Not only the design and planning professions, the building industry and the national economy, but also every resident in South Africa will be affected by the new National Building Regulations which came into force on September 1. Although regarded in general as a very significant improvement on the previous situation, not everybody is satisfied with all aspects covered by or omitted the new regulations. At a special seminar organized by SAlCE's Division of Urban Engineering recently, more light was thrown on many aspects of the new laws.
Geotextiles can be used to prevent pumping distress on railway tormallons. Geotexille usage to date has however been limited by the unacceptable degree of holing which has occurred in service. Guidelines, based on field experience over the past 10 years, are given for the selection and installation of geotextlles. The application of these guidelines is expected to result in a slgnificant reduction In the degree of holing. The role of geotexliles and the need lor protective layers are discussed. It is concluded that geotexille separation layers have a great potential for use in remedial works on distressed railway formations.
Following some experimental observalions in the Crocodile River near Brits, it was shown in this paper Ihal the Colebrook-White equation loses its validity in the extreme rough turbulent zone where Manning's n exceeds about 0,05. Consequenlly, it was recommended that the Colebrooke-White equation should not be applied in this zone.