Demolition of Arch Bridges

This paper is intended to show how wind excitation is a major effect in the design of steel chimneys. The static behaviour is well covered by publications and Codes, but the same is not true of the dynamic behaviour. Accordingly, this is presented in a form that closely parallels static methods and combines with the static calculations to obtain overall values of amplitudes, stresses or defections. Structurally sound approximations are given for values of the various parameters, which are within a few percent of ‘exact’. The calculations obtain the aerodynamic forces acting on a chimney, the resulting amplitude of vibration, the dynamic stress, and an assessment of whether metal fatigue might cause dificulty. An example is included of a 80m-high chimney of 3.25 m diameter to show that the dynamic procedure is quite feasible for hand calculations in a standard design office. Professor A. Bolton

This paper deals with the problems faced by the first arrivals in the new Colony of New South Wales, who lacked supplies of suitable materials and people skilled in building construction, and with the gradual development of a ‘colonial’ technology. The second generation produced some surprisingly good buildings in the circumstances. Professor H.J. Cowan

Dr R. D. Henshell (PAFEC Ltd) I should like to congratulate Dale Carlton and his team, and the other teams he works with, on holding a number of records in respect of the largest problems of different categories that have ever been tackled in the history of finite elements.