Cable-stayed System Research Articles

Dynamic modeling and analysis on planar free vibration of long-span arch bridges during construction

The cantilever construction model, which consists of the arch, towers and cables, can be regarded as a cable-stayed system and is widely applied in constructing long-span arch bridges. The vibration induced by this temporary structure's unstable property has a safety risk and deserves to be concerned. Thus, a fully analytical beam-spring-arch model is presented for the cantilever and closure construction states of long-span arch bridges. Subsequently, based on the boundary and continuity conditions, the governing differential equations for in-plane free vibration are derived according to the Hamilton principle and solved using the transfer matrix method to determine frequencies and mode shapes of the system. Meanwhile, the results calculated by the proposed method are verified with the finite element method. Finally, the effects of structural parameter variations during construction on in-plane vibration properties are investigated. The results show that as the length of the erected arch rib gets longer, the system's first six-order frequencies and mode shapes are significantly affected. Moreover, the veering phenomenon is observed. The cables can increase the frequencies of the system to a certain extent. The model that neglects the tower's vibration would overestimate the stiffness of the erection system unless the tower's stiffness is much bigger than the arch.

НОВІ ТЕНДЕНЦІЇ У ФОРМУВАННІ СУЧАСНОГО ОБРАЗУ БАГАТОПОВЕРХОВОГО ЖИТЛОВОГО БУДИНКУ

The article is devoted to a thematic study of new directions in the design of multistorey residential complexes. The factors affecting the conceptual and design decisions of architects are analyzed. The article provides examples of the most famous multistorey residential complexes built recently in different countries. The most famous building is the residential complex. «Interlacing» in Singapore. The project uses the principle of intersection of individual and public spaces in both horizontal and vertical directions. The author of the project abandoned the traditional vertical development scheme for Singapore, resulting in a unique example of a modern urban approach to housing design and organization of the natural environment. The second considered example of high-rise housing is the «Beirut Terraces» complex. The building is designed as a high-rise «shelf» at different levels of which there are apartments of different terraces that form the main artistic accent of the entire building. The building fits well into the surrounding dense urban development, while demonstrating the achievements of modern building technologies. The third example is the «Vancouver House», a multistorey residential complex with public premises on the first floors. structure, which fits into the so-called “parametrism” style, which has become especially relevant recently. The solution of the main building of the complex is interesting, especially its “anti-gravity” silhouette image. To create it, an internal cable-stayed system with vertically stretched metal cables was used. Multistorey residential buildings successfully solve the problem of compaction of residential development and increase the efficiency of the use of free territories, create economic prerequisites for organizing public spaces in the immediate vicinity of housing, which significantly increases the comfort and prestige of living in these complexes.

Substantiation of cable-stayed system parameters for RopeCon continuous belt conveyors

A belt conveyor has recently become one of the critical transportation systems in the mining industry. New engineering solutions towards improvement of belt conveyors with a view to overcoming complexities associated with rugged landscape during transport of loads in bulk conditioned creation of a new RopeCon continuous belt conveyor. This conveyor is a combination of a cableway and a belt within a complex suspension system with support towers arranged at a design spacing subject to the tilt angle of the conveying route. The belt conveyor structure is examined in terms of its parameters for the further calculations. The estimation criteria of loads on the cable-stayed system of the suspension conveyor by analogy with the aerial tramways and the adherence safety of the cables and support frame brackets are determined. The load transmission factors for the load cables via support frames to be equivalent to the adherence safety between the cables and the support frame brackets are recommended. Optimization of the cable-stayed system parameters and the roller spacing reduces to finding optimal values of the utilization factors of the breaking strength of the cables and the load transmission factors between the guide cables and the load cables. Solution of this problem involves the mathematical methods and takes into account the cable sag limitation between the support towers to ensure the transverse stiffness of the cable-stayed system and to meet the cable endurance capability requirement.

