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1
M, Ensari Yigit, Anil Ozdemir, Fethi Sermet e Murat Pinarlik. "Analysis of Offshore Wind Turbine Towers with Different Designs by Finite Elements Method". International Journal of Advanced Research in Engineering 4, n. 3 (25 settembre 2018): 1. http://dx.doi.org/10.24178/ijare.2018.4.3.01.
Testo completoAbstract (sommario):
It is known that the use of renewable energy has an increasing trend in whole world. Wind energy is one of the renewable energy types, as well is among the cleanest and most economical energy sources. Nowadays, in order to provide much more energy from wind, turbine towers are being built higher and the turbine blades have begun to be manufactured longer. Due to these applications, tower and turbine weights are continuously increasing. For this reason, it is necessary to optimize the materials used as well as the dimensions of the turbine towers. In the present study, behavior of TLP floating wind turbine towers with three different designs under wave, hydrostatic and static loads were investigated. In order to clarify the effect of these loads, turbine designs were analyzed in the ratio of 1/5 using finite elements method. Steel, reinforced concrete and hybrid (reinforced concrete and steel) wind turbine towers tied to sea floor at a depth of 10 meters rigidly by TLP floating method. In this context, 10-meter-high turbine towers having three different designs which static analyzed previously were used for investigate effects of wave and hydrostatic loads. Turbine structures analyzed with ABAQUS finite elements model. The deformations and stress values of underwater turbine structures were obtained and compared with each other. As it can be seen from analysis results, compared to the reinforced concrete design, the displacement of steel tower design decreased 77.84%. It is seen that the torsion effect was dominant in the steel tower design. However, the decreasing displacement value for steel design was recorded as 44.43% compared to the hybrid tower design.
2
Gong, Yikai, e Martin Noël. "Finite Element Model of Concrete-Filled, Fiber-Reinforced Polymer Tubes for Small-Scale Wind Turbine Towers". CivilEng 5, n. 1 (2 febbraio 2024): 169–90. http://dx.doi.org/10.3390/civileng5010009.
Testo completoAbstract (sommario):
The finite element method was used to study the feasibility of concrete-filled, fiber-reinforced polymer tubes (CFFTs) for small-scale wind turbine towers in remote areas. Although CFFTs have been successfully employed for a variety of structural applications, their use for wind turbine towers is novel and has yet to be investigated in detail. The objective of the study was to identify, for the first time, the most important parameters for design and compare the behavior of CFFT towers versus conventional steel and concrete towers. The model was first validated using experimental results reported in the literature followed by a series of parametric studies to evaluate the importance of several key parameters. In the first phase, the effect of different geometric properties (taper and concrete filling ratio) and reinforcement configurations (FRP laminate configuration, steel reinforcement ratio, and prestressing level) were investigated for cantilever tower models with concentrated lateral loads. A 10 m high CFFT wind turbine tower model was subsequently modeled and studied under different loading configurations. The influence of the height-to-diameter (h/D) ratio on cantilever CFFT models was also studied and a conservative preliminary design that can be refined for specific turbine systems and wind conditions was adopted using the h/D ratio. The CFFT tower model was compared to concrete and steel tubular models with similar geometry to study the advantages of CFFT towers and showed that CFFTs can be an efficient alternative.
3
Shchedrolosiev, O., O. Uzlov e K. Kyrychenko. "IMPROVING CONSTRUCTIVE AND TECHNOLOGICAL CONNECTING JOINTS OF REINFORCED CONCRETE PONTOON WITH A TRANSVERSE DIAPHRAGM AND A METAL TOWER IN A FLOATING COMPOSITE DOCK". Scientific Bulletin Kherson State Maritime Academy 1, n. 22 (2020): 142–52. http://dx.doi.org/10.33815/2313-4763.2020.1.22.142-152.
Testo completoAbstract (sommario):
The analysis of the known technical decisions in dock construction field, rationalizing production resources at composite docks construction is given. It is established that the available solutions do not specify the recommendations for lowering the metal content in the reinforced concrete pontoon of composite floating docks. As a result of the conducted research, the design of floating composite docks was improved by reducing sets in the reinforced concrete pontoon. The rationality of a pontoon design construction without installation of frames, floors, and beams under towers is substantiated. Technological recommendations for the transverse partitions installation between the inner boards in 4 spaces, i.e. in 3 meters in contrast to the classical design in which the distance between the partitions is 1.5 meters, were described. The analysis of the design features of the reinforced concrete pontoon connecting joints with the transverse diaphragm and the metal tower of the floating composite dock is carried out, the difficulties that arise are described. The design and technological recommendations for the construction of the reinforced concrete pontoon joints with the transverse diaphragm and the metal tower have been developed. The floating dock construction sequence and technological operations ensuring concrete’s strength, water tightness and frost resistance at intersection joints are described. Solutions that increase the local adhesion of concrete to cross-shaped parts and prevent its exfoliation have been developed. The traditional scheme of the composite dock construction and a structural joint of a metal tower with a reinforced concrete pontoon is given. The composite dock construction scheme and the construction scheme of the joints of the reinforced concrete pontoon with the transverse diaphragm and the metal tower, which are designed for the construction of floating composite docks with reduced metal content in the pontoon, have been improved.
4
Gong, Cheng Lin, Hua Liu e Jian Zhang. "Study on Dynamic Properties of the Intake Tower with Finite Element Method". Applied Mechanics and Materials 501-504 (gennaio 2014): 1888–91. http://dx.doi.org/10.4028/www.scientific.net/amm.501-504.1888.
Testo completoAbstract (sommario):
Intake tower is a complex structure, which has complex boundary conditions and has complex loading situation. Intake tower is made up of reinforced concrete ,which is thin-wall hollow structure. It builds in the near the shore in the reservoir, its top bridge connects to the banks of the river, The tower is in the water and is under pressure, intake towers safety is very important under the action of earthquake. Based on the large finite element software ANSYS, the dynamic properties of the intake tower is studied, and the intake tower+ foundation is also studied. The research conclusions can be used as reference for engineering design.
5
Wen, Yang, e Fei Zhou. "Time-History Analysis of Seismic Response for the Concrete-Filled Steel Tubular Wind Turbine Tower Based on Finite Element Method". Advanced Materials Research 163-167 (dicembre 2010): 2176–80. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.2176.
Testo completoAbstract (sommario):
In the article based on the geometric characteristics of the tower and force characteristics, the author designs the concrete-filled steel tube (CFST) 3 limbs column tower, and establishes finite element model of the tower. We carry on time history analysis of the concrete-filled steel tubular wind turbine tower based on finite element method when the earthquake wave is different. Under rare earthquake, the majority bars of the concrete-filled steel tube 3 limbs column tower are in the elastic stage, only a small number of bars in the top and the bottom are into the plastic phase. The post-seismic displacement at the top of tower is 1.1m which is slightly less than the tower height of 1 / 50 (1.26m) and meets the seismic requirements of the region. The analytical result may provide the foundational test data and advice for the design of the CFST wind turbine tower.
6
Apcarian, Anabel, Gabriel Contreras, Juan Manuel Labriola e Emmanuel Quiróz. "Comparison of Alternatives for Multi-MW Wind Turbine Towers in Northern Patagonia, Argentina". Buildings 14, n. 7 (4 luglio 2024): 2045. http://dx.doi.org/10.3390/buildings14072045.
