Book Description

Please note that this is a scanned copy of a paper originally published in 1990, so the text is not as clear as in documents created as pdf files.

Supplement 3 to ’The designer’s guide to wind loading of building structures.’

Framed building structures can be more susceptible to wind forces during construction than when completed. The wind forces on the unclad structures can be comparable to those when the building is clad but there is often little dead weight to counteract tensions that may occur at joints and foundations due to uplift. Force coefficients calculated by the method of the UK wind code (British Standard Code of Practice CP 3:Chapter V:Part 2) for multi-framed structures are known to be very conservative, particularly when the number of frames is large. This guide has been developed to provide a quick but realistic assessment of the wind forces in these conditions.

The guide covers choice of the design wind speed for temporary conditions, and provides up-to-date guidance on drag forces on multiple frames. Graphs of force coefficient against solidity ratio and number of frames are provided for rectangular buildings and guidance is given on the application of these curves to practical structures. In some cases the general height of surrounding buildings and direct shielding by specific upwind buildings can substantially reduce the wind loads on downwind building frames. In some circumstances it may be considered worthwhile to take account of these effects in temporary stability calculations, and some recommendations for their assessment are given in the Appendix.

This guide should be used in conjunction with CP 3:Chapter V:Part 2 for basic wind speeds and other aspects not covered in the guide. Wind loads calculated using this guide are compatible with those of CP 3:Chapter V:Part 2; they are working (characteristic) loads to which the appropriate partial load factors defined in the relevant design codes must be applied.

This design guide was written by Ove Arup & Partners in consultation with the Building Research Establishment and representatives of the steelwork construction industry.