Disclaimer: This resource has been prepared to help the workplace parties understand some of their obligations under the Occupational Health and Safety Act (OHSA) and regulations. It is not legal advice. It is not intended to replace the OHSA or the regulations. For further information please see full disclaimer.
This information bulletin is intended to raise awareness about the potential for serious injuries that could result from the collapse of timber dome structures. Timber dome structures are usually used by transportation and road maintenance authorities, municipalities, and snow removal contractors to protect and store sand and salt used for winter road maintenance.
In March and April 2014, four timber dome structures collapsed in various locations in Ontario. Each collapse was started by an unbalanced snow load that was imposed on the structure – usually at the lower panels of the domes. Contributing factors may have included a lack of snow removal at the base of the domes, inadequate structural inspections, construction issues with the panel glued joints and the lack of a maintenance program.
Timber dome structures are located throughout Ontario. A large number of these are in exposed areas that are frequently subject to weather extremes, such as heavy snow and high wind. In addition, these timber dome structures are highly susceptible to heavy equipment damage. These factors, if not monitored, will reduce the service life of the individual structural components, which undermines the structural integrity of the entire dome and can lead to structural collapse.
Employers and owners of timber dome structures should have the structural integrity of the domes inspected by a professional engineer (P.Eng) familiar with timber dome construction. Any design flaws or other deficiencies identified by the P.Eng should be repaired and corrected as recommended.
Relevant legal requirements under the Occupational Health and Safety Act (OHSA) include but are not limited to:
For more information, contact the Ministry of Labour Health & Safety Contact Centre toll free at 1-877-202-0008.
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