Construction Of Tower Research Articles

Increasing corrosion and mechanical resistance destruction of welding cover capacities water towers

The paper considers standard methods for determining the corrosion and mechanical characteristics of pipes and their welded joints, steel shell structures for water supply to consumers. It was found that sharp fluctuations in the values of microhardness in the zone of thermal influence of the welded joint exceed the baseline values in the middle part of the weld and the base metal of the pipe. The obtained results can be used to test the performance of carbon steel steels designed for the construction of water towers of long service life in corrosive environments. Under the action of the temperature gradient on the outer surfaces of the walls of the water tank tensile stresses occur, and on the inner surfaces-compressive, which is a favorable factor that reduces the risk of corrosion. Temperature stresses that occur in the case of temperature inhomogeneity along the contour of the cylindrical tank are unfavorable. Stresses from the weight load are small and do not have a significant effect on the destruction of the steel tank, because they are compressive. The value of technological final stresses was determined experimentally by mechanical strain gauge according to the classical method, as well as with the help of electric strain gauges and ultrasonic method according to the method of E. O. Paton Electric Welding Institute (PWI). It has been experimentally established that the most dangerous final welding stresses in assembly seams, the value of which for the longitudinal stress component is close to or exceeds the yield strength , and for the transverse – close to the yield strength , while on steel plates VSt3 of the same thickness . It is likely that welding during installation in conditions of rigid compression of the metal causes an increased level of final stresses. The magnitude and sign of the final stresses significantly depends on the method of installation. Even during block installation, when the water tower is mounted from several pre-annealed blocks, the connection between the mounting ring seams in some areas of the base metal near these seams during fitting creates significant stresses (up to 17.6 kgf / mm2), in some areas – up to 6 kgf / mm2. When sheet assembly stresses can reach a level close to the yield strength.

D1244: Design and Construction of the First Adaptive High-Rise Experimental Building

An interdisciplinary research team of the University of Stuttgart has been working extensively since 2017 on the development and integration of adaptive systems and technologies in order to provide solutions for a more sustainable built environment. An experimental 36.5 m tall high-rise building, called D1244, was designed and completed in 2021 to show the potential of adaptive structures and facades as well as to verify on a real scale the developed systems and the related numerical predictions. The building was designed to offer a flexible experimental platform: each component is dismountable so that structural as well as facades elements can be replaced with new ones introducing new functionalities to be investigated. The structure is currently equipped with twenty-four hydraulic actuators that are installed in the columns and diagonal bracers. Strain gauge sensors and an optical tracking system are employed to monitor the state of the structural system. This paper describes the design and construction of the adaptive tower as well as the preliminary experimental testing on different scaled structural prototypes. The research work on these prototypes provided relevant information for the final set-up of the high-rise building. An outlook on future research, including the planned first structural testing phase and the implementation of adaptive façade systems, is included at the end.

Nuraghi as Ritual Monuments in the Sardinian Bronze and Iron Ages (circa 1700–700 BC)

AbstractStarting with a brief review of different theories about the residential and defensive uses of Sardinian nuraghi (monumental stone towers), the author assesses their ritual significance and functions from the standpoint of architecture and design, similarities to other cult buildings, and associated features and finds. Evidence for cult activities in certain towers has grown in recent years and is widely accepted for the Iron Age (circa 950–700 BC) and later. By contrast, ritual practices are not often recognized for the much longer period of tower construction and usage in the Bronze Age (circa 1700–950 BC). This is attributable partly to the now dominant hypothesis of a transformation in the function and status of nuraghi in the Iron Age and an assumed separation between sacred and secular buildings in the nuragic period. The author challenges this perspective while discussing the contribution of ritual to the social, economic, and political uses of nuraghi in the Bronze Age.

Experimental study on the joint bearing behavior of segmented tower structures subjected to normal and bending shear loads

AbstractThis article deals with the analysis and evaluation of the structural behavior of segmented tower constructions in large‐scale experimental investigations. For this purpose, a tower model with dry horizontal joints on a scale of approximately 1:10 is constructed and loaded. The objective of these large‐scale investigations is to determine the load‐bearing behavior of concrete segment towers subjected to normal force (external prestressing), bending, shear force and torsion and to derive more efficient and realistic design models. The transfer of shear stresses between individual segments is ensured by frictional resistance in the horizontal joints due to prestressing. The current design models are based on plane flange surfaces at the top and bottom of the segments as well as their ideal circular ring shape. This assumes a constant normal stress distribution for the compression connection. Within the large‐scale experimental tests, findings for uneven force distribution in the horizontal joints due to prestressing and shear bending were obtained, that have a significant impact on the design models. However, for the evaluation of the results and the projection onto the real construction components, the scale effects must be urgently taken into account.

