Construction Of Tower Research Articles

COMPARATIVE STUDY OF FOUR LEGGED SELF-SUPPORTED ANGULAR TELECOMMUNICATION TOWER ON GROUND AND MOUNTED ON ROOF TOP

Due to increase in demand, huge number of telecommunication towers has been built in India during last few decades with the compulsion to provide efficient communication. Consequently, telecommunication sector in the country has expanded rapidly. Expanding base possesses challenges to mobile operators in terms of augmenting and upgrading infrastructure to uphold to excellence of services. A rapidly rising subscriber and a more rigorous band allocating organization may create a higher requirement of tower sites for operators to accommodate more subscribers. Hence it became an expensive and tedious task to spot ample land for construction of towers. This led to the extensive use of the rooftop of multi-storeyed buildings for installing communication towers. Formerly the majority of the buildings were not cautious to carry a roof top tower, however owing to the altered needs; buildings were rehabilitated to carry roof top towers. In this report analysis of 4 legged angular self-supporting telecommunication towers is performed. Assessment is done based on modal analysis, by comparing the results of roof top tower and ground based tower. In support of this intention, two 4 legged self-supporting telecommunication towers of 24m and 21m are modeled on roof top of a building and on the ground, considering the effects of wind loads as per Indian condition. Effects of wind on towers are employed from the IS 875 (Part 3)-1987 by using STAAD pro finite element software. The tower and building is analysed by placing towers at centre of roof. Axial forces experienced by the structures too have been obtained

Limiting distribution and error terms for the number of visits to balls in non-uniformly hyperbolic dynamical systems

We show that for systems that allow a Young tower construction with polynomially decaying correlations the return times to metric balls are in the limit Poisson distributed. We also provide error terms which are powers of logarithm of the radius. In order to get those uniform rates of convergence the balls centres have to avoid a set whose size is estimated to be of similar order. This result can be applied to non-uniformly hyperbolic maps and to any invariant measure that satisfies a weak regularity condition. In particular it shows that the return times to balls is Poissonian for SRB measures on attractors.

Introduction to a quantitative method for assessment of visual impacts of Tehran Towers

Landscape arrangement significantly influences observer’s visual experience of the environment. Since measuring this qualitative experience is more based on personal judgments than mathematical techniques, representing “quantifying methods” in this field demands a significant amount of caution and accuracy. This research is an attempt to quantify visual impacts of seven-story- and higher-buildings on observers’ view of Tehran’s district 3 from 1993 to 2006. For this purpose observers’ visibility of the surrounding landscape was calculated for 17 random points of the region, at 1.5 and 10 m, before and after construction of towers in that period by use of Geographical Information System (GIS, Arcmap V.9.2). The result of this research indicates that visibility of citizens of Tehran has decreased from 13% in 1993, after construction of 12 towers, to 45% in 2006 after construction of 255 towers. The objective of this research was to assess the visual impacts of structures on landscape and to attempt to clarify the necessity and importance of applying Visual Impact Assessment (VIA), among other environmental assessments in new urban developments. Key words: Landscape, geographic information system (GIS), viewshed, visibility, building, regional planning, visual impact assessment.

Modeling in SolidWorks and analysis of temperature and thermal stress during construction of intake tower

With a focus on the intake tower of the Yanshan Reservoir, this paper discusses the method of modeling in the 3D CAD software SolidWorks and the interface processing between SolidWorks and the ANSYS code, which decreases the difficulty in modeling complicated models in ANSYS. In view of the function of the birth-death element and secondary development with APDL (ANSYS parametric design language), a simulation analysis of the temperature field and thermal stress during the construction period of the intake tower was conveniently conducted. The results show that the temperature rise is about 29.934 °C over 3 or 4 days. The temperature differences between any two points are less than 24 °C. The thermal stress increases with the temperature difference and reaches its maximum of 1.68 MPa at the interface between two concrete layers.

Hysteresis in column systems

In this paper one column of a telescopic construction of a bell tower is investigated. The hinges at the support of the column and at the connecting joint between the upper and lower columns are modelled with rotational springs. The characteristics of the springs are assumed to be non-linear and the hysteresis property of them is represented with the Preisach hysteresis model. The mass of the columns and the bell with the fly are concentrated to the top of the column. The tolling process is simulated with a cycling load. The elements of the column are considered completely rigid. The time iteration of the non-linear equations of the motion is evaluated by the Crank-Nicolson schema and the implemented non-linear hysteresis is handled by the fix-point technique. The numerical simulation of the dynamic system is carried out under different combination of soft, medium and hard hysteresis properties of hinges.