Design and Physical Detection of Bridge Tower and Externally Prestressing Cable for Existing Bridge Strengthened by A Cable-Stayed System

With the continuous development of economy, the increasing traffic volume has brought greater burden to highway bridges. In this paper, a Yellow River Bridge is taken as an example. The cracking and deflection of the box girder of the main bridge have affected the structural performance requirements of the bridge operation. Based on this situation, the cable-stayed system is used to reinforce the bridge, and the construction process of bridge tower, cable saddle, steel anchor box and external beam is described in detail. The theoretical calculation and practice show that this method can effectively strengthen the bridge structure, and the cable-stayed system reinforcement method, as a mature, reasonable and operable construction technology, provides relevant reference for the reinforcement research of similar bridges.

Segmental Intelligent Model Test of Box Girder Bridge Strengthened By a Cable-Stayed System by Mathematical Calculation

Dongming Yellow River Highway Bridge is an important super large bridge across the Yellow River on national highway 106. In order to effectively improve the cracking and deflection of the bridge, the cable-stayed system is used to reinforce the main girder of the project. In order to analyze the stress state of joist, bracket and box girder, the static loading of cable is carried out through scale model test to study the mechanical properties of concrete box girder segment, joist and bracket, verify the reliability of bracket and concrete box girder anchorage, and optimize the reinforcement method of cable-stayed system according to the test results.

Optimization problem of external dynamic influences for the elimination of vibration phenomena in composite elastic building structures

The paper considers the actual task of construction engineering: the elimination of harmful (undesirable) vibration phenomena in composite metal building structures and bridge cable-stayed systems – complete damping and vibration of the bridge cable-stayed system entails the calming of the entire bridge structure. Similar problems arise when designing devices that lead to dynamic rest of network antenna structures. The presentation of the material is based on the main provisions of the modern theory of optimal control of distributed differential systems with network carriers. An extensive literature is devoted to the sanctification of the research of the mentioned problem, however, an exhaustive solution of the problems of controlling elastic structures by external influences of various types (distributed, boundary, starting, and point control) and a comparative analysis of their properties did not find their place in these studies. In addition, the ways of algorithmization of previously obtained results are not always specified. The paper uses a mathematical model describing small oscillations of a spatial string system. It is convenient to use such a system and approaches to the analysis of its mathematical model as a fairly simple fundamental object when considering a more complex object, which is an elastic system of more complex elements. The results of the work are presented in a form that makes it possible to formalize the computational procedure, which is convenient for algorithmizing the process of determining the solution, and therefore for the modern application of computer technology. It remains to add that the work indicates ways to transfer the obtained results to the case of analyzing optimal control problems with carriers on multidimensional network-like domains.

Causes of the Collapse of the Polcevera Viaduct in Genoa, Italy

The article investigates the causes of the Morandi viaduct collapse in Genoa. This three-span viaduct was a part of the A10 motorway leading to Savona. The structure design of the viaduct supports and diagonal stay cables was unique. The viaduct included three cable-stayed system, each supported a three-span continuous beam by two sets of prestressed concrete cables on the two sides of the pylon across the width. The pair of V shapes piers supported upside-down V pylons that supported the top ends of two pairs of diagonal stay cables. The stays were constructed from steel cables with prestressed concrete shells poured on. This article provides information on the technical condition of the viaduct and the way of strengthening the cables in the early 1990s. At that time, the author of the article visited the structure. In August 2018, the viaduct collapse occurred, and one of the structure supports collapsed. In June 2019, during the demolition process, the other two supports were destroyed. Since in Venezuela and Libya there are still two more bridges with a structure similar to that in Italy, the concept of strengthening the structure, as proposed by the author of the article 25 years ago, may still be useful.

