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Civil-Comp Proceedings
ISSN 1759-3433
CCP: 93
PROCEEDINGS OF THE TENTH INTERNATIONAL CONFERENCE ON COMPUTATIONAL STRUCTURES TECHNOLOGY
Edited by: B.H.V. Topping, J.M. Adam, F.J. Pallarés, R. Bru and M.L. Romero
Paper 145

Damage Assessment of a Self-Weight Metallic Roof with Skylights using the Finite Element Method

J.J. Del Coz Diaz1, F.P. Álvarez Rabanal1, P.J. García Nieto2 and A. Lozano Martínez-Luengas1

1Construction and Manufacturing Engineering Department, 2Department of Mathematics,
University of Oviedo, Spain

Full Bibliographic Reference for this paper
J.J. Del Coz Diaz, F.P. Álvarez Rabanal, P.J. García Nieto, A. Lozano Martínez-Luengas, "Damage Assessment of a Self-Weight Metallic Roof with Skylights using the Finite Element Method", in B.H.V. Topping, J.M. Adam, F.J. Pallarés, R. Bru, M.L. Romero, (Editors), "Proceedings of the Tenth International Conference on Computational Structures Technology", Civil-Comp Press, Stirlingshire, UK, Paper 145, 2010. doi:10.4203/ccp.93.145
Keywords: finite element analysis, cable-arch structure, nonlinear buckling, plasticity, large displacements.

Summary
In this work, a structural analysis using the finite element method is carried out to study the structural collapse of a metallic roof with skylights subject to slef-weight located in Cabañaquinta's schoolyard, Spain.

Several modern lightweight structures use curved compression members such as the self weight metallic roof in this case, but until now the structural performance of these members is not well understood [1,2,3,4]. In many cases, these members are subjected to eccentric loading, such as the spar cable subject to a tensile load, which creates another important inconvenience to predict its structural resistance. Furthermore, skylights on the metallic roof cause important discontinuities in the continuous compression members and add much more complexity to the analysis [3,4].

In order to determine the structural behaviour of the roof, a detailed study of the snow loads, material properties and characteristics of the same has been modelled. For this purpose, a full three-dimensional finite element model of this cable-arch structure was implemented using shell and truss elements, taking into account the nonlinear buckling phenomenon.

To tackle this structural problem, a damage assessment is proposed based on the non-linear post-buckling analysis of the self-weight metallic roof using the finite element method. From this analysis, the following results can be stated:

  • The structure is able to support about the 88.5% of the total load and, after that, the collapse of the cable-arch occurs.
  • The load value without snow accumulation is less than the collapse load of the roof and, consequently, this cable-arch structure is not able to support the total snow load.
Consequently, future projects must be taken into account the additional snow accumulation load. Besides, the skylight introduces very important buckling distortions and this must be removed. A tile thickness increment is also recommended, from 1.25 mm to 1.5 mm thick, as it is analyzed in other previous work [1].

Finally, this paper shows that advanced numerical analysis using the finite element method could offer significant information about the structural collapse of this type of metallic roof with skylights, and it proposes structural design recommendations to avoid this type of catastrophic failure of the roof.

References
1
J.J. del Coz Díaz, P.J. García Nieto, J.A. Vilán Vilán, J.L. Suárez Sierra, "Non-linear buckling analysis of a self-weighted metallic roof by FEM", Mathematical and Computer Modelling, 51(3-4), 216-228, 2010. doi:10.1016/j.mcm.2009.08.032
2
K. Bathe, "Finite element procedures", Prentice-Hall, New Jersey, Englewoods Cliffs, 1998.
3
H. Zien-El-Din, A. El-Sheikh, F. Smith, "Behaviour of curved and continous compression members", Engineering Structures, 24, 1499-1507, 2002. doi:10.1016/S0141-0296(02)00069-X
4
Y. Zhao, H. Kang, "In-plane free vibration analysis of cable-arch structure", Journal of Sound and Vibration, 312, 363-376, 2008. doi:10.1016/j.jsv.2007.04.038

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