Testo completoAbstract (sommario):
The Patagonian region of Argentina has great wind potential. In this geographical area of complex terrain, the local wind is influenced by the proximity of the Andes Mountain chain, and it is very intense and turbulent. The wind profiles, turbulence intensity, and average wind speeds at the site do not meet the recommended values in the standards. This issue could have a significant impact on the design loads for structures installed in the region. The objective of this work was to compare the behavior under extreme wind load on different types of towers for multi-MW wind turbines in situ. For this, a hybrid tower, a concrete tower, and a steel tower of equal dimensions were compared. Additionally, we analyzed the influence of the cross-sectional shape of concrete on hybrid towers. The flow pattern around the structures was studied using a solid wall model. As for the towers, we implemented a stress–strain elastic analysis. We calculated the stress fields, displacement fields, and aerodynamic behavior for each tower. We conclude that hybrid towers present the most optimal behavior. Among the different cross-sectional shapes analyzed for this type of tower, we found that all of them show advantages and disadvantages, with the circular section being the one that has the highest average performance from the resistance and aerodynamic standpoint.
7
Li, Bin, Qun Hui Zhang e Chun Yan Gao. "Numerical Simulation on the Mechanical Performance of the Wind Generator Latticed Concrete-Filled Steel Tubular Tower". Applied Mechanics and Materials 578-579 (luglio 2014): 751–56. http://dx.doi.org/10.4028/www.scientific.net/amm.578-579.751.
Testo completoAbstract (sommario):
Nonlinear finite element parameters analysis on the lattice type steel pipe concrete wind turbine tower, it shows the entire process of load bearing, failure mode and ultimate bearing capacity, researches on the influence law of aspect ratio, form of tower webs, tower diameter to thickness ratio and web member stiffness to tower column stiffness ratio on the ultimate bearing capacity and tower failure mode. The finite element analysis results shows that the tower aspect ratio λ, the diameter-thickness ratio γ of tower columns and the increase of stiffness ratio β between web members and tower columns has great influence on ultimate bearing capacity and failure mode, while the form of webs has small influence on that. with the increase of tower aspect ratio λ, the decrease of diameter-thickness ratio γ of tower columns and the increase of stiffness ratio β between web members and tower columns, the ultimate bearing capacity of this kind of latticed towers increase, the failure mode changed from Web local buckling to The combined damage of Web local buckling and the tension tower yield. This paper suggests that in the design of wind turbulent generator tower, the tower aspect ratio λ should be best controlled at 1/9, the bottom layers of this kind of tower should best use the re-divided web members, and other web member forms used on above layers, the diameter-thickness ratio γ of tower column should be taken less than 30, and the stiffness ratio β between webs and columns should be controlled less than 0.05 in order to avoid damage occurring on the tower columns earlier than the webs. The results can provide evidence for the engineering design.
8
Belov, Vyacheslav, Evilina Galieva e Roman Verkhovskiy. "Technical and economic assessment of the possibility of using a thermal and moisture protection screen to increase the resistance of the reinforced concrete cooling tower shell to operational conditions". BIO Web of Conferences 107 (2024): 06017. http://dx.doi.org/10.1051/bioconf/202410706017.
Testo completoAbstract (sommario):
During the operation of chimney-type evaporative cooling towers which are made of monolithic reinforced concrete, the shell is exposed to various aggressive environmental influences and the carried-away part of the recycled process water leading to its premature destruction. This article illustrates a method of protecting the shell tower of a reinforced concrete cooling tower from the aggressive effects of the operating environment using a thermal and moisture protection screen design – a ventilated curtain wall with a cladding of fiberglass sheets. By the finite element method, using the ANSYS PC, a calculated analysis of temperature values and air velocity in the air gap was performed, resulting in the geometry of the air gap. To assess the overall change in the percentage of reinforcement, the corresponding strength calculations of the cooling tower shell were made with and without a thermal and moisture protection screen. Subsequently, the corresponding technical and economic analysis of the proposed design option was carried out. As a result the use of thermal moisture protection screen allows significantly redact capital costs during the construction of new cooling towers and decrease expenses for periodic major repairs in the operational cycle, thereby increasing the durability of the cooling tower.
9
Gain, Akash Asim. "Seismic Response Evaluation for Gate-Type Twin Tower Reinforced Concrete Frame Structure". International Journal for Research in Applied Science and Engineering Technology 12, n. 5 (31 maggio 2024): 5358–69. http://dx.doi.org/10.22214/ijraset.2024.62801.
Testo completoAbstract (sommario):
Abstract: As the population increases tremendously the horizontal space in urban areas are insufficient to construct a building so it is very essential to go for vertical construction. In this research The 11 storey gate type twin tower reinforced concrete frame building having the top three floors horizontally connected is analyzed by using finite element modeling software. By using linear static and dynamic analysis, the seismic responses are computed and compared for various models such as twin towers without any connection, twin towers with one-way connection, and a gate-type twin tower structure with the top three floors connected. It examines storey drift, displacement, and base shear in seismic zone III on medium soil. The results finds that structural responses to the gate building show both decreases and slight increases when compare to without connected buildings. So By connecting twin tower buildings, not only is an innovative architectural design achieved, but a roadway between the towers can also be provided., In addition, the horizontal space at the top floors after connecting the towers can also be used for residential, commercial, and office accommodation purposes.
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Vamsi Krishna, B., P. Sudheer Kumar, Kurma Chandana, Shyamala Bhoomesh e P. Venu Gopal. "Comparative Analysis & Design of RCC & Steel Preheater Tower Structure by Using STAAD. Pro". IOP Conference Series: Earth and Environmental Science 1130, n. 1 (1 gennaio 2023): 012025. http://dx.doi.org/10.1088/1755-1315/1130/1/012025.
Testo completoAbstract (sommario):
Abstract A liquid material after water concrete is the most consuming material in the world, concrete is the most important construction material used extensively to construct buildings, dams, roads, etc. As we know that concrete is a composite material with cement, coarse & fine aggregates bonding together with water that gives hardness with time. As per the 2018 year statistics, India is the second largest producer of cement in the world with 460 million tonnes per year which is over 8% of the global installed capacity. Cement is the most important material in concrete, In India, at present, there are 120 major cement plants and nearly 300 mini cement plants are manufacturing the cement. In Cement plants ‘Preheater tower’ is used, these preheater tower consists of several cyclones, these raw materials are fed at the top of the preheater tower through cyclones it travels to the bottom of the preheater tower, each cyclone in the preheater serves as a heat exchanger and a separate. In this project, a comparative analysis & design will be done between both the RCC structure & Steel structure Preheater tower as per Indian design standards by using Staad Pro software. In this design process, the loads which are affecting the structure will be taken and designed. And also the pros & cons will be discussed between the RCC & Steel structure Preheater tower. Here the height of the RCC and steel Preheater tower taking as 110 meters. It is observed that Maximum displacements at a height of 110 mts in RCC preheater tower are 130.59 mm and Steel preheater tower is 102.238 mm. The Maximum Moment at critical load combination is more in RCC preheater tower (i.e 205.6 kN.m) than Steel preheater tower (i.e 190.1 kN.m).The Maximum shear at critical load combination is more in Steel preheater tower 62.0 kN is more than RCC preheater tower 28.7 kN.
