Temporary Demountable Structures
The Institution of Structural Engineers, supported by the Health and Safety Executive, has published guidance on Temporary Demountable Structures. This fourth edition contains essential information on the procurement, design, erection and use of temporary demountable structures, including: grandstands; stages; fabric structures; hospitality units; and fencing and barriers. Towers and masts that support media facilities are also included.
Demountable structures are widely used for a variety of functions at public and private events and can be found at exhibitions, sporting events, musical concerts and social occasions. Some may carry substantial numbers of people during major events and structural safety is extremely important.
What’s in the guidance?
Detailed recommendations are given for grandstands, stages and special structures. There is a section on fabric structures and further advice on ancillary and special structures to support lighting equipment, video screens, loudspeakers, and the like.
The Guide is based on practice in the United Kingdom and Europe but the principles described are appropriate for application elsewhere. It is also intended for clients, event organisers and venue owners, designers, regulatory and local authorities, as well as contractors and suppliers of demountable structures. It is concerned with the structural safety and adequacy of demountable structures used for temporary purposes and also with the overall planning and management of events.
The temporary structures industry differs from that of permanent structures in that it is much more fluid. At many events there are short timescales for the whole design and construction process. Responsibilities may be divided with no clear chain of command and regulations are complex. A temporary stage may be erected for a small event, the performance held, and the structure dismantled within a few days. Large events usually have a formal management process in place but there are still anomalies with control and with quality assurance.
Another difference with more traditional buildings is that imposed loads from people and wind are relatively high in proportion to dead load. There is more dynamic behaviour involved and different hazards to be considered. Very large numbers of spectators are accommodated in such structures so the life-safety risks have to be taken extremely seriously.
The Sports Grounds Safety Authority contributed to the development of the guidance via the Advisory Group on Temporary Structures.
Tools and resources
Dynamic Performance and Testing of Grandstands
Dynamic performance requirements for permanent grandstands subject to crowd action - Interim guidance on assessment and design.The principal advice given in the Guidance concerns the recommended vertical natural frequencies and horizontal load resistance of grandstands considered necessary to provide the safety and comfort of the public at a range of sporting and other entertainment events.
When should the first annual inspection and structural appraisal be undertaken at a new, or recently completed, stadium?
It is usual that the safety certificate or operations manual will require ground management to obtain every 12 months , a report from a competent person that the structural elements have been inspected and found to be adequate.