Issue 11

During the course of the discussion, Professor Harris stated that the elliptical arch ribs carrying the road over the Claerwen Dam were of prestressed stone. If it is not too unseemly to hoist the President with his own petard, I must comment, 'Not so!' J.A. Williams

Mr. W. K. E. Jones (Andrews, Kent & Stone): It is most important that NHBC should give the widest possible publicity to the sorts of problem outlined in this paper-especially among their members.

Kwai Chung Incinerator is a four-stream refuse incinerator having a designed continuous capacity of 900 t per day, and a peak rating of 1200 t per day. Tenders for the mechanical plant were invited, assessed, and accepted by the Public Works Department before the detailed design of the civil and structural works described in the paper was begun. R.C.T. Ho, D.M.A. Hook and D.F. Marshall

The use of timber roof trusses has, during the past few years, become widespread in housing construction in Ireland. This paper discusses the position of timber in the building industry, and sets out the criteria used in drafting the Irish Standard for trusses. Also discussed is the approach adopted for controlling manufacture to the requirements of the standard. N.V. Torpey

The purpose of this paper is to outline some users' problems and matters of concern with regard to timber trussed rafters in the United Kingdom at the present time, and to discuss points relating to design, materials, fabrication, handling and fixing, and durability. J.R. Watson

Correspondence that has appeared in The Structural Engineer concerning timber trussed rafters is related to the BRE work on trussed rafters published in CP 83/78. W.H. Ransom

Excessive caution The point has been made in several contributions to this column that recent legal decisions concerning negligence on the part of approving authorities have led to excess of caution and unnecessary expense. Mr. S. B. Tietz takes up the issue in respect of foundations when he writes: There has been considerable discussion at different times regarding the effect of Anns v. Merton and the requests by local authorities to deepen foundations. One main factor missing in such discussions has normally been hard evidence. Verulam