11
Xiong, Zhi Hua, Yun Cheng Feng, Song Lin Song e Jiang Bo Wang. "Optimization Design of Large Span Cable-Stayed Bridge in High Seismic Risk Zone". Applied Mechanics and Materials 353-356 (agosto 2013): 2015–19. http://dx.doi.org/10.4028/www.scientific.net/amm.353-356.2015.
Testo completoAbstract (sommario):
To ensure seismic safety of a large span cable-stayed bridge, two alternative pylon shapes and section types were studied. Nonlinear time history analysis was performed in the context. It is found that the A-shaped pylon is much stiffener than the H-shaped pylon in terms of deformation. The steel A-shaped pylon can significantly reduce the seismic demands of the key member including tower drift and moment. A ductile steel link between towers is proposed for the optimization of design in the paper. The A-shaped reinforced concrete tower with ductile steel link was proved to be a relatively balanced plan considering engineering, aesthetic and economic factors.
12
Zhu, Chun Xia, Sheng Qing Gu e Jiu Fu Jin. "Research on Design of Inner-Climbing Tower Crane Supporting System". Applied Mechanics and Materials 328 (giugno 2013): 338–42. http://dx.doi.org/10.4028/www.scientific.net/amm.328.338.
Testo completoAbstract (sommario):
Safety is essential for tower cranes in construction engineering, as the inner-climbing tower crane is widely used in the construction of high-rise structures, design safety, reliability and support system which can be turnover is an important prerequisite for protecting the safety of construction. By understanding the interrelationships between construction environment of Henglong Plaza Twin Towers in Shenyang city and ZSL2700 tower, the article will analyse the support system for the project. It mainly uses finite element analysis software ANSYS which can create mechanical status of modeling to analyzing the supporting structure. It can guarantee the structures rationality and the security reliability. Project Summary Shenyang municipal government square tower engineering which building height is 350.6m has the underground layer 4 and the ground 70 layer. The office building has used the frame core tube structure system. The outside frame is composed by the square shape section coagulation earth pyramid and the peripheral steel girder. The rectangular core tube was the reinforced concrete, while in the core tube outer wall has established some steel pole. This project adopt two boom tower cranes from Zhongsheng construct machine company (Nanjing).The first number tower crane is ZSL750, which maximum torque is 750tm; the second number tower cranes is ZSL2700. This paper takes the ZSL2700 tower crane as an object, studying this machines stressful condition of attachment system. The ZSL2700 tower cranes most high-torque is 2600tm, pitching arm angle ranges 85-65 .The maximum lifting load is 100t. The biggest hoisting up scope is 55m, which lifting load is 37.6t.When the crane surpasses the permission lifting load or the hoisting up moment of force, PLC can break the power implementation protection automatically. The tower machine need carry on 19 climbs in the construction process. Fig. 1 Two tower crane installation location diagram
13
Ma, Xin Wei, Sen Zeng, Chong Hai Dong, Zhi Yu e Guan Qi Huang. "Design of Assembled Post-Tensioned Prestressed Reactive Powder Concrete Wind Turbine Tower". Advanced Materials Research 1055 (novembre 2014): 38–43. http://dx.doi.org/10.4028/www.scientific.net/amr.1055.38.
Testo completoAbstract (sommario):
This paper proposes a new type of assembled post-tensioned prestressed reactive powder concrete (RPC) turbine tower structure. It includes the structure design of 200kW wind turbine tower according to the specifications, calculation of loading combinations and internal force, checking calculation of bearing capacity, prestressed concrete design and calculation of reinforcement. Local stress applied on the structure is analyzed by the finite element software of ANSYS, and the calculation results show that the bearing capacity calculation of RPC tower satisfies the requirements, and it is economical comparing with the traditional steel structures.
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Xu, Yan, Zeng Zeng, Cunyu Cui e Shijie Zeng. "Practical Design Method of Yielding Steel Dampers in Concrete Cable-Stayed Bridges". Applied Sciences 9, n. 14 (17 luglio 2019): 2857. http://dx.doi.org/10.3390/app9142857.
Testo completoAbstract (sommario):
Restrained transversal tower/pier–girder connections of cable-stayed bridges may lead to high seismic demands for tower columns when subject to earthquake excitations; however, free transversal tower/pier–girder connections may cause large relative displacement. Using an energy dissipation system can effectively control the bending moment of tower columns and the relative tower/pier-girder displacement simultaneously, but repeated time history analyses are needed to determine reasonable design parameters, such as yield strength. In order to improve design efficiency, a practical design method is demanded. Therefore, the influence of yielding strength at different locations is studied by using comprehensive and parametric time history analyses at first. The results indicate that yielding steel dampers can significantly reduce the bending moment at tower columns and the relative pier–girder displacement due to the system switch mechanism during the vibration. Meanwhile, the yielding steel damper shows its general effect on reducing relative displacement between all piers/tower columns and the main girder as well, with only a localized effect on controlling seismic induced forces. Furthermore, a practical design method is proposed for engineering practices to determine key parameters of the yielding steel damper.
15
Guang, Ming, Hong Sheng Li e Hua Guo Yang. "New Technology of Installing the Attached Self-Climbing Tower Steel Gantry Cranes". Applied Mechanics and Materials 484-485 (gennaio 2014): 245–53. http://dx.doi.org/10.4028/www.scientific.net/amm.484-485.245.
Testo completoAbstract (sommario):
The Liujiaxia Bridge is 536 m span steel truss stiffening Girder Bridge, tower with double-column steel concrete structure, which is the world's largest diameter, the largest steel plate thickness of concrete pylon. Sarasota manufactured using standard pipe segment, group fight scene segment piecewise hoisting tower segment perfusion within the micro-expansion concrete construction technology, tower maximum height of 61.5 meters. This paper describes a piecewise Sarasota steel installation, piecewise perfusion within the micro-expansion concrete tower new construction method - attached to a self-climbing tower bridge gantry crane mounted pylon construction technology of large steel components. Of the "entity attached to the pylon installation of equipment by section climb" design, composition and construction applications are described in detail.
16
Ma, HongWang, e Ran Meng. "Optimization design of prestressed concrete wind-turbine tower". Science China Technological Sciences 57, n. 2 (16 gennaio 2014): 414–22. http://dx.doi.org/10.1007/s11431-013-5442-8.
Testo completo
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Zhang, Ming, e Heng Le Wang. "Construction Simulation and Construction Speed Analysis of Natural Draft Cooling Towers". Applied Mechanics and Materials 353-356 (agosto 2013): 3559–65. http://dx.doi.org/10.4028/www.scientific.net/amm.353-356.3559.
Testo completoAbstract (sommario):
Using the finite element code ABAQUS and taking account of the wind load reduction, this paper presents a set of construction simulation methods of concrete cooling towers. A natural draft cooling tower at Taishan nuclear power station in Guangdong province, China, under three speeds of construction is simulated. Displacement and stress distributions of the cooling tower in the different construction stages are obtained. Some interested parts of the cooling tower are analyzed in detail and the variations of displacements and stresses of these parts with the construction are concluded. A comparative study of the influence of construction speed on displacements and stresses is performed as well. The analyses and proposals of this paper may be used as reference to the cooling tower design and construction.