The Curved Cable-Stayed Bridge Directrices Design Method for Maximizing Structural Efficiency, and its Application to Footbridges

This paper describes the principles, analysis and capacities of the axial-deck method developed in research on the optimization of the curved bridges directrices takin place at the UPM university in Madrid. The axial-deck method focuses on the two main structural challenges of curved cable-stayed bridges: the horizontal component of the load introduced by the stay cables on the deck; and the big torsion forces in the deck due to the unbalanced cable-stayed system. Hitherto, these problems have been addressed, either by optimizing the position of the tower and its geometric characteristics, or by modifying the morphology of the stay-cable system. Very little has been written about the possibilities of linking the structural behaviour to the deck directrix. This paper starts by describing the ideal solution equations, without considering the structure as statically indeterminate. Then, based on these equations, it follows the evolution of the method to a nonlinear iterative system. This evolution allows designs to be developed that consider the flexibility relation of all the structural systems involved in the problems. Finally, the method is validated with the redesign of two existing curved pedestrian bridges from prestigious engineering firms and the paper concludes with a structural behaviour analysis of all designs.

Temperature Effect on Main Girder of Strengthened Dongming Huanghe River Highway Bridge in Service

The main girder of Dongming Huanghe River Highway Bridge was the first prestressed concrete (PC) continuous box girder bridge strengthened by a cable-stayed system in China. In order to study the temperature effect of the main girder structure of Dongming Huanghe River Highway Bridge after reinforcement, based on the measured data of middle span deflection, key section strain and typical crack width, the curve equations of strain and temperature of main girder were obtained by the regression analysis method. The results show that the annual strain value of main girder changed with the acquisition time in a sinusoidal function, and was linearly related to the temperature. The variation of mid-span deflection decreased gradually from side span to middle span, and varied dynamically with temperature in the whole girder, which also has obvious correlation with temperature. The crack width fluctuated up and down in a certain numerical range, which belonged to respiratory cracks and had equally correlation with temperature.

Research on long-term deformation monitoring of PC box girder bridge strengthened by a cable-stayed system

To study the down-warping improvement for main girder of Dongming Huanghe River Highway Bridge after the reinforcement of the cable-stayed system, the long-term data of the main girder deflection were collected from 2018 to 2020, and the effects of different years, quarters and span on main girder deflection were analyzed, the results showed that the main girder deflection tended to be stable within 9 months after the reinforcement, the down-deflection trend of main girder was effectively suppressed within 3 years, and the effect of the cable-stayed reinforcement was obvious. Compared with 2018, the mid-span of main girder was generally raised in the first quarter of 2020, but the mid-span down-deflection was increased in the second, third and fourth quarters. In the relatively high average atmospheric temperature of each year, the main girder had improved as a whole, and the temperature had a great influence on the deflection of main girder, especially in the third quarter of higher temperature, it can be seen that the deflection of each span fluctuated greatly.

Deformation analysis of cylindrical lattice body of spacecraft in zone of high-pressure tank attachment

Finite element analysis of the strain-stress state in a load-bearing shell of the spacecraft body under longitudinal and lateral inertia loads was carried out. The shell is a composite anisogrid structure constituted by circumferential and helical ribs made of carbon fiber composite. A massive fuel storage tank is fixed inside the shell by means of a cable-stayed system. The shell structural behaviour in the zone of fuel tank installation was particularly addressed. A local reinforcement with additional circumferential ribs was shown to remarkably reduce the stress level and deflection in the tank attachment zone.

The design of super long span pedestrian landscape cable stayed bridge with sightseeing bridge tower

According to the design requirements of the super long-span pedestrian landscape cable-stayed bridge in Lake view Park, a kind of sightseeing tower-style pedestrian landscape three-tower cable-stayed bridge structure system was proposed. Sightseeing tower type bridge tower structure and duck egg arched bridge tower replace traditional cable-stayed bridge tower structure. Through the establishment of Midas finite element analysis model, dynamic modal analysis research was carried out. The analysis shows that: the sightseeing tower structure and the cable-stayed bridge tower structure are combined into one, and the two have good structural matching.

