Erection Method Research Articles

A Critical Review of Alternative Erection Methods for Overhead Line Towers

A Critical Review of Alternative Erection Methods for Overhead Line Towers

COMPARISON OF NEOLITHIC HOUSING IN JAPAN AND UKRAINE

The national habitation of Japan and Ukraine during the Neolithic period is studied: comparison of methods of erection of frame structures, influence of lifestyle on the appearance of dwelling in both countries, as well as influence of religion on the arrangement of habitation in Ukraine and Japan, their common and distinctive features. The methods of preserving the architectural monuments in Japan, as well as the forecasts regarding the further state of traditional folk habitation in Ukraine without urgent restoration and renovation.Key words: traditional accommodation, wooden architecture, architecture, Neolith, Trypillia, Ukraine, Japan.

Penerapan Fahp Pada Pemilihan Metode Pelaksanan Erection Box Girder

Many parties are involved in a construction project, so in deciding a method of implementing the box girder erection many criteria are taken into consideration. Consequently, decision making is not easy for decision makers. A simple, frequently-used, and popular method for decision making is Fuzzy-Analytical Hierarchy Process (F-AHP) which is designed to overcome the problem of multi criteria decision making (MCDM) in the subjective assessment process. This study aims to obtain the correct method of implementing the box girder erection to be used. Based on previous research, the criteria for determining box girder erection method are the criteria for job risk, work quality, implementation time, implementation process, work safety, and work costs. The alternatives compared are the tandem crane method and the launching gantry method. The data in this study were collected through questionnaires distributed to the expert parties involved in Jakarta - Cikampek II Elevated Toll Road Project. F-AHP analysis is based on the weighting of quantitative criteria as a result of normalized calculations and qualitative criteria from the results of the respondents questionnaires which were then made pairwise comparisons assisted by Microsoft Excel software. The results of the analysis show that the occupational safety criteria are the most influential criteria with a weight of 0.454, then followed by job risk criteria (0.169), implementation time (0.119), work quality (0.114), implementation process (0.084), and work costs (0.061). The most appropriate method used in the work of the box girder erection at Jakarta - Cikampek II Elevated Toll Road Project is a launching gantry method with a value of 0.597, while the tandem crane method has a value of 0.403.

Сучасний розвиток індустріальних методів зведення малоповерхового житла різних категорій

Сучасний розвиток індустріальних методів зведення малоповерхового житла різних категорій

Construction Scheme of the Formwork Support for Overweight Beams

With the rapid increase of the number of high-rise and long-span buildings, oversize and overweight concrete structural beams have emerged. The concrete formwork support for overweight beam faces great risks. To prevent the collapse of formwork support system, it is extremely important to improve the design and construction levels of the formwork support system for overweight beams. Through the actual engineering research, this paper analyzes the material selection and the erection method of formwork and support, and also conducts the mechanics calculation on them. Besides, this paper also introduces the installation and dismantling of the formwork for overweight beams, as well as the construction requirements. This paper proposes to control the design and construction quality of the formwork support system for overweight beams to ensure the stability of the support system. The research results provide references for other similar projects.

Empowerment of Rural Women through Entrepreneurship Development Training – The Case of Bio-Waste Management in Southern Tamil Nadu

Madurai and Virudhunagar Districts of Tamil Nadu is blessed with vast resource potentials especially of soil and water which had motivated the farming community to adopt different seasonal and perennial crops like vegetables, cereals, pulses, and fruits. After the harvest of farm produce, the residues are left unutilized and go waste and sometimes add to production problems. A project was aimed to find the means of effectively utilizing the biowaste resources into the value-added products like Organic Manure, Cultivation of Milky Mushroom and Biopesticide Production etc. These practices are successful and hence it is planned to impart capacity building programs to empower the landless, marginal Rural Scheduled Caste and Scheduled Tribe Women are hailing in the poverty line. Accordingly, one hundred beneficiary women were identified and selected for capacity building and guided them to establish value-added products like Milky Mushroom from the biowaste resources. During the training and demonstration programs, the method of erection of mushroom shed, cultivation of milky mushroom, methods of spawn production, bed preparation utilizing the waste resources, harvesting and marketing of mushroom to the beneficiaries through identified experts in the related field. Though all the respondents were actively participated in Bio degradation, Bio Pesticide, and Milky Mushroom production activities, the impact created in the study area were found to be only to the level of 45 per cent whom had shown much interest in establishing Milky Mushroom and the Spawn Production activities and started earning considerable income per month motivated them to run quality life in their environs. Besides, the details of activities performed by the respondents and their enhancement in earning capacity and the marketing practices followed are also discussed in this paper..

