Technical Guidance Note (Level 1, No. 20): Site Investigations

The twisting of elements within structures due to eccentric loading is something that is best avoided as far as is possible. Such actions develop torsion forces in elements against which they were not designed to withstand. This Technical Guidance Note concerns this buildability and detailing issue that structural engineers must become familiar with in order to avoid otherwise unforeseen problems that can lead to significant remedial works on site and in some cases failures.

This Technical Guidance Note is an introduction to the assessment of floor vibrations. Since the adventof lighter structures that have longer spanning elements within them, the built in dampening effectbuildings have had historically has become less pronounced. Despite this, floor vibration canbe an overlooked criterion during the design process. This can lead to expensive remedial works being carried out on structures after they have been built, as occupants complain of discomfort due to excessive movements and vibrations. (This article was updated in October 2016 to reflect errata issued since its original publication.)

This Technical Guidance Note concerns lateral loads that are applied to barriers and wheel axle loads from vehicles. Barrier loading is dealt with slightly differently to other forms of imposed loading. The nature of the loading can vary from people leaning against barriers to vehicles colliding with them at speed. Axle loading from vehicles has to be treated somewhat differently to other forms of imposed loading. While it is possible to assume a blanket area load to represent them, it is the point load from each wheel that needs closer attention.