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Zhang, Ming, e Heng Le Wang. "Global and Local Stability Checking Method of Natural Draft Cooling Towers during Construction". Applied Mechanics and Materials 353-356 (agosto 2013): 3009–14. http://dx.doi.org/10.4028/www.scientific.net/amm.353-356.3009.
Testo completoAbstract (sommario):
Checking the global and local stability of cooling towers during construction is very important to construction safety and reasonable construction process. On the basis of existing researches and by combining the checking method of global and local stability of cooling towers in operation period given in the present design code, this paper presents a method with implementation steps to check the global and local stability of cooling towers during construction. The method is verified to be simple and effective by a cooling tower example. The example analysis indicates that the global stability of cooling towers decreases with the construction height and achieves the minimum when the topmost layer is just built, though it increases bit when all concrete layers reach the design strength. The local stability of cooling towers during construction is poor in the range of 1/5 to 3/5 tower height and should be paid great attention during construction.
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Mamin, Aleksandr N., Kirill V. Avdeev, Vladimir V. Bobrov, Aleksandr V. Reutsu e Aleksej B. Chaganov. "Strength characteristics of load-bearing reinforced concrete structures of the Ostankino television tower". E3S Web of Conferences 410 (2023): 02021. http://dx.doi.org/10.1051/e3sconf/202341002021.
Testo completoAbstract (sommario):
The article describes the design features of the Ostankino TV tower in Moscow. The main results of the earlier works of the load-bearing reinforced concrete structures of the TV tower column and foundations are presented in the article. The authors examined the internal and external surfaces of reinforced concrete structures of the entire height of the tower with selective defectoscopy and determined the actual strength of concrete by non-destructive methods. The figures of this work show the main structural reinforced concrete elements and a distribution graph of strength characteristics of the height of the structure. Despite the noticeable height changes, the concrete strength in all parts exceeds the value provided for in the project.
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LIU Jinlong, e LI Changhua. "A Design of Fabricated Concrete Foundation for Tower Crane". International Journal of Advancements in Computing Technology 5, n. 6 (31 marzo 2013): 934–44. http://dx.doi.org/10.4156/ijact.vol5.issue6.110.
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Lin, Feng, e Qiheng Zhong. "Mitigation of Ground Vibration due to Collapse of a Large-Scale Cooling Tower with Novel Application of Materials as Cushions". Shock and Vibration 2017 (2017): 1–14. http://dx.doi.org/10.1155/2017/6809246.
Testo completoAbstract (sommario):
Ground vibration induced by the collapse of large-scale cooling towers in nuclear power plants (NPPs) has recently been realized as a potential secondary disaster to adjacent nuclear-related facilities with demands for vibration mitigation. The previous concept to design cooling towers and nuclear-related facilities operating in a containment as isolated components in NPPs is inappropriate in a limited site which is the cases for inland NPPs in China. This paper presents a numerical study on the mitigation of ground vibration in a “cooling tower-soil-containment” system via a novel application of two materials acting as cushions underneath cooling towers, that is, foamed concrete and a “tube assembly.” Comprehensive “cooling tower-cushion-soil” models were built with reasonable cushion material models. Computational cases were performed to demonstrate the effect of vibration mitigation using seven earthquake waves. Results found that collapse-induced ground vibrations at a point with a distance of 300 m were reduced in average by 91%, 79%, and 92% in radial, tangential, and vertical directions when foamed concrete was used, and the vibrations at the same point were reduced by 53%, 32%, and 59% when the “tube assembly” was applied, respectively. Therefore, remarkable vibration mitigation was achieved in both cases to enhance the resilience of the “cooling tower-soil-containment” system against the secondary disaster.
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Yao, Xie. "The Analysis of Wind Power Generation Tower Based on SSI Effect". Applied Mechanics and Materials 333-335 (luglio 2013): 1500–1503. http://dx.doi.org/10.4028/www.scientific.net/amm.333-335.1500.
Testo completoAbstract (sommario):
With the development of wind turbines trend of single machine but large capacity, and with the concrete wind-turbine tower has many advantages such as corrosion resistance, high stability, convenient manufacture in-site and lower maintenance cost, concrete tower will have more and more wide prospect. Application of large finite element software FINAL, the main research is the influence of SSI effect on wind power tower natural vibration frequency. We can know that SSI effect is very important for wind power tower natural vibration frequency. So we can not ignore the influence of the interaction between soil and structure. We should pay more attention to this actor when we design or analyse a wind power tower.
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Yan, Yi Zhi, Chang Xin Xiong, Xiao Cheng Wen e Wei Hong Li. "Structure Seismic Analysis on Intake Tower of Spillway Tunnel". Advanced Materials Research 1065-1069 (dicembre 2014): 1427–32. http://dx.doi.org/10.4028/www.scientific.net/amr.1065-1069.1427.
Testo completoAbstract (sommario):
According to a intake tower of spillway tunnel established the intake tower structure—water—foundation 3-D finite element model for seismic analysis, by the response spectrum method in original design seismic parameters and new parameters of the project on horizontal and vertical dynamic response of the intake tower. The results shown that the structure of maximum dynamic stress concentration appeared near the junction of the tower with backfill concrete, where the weak parts of seismic, used the new seismic parameters calculated show greater damage on the tower, but couldn’t overturn, meet the seismic design requirements.
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Lupi, Francesca, Hans Juergen Niemann, Claudio Borri e Udo Peil. "Design of Solar Towers for Extreme Storm Conditions and for Vortex Excitation". Applied Mechanics and Materials 283 (gennaio 2013): 35–39. http://dx.doi.org/10.4028/www.scientific.net/amm.283.35.
Testo completoAbstract (sommario):
The structure of Solar Updraft Towers is basically a circular cylinder, which may turn into a hyperboloid at lower levels in order apply benefits of shape strengthening. The height of the tower is up to 1.5 km and it is usually designed as a thin reinforced concrete shell. The wind action is the main natural hazard, which plays a decisive role for the feasibility of the technology. An extensive wind tunnel investigation has been recently performed at WiSt laboratory at Ruhr-University Bochum (Germany) and at Criaciv laboratory at University of Florence (Italy). The tests highlighted in no-efflux conditions (out-of-use of the power plant) a new phenomenon egarding cross-wind loads, induced by a bi-stable and asymmetric flow distribution. It is created by compartments between stiffening rings along the tower and enhanced by a strong interaction with free-end flow structures at the top of a finite length circular cylinder. A proper positioning of the rings should allow to avoid this phenomenon.
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Magomedov, Marsel A. "Efficient surface foundations for power lines". Journal «Izvestiya vuzov. Investitsiyi. Stroyitelstvo. Nedvizhimost» 11, n. 3 (2021): 440–45. http://dx.doi.org/10.21285/2227-2917-2021-3-440-445.
Testo completoAbstract (sommario):
Surface foundations help improve the mechanical performance of transmission towers. In this work, we examined and identified the most effective structures of surface foundations to be used as trans-mission towers. In the study, general scientific methods were used: comparison, analysis, observation, synthesis, generalisation, systematisation, modelling, as well as the graphical presentation of the re-sults obtained. In the course of the work, the most common structures of surface foundations were considered – lattice poles and concrete blocks. An efficient design of a surface foundation with an in-creased bearing area and a rational position of reinforced concrete main girder have been proposed, which allows the strain in the support nodes, the pressure under the foundation bed and the defor-mation of the foundation blocks to be reduced. This design is recommended as a transmission tower to be used on soft soils.