Launched north approach viaduct in the new Queensferry crossing, UK: design and construction

Launching is a bridge erection method that provides significant advantages when there is difficult underdeck access for falsework, crane and heavy plant. In such cases, assembling the deck in a more accessible position and launching it over the piers may mean a significant saving of resources. In some cases access is simply not possible due to other constraints, for example over environmentally protected areas. This is the case of the north approach viaduct of the new Queensferry Crossing, a major cable-stayed bridge over the Firth of Forth in Scotland, UK. This paper provides a description of the approach viaduct north and its launch process. This viaduct is a single/twin-girder bridge with composite section and two spans of 101·5 m and 104 m. Owing to its particular characteristics and impressive launch weight of 6200 t, the launching process has not been conventional, and particular solutions have been used and combined to ensure full compliance with the strict design constraints. The assembly process was not conventional either, owing to space constraints and the weight and size of the pieces.

Failure of the Wroclaw needle tower's support during restoration

The method of erection of steel structures can have a major impact on the development of adverse internal forces in the elements of the structure, resulting in even structural failure (Hotała and Rykaluk, 2012; I.O.Otunniyia,b, D.T. Oloruntobab, S.O. Seidub, 2018; Albermani et al., 2009 [6–8]). This paper describes the operations involved in the controlled laying down of the Needle Tower in Wroclaw. As the Tower was being lifted via rotation relative to its pivot supports the shank of one the supports was sheared. Consequently, the damaged support had to be reconstructed. The results of static load calculations of the Tower mast for the successive phases of laying down and uprighting the Tower are presented. On the basis of the calculations, material tests and numerical simulations an attempt is made to determine the causes and mechanism of the support shank failure during the lifting of the Tower.

Performances of Steel-Concrete Composite Construction with Demountable Shear Connectors – Review

Composite steel-concrete constructions with demountable (bolted) have the prime privilege of the capability to be untied and taken to pieces, furthermore, they remain suitable for tying again to assemble efficient composite structures. Long-term behavior and durability issues may need replacement of concrete slabs or their parts through maintenance of composite bridge decks. It is a complicated procedure and requires a lot of time in case of the popular traditional welded head stud. Dismantling and replacement of concrete slabs can be effortless by using bolted shear connectors. It is also so important for the sustainability stand point owing to remove of the structure at its life time end easily. Construction by using demountable shear connectors permits the development of faster erection methods. During casting of the reinforced concrete slab bolts can be embedded in it. Then, on site, they are assembled to the predrilled top flange of the steel section of the composite member. For certain application, composite structures with demountable shear connectors can prove their competition economically for their faster erection and lower life cycle costs. The present paper provides a comprehensive overview of most recent published research on composite steel-concrete systems in which the two partial interaction components (slip and uplift resistances) are furnished by demountable shear connectors. It also describes, in detail, properties of the main types of shear connection demount abilities innovated so far.

How to Design Economical Network Arches

The network arch is an economical bridge type that can look good and needs 35 to 50 % less steel. Economical methods of erection using light steel skeletons can be found. The network arch is defined by having hangers that cross each other at least twice [1]. The arches are made of steel. When the distance between the arches is less than 20m, the author thinks that the tie should normally be made of concrete.

