Concrete Tower Research Articles

Ultimate Deflection Capacity of Lightly Reinforced Concrete Intake Towers

This paper describes a series of experimental research efforts focused on characterizing the ultimate flexural behavior of lightly reinforced concrete intake towers. The main objective of this research was to provide empirical data to be used in the development of a simplified analysis procedure for seismic evaluation of this type of structures. The studies included an experimental investigation of the flexural behavior of 1/8-scale model rectangular concrete intake towers under monotonic and cyclic lateral loads. Further experimentation was conducted to quantify the influence of the parameters governing the deflection capacity of these structures. An empirical expression is presented for the ultimate deflection capacity of lightly reinforced towers with rectangular sections.

Wind-Induced Response of a Concrete Tower of Wind Turbine

Wind-Induced Response of a Concrete Tower of Wind Turbine

Wind Response Control of Building with Variable Stiffness Tuned Mass Damper Using Empirical Mode Decomposition/Hilbert Transform

The effectiveness of a novel semiactive variable stiffness-tuned mass damper ~SAIVS-TMD! for the response control of a wind-excited tall benchmark building is investigated in this study. The benchmark building considered is a proposed 76-story concrete office tower in Melbourne, Australia. It is a slender building 306 m tall with a height to width ratio of 7.3; hence, it is wind sensitive. Across wind load data from wind tunnel tests are used in the present study. The objective of this study is to evaluate the new SAIVS-TMD system, that has the distinct advantage of continuously retuning its frequency due to real time control and is robust to changes in building stiffness and damping. In comparison, the passive tuned mass damper ~TMD! can only be tuned to a fixed frequency. A time varying analytical model of the tall building with the SAIVS-TMD is developed. The frequency tuning of the SAIVS-TMD is achieved based on empirical mode decomposition and Hilbert transform instantaneous frequency algorithm developed by the writers. It is shown that the SAIVS-TMD can reduce the structural response substantially, when compared to the uncontrolled case, and it can reduce the response further when compared to the case with TMD. Additionally, it is shown the SAIVS-TMD reduces response even when the building stiffness changes by 615% and is robust; whereas, the TMD loses its effectiveness under such building stiffness variations. It is also shown that SAIVS-TMD can reduce the response similar to an active TMD; however, with an order of magnitude less power consumption.

Model Predictive Control of Wind-Excited Building: Benchmark Study

In this paper, a “third generation” benchmark problem that focuses on the control of wind excited response of a tall building, using the Model Predictive Control (MPC) scheme, is presented. A 76 story, 306 m tall concrete office tower proposed for the city of Melbourne, Australia, is being used to demonstrate the effectiveness of MPC. The MPC scheme is based on an explicit use of a prediction model of the system response to obtain the control actions by minimizing an objective function. Optimization objectives in MPC include minimization of the difference between the predicted and desired response trajectories, and the control effort subjected to prescribed constraints. By incorporating input/output hard constraints, the MPC scheme provides an optimal control force that satisfies the prescribed constraints.

Benchmark Problem for Response Control of Wind-Excited Tall Buildings

This paper presents an overview and problem definition of a benchmark problem for the response control of wind-excited tall buildings. The building considered is a 76-story 306 m concrete office tower proposed for the city of Melbourne, Australia. The building is slender with a height to width ratio of 7.3; hence, it is wind sensitive. Wind tunnel tests for such a 76-story building model have been conducted at the University of Sydney and the results of across-wind data are used in the present benchmark problem. Either active, semiactive, or passive control systems can be installed in the building to reduce the wind response, although only an active control sample problem has been worked out to illustrate the control design. In the case of active control systems, either an active tuned mass damper or an active mass driver can be installed on the top floor. In the case of passive or semiactive systems, such as viscous dampers, viscoelastic dampers, electrorheological, or magnetorheological dampers, etc., control devices can be installed in selected story units. Control constraints and evaluation criteria are presented for the design problem. A simulation program based on the linear quadratic Gaussian technique has been developed and made available for the comparison of the performance of various control strategies.

