The 2012 World Congress on Advances in Civil, Environmental, and Materials Research (ACEM’ 12)Seoul, Korea, August 26-30, 2012

FEM ANALYSIS OF TENSION STRUCTURES WITH EXPERIMENTAL WIND ACTION

Fabio Rizzo1), Piero D'Asdia2), Federica Speziale3) 1), 2), 3) Dept. of Engineering and Geology

(Inter-University Centre for Building Aerodynamics and Wind Engineering) University of Chieti-Pescara, Viale Pindaro 42, 65127 Pescara, Italy

1) fabiorizzo79@libero.it,

ABSTRACT This paper describes the design of a tension structures to cover a sport arena. Wind tunnel details are used to evaluated wind action static and dynamic in order to perform non linear static and dynamic analyses. Wind forces in time histories are evaluated from pressure coefficients acquired in wind tunnel and time histories of displacements are evaluated in order to study the dynamic deformed shape. An interesting comparison between the existent structure, realized with a spatial reticular steel structure, and the tensile-structure proposed, puts in evidence the high performance of this second kind of structure and its low dead load. This is a very important characteristic in a particularly vulnerable seismic zone. 1. INTRODUCTION

Sports arenas, indoor swimming pools, skating park, conference spaces are buildings that need to cover large spans without intermediate supports. Tension structures, and hyperbolic paraboloid shape in particular, are the most flexible structures to realize free spaces. Furthermore, such structures meet the requirements of today’s market in terms of lightness, innovation of materials and cost-effectiveness. Thus, considering the developments obtained in the research aimed at parameterization of the structural responses of hyperbolic paraboloid cables nets illustrated in a previous proceeding (Rizzo et all ACEM 12), this paper shows a design of a tension structure covering a sport arena located in Chieti (Italy). This project is based on aerodynamic wind tunnel and its detail is used to evaluated wind action static and dynamic in order to perform non linear static and dynamic analyses. Finally, to complete this study, the present work describes an interesting comparison between the existent structure, realized with a spatial reticular steel structure, and the new structure, realized with a tension structure to put in evidence the high structural performance of this second kind of structure and its low dead load. In fact, such structures have a ratio between live loads and dead loads which is

1) PhD, Researcher 2) Professor 3) PhD student

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[m]

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(a) Fig. 7

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ments M

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[m]

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(b) S1 (a) cable

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4

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[m]

0.218

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maximum

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]

81

Table 7: Comparison between non-linear static and dynamic analysis.

Wind_0°

Δf

[m]

Non-linear Static Analysis (Cp,min) 0.218

Non-linear Dynamic Analysis 0.260

CONCLUSION This paper describes a project of a sport arena with medium span using an hyperbolic paraboloid tension structure made of cables net. Results show that is possible to cover 80 m of span with a cables net that weighs 0.4 KN/m2, which presents cables with areas that do not exceed 6 cm2, with a diameter not greater than 3 cm. If you consider that, currently, the same span is covered with a common spatial reticular steel structure, with a height of the single beam that exceeds 1.50 m, with a structural weight four times bigger than the one of the cables net, you can understand how the advantage of using cables net is relevant both in terms of formal and structural lightness. So, the tension structure results less expensive than a traditional one. Then the paper comments static and dynamic non-linear analysis results conducted on cables net. In particular, analysis consider wind action. It is calculated using the pressure coefficients acquired through experimental wind tunnel tests. Such tests have provided pressure coefficients for minimum, mean and maximum values and as time history. These coefficients were used to perform non-linear static analysis with wind action evaluated for mean, minimum and maximum pressure coefficients and to perform non-linear dynamic analysis applying wind action as a time history of force, calculated using the single time histories of the pressure coefficients. It showed that the results of dynamic analysis are very similar to the results obtained with static forces calculated using the mean pressure coefficients, demonstrating that it is possible to simplify experimental data when making a global analysis. So, the paper shows that you can use experimental results obtained in a simplified form even for very deformable structures such as cables nets. This would permit designers to make a preliminary dimension calculation of cables nets with a hyperbolic paraboloid shapes, in the form examined, using appropriate pressure coefficient values. REFERENCES Cook, N.J., Mayne, J.R. (1978), On design procedures for wind loading, Building Research Estabilishment, Garston. Cook, N.J., Mayne, J.R. (1979), “A novel working approach to the assessment of wind loads for equivalent static design”, Journal of Wind Engineering and Industrial Aerodynamics, 4, 149-164.

Cook, N.J., Mayne, J.R. (1980), “A refined working approach to the assessment of wind loads for equivalent static design”, Journal of Wind Engineering and Industrial Aerodynamics, 6, 125-137. Gumbel, E.J., Statistic of extremes, Columbia University, Press: Lieblein J. (1974), Efficient methods of extreme value methodology, Report 74-602, National Bureau of Standards: Washington. Majiowiecki, M., (1994), Tensostrcture: Design and control, Crea, Milano. (in Italian). Rizzo, F., D’asdia, P., Lazzari, M., Procino, l., (2011) “Wind action evaluation on tension roofs of hyperbolic paraboloid shape”, Engineering Structures, Vol. 33, Issue 2, 445-461. Rizzo, F., D’Asdia, P., Ricciardelli, F., Bartoli, G. (2012). “Characterisation of pressure coefficients on hyperbolic paraboloid roofs”, Journal of Wind Engineering & Industrial Aerodynamics, Vol. 102(C), 61-71. Simiu, E., Scanlan, R.H., (1996), Wind effects on structures, Third edition, John Wiley & Sons, New York.