The Failure Loads of Steel and Structural Aluminium Alloy Portals

Synopsis In the finite-element method of structural analysis stiffness matrices are derived after a displacement form has been assumed. These element stiffness matrices are then combined in order to get the solution for the whole structure. For isotropic and orthotropic plates several authors 1-4 have derived satisfactory element stiffness matrices for plates supported in various ways. This present paper extends the range of the method by deriving stiffness matrices for plates, which include the effect of an elastic foundation, for two of the assumed displacement forms. A stiffness matrix for a beam on an elastic foundation is also presented. The effect of the foundation is assumed to consist of two parts: (a) the spring type reaction which is directly proportional to the displacement and (b) a spring-coupling action which simulates shear resistance in the foundation. The correctness of the stiffness matrices is adduced by comparison of calculated results obtained by their use with experimentally obtained values and, where possible, with values calculated by other theoretical methods. Brief details are given of an Algol computer programme which has been specially written for finite-element problems and which is capable of dealing with large-order matrices. R.T. Severn

The paper describes an installation for pumping water from the River Humber into King George Dock at Hull in order to stabilize clock water-level for shipping purposes. It deals with the design and construction of the numerous sections of thc work which together form the entire schenlc. including the underground culvert intake arrangements, pump house, etc. The methods adopted to meet the stringent time schedule and the peculiar sitc conditions are described and tlctails arc given of the more interesting of the many different problems cncountcrctl in this somewhat unusual project. R.A. Fisher

Two Vice-presidents of the Institution initiated the debate on 13 January-Dr. A. R. Collins, speaking in favour of the motion, and Mr. Brian Scruby against. The following report of the proceedings is offered against the background of the note which appeared in The Structural Engineer, January 1966, p.3 and, as mentioned by Mr. Scruby in his opening remarks, in the knowledge that it was the Institution’s custom that the first Ordinary Meeting of the New Year should be conducted in a lighter vein.