static and dynamic analyses of guyed antenna towers

336 Pages·2000·10.75 MB·English

STATIC AND DYNAMIC ANALYSES OF GUYED
ANTENNA TOWERS
YOHANNA M. F. WAHBA
B.Sc.(EIons), M.A.Sc., P.Eag., P.E.
A Dissertation
subrnitted to Collcge of Graduate Studies and Research through
Civil and Envitonmental Engineering Program
in partial Nfilment of the requirements for the
degree of Doctor of Philosophy at the
University of Windsor
Windsor, Ontarîo, Canada
1999
1+1 National Library Bibliothèque nationale
dcanacia du Canada
uisitions and Acquisitions et
~iograPhiSce Mces services bibliographiques
The author has granted a non- L'auteur a accordé une licence non
exclusive licence allowing the exclusive permettant à la
National Library of Canada to Bibliothèque nationale du Canada de
reproduce, loan, distribute or sel1 reproduire, prêter, distribuer ou
copies of this thesis in microfonn, vendre des copies de cette thèse sous
paper or electronic formats. la fome de microfiche/film, de
reproduction sur papier ou sur fomat
électronique.
The author retains ownership of the L'auteur conserve la propriété du
copyright in this thesis. Neither the droit d'auteur qui protège cette thèse.
thesis nor substantial extracts fiom it Ni la thèse ni des extraits substantiels
may be printed or otherwise de celle-ci ne doivent être imprimés
reproduced without the author's ou autrement reproduits sans son
permission. autorisation.
Canada
Yobanna M. F. Wahba
1999
AI1 Rights Reserved
1 hereby declare that 1 am the sole author of this document.
1 authorize the University of Windsor to lend this document to other institutions or
individuals for the purpose of scholarly research.
Yohanna M. F. Wahba
1 M e ra uthorize the University of Windsor to reproduce the document by photocopying or
by other means, in total or part, at the request of other institutions or individuais for the
purpose of scholarly research.
Yohanna M. F. Wahba
THE UNIVERSITY OF WiNDSOR requires the signatures of al1 persons ushg or
photocopying this document.
Please sign below, and give address and date.
in this investigation, the static response of guyed communication towen is
investigated using two different finite element models (three-dimensional ûuss model.
and an equivalent beam model), and a beam-on-non linear spnngs analogy. A
cornparison between the analytical techniques is presented for different loading Ievels.
Results from the anaiytical models are verified by testing four scale model towers to
collapse. The analytical techniques are also extended to prototype towers and
conclusions are drawn regarding the suitability of the analfical models to the static
analysis of such towers.
A dynarnic testing facility (shake table), suitable for testing of communication
towers, was designed, built, and instrumented at the Structural Engineering Laboratory at
the University of Windsor. This study presents the experimental investigation, testing
facility set-up, construction of models, materials and procedures used for the static, fiee
vibration, fmed vibration, and ultimate load tests of guyed tower models. The facility was
used to test five scaled guyed tower models under fke vibrations and foiwd base motion.
The tests substantiated the theoretical nnite element techniques.
The finite element analysis is appiied to eight prototype towers subjected to fiee
vibration and forced vibration motion. A parametric study on 33 towen is conducted to
investigate the main parameters influencing the fhx vibration of these structures. Based on
this parametric study, three empirical equations were derived to estimate the fundamental
natural fiequencies of the tower. These estirnated fiequencies would be valuable in
establishg the dynamic characteristics of the towers for use by design engineers.
ACKNOWLEDGEMENTS
The author wishes to express his deep appreciation and gratitude to his advisors Dr.
M. K. S. Madugula and Dr. G. R Monforton, for their constant support and valuable
-
supervision during the development of this research. To them 1 say, "1 am gratefhi thank
you".
The author wishes to thank Dr. G. Abdel-Sayed, for his help and encouragement
throughout the duration of the author's graduate studies.
Many Thanks are also due to Mr. D. Marshall, for his encouragement and for the
pictues of towers that he supplied me. Also, th& to Messrs. G. Patton, K. DeBelser, R.
Sullivan, of LeBlanc Ltd. for their support and encouragement to complete this dissertation.
The author wishes to acknowledge the financial support provided by the Naturai
Sciences and Engineering Research Council of Canada, The Ministry of Colleges and
Universities d Ontario, and the University of Windsor.
Finally, the author is deeply grateful to his parents and his wife for their great
support, understanàiig, and patience throughout the course of this research; to them 1 Say
''Thanks".
viii
TABLE OF CONTENTS
List of Tables xiii
88.8888.8888. 8m.m88m8m88m.888888888888m88.m88o8.8.8.8a888888m888.w8o888888.m8.88888m8888m...8,a~.888
1- 4 Contents and Amuigement of the Dissertation ....... .. .. .. ... ... ...... .. . .. .. . .. . .... .. . ............ .....* 6
CHAPTER II BACKGROUND AND REVlEW OF LITERATURE 11
mm8888.8m888..a888.....
3.3 Finite-Elefnent Approach ......................................................................................... 26
3.3.1 Description of the Finite-Elemeat Program 'ABAQUS' ...................................... 30
3.3.2 Finite-Element Modeliing of Guyed Communication Towers ............................. 30
3.3.2.1 Mast Modelling ........................................................................ 31
(a) 3 D-Truss Model ....................................................................3. 1
(b) 3D-Beam Mode1 .....................................................................3 2
(c) Beam Mode1 ............................................................................-.3 2
3 -3. 2.2 Guy Modelling ...................................................................-.3 4
3.3.2.3 Boundary Conditions ........................................................... -34
3 .3.2.4M aterial modelling ............................................................ 35
(a) Mast Matenal ............................................................................. -35
@) Guy Cables ............................................................................. -35
3.3.3 %tic ~ W......S......... ................................................................................... 36
3.3 -4 Free-wxation halys is ..................................................................................... 37
3 03 .5 Nm-Limar W d ch d ysi s ........................................................................3..9.
3 -3- 6U p-to-Collapse Anal~si.s.. ................................................................................. 40