Contents page

The Structural Engineer

A simple and convenient method using higher order finite elements is proposed for the approximate analysis of laterally loaded spatial wall systems consisting of shear cores and shear walls with individual large openings. Each opening is taken into account by incorporating a ‘negative’ stiffness matrix of a lower order element into the overall stiffness matrix through the superelement concept. The simplicity and accuracy of the method are demonstrated through several examples, including planar and non-planar walls. L.G. Tham and Professor Y.K. Cheung

The Structural Engineer

Mr R. C. Hairsine (F): In the first part of his paper, Professor Ingold illustrates the relationships between the principal variables affecting the design of an L-shaped retaining wall. The L-shaped wall is a special case of the T-section wall which was treated in my paper given to the Institution of Civil Engineers. This work explains the derivation and application of a single design chart relating all the parameters affecting local stability of the retaining wall section. The chart facilitates the direct design of economic base proportions and sensitivity assessment. Simple adjustments enable the simple basic model to be extended to cover gravity sections, groundwater, and multiple strata. The chart has since been rearranged by J. C. Steedman and is included in the Reinforced concrete designer’s handbook.

The Structural Engineer

This paper examines the application of equations used to define the effect of section depth on the ultimate bending stress of timber to characteristic stress values obtained from tests carried out at Princes Risborough Laboratory and in Canada. It deals specifically with the determination of the most suitable general equation for adjusting test results to a standard depth. From a comparison of root mean square differences between depth factors obtained from the test results, and those predicted by the equations, it is concluded that, for visually stress-graded softwood timber, the depth effect is best defined by the equation K = (200/h)0-4 A.R. Fewell and W.T. Curry

The Structural Engineer

Studies have been carried out on a range of medium-rise unbraced steel frames. The results indicate whether the serviceability limit on sway or ultimate strength will dominate design under combined loading. D. Anderson and T.S. Lok