Author: Evans, C J
First published: N/A
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Evans, C J
The paper discusses the more usual causes of structural failure and deterioration found by the authors in ancient structures. Seven particular problems and their solutions are described:
The Divinity School and Bodleian Library, Oxford,
The Church of St. Peter Mancroft, Norwich,
The Woolhouse, Southampton,
All Souls College, Oxford,
Pembroke College, Oxford,
E.W.H. Gifford and P. Taylor
The following is an abstract of a paper which is filed in the Institution's Library (reference X(8)). Copies are available for borrowing by members of the Institution in the United Kingdom or can be consulted at the Institution.
Several well-known forms of construction contain flexible cables as structural components, e.g. the guys of guyed masts, the suspension cables of suspension bridges,
the wire ropes used on cableways, and the conductors of overhead electric lines. With all these structures it is a matter of common experience that the stiffness of the cable element is very much less in a transverse direction than in an axial direction. This feature has very important side effects since it makes it possible for the cable,
if suitably excited, to undergo low frequency large amplitude oscillations in a transverse direction. In practice such phenomena are by no means uncommon and in the following work a theoretical and experimental investigation of the behaviour of a cable executing free oscillations in its own vertical plane are studied. Such problems arise when a cable carrying some arbitrary load system suddenly sheds all or some part of this. Approximate solutions are given based on two premises. In the first the self-weight of the cable and its applied loads are treated as a continuous distribution along the cable; this is referred to as the 'continuous mass model'. In the second the weight is considered concentrated at a finite number of equidistant points along the cable. This arrangement is referred to as the 'lumped mass model'.
Mr. W. J. Larnach (Associate-Member) writes:-
‘This paper is of particular interest since it describes a method for the calculation of influence lines which in essence is identical with that which I have presented in an earlier paper1 and in my recent book. The only point of difference is the treatment of the effect of sidesway; the author uses an application of the reciprocal theorem (first proposed, it seems, in his reference 1) whilst I adopted the technique of shear balance.'