A system consists of lifted steel tank and four assembly supports with variable assembly conditions

Abstract In the method of steel tank erection, consisting in assembling the roof and the next courses (segments) of the shell at the ground level, starting from the top one (the so-called hydraulic jacking-up method), the assembled part of the tank is lifted using assembly supports (towers, trestles), hydraulic jacks and ropes. Supports are located inside or outside the tank, and their bases are usually not anchored. During the assembly work, numerous contaminations can appear under the bases of the supports; therefore, boundary conditions of the system consisting of the elevated tank and assembly supports may change, influencing the field of displacements and stresses in the elements of this system. This article presents the results of numerical tests of an exemplary mounted tank – mounting support system – at various possible coefficients of friction between the bases of the supports and the ground. The influence of the support conditions on the effort of the essential elements of the system was assessed. Calculation difficulty was noted to determine the directions of horizontal responses of the supports. It was assumed that these directions did not change after exceeding the values of the friction forces. The analysed tank collapsed during its erection.

THE APPLICATION OF THE FINITE ELEMENT METHOD FOR STATIC BEHAVIOUR ANALYSIS OF THE ASYMMETRICAL ONE-PYLON SUSPENSION BRIDGE BUILT-IN BENDING CABLES OF DIFFERENT RIGIDITY

The article presents the results of the numerical analysis of the asymmetrical one-pylon suspension bridge built-in rigid cables. The models for the suspension bridge with the cables of different rigidity are analyzed by comparing vertical displacements, bending moments and strains in the structural members of the bridge. The numerical analysis was performed by examining the bridge under symmetrical and asymmetrical loading and different erection methods. The stress-strain state of a single asymmetrical pylon with the cables of different rigidity and the rational relationship between cable rigidity and girder stiffness has been established.

Stability analysis of newly developed polygonal cross-sections for lattice wind towers

The pursuit for cheaper energy is leading the current wind tower design to increased heights. Common wind turbine tower designs would generate unjustified costs for transportation and erection leading to inefficient use of materials. In order to reduce these costs, several simplified erection methods have been proposed. One of such is the hybrid lattice-tubular steel tower. For economic feasibility, built-up cold-formed polygonal cross-sections have been proposed for the lattice part. This article presents a numerical investigation of the failure modes of closed polygonal cross-sections. The first part contains a presentation of structural systems which incorporate elements composed of plates and cold-formed members. The evaluation of the polygonal sections is done by means of finite element analysis considering local and global geometrical imperfections and residual stresses generated in the fabrication procedure. A comparative study is performed between several finite element models to propose a corresponding European buckling curve for calculating the flexural buckling resistance. The results show that the design of polygonal sections can be done according to European buckling curves methodology.

Analytical Solution for Horizontal Tension of Main Cable in Erection of Stiffening Girder

The horizontal tension of main cable is a key parameter to guarantee the safety of tower, form gravity stiffness and keep main cable shape correct during erection of stiffening girders. Instead of complicated Finite Element Modeling and iterative algorithms, simply analytical solutions of horizontal tension of main cable were deduced for two classical erection methods of stiffening girder based on the mathematical analogue and work-energy principle. Numerical method was also adopted to verify the analytical solutions on analysis of a single span suspension bridge. The results from analytical solution are found to be in good agreement with the numerical results. The theoretical results show that the presented analytical solutions can be easily applied in the calculation of the horizontal tension of main cable in any erection stage.

Большепролетные металлические купольные покрытия и их возведение

The article presents the main types of geometrical and structural systems of steel frameworks of metal dome roofs. Based on the geometrical system, three main types of metal domes can be specified: ribbed domes, ribbed domes with rings, and lattice domes. Lattice domes can be cyclically symmetrical with repeating sectorial patterns, or geodesic, that are based on geodesic polyhedrons, inscribed in a sphere. Based on the structural system, the frameworks of ribbed domes can have single chord or dou- ble chord ribs. Geometric system of the framework of a large-span metal dome governs the method of its erection which in its turn defines the structural solutions for the elements of the framework and the sequence of their assembly. The paper describes the following methods of erection of large-span domes: erection by crane from the ground with temporary supports, placement of the complete structure or large elements of the dome, and cantilever erection. The examples of large-span metal domes built in different countries of the world are reviewed with respect to the method of construction used. General characteristics of the structural system of the framework of each dome are presented. The examples are used to demonstrate that the method of construction of a large-span metal dome roof is dependent on the geometric system of its framework. It is noted that metal domes are widely used as structural solutions for roofs of buildings of different types. It is noted that erection with temporary supports of different types, or ground assembly are mostly used for the construction of relatively low double layer domes, or high single-layer domes. For large-span double-layer metal domes of considerable high the method of cantilever erection is usually preferred.

