A consistent FEM-Vlasov model for hyperbolic cooling towers on layered soil under unsymmetrical wind load

Karakas, Ali I.; Özgan, Korhan; Daloglu, Ayse T.

doi:10.12989/was.2016.22.6.617

Cited by 3 publications

(3 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Hizal and Catal [17] investigated the dynamic response of the axially loaded Timoshenko beams on modified Vlasov foundations by using the separation of variables method. Karakas et al [18] explored the seismic response of a hyperbolic cooling tower resting on elastic foundations represented by a three-parameter Vlasov model. However, the drawback of the Vlasov model is that it introduced an attenuation parameter, whose value must be estimated.…”

Section: Introductionmentioning

confidence: 99%

Two Novel Vlasov Models for Bending Analysis of Finite-Length Beams Embedded in Elastic Foundations

Yue

Fan

et al. 2022

Buildings

View full text Add to dashboard Cite

The issue of soil–structure interaction (SSI) is essentially to analyze the influence of complex media on the mechanical behavior of supported structures. With the development of underground space, geological structures and space constraints put forward higher requirements for foundations and buildings. In this paper, the effects of soil heterogeneity and embedment depth on the bending of finite-length beams embedded in two novel Vlasov elastic foundations are investigated. Firstly, the constitutive relations of subsoil are simulated by Gibson and transversely isotropic soils, and the type of elastic foundation is described by the modified Vlasov model. Then, based on variational principles, the governing differential equations for the deformation and attenuation parameters of beams embedded in elastic foundations are derived by taking the variation of the minimum potential energy of the system, and the characteristic coefficient related to the embedment depth is introduced. Finally, the mechanical performance of the beam and foundation is obtained by an iterative technique and the Fourier series method, and an extensive parametric study is performed to examine influence of some basic parameters on the deformation and internal forces of the system. The results show that the mathematical expressions of two refined elastic models are in good agreement with those of the traditional Vlasov foundation after degradation. The iterative technique based on the principles of solid mechanics can be employed to obtain more reliable model parameters. More importantly, with the increase in the embedment depth, the mechanical responses of the beam and subgrade forces decrease. The main reason is that the restraint effect of the soil media around structures, which leads to the reduction of the characteristic coefficient affecting the displacement of beams. Moreover, the heterogeneity of soil, including Gibson characteristics and transverse isotropy, should be considered according to specific working conditions in civil engineering.

show abstract

Section: Introductionmentioning

confidence: 99%

Two Novel Vlasov Models for Bending Analysis of Finite-Length Beams Embedded in Elastic Foundations

Yue

Fan

et al. 2022

Buildings

View full text Add to dashboard Cite

show abstract

“…It was observed that there were large increases in tensile strength and small increases in meridian strength due to the wind effect, and also changes in displacement values occured as a result of wind and earthquake effects. Karakas et al [6] examined the behavior of the cooling tower structure under the effect of wind by using the Vlasov soil model. It was seen that shear forces, bending and torsional moments at the columns increased when the structure-soil interaction was taken into consideration.…”

Section: Introductionmentioning

confidence: 99%

Investigation of behavior of cooling tower structure under external loads

Çarhoğlu

2021

Cumhuriyet Science Journal

View full text Add to dashboard Cite

Cooling towers are high and thin structures which are widely used at the industry and nuclear facilities. These structures are built on column elements as reinforced concrete. Determining the behavior of the buildings affected by the dynamic loads such as wind and earthquake is very important in terms of preventing the loss of life and property. In this study, hyperbolic cooling with 117m height tower was examined and the behaviors of the structure in earthquake and wind effects were investigated. During the application of the wind load, 25m / sec wind velocity was applied and three ground motion records were applied to the structures in the course of the earthquake analysis. The wind load was calculated in accordance with the ASCE 7-10 standard and it was given as angular. As a result of the analysis, the values of the displacement and stress were obtained and examined. According to the results of the wind load analysis; As the height of the tower increases, the values of wind load increase and the displacement values occurring in the building increase. The values of displacement and stress vary angularly depending on angular wind load. It is seen that the highest values of displacement and stress values were obtained in Kobe earthquake. Displacement values were examined depending on the height and the largest displacement values were obtained at the top part.

show abstract

“…Among them, wind load is the control load of the design of tower body, pillars, and ring foundation . Seismic effect will produce a large impact on the stress status of the ring foundation . The computed load effect is directly related to the value of damping ratio.…”

Section: Introductionmentioning

confidence: 99%

Identification of damping ratio and its influences on wind‐ and earthquake‐induced effects for large cooling towers

et al. 2018

Structural Design Tall Build

View full text Add to dashboard Cite

Summary Standard 5% damping ratio for high‐rise concrete structures is generally used for dynamic analysis under the action of wind and earthquakes in the existing cooling tower regulations and researches. But considering the unique configuration and material attributes of large cooling towers, the actual damping ratio must be far smaller than the recommended. However, only a few field measurements of damping ratio for large cooling towers have been conducted; neither are there thorough investigation into the qualitative and quantification of wind and seismic effects under different damping ratio. To fill this gap, field measurements of a large cooling tower standing 179 m in northwestern China was performed and acceleration vibration signals at representative positions of the tower under ambient excitation were obtained. The vibration signals were preprocessed combining random decrement technique and natural excitation technique. Three pattern recognition methods (auto‐regressive and moving mean model, Ibrahim time domain, and spare time domain (STD)) were applied to analyze the frequencies, damping ratios, and modes of vibration for the first 10 order modes. Following the line of thought of modal combination, the equivalent synthetic damping ratio was derived. Under 5 damping ratios (0.5%, 1%, 2%, 3%, and 5%), a comparative analysis on the dynamic responses of the cooling tower to wind and single seismic loading by using full transient method was performed. On this basis, the patterns of influence of damping ratio on wind‐induced vibration, wind vibration coefficient, and time history and extrema of seismic responses were extracted. Finally, different combinations of dead weight, wind, temperature in winter, sunshine duration, and seismic intensity and those of accidental seismic effects (8 working conditions) were considered, using equivalent synthetic damping ratio and standard damping ratio. Thus, the most unfavorable working conditions were identified under actual and standard damping ratios for the large cooling tower. Our research findings provide reference for determining the value of damping ratio in large cooling towers and deepening the understanding on the influence mechanism of damping ratio.

show abstract

A consistent FEM-Vlasov model for hyperbolic cooling towers on layered soil under unsymmetrical wind load

Cited by 3 publications

References 10 publications

Two Novel Vlasov Models for Bending Analysis of Finite-Length Beams Embedded in Elastic Foundations

Two Novel Vlasov Models for Bending Analysis of Finite-Length Beams Embedded in Elastic Foundations

Investigation of behavior of cooling tower structure under external loads

Identification of damping ratio and its influences on wind‐ and earthquake‐induced effects for large cooling towers

Contact Info

Product

Resources

About