Assessment of nonlinear structural vertical-torsional coupling in cable-supported bridges

Using simplified mathematical representations of suspension bridges, mathematicians have demonstrated that a vertical dynamic forcing can cause large torsional vibrations due to geometric nonlinearities of the bridge that appear to be a structural dynamic instability. Compared to the extensive research that has been conducted on the dynamic behavior of cable-supported bridges, the approach used by the mathematicians appears too simplistic. This is due to the fact that the dynamic force considered by the mathematicians is approximate compared to actual dynamic loadings on bridges, especially those originating from wind. However, they raise a point that is not considered in the wind design of cable-supported bridges, i.e., a possible nonlinear structural coupling between the modes of vibration that could be detrimental to the bridge performance. Therefore, this paper presents a preliminary investigation of nonlinear vertical-torsional coupling in long-span bridges using a simplified practical approach. The proposed method relies on the finite element method and nonlinear pushover analyses. Using this approach, the nonlinear structural coupling is assessed for the numerical models of five suspension bridges and two cable-stayed bridges. The method allows determining the nonlinear stiffness parameters of equivalent systems having between one and three degrees of freedom (lateral, vertical and torsional). Since the proposed technique relies on the modes of vibration and can account for the interaction between the vertical and torsional effects, it can be used to judge which ones of the bridges considered are likely to be the most susceptible to nonlinear mode coupling under wind loads. The analysis results for the seven bridges shows that the suspension bridge system has a greater nonlinear vertical-torsional coupling in comparison to the cable-stayed system. Additionally, it is demonstrated that the span length has an influence on the vertical-torsional coupling. The results also show that the nonlinear coupling is slightly affected by lateral effects.

Study on Mechanical Properties of Main Girder of Continuous Box Girder Bridge Strengthened By A Cable-Stayed System

The local stress concentration of the main girder during the tensioning construction of the continuous box girder bridge strengthened by the cable-stayed system is more prominent, which may lead to the sudden damage of the structure. Therefore, this paper studies the key section stress and deformation of the main girder in combination with the real bridge test. The results show that the maximum tensile and compressive stress increase of the main girder appears at the root floor and midspan floor; The tensile action strengthens the compressive stress between the anchorage point of the long cable and the anchorage point of the short cable to the top of the pier, which releases some of the compressive stress across the mid-slab, improves the stress state of the main girder, and improves the shear load of the main girder ability; With the increase of the cable force, the main tensile stress of the web in the anchoring area first increases and then decreases. The lifting amount of the midspan section of the main girder accounts for 20.06% of the total deflection, and the effect of the cable-stayed system on improving the deflection of the main girder is obvious.

Development and Research of Mathematical Models of Deployment of Mobole Parts of Transformable Space Construction. Part I

The process of deployment elements of constructions and adjustment of the radio-reflecting network of large-sized transformable space-based reflector with the use of a cable-stayed form maintenance system is considered. The deployment process can be broken down into separate phases. At each stage, the movement is due to the impact on the design of the actuator — the element of the control system. Energy for the deployment of the reflector elements is produced by drives, in particular an electric machine. The use of this type of actuator allows you to control the process of disclosure. Due to the fact that currently achieved a huge process in computer technology that allows you to perform three-dimensional computing operations in a short time, it is particularly important to use optimal control algorithms. When deployment the reflector for two types of motion — rotational and translational — mathematical models based on Lagrange equations of the II-kind are obtained. These mathematical models take into account such parameters as dissipation, the presence of longitudinal and transverse deformation. The models provide for the presence of a stop and a lock, as an Executive element in the deployment selected brushless DC motor. All the observations made allow us to formulate a smooth statement disclose items on the stop with minimum oscillation of the structure. The developed models allow to analyze the n-th number of natural oscillation frequencies. Modeling with different parameters of the model is carried out. The parameters of the transition process of the spoke at the opening of the first link with the other links embedded in it and at the fully covered spoke are analyzed. It is shown that depending on the mass-dimensional parameters there is a significant change in the dynamics. For the spoke extension stage, the weight and size characteristics have little effect on the opening dynamics. The smaller the Young’s modulus and density of the material, the greater the damped longitudinal oscillations.. The simulation of this stage with a spoke made of different materials is carried out. Various methods are proposed to reduce the opening time at all stages and minimize transverse and longitudinal oscillations. The possibility of application of the developed mathematical models for a wide range of tasks is shown.