The Timber Tie Beam: The Analysis of Spatial Framework Joint

The popularity of timber buildings is increasing at the moment. Timber is used as a main material for constructions of buildings, bridges and towers. Especially halls or office buildings need a construction of roof made by tie beams. Using of steel fasteners is quick, cheap and secure solution of joints in timber frame construction. There was a requirement for visible tie beam. For this reason the special joints by nogs were created, to design aesthetical and secure construction. This work studies a spatial frame work of unique timber tie beams. Their construction is engineered by four beams in two mainstreams. The critical point in the construction is a spatial joint in the cross of the beams. Therefore the FEM models have been created. The FEM results are compared with a real load test, performed on a real timber model. That way, we were able to monitor the critical spatial joint.

输电线路大型铁塔组立专用塔式起重机的设计与优化

针对输电线路工程铁塔塔材重、塔身高、就位难度大、安装精度要求严、施工环境复杂、安全风险大的特点，综合考虑重量、可操控性、施工效率、场地占用等因素，开展专业化设计，研制成功输电线路组塔大型专用塔式起重机，采用单动臂上回转结构、装配式基础、平衡重系统、分片式标准节、下顶升机构、自拆卸施工等先进的技术方案，具有施工效率高、安全性好、场地和人员占用少等优点，满足了特高压工程铁塔的组立施工需要，已在特高压电网施工中得到广泛应用。 Transmission line tower has the features of tower material weight, tower height high, difficulty in installation, high accuracy, complicated installation, complex construction environment and grave risk. Comprehensive consideration of weight, maneuverability, construction efficiency, site occu-pancy and other factors, to carry out professional design, the large special tower crane used for the large tower of transmission line is successfully developed. The special tower crane adopts the advanced technological scheme such as single jib, the top rotary structure, the assembling founda-tion, the balanced weight system, the chip standard section, the under jacking mechanism and the self-removal function. The special tower crane has the advantages of high efficiency, good safety, small space and personnel, etc. The special tower crane meets the need of the construction of the special high pressure engineering tower, and has been widely used in the construction of UHV power network.

The mobilization of aluminum into the biosphere.

Aluminum is currently the most widely used non-ferrous metal, and its extraction and purification from geological stores exceeds that of any other metal except iron (1, 2). In 2013, global primary aluminum production was ~52 million tons (104 billion pounds) or about 15 pounds for very person on the earth (1–4). The global outlook for aluminum demand from developing countries such as Brazil, China, India, and Indonesia is rapidly increasing, due to new applications for aluminum and aluminum alloys in infrastructural support, transportation including automobiles, aviation and aerospace applications, electrical transmission, and the generation of energy, including catalytic zeolites in the petroleum and petrochemical industries (5). Interestingly, the largest “machine” built by humankind is the domestic and international networks for the transmission of electricity. Although traditionally-used copper has a higher electrical conductivity, aluminum is only slightly less so, being lighter, more ductile, and less expensive; aluminum is now widely used for both high-voltage tower construction and the electrical transmission wires themselves (2–5). It has been estimated that within the next 10 years aluminum production will exceed that of the previous 150 years (1–3). This prolific de novo generation of aluminum combined with its highly efficient recycling means this metal is becoming increasingly present in our biosphere, defined as the sum of all ecosystems and living organisms on the earth. This short “Opinion” paper will overview and comment on the current massive mobilization of aluminum into the earth’s biosphere.

오픈소스를 활용한 사건 아카이브 구축에 관한 연구 - 밀양 송전탑 건설 갈등 사건을 사례로 -

The purpose of the study is to implement the digital archives to document environmental conflicts using open source Omeka. Mi-ryang Transmission Tower Construction Conflict is the selected case because it is very crucial and continues until today for more than 10 years. It begins with analyzing domestic and international cases of archives developed using Omeka. Based on these analysis, it draws the directions of developing Mi-ryang archives. It also investigates and analyzes the Mi-ryang conflicts as the contexts of records creation, acquire the actual records from a Mi-ryang civic group, and finally implement the collections and exhibits of Omeka-based archival system.

