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CROSS Safety Report

Underpass ceiling collapse

Report ID: 140 Published: 1 July 2009 Region: CROSS-UK

This report is over 2 years old

Please be aware that it might contain information that is no longer up to date. We keep all reports available for historic reference and as learning aids.


Six months after completion, the ceiling structure to the soffit of an underpass collapsed.

Key Learning Outcomes

For civil and structural design engineers:

  • Connections can often be the weak link in structures and attention to detail is required to ensure what is designed can be fabricated

  • Careful consideration is required for connections, particularly at interfaces between different materials. The role of tolerances should not be overlooked.

  • An attribute of ‘safety’ is to assure that the design is not disproportionately vulnerable to minor error

  • The recent alert by the Standing Committee on Structural Safety (SCOSS) – The selection and installation of construction fixings, provides helpful guidance

Full Report

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The Full Report below has been submitted to CROSS and describes the reporter’s experience. The text has been edited for clarity and to ensure anonymity and confidentiality by removing any identifiable details. If you would like to know more about our secure reporting process or submit a report yourself, please visit the reporting to CROSS-UK page.


This was an underpass for cars and pedestrians to access the central courtyard of a residential complex. The soffit of the structure was finished with an internal suspended ceiling construction anchored to the concrete soffit. The ceiling was boarded and rendered.

Six months after handover and whilst the residential building was inhabited there was a total collapse of the ceiling structure. It is believed that the failure was caused by wind suction. Fortunately, it happened late at night and there were no injuries. The ceiling was replaced by a structural frame of cold rolled steel.

Expert Panel Comments

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Expert Panels comment on the reports we receive. They use their experience to help you understand what can be learned from the reports. If you would like to know more, please visit the CROSS-UK Expert Panels page.

It is fortunate that most collapses of this type reported to CROSS have occurred at night or other times where no one has been underneath. Indeed, this represents one of the strengths of the scheme in that trends can be detected before the headline cases of deaths and injuries from structural failures. However, the information is only of value when action is taken and it may be timely to give more publicity to the Standing Committee on Structural Safety (SCOSS) alert – The selection and installation of construction fixings.

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