On the Creation of a High-Speed Transport Highway in St. Petersburg

As part of student research at the St. Petersburg University of architecture and construction, alternative proposals are being developed for the creation of a circumferential high-speed highway with a total length of 147.2 km. Тhe scheme is proposed in the form of a polygon with HUB in the nodes and consists of three main parts: 1 above-ground (62.6 km), 2 above-water (29.6 km) and 3 surface-underground (55.0 km). The main tracks are located in a four-tube steel beam, each tube of which is organized by the technology of vacuum tube transport with a pressure of 10% of the normal for high-speed passenger trains on a magnetic levitation cushion using a linear traction motor (Maglev system). The rail base of the 1520 mm gauge is located along the entire length of the track, both in parking lots, acceleration and braking zones, and on the main high-speed sections for movement with a maximum speed of 500 km per hour.
 The main direction of research was the development of load-bearing structures that provide the necessary functionality, reliability and safety of structures. In order to reduce the noise impact on the metropolis, overcome numerous artificial and natural obstacles, improve anti-terrorist protection, the main level of the rail track for the above-ground and above-water structures was adopted at +88.00 in the Baltic elevation system. Calculations of variants with determination of internal forces in elements and movements of nodes with use of the program complex SCAD Office 21.1are executed, when accounting for the full range of loads taking into account dynamic effects and non-linearity. The selection of cross-sections of elements according to the method of limit states according to the current norms is carried out. The advantage of the arch-cable-stayed variant with a span of 360 m in strength, stability, stiffness and vertical size (height of supports) is shown.
 The continuation of research and design work on this topic should lead to the emergence of a district high-speed transport system at the borders of communication between St. Petersburg and the Leningrad region with passenger traffic, quite comparable to the metro line.
 Aim: To develop a district high-speed transport system at the borders of St. Petersburg and Leningrad region with passenger traffic comparable to the metro line.
 Materials and Methods: Using the software package "SCAD Office 21.1", the trestle structures are calculated for the combination of operating loads, forces and influences, including the consideration of dynamic aspects and nonlinearity, as well as the selection of cross-sections of elements by the method of limit states. To determine the optimal trestle structures of high-speed highways, namely high-rise and long-length metal structures supporting the overpass beam, calculations with the selection of cross sections of four variants of cable-stayed systems (arch-cable-stayed; cable-stayed rod with inclined cables and steel lattice pylons; the same, steel pipe-concrete pylons; cable-stayed rod system with suspensions according to the patent US5950543 (A).
 Results: the results of the trial design adopted arch-cable option with a span of 360 m according to the criterion of metal consumption, the consumption of steel amounted to 20.9 tons per 1 m length of highway.
 Conclusion: the estimated volume of passenger traffic per day for the four-track high-speed line will be 280 thousand passengers, and 102 million passengers per year, which is quite comparable to this figure for the metro line.

Construction Techniques for Strengthening of Dongming Yellow River Road Bridge by the Cable-Stayed System

The Dongming Yellow River Highway Bridge (75+7×120+75 m), is a large span prestressed concrete rigid frame and continuous combination beam bridge, which was the first bridge strengthened by cable-stayed system in China. Using towers and stay cable system, the main bridge was transformed to provide vertical support with superstructure. For the foundation reconstruction, bored piles were constructed as new pile foundations on both sides of the original pile foundations. After cofferdam pumping, to ensure the positioning of the protective tubes, the reinforcing bars, concrete cover and concrete piles left in the river bed were removed by using brush drilling rigs, long arm digging machines and frogmen, while the "U-tube" method was used to grout at the bottom of the piles. The diamond wire saw cutting technology was adopted to complete the transformation of the old caps and insert shear nails. Using the post-pouring strip temporary shields, the new caps and old caps were connected until the tensioning of the cables was finished. To ascertain the arrangement of the reinforcement on the floor and the prestressed reinforcement, and then stick the positioning plates on the floors, bonded rebars holes were drilled utilizing the hydraulic core drill that was made. The joists and the brackets are manufactured by the factory and assembled in the construction site. Gantry cranes and angle fine-tuning devices were used to install the joists and brackets, and then the connecting bolts were inserted. Concurrently, material was transported through the hole in the roof of the middle-span, and the steel supports within the box were installed. From the middle towers to the side towers, from the short cables to the long cables, cables were tensioned by batches and levels with constant monitoring throughout the whole process of this tensioning construction. Finally, the external prestressed strands inside the box were adjusted and the bridge deck construction was completed.

