numerical calculation method for studying the stress-strain state of large-span buildings and structures. The analysis of the calculation results made it possible to choose the optimal variant of the structural solutions of the building frame. The check of the dynamic characteristics of the proposed structural solution of the building frame is carried out. The obtained results of the dynamic calculation showed the correctness and efficiency of the adopted structural solutions of the building frame.

Computational modelling of mechanical response of glulam beams due to moisture inducted delamination

Glued laminated timber beams are nowadays used as load-bearing beams of large-span structures that operate in various humidity conditions. Typical application areas are aqua parks with high humidity as well as market halls with low humidity. It is related to the possibility of the occurrence of cracks typical for the drying of wood, even with such controlled conditions of production technology as glued laminated timber. Cracks visible on the used girders raise doubts as to the safe operation of the structures. The subject of this paper is the computational simulation and the evaluation of the influence of beam delamination on the mechanical response of the structure. The attention was established on a typical two-span beam of constant height with a slight slope to the horizontal. The numerical analysis was carried out for three variants of the location of potential delamination of different scope. The beams were modeled as a problem of the linear theory of elasticity in a plane stress state with orthotropic material properties. The calculations were made in the Abaqus software environment. The results obtained in the paper allow to determine the areas in which the presence of delamination or cracks should be considered dangerous from the point of view of the safety of operation. Computational analysis is helpful in assessing the safety of structures where cracks appear. Theoretical considerations are supplemented by an example from engineering practice.

Technological features of metal structures strengthening by gluing of high-strength FRP-systems during reconstruction

The building heritage of Ukraine includes numerous examples of metal structures, especially used in industrial buildings and for large-span structures. The use of metal structures in construction is primarily due to their mechanical properties. They are frost-resistant and can withstand temperatures down to -65 degrees, tough, resistant, durable and reliable. They can also be used in areas with increased seismic activity. But, in certain situations metal structures need to restore or strengthen due to structural defects, wear of load-bearing elements, as well as in order to increase the bearing capacity. In some cases, strengthening with fiber-reinforced polymer composites (FRP) gives better results than traditional methods with metal strengthening.
 A significant part of the Ukrainian architectural and historical heritage is made up of buildings and structures using metal structures. The first designs were made of cast iron or wrought iron (machined or tinned), but they subsequently developed rapidly along with the evolution of methods for forging mineral iron.
 The main cultural reason for the restoration of old metal structures that guarantee structural functionality and load-bearing capacity, based not only on the need to preserve their historical origin, but also on the value of the landscape in which they are located.
 Long-term operation of buildings and their structural elements made of metal without timely maintenance and major repairs, insufficient strength of structural materials, as well as changes in weather conditions and current regulatory documents in Ukraine, often leads to the need to recalculate the load-bearing metal structures of the building frame and strengthen them with the most effective methods, both from the point of view of reliability and from the point of view of profitability, which is influenced by prolonged shutdown of enterprises, stoppage of the production process or the inability to use the adjacent territory to carry out reconstruction work.
 The article discusses the technological features of metal structures strengthening by gluing high-strength FRP-systems during the reconstruction of building, and also provides basic recommendations for the installation, monitoring and maintenance of strengthened elements.

Probabilistic Seismic Capacity Analysis of a Novel Mid-rise Large-span Cassette Structure Using Multidirectional Pushover Method

ABSTRACT This paper investigates a novel mid-rise large-span cassette structure. The unique limit state divisions of the cassette structure are studied by following the probabilistic seismic capacity analysis (PSCA) method. A numerical model is established and verified through the use of shake table test results. Multidirectional pushover analyses is performed, and the directional effect of the 3D cassette structure is considered. The uncertainty present in fourteen major structural parameters is also considered in the modelling by using Latin hypercube sampling (LHS). The probability density function (PDF), cumulative distribution function (CDF), coefficient of variability (COV) and PSCA curves are obtained. The probabilistic distributions of the PSCA curves suggest that the threshold values of the maximum storey drift ratios of the large-span cassette are 1/550, 1/200, 1/60, and 1/25 for the slight damage (SD), moderate damage (MD), extensive damage (ED) and complete damage (CD) limit states, respectively. Furthermore, the average median values and logarithmic standard deviations are also given for the further probabilistic seismic fragility analysis and structural assessment performed. Finally, sensitivity analyses are conducted to examine the effects of critical structural parameters on structural damage measures. The results show that the structural performance is more sensitive to material parameters than load parameters.