Behavior of the frames of large-span metal domes in the process of their installation

Goal. The goal of this paper is to characterize the process of forming the frames of large-span metal domes during assembly process. The load-bearing structural schemes during the assembly of frames differ from those, adopted for their analysis and design. Due to this fact, initial internal forces appear in the structural elements of frameworks that are called assembly forces. Geometric schemes of dome frameworks and the principles of their formation are described for ribbed domes, ribbed domes with annular rings and lattice domes. It is shown how lattice dome frameworks are formed and why they are considered as spatial bar systems. Specific features of the structural solutions for single-layer and double-layer frameworks are described. It is noted that the technological scheme for the assembly of structures of large-span metal domes depends on the structural systems of frameworks and on the methods of their erection. A brief description is given of differrent methods for erecting frameworks of large-span metal domes and of the number of temporary supports and mechanisms used in this process. Review. Different methods of erection are illustrated with the examples of several well-known dome structures built in the world. The evaluation of the influence of each process on the behavior of structures during the installation is given. The nature of the work of individual structures and a frame is described for the process of erecting large-span metal domes. The emphasis was made on the significant differences in the nature of work of structural systems of dome frame-works with different ways of their installation. Research. Computer models of the lattice metal domes are made of steel I-bars with rigid connections at the joints. Additional models were created for incomplete frameworks to study alternative ways of erection. For each assembly model of the dome framework, computer analysis was performed for the action of its self-weight. Stresses in the structural members, obtained as a result of the analysis, were compared with the stresses in the corresponding elements of the design model of the framework under the self-weight. Conclusions. The conclusion is made that the stresses in the elements of frameworks of the large-span metal domes are unavoidable when they are erected. The necessity of compulsory analysis of frameworks for erection conditions in the design of large-span metal domes was noted.

Computer analysis of the behavior of large-span metal domes with different methods of installation

A brief characteristic of the process of forming the frameworks of large-span metal domes during the installation process is given. A general description of the structural solutions of the frameworks of ribbed domes with annular rings and lattice large-span metal domes is presented. Alternative ways of modeling structural connections of the elements of the frameworks are discussed for domes with different types of structural systems. The load-bearing structural schemes during the assembly of frameworks differ from those, adopted for their analysis and design. Due to this fact, initial internal forces appear in the structural elements of frameworks that are called assembly forces. For the research purpose, design computer models of ribbed dome with annular rings and of sectorial lattice metal dome were developed with the span of 48 m and the height 12 m. The lattice is made of steel I-bars with rigid connections at the joints. The investigated dome frameworks are supported along the contour by permanent columns through hinge supports. On the basis of de-sign models, additional models were created for incomplete frameworks to study alternative ways of erection, which differed from each other in the number of temporary supports with hinge connection to the framework and hinge connections of the bar elements at the joint above the temporary support. Each of these models interpreted the intermediate state of the erected dome framework with its characteristic structural scheme. Depending on the number of temporary supports, three installation schemes were considered for the ribbed-ring dome, and four schemes - for the sectoral-lattice dome. Assembly computer models included the following types of temporary supports: central support, central and one row of intermediate supports, central and three rows of intermediate supports, support under each joint of a frame-work. For each assembly model of the dome framework, computer analysis was performed for the action of its self-weight in order to determine their stress-strain state. Stresses in the structural members, obtained as a result of the analysis, were compared with the stresses in the corresponding elements of the design model of the framework under the self-weight. Based on the obtained data, graphs and diagrams were constructed reflecting the level of assembly stresses in the structural elements of the frame in comparison with design values taking into account the type of work (compression or tension). Various groups of elements are considered along the entire height of the dome frames. The conclusion is made that the stresses in the elements of frameworks of the large-span metal domes are unavoidable when they are erected, and the level of these stresses for specific erection methods is significant. The methods of erection and the types of structural elements that can affect the reliability of dome frames are indicated. The necessity of compulsory analysis of frame-works for erection conditions in the design of large-span metal domes was noted.