Quantification of the Seismic Behavior of a Steel Transmission Tower Subjected to Single and Repeated Seismic Excitations Using Vulnerability Function and Collapse Margin Ratio

Transmission towers are a vital lifeline for modern living and are crucial structures that must remain operational even after a seismic event. However, the towers are largely designed to withstand the effects of wind alone and not earthquakes, and the seismic influences on tower design and construction have hitherto been ignored. The purpose of this study was to evaluate the seismic performance of a latticed steel transmission tower-line system that is subjected to a variety of seismic situations (Far-Field, Near-Field and Repeated Earthquakes) using probabilistic vulnerability functions and Collapse Margin Ratios in accordance with FEMA-P695. Nonlinear Time History Analyses were performed by incorporating an array of 36 strong ground motions to develop the Incremental Dynamic Analysis and to generate the fragility functions for three performance limit states as referenced in FEMA 356. The results showed that the single event seismic performance of the tower is better than its performance after multiple ground motions owing to aftershock impact, while near-field excitations led to greater susceptibility and fragility than far-field scenarios. Thus, near-field ground motion is more harmful to the tower and could result in its failure or collapse with only a small reduction in damage relative to the impact of the aftershock.

Fiber element modeling of circular double-skin concrete-filled stainless-carbon steel tubular columns under axial load and bending

Circular concrete-filled double-skin steel tubular (CFDST) columns with external stainless-steel are high-performance composite columns that have potential applications in civil construction including the construction of offshore structures, bridge piers, and transmission towers. Reflecting the limited research performed on investigating their mechanical performance, this study develops a computationally efficient fiber model to simulate the responses of short and slender beam-columns accounting for the influences of material and geometric nonlinearities. Accurate material laws of stainless steel, carbon steel, and confined concrete are implemented in the mathematical modeling scheme developed. A new solution algorithm based on the Regula-Falsi method is developed to maintain the equilibrium condition. The independent test results of short and slender CFDST beam-column are utilized to validate the accuracy of the theoretical solutions. The influences of various column parameters are studied on the load-axial strain [Formula: see text] curves, load-lateral deflection [Formula: see text] curves, column strength curves, and interaction curves of CFDST columns. Design formulas are suggested for designing short and beam-columns and validated against the numerical results. The computational model is found to be capable of simulating the responses of CFDST short and slender columns reasonably well. Parametric studies show that the consideration of the concrete confinement is important for the accuracy of the prediction of their mechanical responses. Furthermore, high-strength concrete can be utilized to enhance their load-carrying capacity particularly for short and intermediate slender beam-columns. The strengths of CFDST columns computed by the suggested design model are in good agreement with the test and numerical results.

Quenched Decay of Correlations for One-dimensional Random Lorenz Maps

We study rates of mixing for small random perturbations of one-dimensional Lorenz maps. Using a random tower construction, we prove that, for Hölder observables, the random system admits exponential rates of quenched correlation decay.