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Wen, Yang. "The Study on Force Behavior of Concrete Filled Steel Tube Lattice Wind Turbine Tower with Three Limb Columns". Applied Mechanics and Materials 178-181 (maggio 2012): 179–83. http://dx.doi.org/10.4028/www.scientific.net/amm.178-181.179.
Testo completoAbstract (sommario):
This paper refers to currently the 1.5MW cone tube type wind-driven generator tower, design the model of the concrete-filled steel tube wind turbine tower with three limb columns, and research on the force performance, such as the change of internal force, the process of failure, hysteretic behavior, bearing capacity, ductility and energy dissipation capacity by the pseudo-static experiment on the scale model of wind turbine tower. The study shows that the P- hysteretic curve of lattice concrete-filled steel tube wind-driven generator tower with three limb columns is asymmetric, relatively full “spindle” and the phenomenon of “knead shrink” is not obvious, which account for it has good force behavior and energy dissipation capacity. This kind of tower structure, of which the reverse bearing capacity is greater than the positive, and the reverse ductility coefficient is less than the positive, indicates that it’s reverse plastic deformation ability of the tower structure is weaker than it’s positive.
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Čajka, Radim. "Analysis of Prestressed Concrete Tower for Wind Turbine Generator". Advanced Materials Research 772 (settembre 2013): 622–29. http://dx.doi.org/10.4028/www.scientific.net/amr.772.622.
Testo completoAbstract (sommario):
In the paper is presented a parametric study on possibilities of designing and realizing a prestressed reinforced concrete tower for a wind turbine, WEG 400, as an alternative solution replacing a steel structure. WEG 400 is a generation of a double-blade wind turbine with the rotor diameter of 36.7 m. Key design criteria include extreme static/dynamic loads, cyclical loading and natural frequency. The supporting structure of the tower needs to be easy to dispose from prefabricated prestressed concrete elements.
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Li, Shu Jin, Xiao Yu Xu, Wen Jie Lu e Yi Gang Fu. "Non Shrinkage Self-Compacting Steel Box Concrete Application in a Landscape Tower". Advanced Materials Research 919-921 (aprile 2014): 164–68. http://dx.doi.org/10.4028/www.scientific.net/amr.919-921.164.
Testo completoAbstract (sommario):
According to the design and construction characteristics of steel box concrete girder of a large landscape tower, C40 grade non shrinkage self-compacting concrete meeting engineering requirements was produced. The fresh concrete workability, early age shrinkage are researched, construction technology and detection methods are discussed combined with the practical engineering of steel box concrete girder.
29
Zong, Xiang, e Xiang Wang. "Research on Thermodynamical Performance of Concrete with Excessive Fly Ash Added in the Pile Cap of Well Tower". Advanced Materials Research 243-249 (maggio 2011): 6087–92. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.6087.
Testo completoAbstract (sommario):
To meet the demand of high performance of mass concrete in a pile cap of well tower, excessive replacement of fly ash was applied to the mass concrete. Based on the theory of hydration heat of cement, several thermal parameters of mix proportion were analyzed and simulated test analyses and setting time test analyses were conducted in the laboratory. The results and data collected in the project locale both show that applying excessive replacement of fly ash reduces hydration heat of mass concrete in the pile cap of well tower, which extends setting time in mass concrete and avoids the cracks caused by temperature stress. The results achieve favorable effect and provide reference for design and construction of mix proportion in the project of mass concrete.
30
Oishi, Tsuguo, e Yasuo Inokuma. "Aesthetic Design of Odawara Port Bridge". Transportation Research Record: Journal of the Transportation Research Board 1549, n. 1 (gennaio 1996): 108–13. http://dx.doi.org/10.1177/0361198196154900116.
Testo completoAbstract (sommario):
The Odawara Port Bridge is located at the mouth of Odawara Port. Selecting a bridge type that symbolized the entire project and blended well with the surrounding area was critical. To achieve this, an extra-dosed prestressed concrete box girder with a main span of 122 m was selected. Construction of this bridge type is the first in the world. Special characteristics of this bridge type are a lower tower height than that of a cable-stayed bridge, the use of a saddle at the top of the towers, and the incorporation of epoxy-coated strands for diagonal cables. The design of the various sections of the bridge was achieved by integrating the characteristic shape of the towers with cable profiles while establishing horizontal continuity with the main girder. As a result of the integration process, the following design objectives were adopted: (a) constant main girder depth; (b) inverted trapezoidal main girder cross section; (c) towers without a connecting beam at the top; (d) a fan-shaped saddle; (e) compact cable vibration dampers; (f) graded metallic coloring of cables; (g) integrated steel railing and road surface lighting; (h) nighttime bridge lighting, and (i) encased drainage pipes.
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GAMA, P. V. C. N., e T. N. BITTENCOURT. "Economic viability of ultra high-performance fiber reinforced concrete in prestressed concrete wind towers to support a 5 MW turbine". Revista IBRACON de Estruturas e Materiais 10, n. 1 (febbraio 2017): 1–14. http://dx.doi.org/10.1590/s1983-41952017000100002.
Testo completoAbstract (sommario):
Abstract The Ultra-High Performance Fiber-Reinforced Concrete is a material with remarkable mechanical properties and durability when compared to conventional and high performance concrete, which allows its use even without the reinforcement. This paper proposes the design of prestressed towers for a 5 MW turbine, through regulatory provisions and the limit states method, with UHPFRC and the concrete class C50, comparing the differences obtained in the design by parametric analysis, giving the advantages and disadvantages of using this new type of concrete. Important considerations, simplifications and notes are made to the calculation process, as well as in obtaining the prestressing and passive longitudinal and passive transverse reinforcement, highlighting the shear strength of annular sections comparing a model proposed here with recent experimental results present in the literature, which was obtained good agreement. In the end, it is estimated a first value within the constraints here made to ensure the economic viability of the use of UHPFRC in a 100 m prestressed wind tower with a 5 MW turbine.
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Indriūnas, Saulius, Romualdas Kliukas e Algirdas Juozapaitis. "Behavioral Analysis of a Mast with a Combined Prestressed Stayed Columns System and Core of a Spun Concrete Circular Cross-Section". Buildings 13, n. 9 (27 agosto 2023): 2175. http://dx.doi.org/10.3390/buildings13092175.
Testo completoAbstract (sommario):
Widely used telecommunication structures are usually of the tower or mast type. For medium and tall telecommunications structures, tower-type constructions become less efficient compared to mast-type structures. The goal of our article is to discover a new, efficient telecommunication structure. For relatively low heights, tower systems can be designed with a continuous cross-section, in most cases using reinforced concrete elements. Among them, efficient spun concrete elements, whose load-bearing capacity is higher than that of ordinary solid reinforced concrete elements due to the technological features of their production, should be mentioned. A significantly higher efficiency of masts can be achieved by employing various combined structural systems that utilize a prestressed stayed columns system. It should be noted that there are not many solutions for prestressed stayed columns systems with spun concrete core elements and that research into their design and behavior is not yet sufficiently developed. The behavior of this combined structure is analyzed with regard to the geometric and physical nonlinearity of its elements. The strength and stability of the spun concrete core of such a combined system are evaluated. The impact of the prestressing of this prestressed stayed column structure on the internal forces and displacements of the reinforced concrete core is analyzed. The performance of the new structure compared to conventional tower and mast structures is presented. In the article, it has been determined that by applying the prestressed stayed columns system to telecommunication structures, the innovative structural system becomes 2.5 times more efficient than the classic mast and 5 times more efficient than the typical tower system on the mass criterion.
