Report BR 173 Design guide for wind loads on unclad framed building structures during construction

Publication Year

1990

Document Status

Current

Abstract

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 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.

Author

Willford, M. R. and Allsop, A. C.

Publisher Information