Assessment of capacity curves for transmission line towers under wind loading

다국어 초록 (Multilingual Abstract)

The recommended factored design wind load effects for overhead lattice transmission line towers by codes and standards are evaluated based on the applicable wind load factor, gust response factor and design wind speed. The current factors and design wind speed were developed considering linear elastic responses and selected notional target safety levels. However, information on the nonlinear inelastic responses of such towers under extreme dynamic wind loading, and on the structural capacity curves of the towers in relation to the design capacities, is lacking. The knowledge and assessment of the capacity curve, and its relation to the design strength, is important to evaluate the integrity and reliability of these towers. Such an assessment was performed in the present study, using a nonlinear static pushover (NSP) analysis and incremental dynamic analysis (IDA), both of which are commonly used in earthquake engineering. For the IDA, temporal and spatially varying wind speeds are simulated based on power spectral density and coherence functions. Numerical results show that the structural capacity curves of the tower determined from the NSP analysis depend on the load pattern, and that the curves determined from the nonlinear static pushover analysis are similar to those obtained from IDA.

참고문헌 (Reference)

1 Simiu, E, "Wind effects on structures" 1996

2 Vickery, B.J, "Wind action on simple yielding structures" 4 : 7-120, 1970

3 Wyatt, T.A, "Ultimate load behavior of structures under wind loading" 1971

4 Banik, S.S, "Tornado Hazard Assessment for Southern Ontario" 34 : 809-842, 2007

5 Davenport, A.G, "The relationship of wind structure to wind loading" National Physical Laboratory 1965

6 Davenport, A.G, "The dependence of wind load upon meteorological parameters" University of Toronto Press 1968

7 Da Silva, J.G.S, "Structural assessment of current steel design models for transmission and telecommunication towers" 61 : 1108-1134, 2005

8 Kaimal, J.C, "Spectral characteristics of surface layer turbulence" 98 : 563-589, 1972

9 Natarajan, K, "Reliability based optimization of transmission line towers" 55 (55): 387-403, 1995

10 Krawinkler, H, "Pros and Cons of a pushover analysis of seismic performance evaluation" 20 (20): 452-464, 1998

11 Probabilistic assessment of steel frames designed according to NBCC seismic provisions, "Probabilistic assessment of steel frames designed according to NBCC seismic provisions,PhD Thesis" The University of Western Ontario 2006

12 Twisdale, L.A, "Probabilistic analysis of tornado wind risks" 109 : 468-488, 1983

13 FEMA, "Prestandard and commentary for the seismic rehabilitation of buildings"

14 CSA, "Overhead systems"

15 Chay, M.T, "Numerical and analytical simulation of downbursts for investigating dynamic response of structures in the time domain" 28 (28): 240-254, 2006

16 Savory, E, "Modeling of tornado and microburstinduced wind loading and failure of a lattice transmission tower" 23 : 365-375, 2001

17 Villaverde, R, "Methods to assess the seismic collapse capacity of building structures: state of the art" 133 (133): 57-66, 2007

18 AISC, "Manual of steel construction: Load and resistance factor design"

19 Computers and Structures, Inc, "Integrated structural analysis and design software" SAP2000 version 7.4 2000

20 Vamvatsikos, D, "Incremental dynamic analysis" 31 (31): 491-514, 2002

21 ASCE, "Guidelines for electrical transmission line structural loading"

22 Kyung Ho Lee, "Fragility curves for woodframe structures subjected to lateral wind loads" 한국풍공학회 9 (9): 217-230, 2006

23 Lee, P.S, "Elastoplastic large deformation analysis of a lattice steel tower structure and comparison with full-scale tests" 63 : 709-717, 2007

24 Vamvatsikos, D, "Direct estimation of seismic demand and capacity of multi-degreeof-freedom systems through incremental dynamic analysis of single-degree-of-freedom approximation" 131 (131): 3-19, 2005

25 CSA, "Design criteria for overhead transmission lines"

26 Giovenale, P, "Comparing the adequacy of alternative ground motion intensity measures for the estimation of structural responses" 38 (38): 951-979, 2004

27 H. P. Hong, "Accumulation of wind induced damage on bilinear SDOF systems" 한국풍공학회 7 (7): 145-158, 2004

28 Samaras, E, "ARMA representation of random processes" 111 (111): 449-461, 1985

29 Li, C.Q, "A stochastic model of severe thunderstorms for transmission line design" 15 : 359-364, 2000