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HLADYSHEV, Hennadii, Dmytro HLADYSHEV e Roman ZHURAVLOV. "ESTIMATION OF VARIABILITY OF STEPS OF ARMATURE IN A MONOLITHIC REINFORCED CONCRETE COVER OF A TOWER INDUSTRIAL CONSTRUCTION". Building constructions. Theory and Practice, n. 9 (28 dicembre 2021): 45–53. http://dx.doi.org/10.32347/2522-4182.9.2021.45-53.
Testo completoAbstract (sommario):
The work considers one of the possible reasons for reducing the operational reliability of monolithic thin-walled load-bearing reinforced concrete structures of existing industrial structures in relation to their design solution. As this reason is considered the variability of distances between axes of cores of working inspectedarmature of such designs is quite common.Comparison of design solutions with the qualityof construction and installation work makes it possible to identify the influence of unaccounted factors in the design of monolithic thin-walled reinforced concrete structures, which reduce their serviceability due to variability of concrete strength characteristics and actual longitudinal and transverse reinforcement due to variability of workingsteps. While processing the results of the survey ofmonolithic reinforced concrete thin-walled structures, which perceive the efforts of different levels,the question arises: which step of the working reinforcement, from a large number of actually measured steps, to choose in verified calculations –average or maximum, with extras.In the current norms, an indicator as the averagevalue of concrete strength for the calculation ofreinforced concrete monolithic slab structures doesnot appear, but is used as a statistically reasonablevalue of concrete strength, which takes into account its normalized variability with 95% security.Regulatory documents statistically estimates thevariability of reinforcement strength. At the sametime, they do not take into account the variabilityof the actual reinforcement of monolithic reinforced concrete structures, which is the subject forreconstruction of additional loads, but they aremade without observing the design distances between the reinforcement in these structures.When performing verified calculations of suchstructures for different design situations, to develop working designs for overhaul, reinforcement,reconstruction or dismantling, it is necessary todetermine which actual step of the working reinforcement should be taken with other defined design parameters of the structure.The authors instrumentally investigated and statistically analyzed the data of reinforcement of themonolithic reinforced concrete shell of the towerstructure, which made it possible to reasonablyaccept the values of the reinforcement steps in thetest calculations.
34
Sun, Weiwei, Dina D’Ayala, Jinxing Fu, Wentao Gu e Jun Feng. "Seismic vulnerability assessment of a high-rise molten-salt solar tower based on incremental dynamic analysis". E3S Web of Conferences 194 (2020): 01005. http://dx.doi.org/10.1051/e3sconf/202019401005.
Testo completoAbstract (sommario):
This paper investigates the seismic performance of a high-rise molten-salt solar tower by finite element modelling. The integrated and separated models for solar tower based on the concrete damage plastic model are validated by matching the behaviour of similar reinforced concrete chimney specimens. The modal analysis demonstrates the first four modes of the solar tower are translational vibration. Seismic simulations are developed through the incremental dynamic analysis. The most disadvantageous position of the tower is all concentrated in the opening section under multidirectional seismic excitations. The top displacement of the tower under bidirectional and three-directional earthquake actions is larger than that under unidirectional earthquake actions. The results of the seismic vulnerability assessment show that when the PGA equals to 0.035g, the tower will be intact; when the PGA equals to 0.1g (design peak ground acceleration), the probability of the moderate damage state is within 1.5%; when the PGA equals to 0.22g (maximum considered earthquake), the probability of the destruction state is below 0.7%. The seismic partitioned fragility analysis of the tower under multidirectional earthquake excitations illustrates that there are two peaks in the vulnerability surfaces. The anti-collapse analysis indicates the tower has a good seismic performance under multidirectional seismic excitations.
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Spoth, Thomas, Dyab Khazem e Gregory I. Orsolini. "New Carquinez Bridge, Northeast of San Francisco, California: Technological Design Advancements". Transportation Research Record: Journal of the Transportation Research Board 1740, n. 1 (gennaio 2000): 40–48. http://dx.doi.org/10.3141/1740-06.
Testo completoAbstract (sommario):
The new Carquinez Strait Bridge, northeast of San Francisco, California, will be the first major suspension bridge to be constructed in the United States since the second Chesapeake Bay Bridge in Maryland in 1973. It will replace an existing steel cantilever truss bridge, built in 1927, that was found to be seismically inadequate. The new bridge consists of an orthotropic closed steel box girder superstructure, two main cables 512 mm (20 1/8 in.) in diameter, reinforced concrete towers, and gravity anchorages. The design has set a new standard in modern suspension bridge design in the United States, particularly with respect to seismic safety. Some of the key elements of the design that are discussed are the global design loading criteria for long-span suspension bridges, the design of allowable stresses in main cable wire, the state-of-the-art design detailing of critical welded connections, the finite-element analysis approach for the box girder to determine the actual plate stresses and stress concentrations, and the design of the reinforced concrete tower leg sections for enhanced ductile seismic performance.
36
Li, Jian Ping, Jie Ruan, Pin Tan e Xian Jun Wang. "Simulation Analysis and Structure Optimization of Steel Structure Climbing Formwork with Material Properties Used in the Large Angle Leaning Bridge Tower". Applied Mechanics and Materials 540 (aprile 2014): 201–4. http://dx.doi.org/10.4028/www.scientific.net/amm.540.201.
Testo completoAbstract (sommario):
Steel structure climbing formwork has been widely used in bridge pier and bridge tower, etc. But the design of 30 degrees slope climbing formwork design is rarely involved. The climbing formwork which in the upper surface of leaning bridge tower is affected by concrete buoyancy and the downside is affected by concrete gravity .That cause insufficient stiffness,deformation of the template,non-uniform cross-section of the bridge and large angle deviation which have great harm to the bridge quality .This paper which combined the construction project of Huaibei Xiangwang Bridge establish the mode of climbing formwork, then, import the mode to the Workbench14.5 proceeding simulation analysis. Getting the stress and deformation of the climbing formwork, check the strength and stiffness .Then optimize the structure of climbing formwork to ensure the stiffness and control the deformation of the template. The stress of downside climbing formwork after optimization is uniform and maximum stress is reduced about 30% .This paper provide a reference to the design of the climbing formwork used in the large angle leaning bridge tower.
37
Madina, Bulatova, e L. N. Gumilyov. "Determination of the Most Effective Location of Environmental Hardenings in Concrete Cooling Tower Under Far-Source Seismic Using Linear Spectral Dynamic Analysis Results". Journal of Research in Science, Engineering and Technology 8, n. 1 (29 settembre 2020): 22–24. http://dx.doi.org/10.24200/jrset.vol8iss1pp22-24.
