Keywords: finite element analysis, cable-arch structure, nonlinear buckling, plasticity, large displacements.

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.

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

purchase the full-text of this paper (price £20)

go to the previous paper
go to the next paper
return to the table of contents
return to the book description
purchase this book (price £145 +P&P)