FINITE ELEMENT ANALYSIS OF MULTI-VENT MULTI-SPAN FOLDED-PLATE STRUCTURES

A general finite element computer code for the space analysis of folded-plate structures has been developed based on the stiffness Method. A direct access peripheral storage is used as a scratch file in the formulation of the overall stiffness and load matrices. This made it possible to analyze large multi-vent, multi-Span, folded-plate structures. The stiffness matrix of a one dimensional space frame element assuming nodal forces and displacements at the top points of the cross-sections was derived and used for the simulation of edge beams. The triangular plane-stress element was used for modeling the in-plane action of diap-hragms. Check problems of single-vent simply supported folded-plate
structures with and without edge beams have been solved assuming infinitely stiff end-diaphragms and the results of both displacements and internal stresses were compared with the available "exact" analytical solution. This showed complete agreement in both displacements and stresses. Practical examples of three-vent simply supported and continuous folded-plate roofs have been solved. Effect of edge beams andties were considered. In case of continuous folded-plates, the effect of the inner supports as point supports on the ridges or as a diaphragm supported at the ridge points was considered and discussed. Several practical conclusions have been made.