Methods of erection of high-rise buildings

The article contains the factors determining the choice of methods for organizing the construction and production of construction and installation work for the construction of high-rise buildings. There are also indicated specific features of their underground parts, characterized by powerful slab-pile foundations, large volumes of earthworks, reinforced bases and foundations for assembly cranes. The work cycle is considered when using reinforced concrete, steel and combined skeletons of high-rise buildings; the areas of application of flow, separate and complex methods are being disclosed. The main conditions for the erection of high-rise buildings and their components are singled out: the choice of formwork systems, delivery and lifting of concrete mixes, installation of reinforcement, the formation of lifting and transporting and auxiliary equipment. The article prescribes the reserves of reduction in the duration of construction due to the creation of: complex mechanized technologies for the efficient construction of foundations in various soil conditions, including in the heaving, swelling, hindered, subsidence, bulk, water-saturated forms; complex mechanized technologies for the erection of monolithic reinforced concrete structures, taking into account the winter conditions of production and the use of mobile concrete-laying complexes and new generation machines; modular formwork systems, distinguished by their versatility, ease, simplicity in operation suitable for complex high-rise construction; more perfect methodology and the development of a set of progressive organizational and technological solutions that ensure a rational relationship between the processes of production and their maximum overlap in time and space.

Defining Appropriate Temperature for Perfect Erection Time of Steel Arch Bridge Closure to Minimize the Effect of the Thermal Stress. Case Study: The New Kutai Kartenagara Bridge, Indonesia

The impact of temperature change could govern the final stress of structural elements in the long-span steel bridges. The study was conducted to investigate the effect of temperature change during the construction of a new steel arch bridge, namely the Kutai Kartanegara Bridge. The main bridge has a total spanning length of 470 meters. The erection method of the bridge was the cantilever method with temporary towers, mast cranes, and stay cables. The deflections and internal forces of the steel elements were analyzed using the Midas Civil software. The study focuses on the effort to find the perfect erection time for the closure with regards to the temperature. By measuring the temperatures of the steel elements during the construction, it was found that they varied between 19 and 64 degrees Celsius. From the results of the analyses with various temperatures, it can be concluded that the recommended temperature for the closure erection was 44.6 degrees Celsius. This temperature is similar with the air temperature between either 6 AM and 12 noon or 12 noon and 6 PM. During this periods of time, the effect of thermal stress on the final internal forces in the bridge elements was found much lesser than those obtained during any other period of time.

RAS: a robotic assembly system for steel structure erection and assembly

This research focuses on a long-standing, yet critical problem in the erection of steel structures. In the current state of practice, steel workers must stand on an unfinished structure to assist with the assembly of structural elements manually. They must pull on the wire hanging under the rigging elements to align the bolting holes of the moving and fixed elements. This work is often performed in high places, which can be very risky. Therefore, we have developed a robotic assembly system (RAS) for steel beam erection and assembly to prevent workers from having to work in a high place. The RAS consists of four methods: rotation, alignment, bolting, and unloading. The rotation method involves a flywheel installed on top of the rigging beam, which aims to rotate the beam to the assembly angle. The alignment method includes both vertical and horizontal alignment. The vertical alignment relies on a camera and a marker on the column to align the beam altitude. The horizontal alignment relies on a specially-designed beam, which allows for it to be smoothly guided into the right position. The bolting method is used to connect the beam to a fixed element. We designed an additional guide hole above each bolt hole. The bolt can be inserted in the guide hole and slid to the bolt hole. The unloading method is used to unload the crane cable and the RAS. We use a pin mechanism for the beam-hook connection so it can easily be unplugged by a motor. The system is built in a scaled experimental construction site to validate its feasibility. The results show that the RAS can operate the assembly process without humans working at risky heights, and can complete faster than the traditional method. In conclusion, we have developed a robotics assembly system that can help reduce the frequency of accidental falls during the steel beam assembly process. The RAS adheres to the process of the current erection method and can be broadly introduced to existing construction sites.