Church Building and Society in the Later Middle Ages by Gabriel Byng

Reviewed by: Church Building and Society in the Later Middle Ages by Gabriel Byng Judy Bailey Byng, Gabriel, Church Building and Society in the Later Middle Ages (Cambridge Studies in Medieval Life and Thought: Fourth Series, 107), Cambridge, Cambridge University Press, 2017; hardback; pp. xi, 324; R.R.P. £75.00; ISBN 9781107157095. This well-researched volume on the administration, management, and financing of English parish church construction in the late medieval period takes a different perspective from that of previous scholars. Gabriel Byng does not seek to add to the literature about pious motivation. Rather, he examines the ‘nuts and bolts’ of church building—the financing of building projects, the management of projects via contracting committees and fabric wardens, and the complex nature of fundraising efforts. It is refreshing to read a new perspective about the surge of parish church building in the late medieval period. Byng’s work concentrates on the political economy of the parish rather than individual piety or community cohesion. The integration of economic data such as prices for raw materials, labour costs, and wages, with churchwardens’ accounts and contracts indicates that these projects were often complex and multi-faceted. Project managers needed considerable financial acumen to manage church building in England at this time. The volume is divided into six chapters. The first two chapters examine the financing of building projects; firstly, by parishioners, and secondly through patronage by ecclesiastical institutions or the gentry. Chapters 3 and 4 examine how the construction was organized. The key role of churchwardens in the parish has been examined by many scholars such as Beat Kümin in his 1996 book The Shaping of a Community: The Rise and Reformation of the English Parish c. 1400–1560 (Ashgate, 1996). Byng confirms this role by adding that parishes with strong wardens, who were held in high regard and had the ability and wherewithal to access funds, could galvanize the community and push through projects. However, if the project grew too large or complex, temporary contracting committees or fabric wardens were employed. The final chapter explores the role in organizing building construction by the clergy, gentry, or the aristocracy. In one example, Byng uses private fabric accounts kept by the lord of the manor, John Bolney, to analyse the construction of the parish church tower in Bolney, West Sussex, in 1536–37. These accounts clearly show that John Bolney shared financial and organizational responsibility with the parish. The churchwarden arranged lodgings for two masons and organized the contract for timberwork. Without these surviving accounts, it might well be assumed that the parish had no role in the tower construction. [End Page 279] This book is an excellent addition to the large corpus of material on the late medieval parish. It provides a holistic insight into the economic, social, and political complexities of parish church building. Judy Bailey Barmera, South Australia Copyright © 2022 Judy Bailey

Simulation Analysis and Application of Super High-rise Tower Construction Process

Wenzhou Lucheng Square Phase IV project, whose main tower reaching 378.8m high, belongs to the super high-rise building structure. Considering the influence of shrinkage and creep characteristics of concrete on vertical deformation differences of components, Midas Gen was used to simulate and analyze the whole construction process of the main tower. The analysis results of different working conditions are compared, the rationality of the construction scheme is checked and a general conclusion is drawn.

Determination of the drag coefficient of lattice structures under wind load using porous media approach

The power transmitters, guyed masts and other lattice structures are exposed to wind action. The aerodynamic forces acting on tall tower constructions have crucial importance on the stability of the structure. The lattice structure drag coefficient determination is the subject of the international standards ESDU 81027 and 81028 and Eurocode 3 Part 3.1, but it can also be determined by numerical methods. For that purpose modelling using CFD proved to be both accurate and reliable. In this study the fluid-flow around the segment of a power transmitter was simulated by a 3-D model, where the geometry of the segment is approximated with a porous structure having the appropriate factor of porosity, in order to simplify the geometry. We have used three representative models of turbulence, standard k-? model, RNG k-? model, and Reynolds stress model. Drag coefficient values are extracted from the flow field and compared for all studied cases and with available experimental results from the wind tunnel. Simulations were performed for four wind velocities between 10 m/s and 30 m/s. The results are supplemented by the ones obtained by artificial neural network. The aim of this study is to show how the simple turbulence model coupled with approximated geometry can be used in the analysis of the aerodynamic forces acting on the lattice structure.

Lightning protection performance of quadruple-circuit 500 kV transmission lines on the same tower with composite cross arm

In recent years, composite materials cross-arm (CMCA) towers have been gradually used in 10 kV, 35 kV or other transmission lines with lower voltage level in China. However, it is rarely used in higher voltage level transmission lines, especially in multi circuit lines on the same tower. Because of its higher height, we should pay more attention to the lightning protection performance of high voltage level multi circuit lines on the same tower. In this work, the simulation and calculation analysis of Lightning stroke model of quadruple-circuit 500 kV transmission line is done to compare CMCA tower with steel tower. The research shows that the tolerance lightning level of CMCA tower is superior to conventional steel tower, The lightning withstand level of single circuit flashover is 45% higher than that of steel tower and the minimum shielding failure lightning withstand level is 47% higher than that of steel tower. The data can provide the theoretical basis for the construction and optimization design of high voltage CMCA tower.