Experimental test and hysteretic behavior of single cross-arm PCS-BRBs

An innovative buckling-restrained brace (BRB) is devised by imposing a cable stayed system (CSS) on a common BRB, namely single cross-arm pre-tensioned cable-stayed buckling-restrained brace (SPCS-BRB). Its overall external stiffness thus load-bearing capacity can be dramatically enhanced over the common BRB. A previous study conducted by the authors investigated comprehensively the elastic buckling behavior of the brace, yet experimental investigations and detailed design suggestions were not provided. Two SPCS-BRB specimens have been devised and tested. Test results revealed that both specimens possessed excellent hysteretic response with stable hysteretic curves, which fulfilled the ductility requirement specified in the AISC seismic provisions. The adopted simplified Finite Element (FE) model for experimental simulations corresponds well with the obtained test results. Moreover, additional FE analysis (FEA) has been conducted on the SPCS-BRBs subjected to monotonic and cyclic axial loads, respectively as to validate the test results further. In addition, threshold values of restraining ratios are obtained by guaranteeing the cables to remain tensioned prior to attaining ultimate failures, and ensuring maximum load resistance of the SPCS-BRBs is obtained. It is observed from the FEA that global instability failures of the SPCS-BRBs are caused by expansion of yielding at the extreme fibers of the external tube. Finally, FEA has been conducted on the load resistance of the SPCS-BRBs by considering the effect of interactive buckling and prestressing force of cables. It is found that interactive buckling could become critical in dominating the load resistance of the SPCS-BRBs when single-wave symmetric buckling mode is considered.

INVESTIGATION OF LAUNCHING PROCESS FOR STEEL REINFORCED CONCRETE FRAMEWORK OF LARGE BRIDGES

Bridges are considered as the most complicated, labour-consuming and expensive components in roadway network of the Republic of Belarus. So their construction and operation are to be carried out at high technological level. One of the modern industrial methods is a cyclic longitudinal launching of large frameworks which provide the possibility to reject usage of expensive auxiliary facilities and reduce a construction period. There are several variants of longitudinal launching according to shipping conditions and span length: without launching girder, with launching girder, with top strut-framed beam in the form of cable-stayed system, with strut-framed beam located under span. While using method for the cyclic longitudinal launching manufacturing process of span is concentrated on the shore. The main task of the investigations is to select economic, quick and technologically simple type of the cyclic longitudinal launching with minimum resource- and labour inputs. Span launching has been comparatively analyzed with temporary supports being specially constructed within the span and according to capital supports with the help of launching girder. Conclusions made on the basis of calculations for constructive elements of span according to bearing ability of element sections during launching and also during the process of reinforced concrete plate grouting and at the stage of operation have shown that span assembly with application of temporary supports does not reduce steel spread in comparison with the variant excluding them. Results of the conducted investigations have been approbated in cooperation with state enterprise “Belgiprodor” while designing a bridge across river Sozh.

Mobilna derivacijska hidroelektrana za opskrbu rezerve vode i energije za rekreacijske sadržaje i instalacije u marini na Ruskom otoku

The article considers the problems of justification of derivational micro-HPP usage for reserve water supply and standby power service of harbour installations for Russky Island. The first part of the article describes the justification of the power supply necessity for recreation facilities and yachting harbour installations (marinas) on Russky Island, including the prospect of their further development and new construction activities. The second part of the article considers the justification of innovative technologies usage of mobile derivational micro-HPP for recreation facilities and harbour installations power supply. The third part of the article deals with the principal design parameters for calculation of composite mobile diversion conduit and its cable-stayed system schemes which are used to fix the diversion conduit in light of wind effects. The forth part of the article shows the simulation modeling of the diversion conduit.