Prefabrication Technology for Upgrading Public Housing in Singapore: a Case Study of Chin Swee Upgra

Hip Roofs and Rafters Walter Redmond has written from Smith’s in Bermuda, giving a new twist to this topic: I was greatly interested in the article (4 January 2000) regarding hipped roofs and rafters, especially Professor Arthur Bolton’s comments. The problem of hipped roofs also exists in Bermuda. I have been in the construction/engineering industry for the past 35 years, dealing with timber hipped roofs from the perspective of both industries.

We are accustomed, sometimes, to applying load to beams without giving much thought to the inherent stiffness of the load itself, either in the direction of the force or normal to it. Whether or not we consider arching of masonry is a matter of ‘engineering judgment', perhaps influenced by the requirements of BS 5977: Part 1: Lintels. Studwork partitions have considerable load-relieving stiffness, which we wisely ignore, at least for strength considerations. Items of plant, such as water tanks, have inherent degrees of stiffness that, frequently, are able to distribute load towards the beam’s bearings. In a particular situation, it may be worthwhile considering these factors when we make an ultimate or serviceability limit state assessment of a beam’s behaviour. Richard Harris

Mr A. Cauchi (M) It is well-known that the earthquake of 1693 had a devastating effect on buildings all over Sicily , as well as in Malta. However, I wish to state that many buildings survived that earthquake in Malta and these were also built in stone. The probable reason is that some buildings were better built than others: e. g. the Norman Cathedral of Mdina, probably built around AD 1200, was totally demolished, only its wooden doors surviving, while the Birgu Norman Tower (about 35m high x about 5m at its base and also built around AD 1200 or before) survived all earthquakes and was to be demolished by bombs only in World War 2. Castle Sant Angelo (one of the oldest buildings in Malta) also survived them all and still stands today.