Numerical solution of base shear in high tensioned cable antenna

Document Type : Research

Author

Professor ,Civil Engineering Department ,K.N.Toosi University of Technology, Tehran .Iran

Abstract

A finite element solution based on equevalent elements is proposed for the static and dynamic analysis of tallhigh tensioned cable antennas. To reduce high number of degrees of freedom in space frame body of a structure, a simple equivalent beam element is defined for each simulative substructure. This numerical procedure is applicable to analyze complex three dimensional assemblies of substructures of such similar complex structures. In this analysis wind pressure effects accompanied by change of postentioning loads in nonlinear cable elements, earthquake effects, and any other arbitrary loads on the substructures. Accordingly, the restriction of the loads on the cable elements to gravity and thermal loads can be applied. The algorithm is developed upon an efficient cable elements depending on the given position and curved geometry of the cable, its end forces, and its tangent stiffness matrix. The employed formulation scheme permits any magnitude of deformation for straight or curved elements. The postensioning stresses in cables were considered as initial stresses. To simulate the equevalent elements, both ends stiffness, damping and mass components are calibrated to present the same static and dynamic responses as the selected substructure. To simulate dynamic responses, the equevalent single mass matrix and its adjusted position are carried out to obtain the same frequencies in equevalent elements. The static solution of a complete structure compared well with the results presented by simulated model. This paper proposes an alternative structural analysis modeling strategy for guyed steel towers design, considering all the equivalent structural forces and moments, by using three-dimensional beam finite elements. Comparisons of the above mentioned design models with an alternative, that models the main structure and the bracing system with 3D beam finite elements, are made for existing guyed steel telecommunication towers (325m high). The comparisons are initially based on the towers static and dynamic structural behavior later to be followed by a linear buckling analysis to determine the influence of the various modeling strategies on the tower stability behaviour.

