SR14 Serviceability criteria for buildings (2007)

The increasing use of high-strength materials in building constructions often results in relatively flexible components, which are more prone to deflection problems. Such problems manifest themselves in various ways, including annoying vibrations, unsightly misalignment and, albeit infrequently, structural failure.

Deflection is recognised as a serviceability limit state. Several limits are identified relating to aesthetics, felt movement, vibration, cracking of finishes and potential structural damage. The qualitative assessment of acceptable deflection limits is presented in this report. Methods of analysis for deflection and limits applied overseas are considered.

Deflection limits and the controlling criteria are presented in the form of tables that correlate to the location and function of components. The report discusses the parameters assumed when determining deflection (degree of end fixity, E and I values, loading regime, combined displacements) and the sensitivity of the calculated deflection to these variables.