NUMERICAL SIMULATION OF AERODYNAMIC STABILITY OF LONG-SPAN BRIDGES

Statement of the problem. The aim of the work is to simulate the resonant vibrations of the continuous beam span of the bridge in the direction perpendicular to the wind flow by the finite element method. The article deals with a non-standard situation that arose on May 20, 2010 on the bridge over the Volga River in the city of Volgograd.Results. As a result, an effective algorithm for calculating the aerodynamic stability of large-span bridge structures was developed using one of the most widespread software systems in Russia and neighboring countries - "Lira-SAPR". Recommendations for the selection and modeling of dampers are given. Conclusions. The developed algorithm makes it possible to numerically describe the disturbing force of periodic breakdown of wind flow vortices, which causes resonant oscillations of bridge spans, to apply this force to the design model in Lira-SAPR, and to obtain parameters that make it possible to assess the stress-strain state of the system during oscillations and to select the optimal characteristics of the damping devices.

Shear behavior of panel zone with an eccentricity between beam depths: Parameter study and design methodology

Recently, beam-CFST column connections with an eccentricity between beam depth have been used in engineering practices to fulfill the design requirements of high-rise and large-span space structures. According to the comparison between the numerical data with the current design code, AIJ (1987), and Eurocode (2005), this paper presents a design method to evaluate the shear performance of connection panel zone with an eccentricity between beam depths. The proposed design methods directly superimpose the contribution of the infilled concrete and the outer steel tubular, which take the effect of beam-depth ratio (h2/h1), size effect (D), aspect ratio (H/D), width-to-thickness ratio (D/t), and axial-force ratio (n) into consideration. The design methods showed high accuracy and could be applied to assess the shear performance for connections with an eccentricity between beam depths.

Measurement research on vibro-acoustic characteristics of large-span plate-truss composite bridge in urban rail transit

Large-span plate-truss composite bridge (LPCB) is developing more and more rapidly in urban rail transit. Nevertheless, the bridges are often close to residential buildings, and some even pass through residential areas directly. Compared with small span bridges and ordinary concrete viaducts, the train-induced vibration and noise of LPCB are larger and last longer, and have a greater impact on the residents along the line. Therefore, it is necessary to study the train-induced vibro-acoustic characteristics of LPCB. However, the current research on LPCB mainly focuses on the aspects of bridge structure design, construction, traffic safety and comfortable capability etc, and usually only cares about the global mechanical behavior of bridge structure and train-track-bridge coupling vibration. In order to study the vibro-acoustic characteristics of large-span and complex bridge structures such as LPCB, it is extremely important to obtain and analyze the field measured data. In this paper, the vibration and noise filed measurement of LPCB has been carried out by the authors. The vibration characteristics of track and bridge system have been measured by means of acceleration sensors, which were arranged on the rails, track slab, the center of bridge deck, longitudinal web and transverse web. The noise characteristics of wheel-rail and bridge structure system have been measured by mans of noise sensors, which were arranged beside the track structure and under the bridge structure. Based on the measurement date, the vibro-acoustic characteristic of the LPCB were analyzed in the present paper. It is found that the response of track structures are mainly affected by wheelsets periodic excitation, while the response of bridge structures are determined both by wheelsets periodic excitation and wheel-rail irregularity; the rail and slab are decoupled after beyond the natural frequency of the rail-fastener system (100 Hz); the vibration energy in high frequency band can be effectively suppressed to downward transmission by damping pad floating slab track; the overall vibration level of rail, track slab and bridge are about 130 dB, 114 dB and 118 dB respectively, the overall sound pressure level of track-side and bridge structure are approximately 82 dB(A) and 83 dB(A) respectively.

Assessment of Timber Roof Structures before and after Earthquakes

The global objective of sustainable development has been greatly directed toward the preservation of existing structures. Therefore, condition assessment and reconstruction of existing timber structures have been gaining importance in recent times. This is particularly evident on timber roofs whose elements are exposed to degradation, either because of rheological effects or due to the direct influence of moisture and biological factors. In case of accidental events, such as an earthquake, the question of the structure’s condition is essential for the condition of the entire building. In order to prove the load-bearing capacity and serviceability of existing structures, as well as to check the need for reconstruction, it is necessary to define crucial parameters that are influencing the condition of materials, elements, and systems. Although there are many non destructive testing methods, the frequency and scope of their use, as well as the decision-making approach, have not been defined. In the paper, non-destructive and semi-destructive methods frequently used for timber structures are explained. A systematic review of criteria to be used in the assessment of load-bearing timber structures in a seismic active area was the main objective of this paper as well as the illustration of non-destructive and semi-destructive test methods through a case study involving roof construction of a hundred-year-old building in Zagreb, Croatia. Pre- and post-earthquake inspection was made. The overall condition of the roof structure after two significant earthquakes can be assessed as satisfactory given that the observed system is a large-span and massive roof structure. The presented results and identification of typical damages after the earthquake are presented in order to facilitate policy makers and for the future implementation of development strategies in the renovation of the city.