Off-the-Frame Brickwork: Winterton House, London

Hipped Roofs and Rafters Again Mr T. N. Ganju has written from Melbourne, Australia: Under biaxial bending the plane of bending of the hip rafter is not perpendicular to the neutral axis. The unsymmetrical bending is also caused by the unequal roof areas supported by the rafter, in addition to the reasons stated by Mr R. Seaman (4 January 2000).

This paper is concerned with the response of long-span floors to walking loads. Its purpose is to examine the load models and the evaluation of structural response using data measured on actual floors. The response of one floor to a person walking across it is considered first and, by taking measurements at various rates of walking, the critical load situation is identified The Fourier composition of walking loads is then considered, examining both the loads produced by individual footfalls and the loads produced during walking. The general test procedure is described, the method used to evaluate the Fourier coefficients of the walking loads is explained, and the results obtained for the first eight Fourier coefficients are presented. A procedure for calculating the acceleration generated by walking is described, including a number of simplifications that are appropriate for determining the critical resonance response. The response of floors to crowd loads is then considered, using measurements made on two floors, and the peak accelerations are shown to be of an order similar to the maximum response produced by a single person walking at the critical rate. Finally, the main issues arising from this work are discussed. B.R. Ellis