The basis of the so-called elastic theory is that a stiffened suspension bridge is a linearly elastic statically-indeterminate structure. The theory is appropriate when the stiffening (deck) girder is the primary source of stiffness, as for some 19th century bridges for railways and for some more recent minor structures. Otherwise, gravity stiffness is dominant, as (for example) for recent major suspension road bridges designed by the modern so-called deflection theory (for such structures the elastic theory would overestimate girder bending moments by a factor of two at least, according to Martin). Professor T.M. Charlton
This paper describes both experimental tests and numerical calculations which were performed to verify an ancdytical method of calculating floor vibrations induced by dance-type loads. The basic experimental set-up is described, and experiments which were undertaken to investigate the interaction between people and structures are discussed. To demonstrate the accuracy of the analytical load model, measured and calculated load time histories are compared. The response of a structure to dance-type loads is then checked by comparing finite element and analytical solutions and by comparing experimental and analytical solutions. To emphasise the importance of choosing an appropriate load model when calculating response, examples of resonant response caused by the sixth multiple of the dance frequency are provided. Finally, comparisons are made with the results from similar work conducted at NRC, Canada. B.R. Ellis and T. Ji
This paper is concerned with the response of floors to loading produced by dancing and aerobics, especially where the dancing involves jumping. Its purpose is to provide un analytical method for determining the response of floors to these loads. The characteristics of the load time history are dealt with initially, and, for calculation purposes, the load is expressed in terms of Fourier series. An analytical solution of the forced vibration of simply supported floors is developed, using plate theory and considering several modes of Vibration. The number of Fourier terms that should be considered in the analysis is determined. The solution is then extended for other structures with different boundary conditions. It is predicted that significant accelerations may occur on relatively stiff floors induced by higher Fourier components of the load. (Verification of the method is provided in ref 6.) T. Ji and B.R. Ellis
The end of a 6-year term as a Part 3 examination advisor may be an opportune time to air a few personal thoughts on the past, present and future of this examination. D.J.A. Alsop