Benchmark Structural Control Problems for Seismic- and Wind-Excited Structures

The theme of this special issue of the Journal is benchmark structural control problems for seismicand wind-excited structures. Tremendous progress has been made over the past 2 decades toward making structural vibration control a viable technology for enhancing structural functionality and safety against natural hazards, such as strong earthquakes and high winds. Over the years, many control algorithms and devices have been investigated, each with its own merits, depending on the particular application and desired effect. Clearly, the ability to make direct comparisons between systems employing these algorithms and devices is necessary to focus future efforts in the most promising directions and to effectively set performance goals and specifications. One approach to achieving this goal is to consider consensus approved, high-fidelity, analytical benchmark models that allow researchers in structural control to test their algorithms and devices and to directly compare the results. The ASCE Committee on Structural Control has recognized the significance of structural control benchmark problems. The Committee developed a benchmark study, focusing primarily on the comparison of structural control algorithms for three-story building models. An extensive analysis of these benchmark structural control problems formed the basis for a special issue of Earthquake Engineering and Structural Dynamics ~Spencer et al. 1998a,b!. Several of these algorithms also have been verified experimentally ~Baker et al. 1999!. Building on the foundation laid by the ASCE Committee on Structural Control, new generations of benchmark structural control studies were initiated by the Working Group on Building Control during the Second International Workshop on Structural Control held on December 18–20, 1996, in Hong Kong ~Chen 1996!. As stated by the Working Group, the goal of this effort was to develop benchmark models to provide systematic and standardized means by which competing control strategies, including devices, algorithms, and sensors, etc., can be evaluated. This goal drives the second generation of structural control benchmark problems. As an outgrowth of the workshop in Hong Kong, two benchmark problems for the control of buildings were developed for presentation at the 2nd World Conference on Structural Control held on June 28 to July 1, 1998, in Kyoto, Japan. The first benchmark problem, detailed in Yang et al. ~1999!, proposed a benchmark problem using a 76-story, wind-excited concrete tower designed for Melbourne, Australia. The second benchmark problem, detailed in Spencer et al. ~1999!, used a 20-story structure designed for the Los Angeles area. The structural model in the second benchmark problem was considered to remain perfectly elastic. However, large magnitude earthquakes can cause inelastic behavior in the structural element of civil structures, resulting in nonlinear responses. During the 2nd World Conference on Structural Control held in 1998 in

Second Nanjing Cable-Stayed Bridge

The Second Nanjing cable-stayed bridge over the Yangtze river, China is 11 km downstream from the first Nanjing bridge and passes through Baguazhou, the third largest island in the Yangtze river. The main bridge in the southern section is a cable-stayed bridge with five continuous spans of steel box girder with an orthotropic deck and an epoxy asphalt concrete pavement. The main span is 628 m long. The technical specifications are listed: deck width, design speed, design load, design wind speed, ship collision force, navigational clearance, design flood frequency, deck slope and seismic scale. The design and construction of the deep water foundation of the tower, the reinforced concrete cable tower and main girder are described. The zinc-plated steel cables and their installation are described.

The Use of Prestressing and Precasting in Concrete Water Tanks and Towers in Britain and Ireland

The Use of Prestressing and Precasting in Concrete Water Tanks and Towers in Britain and Ireland

Development of Precast Concrete Tower for Wind Turbine

Development of Precast Concrete Tower for Wind Turbine

The concrete tower for wind power generating system in Nadachi

The concrete tower for wind power generating system in Nadachi

Damped Spectral Element Method for Global Dynamic Analysis of Chimneys

Conventional finite element method has been used successfully in linear and nonlinear analyses in tall chimney structures. The method can be performed by subdividing the large structure with small uniform elements having approximate shape functions. Although this replaces a single complicated structural system with the number of simple uniform elements, in cases of tall concrete chimney structures with cracking and crushing behavior in concrete material and yielding in the reinforcement, the computer time and memory can be large. Hence, it is desirable to search for a procedure requiring lesser number of elements and also less computer time and effort to model a structure. In this respect, attention is paid to the advanced complex damped spectral element method, which benefits from the more accurate and also mathematically complicated shape functions. The use of advanced spectral element method can help engineers to design a complex structure, like a tall concrete tower, with a lower cost and weight. Using a computer program, the proposed formulation has been used to derive the non-linear dynamic response of tall concrete chimney.

Measurement of aerodynamic coefficients of tower components of Tsing Ma Bridge under yaw winds

Tsing Ma Bridge in Hong Kong is the longest suspension bridge in the world carrying both highway and railway. It has two H-shape concrete towers, each of which is composed of two reinforced concrete legs and four deep transverse prestressed concrete beams. A series of wind tunnel tests have been performed to measure the aerodynamic coefficients of the tower legs and transverse beams in various arrangements. A 1:100 scaled 3D rigid model of the full bridge tower assembled from various tower components has been constructed for different test cases. The aerodynamic coefficients of the lower and upper segments of the windward and leeward tower legs and those of the transverse beams at different levels, with and without the dummy bridge deck model, were measured as a function of yaw wind angle. The effects of wind interference among the tower components and the influence of the bridge deck on the tower aerodynamic coefficients were also investigated. The results achieved can be used as the pertinent data for the comparison of the computed and field-measured fully coupled buffeting responses of the entire bridge under yaw winds.