A Study on Dynamic Behavior of Natural Draft Cooling Tower Considering the Effect of Soil-Structure Interaction

In this present era, the technology in advanced construction has developed to a very large extent. Some parts of the constructions are still in the improving stage which includes Cooling tower Construction. Hyperbolic cooling towers are large, thin shell reinforced concrete structures which Contribute to power generation efficiency, reliability, and to environmental protection. Cooling towers use evaporation of water to eject heat from processes such as cooling the circulating water used in oil refineries and in power plants. Nowadays in many thermal power plants, we can see the Cooling tower. So, preserving this industrial structure is an effort to save the cooling tower from dangerous earthquakes. The present-day cooling towers are exceptional structures in view of their sheer size and complexities. Present paper deals with the study of dynamic response that is modal analysis, seismic analysis of the two different cooling towers varying the H/t ratio and thicknesses with fixity at the base boundary condition, and the soil is modelled as raft for the effect of soil-structure interaction using the direct approach. In this paper, hyperbolic cooling towers are modelled using Ansys software, which is a Finite element Software. Results show that the soil-structure interaction effect significantly modifies the earthquake behavior of Hyperbolic Cooling towers.

The Hulks of a 19th-Century Cowes Ketch and a Lighter at Centenary Quay, Woolston, Southampton

The redevelopment of the former Vosper Thornycroft shipyard in Woolston, Southampton led to the discovery of two hulks of 19th-century vessels in remarkable states of preservation. The craft have been identified as those of a Cowes Ketch (also known as a Solent Barge) and a lighter or dumb barge. These are rare examples of local workboats whose numbers, once relatively large, have declined to presumed extinction within the last century. This article presents a summary of the results of the archaeological investigations of the hulks before and after their removal in advance of the construction of a 27-storey tower overlooking the River Itchen.

THE OVERSIZED CARGO FORWARDING: ECONOMIC AND LEGAL ASPECTS

The transport of oversized cargo is becoming more and more popular, which is related to the construction of, inter alia, wind farms to generate electricity in mountain areas or on the coast of the Baltic Sea. Internet communication networks are expanding, thus requiring the construction of new relay towers. Non-divisible elements to be transported are getting longer and more difficult to be delivered and installed in the field. All this must be met by forwarding and transport of industrial long cargo. Such a situation requires specialized vehicles, monitoring and optimization of travel routes.

Internet Connectivity: Is Free Space Optics the Solution?

During the Coronavirus disease 2019 pandemic era, poor internet availability hampered online activity, particularly in the sector of education in Malaysia. The most effective way to address this situation is through the construction of telecommunications towers. However, it takes time due to the significant costs involved. Outdoor use of FSO appears to be more advantageous due to the absence of licensing requirements and the high bandwidth it offers. However, there are limitations. We will explore these FSO restrictions in this paper.

Countermeasures analysis of landslide in the cikeusal village of Tasikmalaya regency

The construction of telecommunication towers aims to improve customer service. So that advances in the field of communication and information technology can be felt by residents who are far away in remote parts of the country. The construction of this tower must be planned as well as possible, especially for areas prone to landslides because towers are usually placed in higher areas. The landslide incident at the location of the telecommunication tower in Cikeusal Village, Tasikmalaya Regency can be used as an evaluation for other areas prone to landslides. The landslide can endanger the settlements under the tower. Field investigations are carried out as a basis for making plans to overcome landslides. The analysis was performed using Plaxis 2D software. The results of the strengthening analysis after the erosion prevention were carried out (with several stage), the factor of safety was 1.805 at section B and 3,228 at section C. The recommendations are given for landslide prevention are replacing the old retaining wall with the new one gradually, adding a column in the middle of the retaining wall, adding bored piles under the retaining wall, making drain pipe on the retaining wall to accommodate water flow from the ground surface, replacing the old stairs for access roads that were affected by landslides with new stairs and made with 2 applications so that the slope of the stairs is not too steep, as well as making a foundation for the stairs. It is hoped that the landslide occurrence and the results of the analysis of slope stability in Cikeusal Village, Tasikmalaya Regency can be used as evaluation material in the construction of telecommunication towers for landslide-prone areas.