Cross effects and calculus in an unbased setting

We study functors F from C_f to D where C and D are simplicial model categories and C_f is the full subcategory of C consisting of objects that factor a fixed morphism f from A to B. We define the analogs of Eilenberg and Mac Lane's cross effects functors in this context, and identify explicit adjoint pairs of functors whose associated cotriples are the diagonals of the cross effects. With this, we generalize the cotriple Taylor tower construction of [10] from the setting of functors from pointed categories to abelian categories to that of functors from C_f to D to produce a tower of functors whose n-th term is a degree n functor. We compare this tower to Goodwillie's tower of n-excisive approximations to F found in [8]. When D is a good category of spectra, and F is a functor that commutes with realizations, the towers agree. More generally, for functors that do not commute with realizations, we show that the terms of the towers agree when evaluated at the initial object of C_f.

Delivering the Emirates Air Line, London, UK: design and construction of the steel main towers

This paper presents the design, fabrication and erection process of the three main towers of the Emirates Air Line cable car, which spans the River Thames in London, UK. The towers consist of geometrically complex arrangements of a circular hyperboloid shaft topped by a tapering elliptical hyperboloid head. The shafts are formed of interlocking, alternatively and differently pitched, spiralling, doubly curved, structural steel plate elements of varied typologies. The paper presents the extraordinary technical demands including the plate forming process, the complex array of loadings, the nature of the wind responses investigated including impacts of aerodynamic effects from cyclic wind loading, specific requirements for advanced connection stiffness modelling to ensure the extremely tight movement criteria, the challenges of erection over the river Thames and the details of site assembly to tight tolerances. This paper is one of a series of four which describe the delivery of the Emirates Air Line project.

Research and Application of Multi-Properties Concrete

Multi-properties concrete (MPC) contains the properties as follows: self-compacting, self-curing, heat dissipation at low water content; low shrinkage; high plasticity keeping and high durability. We applied the concept of “multi-properties concrete” (MPC) during the construction of the West Tower and East Tower both at Guangzhou and Jinji Complex at Shenzhen. The multi-properties concrete is more effective in controlling cracks of concrete, while it is a new type concrete with properties of green and low carbon.

Delivering the Emirates Air Line, London, UK: north and south stations

The Emirates Air Line provides a low-emissions, quick, direct and fully accessible link between the north and south sides of the River Thames in London, UK, and is the easternmost pedestrian crossing of the river. The route runs from Emirates Victoria Dock station (north station) on the north side of the Thames to the Emirates Greenwich Peninsula station (south station), constructed on remediated brownfield land. The cableway runs between the two stations over three major steel towers and two subsidiary ‘compression' towers positioned just in front of each station. This paper – one in a series of four that describe the delivery of the Emirates Air Line project – describes the challenges that were faced in the design and construction of the stations and the compression towers. These challenges included construction of the north station over water in the Royal Victoria Dock, the design of the south station in very close proximity to the alignment of the proposed Silvertown tunnel, coordination of the station structure with the complex mechanical and electrical equipment required for the operation of the cableway systems, and construction of the compression towers to the very tight installation tolerances and operational deflection limits mandated by the specialist subcontractor.

Observed Performance of the One Museum Park West Excavation

AbstractGround movements observed during foundation installation and basement construction of a residential 53-story RC tower are presented. The One Museum Park West building is located in Chicago, Illinois, and was developed using a combination of bottom-up methods, used for the construction of a central concrete core of the building, and top-down methods to build five levels of basements. The excavation extended 13–15 m below grade and was made through soft to medium-stiff clays. The building was supported by drilled shafts and a perimeter wall formed by secant piles that transitioned to tangent piles below the bottom of the cut. The system was laterally braced with RC floor slabs structurally connected to the secant pile walls and the RC core. Field performance data were collected by means of settlement points and inclinometers located close to the walls on two sides of the excavation. The construction sequence and attendant ground movements during each main activity are summarized. As much as 160 mm o...

The Research for Assembling Double Circuit Steel Tube Tower with New inside Pulling Wire

Double Circuit Steel Tube Tower has a large size structural and a heavy weight of components, so the construction of tower becomes more difficult. This article uses the Midas software to simulate the Process of Inside Pulling Wire for Double Circuit Steel Tube Tower erection in windy weather and no windy weather, Researching the influence of the new lifting system and the original lifting system on the whole of lifting system. Through the stress analysis and simulation formajor rigging, we can know which lifting ways can be used when the horizontal displacement of the derrick has or has not strict restrictions, or the lifting weight has been restricted when the Wind load is too strong. New lifting system can lift very heavy tower material and has little affect by windy weather, especially suite for assembling large size structural and heavy weight of components tower.