Active control for a benchmark building under wind excitations

The tall building proposed in the benchmark problem is a concrete office tower, which is wind sensitive due to its slenderness. The wind loads acting on the building are defined by the results of wind tunnel tests conducted at the Sydney University and an active mass driver can be designed for installation on the top floor in order to reduce the structural response under strong wind gusts. In this paper, the control strategy presented for the third generation benchmark control problem for wind-excited buildings (J. Eng. Mech. (1999), submitted for publication) is the simultaneous treatment of both H 2 performance criteria and H ∞ attenuation constraints that demonstrates design tradeoffs and can be applied to the AMD system based on acceleration feedbacks. This control problem can be formulated by linear matrix inequalities in terms of a common Lyapunov function. Solving linear matrix inequalities is a convex optimization problem and efficient interior-point algorithms are now available to solve this problem. Simulation and design results demonstrates that, decreasing H ∞ attenuation constraint can be used to reduce the structural response under wind excitations at the expense of increasing H 2 performance index.

Winter Aggregation Of Harmonia Axyridis (Coleoptera : Coccinellidae) In A Concrete Observation Tower

Aggregations of thousands of multicolored Asian lady beetles, Harmonia axyridis, have appeared each fall since 1993 in a 20.1 m high concrete observation tower at Mt. Gretna, Lebanon County, Pennsylvania. The tower is located in a clearing on a ridge in otherwise regenerated oak-maple-birch forests in Clarence Schock Memorial Park at Governor Dick (326 m elevation, 40° 14.78' N, 76° 27.35' W). Beetles aggregate in the ceiling/wall comers on four different levels in the tower's internal ladderways. Since the tower is open to the public for recreational purposes, one can visit the tower in late fall and witness these aggregations. During some winters, mortality appears very high, suggesting that the tower lacks adequate insulative properties for optimum survival.

The Prestressed Concrete Tower for The Wind Turbine in Nadachi-machi

The Prestressed Concrete Tower for The Wind Turbine in Nadachi-machi

Development of Precast Concrete Tower for Wind Turbine

Development of Precast Concrete Tower for Wind Turbine

Seismic analysis of Tehran Telecommunication Tower using complex fractional modulus

AbstractSeismic response of large concrete tower structures with passive or active damping is important in terms of performance under earthquake loads. The conventional finite element method has been used successfully in linear and nonlinear analyses in large concrete structures. The method can be performed by subdividing the large structure into small uniform elements having approximate shape functions. Although this replaces a single complicated structural system with a number of simple uniform elements, in cases of tall concrete tower structures with cracking and crushing behaviour in the concrete material and yielding in the reinforcement, the computer time and memory can be large. Hence, it is desirable to search for a procedure requiring fewer elements and also less computer time and effort to model the structure. In this respect, attention is paid to the advanced complex damped spectral element method, which benefits from the more accurate and also mathematically complicated shape functions. Use of the advanced spectral element method can help engineers to design a complex structure, such as a tall concrete tower, with lower cost and lower weight. Using a computer program, the proposed formulation has been used to derive the nonlinear dynamic response of the 435‐m Tehran Telecommunication Tower. Copyright © 2002 John Wiley & Sons, Ltd.

The development of the prestressed concrete tower with cast-in place method for large scale wind power generating system

The development of the prestressed concrete tower with cast-in place method for large scale wind power generating system

Full dynamic analysis of Tehran telecommunication tower; linear and nonlinear responses

AbstractDynamic response of large concrete tower structures with passive or active damping is important in terms of performance under dynamic loads. Structural instability mostly arises as a result of losing the energy capacity in the system, which forces the system to act as a mechanism. The purpose of this paper is to present three different finite element models to investigate the linear and nonlinear response of the Tehran telecommunication tower. The tower is ranked the fourth tallest structure in the world and has been under construction since 1997. Using a mathematical model, an efficient method is used to take into account the cracking and crushing of the reinforced concrete material as well as large deformation effects. The linear and nonlinear dynamic characteristics of the large tower may be defined by using an advanced formulation for the concrete element. Then, the proposed advanced element is used to model a full‐scale finite element mesh to derive the dynamic response of the Tehran telecommunication tower structure with use of a computer program. Copyright © 2001 John Wiley & Sons, Ltd.

Active control of along wind response of tall building using a fuzzy controller

This paper focuses on the benchmark problem application regarding the vibration control of tall buildings under along wind excitation. The building under consideration is the 76-story, 306 meter tall reinforced concrete office tower proposed for the city of Melbourne, Australia. The adopted control scheme consists of an Active Tuned Mass Damper (ATMD) where the control action is achieved by a Fuzzy Logic Controller (FLC). The main advantage of the fuzzy controller is its inherent robustness and ability to handle any non-linear behaviour of the structure. This benchmark study is based on specified design constraints for the ATMD to be considered in the design of the proposed control scheme. The robustness of the controller has been demonstrated through the uncertainty in stiffness (+15% and −15% variation from initial stiffness) of the building. The results of the simulation show a good performance by the fuzzy controller for all cases tested. Also the results show that the fuzzy controller performs slightly better than the LQG controller, while possessing several advantages over the LQG controller.