Re‐evaluation and extension of fatigue test data for welded attachments and butt joints

AbstractWelded structures under fatigue loading are widely used in civil engineering. The fatigue strength of components such as welded attachments and butt joints are often determining for the dimensioning of bridges, crane runways or tower constructions. The existing design rules of Eurocode 3, Part 1‐9 are mainly based on experimental data. However, the experimental background of Eurocode 3 Part 1‐9 is partly incomplete. Some fatigue detail classifications are based on numerical modelling and engineering judgement. New findings from experimental research allow a revision of these details, leading to higher fatigue strength classifications in many cases.Firstly an overview of an extensive database for fatigue tests on butt joints and welded attachments is addressed. A method for statistical analysis is presented, which allows the consideration of fatigue tests from different sources by using the design philosophy of Eurocode 3 Part 1‐9 and also meeting the requirements of Eurocode 0.The paper is also going to present some new supplementary experimental investigations on a fatigue detail for transverse end welds of cover plates with blended weld toes, which is traditionally used in German bridge design.Finally a revised and simplified fatigue detail catalogue for welded attachments and butt joints is addressed which is intended as a suggestion for the next generation of Eurocode 3 Part 1‐9.

Construction Key Techniques of Upper Cross-beam for Main Tower of Super-Kilometer Span Rail-cum-Road Suspension Bridge

As the span of the suspension bridge increases, the height of the main tower and the force on the tower increase. The beam profile volume and pouring weight become larger, which increases the risk of high-altitude construction of the main tower and the upper cross beam. The main bridge of Wufengshan Changjiang River Bridge of Lianzhen Railway is the first rail-cum-road suspension bridge in China. The main span reaches 1092m and the total height of the tower is 191.5m. Taking the engineering practice of the upper cross beam of the main tower of Wufengshan Changjiang River Bridge of Lianzhen Railway as an example, this paper introduces the construction difficulties of the upper cross beam of the main tower, the selection of the upper cross beam construction support, the structural characteristics of the support and the construction process. The upper cross beam is constructed asynchronously with the tower. From the bottom of the upper cross beam to the top of the lower cross beam is 121.5m. The upper cross beam was poured in six times with a total concrete volume of 1918m3. The method of small trusses with bracket and floor steel pipe support is used for construction. The finite element analysis software is used to calculate the super-high support of the upper cross beam, and the support strength, rigidity and stability meet the requirements of the specification. At present, the bridge has been partially put into use, which verifies the rationality of the design and construction of the beam support on the main tower. It has strong reference and guiding value.

Development of a transition piece for a self‐erecting wind energy plant

AbstractFor the construction of wind towers with large hub heights up to 200m, the FOSTA research project P1392 HYTOWER [1] investigated a concept for a self‐erecting wind energy plant with steel‐steel hybrid tower. A tubular steel tower is lifted inside a lattice tower using a strand lifting system. During this process the tubular steel tower is stabilized by hydraulic cylinders. A specially developed transition piece is used to accommodate the lifting system during the lifting process and to finally connect the two tower parts. In this paper, the erection process as well as the development of the transition piece is presented.

ANALYTIC HIERARCHY PROCESS BERBASIS TRIANGULAR INTUITIONISTIC FUZZY NUMBER UNTUK PEMILIHAN SUPPLIER BAHAN KONSTRUKSI TOWER

Supplier selection is the process of finding the right supplier, at the right price, at the right time, in the right quantity, and with the right quality. However, it is not easy to identify a good supplier because it requires the fulfillment of several predetermined criteria. In the midst of the Covid-19 pandemic, it has had an impact on carrying out all activities online, for example in work and education. Therefore, the internet today is very influential on everyday life. Thus causing many areas that are still not reached by the internet requires to be able to meet these needs. One way to reach the internet is to build a tower in the area. For this reason, it is necessary to select the right supplier of tower construction materials, at the right price, at the right time, in the right quantity, and with the right quality in tower construction. The purpose of this article is the selection of suppliers of tower construction materials with several predetermined criteria. The method used in this research is Analytic Hierarchy process (AHP) based on Triangular Intuitionistic fuzzy number (TIFN). The Analytic Hierarchy process (AHP) is an effective approach to dealing with multi-criteria decision problems. From these calculations, the best supplier ranking of tower construction materials is vendor B with an overall priority score for the alternative 0.336309 then for the second and third ranked suppliers, respectively, vendor A and vendor C with the overall priority score for the alternative 0.333114 and 0.330577.
 Keywords: Supplier selection; Analytic Hierarchy process (AHP); Triangular Intuitionistic fuzzy number (TIFN).