First hyperbolic times for intermittent maps with unbounded derivative

We establish some statistical properties of the hyperbolic times for a class of non-uniformly expanding dynamical systems. The maps arise as factors of area preserving maps of the unit square via a geometric baker’s map-type construction, exhibit intermittent dynamics, and have unbounded derivatives. The geometric approach captures various examples from the literature over the last 30 years. The statistics of these maps are controlled by the order of tangency (linked to a single parameter α, where 0 < α < ∞) that a certain ‘cut function’ makes with the boundary of the square. Previously, a direct Young tower construction has been used to obtain optimal correlation decay rates of O(n−1/α) for Hölder observables and all values of the parameter α. A central limit theorem (CLT) is obtained when 0 < α < 1.The asymptotics of a natural hyperbolic time for this family of maps are analysed via the same Young tower. By using a large deviations result of Melbourne and Nicol, we prove that the first hyperbolic time is integrable if and only if the parameter satisfies 0 < α < 1. Furthermore, within this restricted range of parameters, concentration inequalities recently established by Chazottes and Gouëzel imply sharp O(n−1/α) bounds on the tail distribution of first hyperbolic times. As shown by Alves, Viana, and others, knowledge of the tail distribution of the hyperbolic times leads to upper bounds on the rate of decay of correlations and derivation of a CLT. Comparing to the results obtained directly for this family of maps, the latter estimates via hyperbolic times are suboptimal, even over the restricted range of parameters 0 < α < 1.

Construction issues affecting the intended acoustical environment of a new court tower

The proficiency to readily identify and resolve construction issues in the field is vital to realizing intended acoustical design goals. In court facilities, inattention to such construction details can result in problematic reductions in speech privacy for confidential deliberations, negotiations, and attorney discussions, structure-borne noise intrusion from holding areas to noise-sensitive spaces, and diminished speech intelligibility in courtroom proceedings. This paper considers examples of acoustics and noise control issues arising during the construction of a new court tower, discussion of their potential effects on the acoustical environment, and methods of addressing these field conditions.

Collective Fall Protection for Construction Workers

Construction safety regulations require protection of workers against falls from elevations. The collective fall protection systems, in most cases, allow workers to move freely without wearing individual fall protection gear. The collective systems which prevent falls are preferred over the fall arrest systems. The latter are employed only if prevention of falls is not feasible. Arresting a fall always carries with it a residual risk of injury to the fall victim. The collective fall arrest systems are employed primarily during construction of electricity or telecomm towers. The aim of this paper has been a review of the collective FPS employed in the construction industry.

Modeling and prediction of the strength based on the time factor in tower construction

On the basis of the documentation, the finite element beam model of the Shukhov’s tower has been constructed. In 1970–1971, after 50 years of exploitation, the study of the Shukhov’s tower was conducted by the specialists. This study has revealed serious defects of the individual elements. It was found that the rolled profiles reaches 10 % of the cross section due to corrosion and the calculated resistance of the individual components is in the range of 170 MPa, which is somewhat lower than the standard values. In the present work the time factor is taken into account as a reduction of the wall thickness of the metal profiles. In this article the state of the stress under the own weight has been examined when the wall thickness corresponds documentation (1921) and after reducing the thickness by 2 mm (2011). Stability analysis has been performed taking into account only the compressive load from the own weight. In this paper the main frequencies and modes of vibration of the tower model, depending on the thickness of the profile wall have been calculated. The results were obtained under the assumption that the loss of thickness of the metal profiles of the tower is accompanied by the proportional loss of the own weight.

ESTIMATING CELLPHONE SIGNAL INTENSITY &amp; IDENTIFYING RADIATION HOTSPOT AREA FOR TIRUNELVELI TALUK USING RS AND GIS

The increased uses of mobile phones have raised pub lic interest in possible health issues associated w ith exposure to electromagnetic energy. For the speedy transmission and avoiding th e construction of more towers, the single tower can be shared by multiple network operators. The simultaneous exposure to multiple fr equency fields, the sum of all the radiation must b e taken into consideration so the radiation intensity level exceeds by several times than the prescribed guideline. Hence, the public is being exposed to continuous, low intensity radiations from these towers. Present Sur vey has been designed to identify signal strength a mong the people dwelling near the base station. Signal Strength predicted by inte gration of NDVI methodology is taken into account f or factors like trees, trunks, leaves, branches, their density and their heights r elative to the antenna heights and also it has been calculated by both theoretical and practical. In this regard the present study, practi cal field investigations of existing towers have be en done by using SCEPTOR (Mobile GIS/GPS receiver). These GPS data fed to GIS for cr eating a new layer along with DEM file and satellit e image for creating virtual model.3D city model has been performed for the stud y area. Finally the radiation hotspot area has been identified by using viewshed analysis.