Keywords

References

1. Leonard, J.W., "Nonlinear dynamics of curved cable elements", Journal of Engng Mech. Div. ASCE, 1973, 616-629.
2. Argyris, J.H., "Continua and Discontinua", Proceeding of Conference on Matrix Methods in Structural Mechanics, 1964, Wright-Patterson Air force Base, Ohio.
3. Hengold, W.M., Russel, J.J., "Equilibrium and natural frequencies of cable structures, (a nonlinear finite element approach)", 1976, Computer and Structures 6. [DOI:10.1016/0045-7949(76)90001-8]
4. Gambhir M.L., and Batchelor, B., "A finite element for 3-D prestressed cablenets", Int. J. Numerical Meth. Engng, 1977, 11. [DOI:10.1002/nme.1620111106]
5. Ozdemir, H., "A finite element approach for cable problems", Int. Journal of Solids Structures, 1979, 15, 427-437. [DOI:10.1016/0020-7683(79)90063-5]
6. Tiv, M., "Condensation in Structural Analysis", Journal of Seismology and Earthquake Engineering, 1995, fourth year, No,4
7. Policani, M.N., Silva, J.G.S. da, Estrella Júnior, L.F., Vellasco, P.C.G.da S., Andrade, S.A.L. de. (2000a). "Structural Assessment of Steel Telecommunication Towers", International Conference on Steel Structures of the 2000's, pp. 251-256, Istanbul, Turkey.
8. Silva, J.G.S. da, Vellasco, P.C.G. da S., Andrade, S.A.L. de, Estrella Júnior, L.F., Policani, M.N. (2000). "Comportamento Estrutural de Torres Metálicas de Telecomunicações", 21th Iberian Latin American Congress of Engineering Computational Methods, CILAMCE 2000, pp.1-10, CD ROM, (In Portuguese), Rio de Janeiro, Brazil.
9. Silva, J.G.S. da, Vellasco, P.C.G. da S., Andrade, S.A.L. de, Oliveira, M.I.R. (2002). "An Evaluation of Structural Steel Design Systems for Transmission and Telecommunication Towers", International IASS Symposium, pp 1-6, Warsaw, Poland.
10. Albermani, F.G.A., Mahendran, M., Kitipornchai, S. (2004). "Upgrading of Transmission Towers Using a Diaphragm Bracing System", Engineering Structures, Vol. 26, N0 6, pp 735-744. [DOI:10.1016/j.engstruct.2004.01.004]
11. Carril Júnior, C.F. (2000). Análise Numérica e Experimental do Efeito Dinâmico do Vento em Torres Metálicas Treliçadas para Telecomunicações, PhD Thesis, Escola Politécnica da Universidade de São Paulo - USP, In Portuguese, São Paulo, Brazil.
12. El-Ghazaly, H.A., Al-Khaiat, H.A. (1995). "Analysis and Design of Guyed Transmission Towers - Case Study in Kuwait", Computers & Structures, Vol. 55, N0 3, pp 413-431. [DOI:10.1016/0045-7949(95)98868-Q]
13. Kahla, N, (1994), "Dynamic Analysis of Guyed Towers", Eng. Structures, Vol. 16, pp. 293-301. [DOI:10.1016/0141-0296(94)90070-1]
14. Kahla N, (2000), "Response of a Guyed Tower to a Guy Rupture Under no Wind Pressure", Engineering Structures, Vol. 22, pp. 699-706. [DOI:10.1016/S0141-0296(99)00013-9]
15. Kitipornchai, S., Albermani, F.G.A. (1992). "Nonlinear Analysis of Lattice Structures", Journal of Constructional Steel Research, Vol. 23, N0 1-3, pp 209-225. [DOI:10.1016/0143-974X(92)90044-F]
16. Madugula, M.K.S., Wahba, Y.M.F., Monforton, G.R. (1998). "Dynamic Response of Guyed Masts", Engineering Structures, Vol. 20, N0 12, pp 1097-1101. [DOI:10.1016/S0141-0296(97)00206-X]
17. Menin, R.C.G., (2002), "Análise Estática e Dinâmica de Torres Metálicas Estaiadas", MSc. Dissertation, Publication E.DM-009A/2002, Depto. de Engenharia Civil e Ambiental, University of Brasília, Brazil (in portuguese).
18. Rao, N.P., Kalyanaraman, V. (2001). "Non-Linear Behaviour of Lattice Panel of Angle Towers", Journal of Constructional Steel Research, Vol. 57, N0 12, pp 1337-1357. [DOI:10.1016/S0143-974X(01)00054-2]
19. Saxena, R., Popplewell, N., Trainor, P.G.S., Shah, A.H. (1989)."Vibrations of Complex Guyed Towers", 12th Biennial Conference onMechanical Vibration and Noise Control, Montreal, Canada.
20. Walba, Y, Madugula, M, & Monforton, G, (1996), "Free Vibration of Guyed Antenna Towers", Advances in Steel Structures - Proceedings of International Conference on Advances in Steel Structures, Hong Kong, Chan, S. L. and Teng, J. G. edts, ISBN:0080428304, pp. 1095- 1100.
21. Wahba, Y.M.F., Madugula, M.K.S., Monforton, G. R. (1998). "Evaluation of Non-Linear Analysis of Guyed Antenna Towers", Computers & Structures, Vol. 68, N0 3, pp 207-212. [DOI:10.1016/S0045-7949(98)00025-X]
22. Albermani, F.G.A., Kitipornchai, S. (2003). "Numerical Simulation of Structural Behaviour of Transmission Tower", Thin-Walled Structures, Vol. 41, N0 2-3, pp 167-177. [DOI:10.1016/S0263-8231(02)00085-X]
23. Veletsos, A.S and Darbre, G.R., (1983), "Free Vibration of Parabolic Cables," ASCE Journal of Structural Engineering, Vol. 109, No. 2, pp. 503-519. [DOI:10.1061/(ASCE)0733-9445(1983)109:2(503)]
24. Starossek, U., (1991), "Dynamic Stiffiiess Matrix of Sagging Cable," ASCE Journal of Engineering Mechanics, Vol. 117, No. 12, pp. 2815-2829. [DOI:10.1061/(ASCE)0733-9399(1991)117:12(2815)]
25. Starossek, U., (1993), "Reduction of Dynamic Cable Stiffness to Linear Matrix Polynomial," ASCE Journal of Engineering Mechanics, Vol. 119, No. 10, pp. 2132-2136. [DOI:10.1061/(ASCE)0733-9399(1993)119:10(2132)]
26. Yamaguchi, H., and Adhikari, R., (1995), "Energy-based Evaluation of Modal Damping in Structural Cables with and without Damping Treatment," Journal of Sound and Vibration, Vol. 181, No. 1, pp.71-83. [DOI:10.1006/jsvi.1995.0126]
Numerical Methods in Civil Engineering
Volume 1, Issue 2
November 2016
Pages 21-30

Files

History

  • Receive Date: 28 January 2014
  • Revise Date: 12 April 2014
  • Accept Date: 22 June 2014

Share

How to cite

Statistics