Testo completoAbstract (sommario):
The feeling of the need to build longer cooling towers increases with the development of the capacity of hydropower plants. So the engineers are trying to design leaner towers, with more buckling resistance using environmental hardening rings. Several studies have investigated the effect of wind strength on these structures, but the effect of seismic acceleration on these structures has been less studied. In this study, by investigating the results of linear spectral dynamic analysis, the optimum location of environmental hardening rings is determined under the influence of earthquake acceleration. The effect of thickness and number of hardening rings on the performance of the tower is also investigated, and the optimum relationship between these two parameters is extracted technically and economically. Different analytical methods can be used to investigate this issue, but using the spectral analysis method besides considering the buckling effects of the tower crust is the most appropriate analytical method for these types of structures.
38
Ju, Yan Zhong, Dong Xu Yu e Wang Dehong. "A Study of the Partially Prestressed Tendons RPC Concrete Pole Connection Design". Applied Mechanics and Materials 166-169 (maggio 2012): 534–37. http://dx.doi.org/10.4028/www.scientific.net/amm.166-169.534.
Testo completoAbstract (sommario):
In order to study and solve the problem of connection on the part of the prestressed tendons RPC concrete pole engineering. Design connecting flange suitable for the existing part of the prestressed tendons RPC concrete pole developed by our group used the connection flange in Steel tower as the prototype.Through the ABAQUS software to establish the finite element model between the connection flange and part of the prestressed tendons RPC concrete pole, and carry out finite element analysis.Through the finite element analysis to get results whether the design of connecting flange can meet the strength requirements when the prestressed tendons RPC concrete pole is under ultimate load, so to get the practical design method of the 500kv part prestressed RPC concrete pole connecting flange.
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Kim, Sungwon, Jung Joong Kim e Taek Hee Han. "Section Design of Internally Confined Hollow Reinforced Concrete Wind Power Tower". Journal of Korean Society of Hazard Mitigation 16, n. 4 (31 agosto 2016): 163–74. http://dx.doi.org/10.9798/kosham.2016.16.4.163.
Testo completo
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Liang, Peng, Xiang Nan Wu e Yue Xu. "Static and Dynamic Behaviours of Three-Tower Suspension Bridges and the Structure Selection of the Mid-Tower". Advanced Materials Research 163-167 (dicembre 2010): 2343–49. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.2343.
Testo completoAbstract (sommario):
In order to discuss the mechanical behaviour differences between the two-tower and three-tower suspension bridges, based on the Taizhou Yangtze River Bridge, three dimensional space finite element models of two-tower, three-tower with concrete mid-tower and with steel mid-tower were constructed. Through the comprehensive analysis, main conclusions are got as follows: due to the mid-tower lack of effective restraint from side cable, compared with two-tower suspension bridges, three-tower suspension bridges have lower total stiffness and natural frequency, with larger deflection-to-span ratio of main girder. So, some factors such as anti-slipping safety factor between the main cable and saddle, deflection-to-span ratio of main girder and force in mid-tower, which are not important in two-tower design, become controlling ones in three-tower suspension bridges. These factors are related to anti-pushing rigidity of mid-tower, but in contradictory demanding for the rigidity of mid-tower. After comprehensive analysis, steel tower with shape of upside-down ‘Y’ meets all demands, and then, was selected as appropriate structure for the mid-tower.
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Halabian, Amir M., e M. Hesham El Naggar. "Effect of foundation flexibility on seismic response of reinforced concrete TV-towers". Canadian Journal of Civil Engineering 28, n. 3 (1 giugno 2001): 465–81. http://dx.doi.org/10.1139/l01-014.
Testo completoAbstract (sommario):
The analysis of tall reinforced concrete TV-towers is commonly simplified by assuming a fixed base and ignoring the effect of soilstructure interaction. However, the foundation flexibility affects the dynamic characteristics of tall structures and influences their dynamic behaviour. To design these towers for dynamic loading, the fundamental natural periods, base bending moment, and base shear force as the most important parameters are needed and must be evaluated properly. In the current study, a finite element formulation for the response analysis of TV-towers subjected to earthquake ground motion accounting for soilstructure interaction is presented. The effects of foundation flexibility on the dynamic behaviour of TV-towers were evaluated for two different types of foundation, shallow footing and deep foundation, and various soil profiles. A typical example for these towers is analysed and the results for a range of soil dynamic parameters are presented. It was found that the foundation flexibility increases the natural periods, alters the natural mode shapes, and decreases the base bending moment. It was also concluded that the effect of soilstructure interaction may have a large effect on the base shear of the tower and should be considered in the analysis, especially for the design of horizontal reinforcement.Key words: soilstructure interaction, TV-towers, natural period, base forces, foundation flexibility.
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Kanvinde, Amit, Peter Maranian, Leonard Joseph e Jeff Lubberts. "Fracture and Fatigue Design of the Wilshire Grand Tower". Engineering Journal 55, n. 3 (30 settembre 2018): 181–89. http://dx.doi.org/10.62913/engj.v55i3.1134.
Testo completoAbstract (sommario):
The 1,100-foot Wilshire Grand Tower in Los Angeles owned by the Hanjin Group is the tallest building in the United States west of Chicago. The building, whose architect is AC Martin Inc., has a slender elevation in one direction, necessitating the use of heavy steel box columns filled with concrete on the perimeter, connected to the concrete core with outrigger trusses. The building has a slender, 272-ft-tall spire, also constructed from steel plates. The height and slenderness of the tower, as well as the spire, and its location in a seismically active zone motivated comprehensive analysis to mitigate the risk of steel fracture within a performance-based design framework. This analysis includes the following components: (1) development of acceptance criteria for earthquake-induced fracture, especially when it may follow years of wind-induced fatigue crack growth; (2) wind tunnel testing; (3) linear and nonlinear time-history simulations to determine stress demands in critical components under appropriate wind and seismic hazards; and (4) fracture mechanics simulations to characterize trade-offs among various design variables to meet the acceptance criteria. The analysis indicates that wind-induced oscillations have the potential to grow fatigue cracks in some components, affecting their performance during a subsequent maximum considered earthquake. This situation is unusual for steel buildings, being the result of the extraordinary height, geometry, heavy steel members, and location of this particular building. The analysis also indicates that fracture risk may be successfully mitigated through existing design and detailing approaches and acceptance criteria, along with use of steel material exhibiting high, but commercially available and affordable, specified Charpy V-notch toughness values.
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Ba, Ling Zhen, Yi Bo Yang, Song Liang, Hai Hong Mo, Hong Cao, Ting Jin Liu e Jun Sheng Chen. "Progress in Study of Concrete Pumping Construction Techniques in Super High-Rise Building". Key Engineering Materials 405-406 (gennaio 2009): 110–16. http://dx.doi.org/10.4028/www.scientific.net/kem.405-406.110.
Testo completoAbstract (sommario):
To super high-rise building, concrete pumping construction is an inevitable choice. This paper introduces the application status and development trend of concrete pumping construction in the super high-rise projects at home and abroad, introduces high-rise pumping concrete from the selection of raw material, mix design, performance evaluation and so on, sums up technical specification of concrete pump and pumping concrete pipe-laying method, in order to provide reference for the high-rise concrete pumping construction in Guangzhou West Tower.
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Zong, Xiang. "Research on the Application of Slipform Concrete of Well Tower in winter". Applied Mechanics and Materials 204-208 (ottobre 2012): 3703–6. http://dx.doi.org/10.4028/www.scientific.net/amm.204-208.3703.
