RR917 - The effect of wind loading on the jib of a luffing tower crane
Following a luffing crane collapse in Liverpool in January 2007, the UK Health and Safety Executive (HSE) were concerned that standards concerned with tower crane manufacture may not offer sufficient protection in relation to slack rope conditions on a luffing tower crane. HSE wished to determine if foreseeable conditions could be identified that could give rise to dangerous operational conditions below maximum in service wind speeds. A luffing tower crane was erected at the Health and Safety Laboratory (HSL), Buxton.
Measurements of wind speed and luffing system tension were taken to determine combinations of wind
speed and jib elevation likely to result in slack luffing rope conditions. Calculations of jib wind loading
were carried out using four standards, FEM 1.001, FEM 1.004, ISO 4302 and BS EN 13001- 2:2004. Wind
loading calculations compared closely with values obtained during the tests. The jib was found to be
susceptible to uncontrolled movement below the maximum in service wind speed and at jib elevations
within the limits specified by the manufacturer. Differences of up to 150% between wind speed readings
provided by anemometers fitted at the jib outer end and the ‘A’ frame were experienced during the testing.
This report and the work it describes were funded by the Health and Safety Executive (HSE). Its contents, including any opinions and/or conclusions expressed, are those of the authors alone and do not necessarily reflect HSE policy.
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