Testo completoAbstract (sommario):
To meet the demand of performance of slipform concrete in a well tower in winter, different blend ratios of early strength water reducing agents were added to the concrete. Compared with reference concrete, their setting time test analyses, workability analyses and tests of mechanical performance and removal of forms were conducted in the laboratory. The results show that concrete with FS-A early strength water reducing agent can greatly improve early strength of concrete and meet the demand of relevant performance of slipform. This research may provide reference for design of mix proportion and construction in similar slipform project.
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Guner, Serhan, e Jean Carrière. "Analysis and strengthening of caisson foundations for uplift loads". Canadian Journal of Civil Engineering 43, n. 5 (maggio 2016): 411–19. http://dx.doi.org/10.1139/cjce-2015-0350.
Testo completoAbstract (sommario):
Many existing self-supporting towers are built with constant-width caisson foundations. Due to the increased demand to add more antennas to the towers, and more stringent strength requirements in recently revised design standards, many existing caisson foundations require significant strengthening for additional uplift resistance. Although a number of retrofit design solutions are frequently used in practice, there is a lack of literature providing guidelines for the proper analysis of retrofitted foundations. This study proposes a detailed analysis and design methodology to significantly increase the uplift capacity of existing caissons through the use of helical micro piles and reinforced concrete cap beams. Strut-and-tie models are developed and nonlinear finite element analyses are undertaken to verify the behaviour of the proposed design. The overall design methodology is presented in a case study involving an existing tower. The proposed design has a general applicability and is suitable for applications where there is limited space around the existing foundations.
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Xiong, Tie Hua, e Shu Guo Liang. "Limit Wind Loads of a Concrete Filled Steel-Tube Transmission Tower". Applied Mechanics and Materials 105-107 (settembre 2011): 1697–704. http://dx.doi.org/10.4028/www.scientific.net/amm.105-107.1697.
Testo completoAbstract (sommario):
Limit wind loads of a Concrete Filled Steel-Tube (CFST) transmission tower in a long-span tower-line system is computed. Firstly, fine Finite Element Method (FEM) model of the tower and its Multiple-Degrees-Of-Freedom (MDOF) model are built and the material nonlinear models including steel-tube and CFST are also modeled. Secondly, based on MDOF model, mean displacements under mean wind force are evaluated and the Root Mean Square Displacement (RMSD) under fluctuating wind force is also evaluated by random vibration theory. Then, Equivalent Static Wind Loads (ESWL) are computed considering the first three order modes. Finally, based on FEM model, the nodes are loaded by the ESWL and the nodal loads increase step by step in order to impel materials into plastic status until calculation can not converge. Plastic analysis shows the tower’s failure is caused by steel-tube element failure and the CFST elements have enough strength reserve. The tower’s three kinds of limit wind loads are computed based on different references and it is suggested to select the limit wind loads, whose corresponding wind velocity is 69.7m/s, as the design limit wind loads of the tower.
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He, Yun Jun, Wei Tai, Jin Zhong Zhou, Guan Jun Zheng e Yao Bi. "Synthesis of Polycarboxylate Superplasticizer for High Strength Concrete and Application in Tianjin Goldin 117 Mega Tower". Applied Mechanics and Materials 438-439 (ottobre 2013): 87–93. http://dx.doi.org/10.4028/www.scientific.net/amm.438-439.87.
Testo completoAbstract (sommario):
A new type of polycarboxylate superplasticizer with high dispersibility was synthesized by the method of free radical polymerization and the hydrothermal reaction. The synthetic process optimized the influencing factors of reaction had been discussed, including proportion of acid and ether, reaction temperature, initiator concentration, heat preservation time and additive. The dispersibility of new product was superior under the condition of low water/cement ratio, testing by gel permeation chromatography and C60 self-compacting concrete. The new product had already been used in Tianjin Goldin 117 Mega Tower project. The performance of C70 fresh mixed self-compacting concrete, which was added with new product, was very excellent in Tianjin Goldin 117 Mega Tower project, and was satisfied with the design code for high-strength self-compacting concrete in China. It is possible to realize industrial production.
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Tian, Lin Gang, Bin Bin Zhen, Hu Huang e Jing Shen. "Study on Failure Mode for Power Intake Structure under Seismic Action". Applied Mechanics and Materials 438-439 (ottobre 2013): 1537–41. http://dx.doi.org/10.4028/www.scientific.net/amm.438-439.1537.
Testo completoAbstract (sommario):
This paper studies on the ultimate failure modes and bearing capacity of high intake tower under the action of seismic load based on nonlinear concrete model. By monitoring the way of crack development and failure process of the tower to study failure mode under the action of various seismic wave, we can conclud that the regional distributions of the structural crack of tower body vary with the duration of an earthquake. In the early period of earthquake, the crack has little effect on the whole structure. After duration of the earthquake, the structure forms penetrable cracks. By studying the cracks development and distribution on the structure of tower body under the action of various seismic waves, we know the failure process and failure mode of high intake tower. The conclusions provide evidence for engineering design and seismic analysis of pertinent engineering.
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Li, Miao, Hao Li e Yang Wen. "Design and Performance Study of a Six-Leg Lattice Tower for Wind Turbines". Buildings 14, n. 4 (1 aprile 2024): 965. http://dx.doi.org/10.3390/buildings14040965.
Testo completoAbstract (sommario):
A new type of spherical node was used to design a laboratory-scale prototype of a six-leg lattice of steel tubes and concrete for application as a wind turbine tower. Repeated load tests were performed on the prototype tower for several weeks to evaluate its load-carrying capacity, deformation, energy consumption, stress distribution based on damage patterns, hysteresis curves, skeleton curves, strength, and stiffness degradation curves. The findings indicated that the prototype tower underwent thread damage to the high-strength bolts of the inclined web and weld damage between the inclined web and sealing plate. Although the stress differences between different measurement points were significant, the stress values were small at most of the measurement points. The maximum equivalent stress value was 294 MPa, which appeared in the middle layer of the BC surface. The P-Δ hysteresis curve had an inverse “S”-shape, and the bearing capacity was high. The maximum energy dissipation appeared in the 1.75 Δy loading stage. The peak load of the specimen can reach 376.2 kN, and the corresponding peak displacement is 37 mm. However, the average ductility coefficient was only 2.33, indicating little plastic deformation. The maximum strain of the tower column foot is 1800 με, and the force of the inclined web member in the middle layer is the largest. The strain of the transverse web bar increased significantly after the tower yielded, which contributed to maintaining the integrity of the structure.
50
Dong, Yi, Nai Qian Feng, Hao Wen Ye, Hu Yan Ling, Li Xun Lin, Li Bin Xu e Hui Sun. "Application Research of C80 High-Performance Concrete for the Guangzhou East Tower". Applied Mechanics and Materials 584-586 (luglio 2014): 1635–40. http://dx.doi.org/10.4028/www.scientific.net/amm.584-586.1635.
Testo completoAbstract (sommario):
With the development of modern building design and construction technology, high strength concrete technology were getting more use in engineering and more requirements. The authors produced C80 HPC by using Portland cement, blast furnace slag, micro bead and Flyash as cementitious material, have prepared the concrete with grade of C80, low pumping resistance (rewinding time less than 6s), low shrink (72h early self-shrinkage value at 0.028%), high workability (slumps over 240mm and divergence over 700mm) and high durability (diffusion coefficient in concrete after 28d was 1.35×10-12 m2/s), which would match the requirements of the Guangzhou East Tower.