Quick Search

Keyword(s)

Classification
- None Selected - Structures - Bridges Structures - Buildings, general Structures - Car parks Structures - Cinemas Structures - Cranes Structures - Dams Structures - Domestic buildings Structures - Earthworks Structures - Factories Structures - Freestanding walls Structures - Highways Structures - Marine Structures - Masts & towers Structures - Multi purpose structures Structures - Multi storey buildings Structures - Power stations Structures - Railways Structures - Retaining walls Structures - Scaffolding Structures - Schools Structures - Sewers Structures - Shopping areas Structures - Stadia Structures - Swimming pools Structures - Temporary structures Structures - Theatres and other entertainment Structures - Towers Structures - Tunnels Structures - Underpasses Structures - Underwater Structures - Walkways Structures - Other Materials - Aluminium Materials - Brickwork and blockwork Materials - Composites Materials - Concrete Materials - Glass Materials - Masonry (unclassified) Materials - Shotcrete Materials - Steel Materials - Stone Materials - Timber Materials - Other Building elements - Balconies Building elements - Barriers & handrails Building elements - Basements Building elements - Beams Building elements - Ceilings Building elements - Chimneys Building elements - Cladding Building elements - Columns Building elements - Connections Building elements - Equipment Building elements - Facades Building elements - Fixings Building elements - Floors Building elements - Foundations Building elements - Frames Building elements - Ground anchors Building elements - Joists Building elements - Piles Building elements - Roofs Building elements - Slabs Building elements - Stairs Building elements - Trusses Building elements - Walls Building elements - Other Concern - Appointment Concern - Building control Concern - Building regulations Concern - Checking Concern - Climate change Concern - Codes and standards Concern - Communication Concern - Compliance Concern - Contracts Concern - Corrosion Concern - Deformation Concern - Design Concern - Deterioration Concern - Disproportionate collapse Concern - Documentation Concern - Drainage Concern - Dynamics Concern - Education and training Concern - Equipment Concern - Explosions Concern - Extreme weather Concern - Fees Concern - Fire Concern - Gas Concern - Groundwater Concern - Impact Concern - Loadings (vertical) Concern - Materials Concern - Near hits & near misses Concern - Products Concern - Quality Concern - Reinforcement Concern - Responsibility Concern - Risk Concern - Robustness Concern - Safety reporting Concern - Seismic Concern - Software Concern - Soils Concern - Stability Concern - Supervision Concern - Techniques Concern - Temperature Concern - Welding Concern - Wind loading Concern - Workmanship Concern - Other Process - Change of use Process - Construction Process - Demolition Process - Design Process - Erection Process - Excavations Process - Falsework Process - Formwork Process - In use Process - Inspection Process - Maintenance Process - Refurbishment/Alterations Process - Repair Process - Scaffolding Process - Temporary works Process - Underpinning Process - Workmanship Process - Other Failure - Collapse Failure - Component failure Failure - Falling items Failure - Other

Ceiling collapse in cinema No 3

Report ID: cross103

Published: Newsletter No 10 - April 2008

Source: CROSS

Report Content

A third cinema had several separate auditoria. Each had a ceiling consisting of a metal grillage supporting plaster board and on top of that was network of cables and ventilation ducts. The net loading was quite heavy at about 70 kg/m2. The load transfer system between separate elements was complicated but the whole was held up on straps fixed to the underside of a concrete soffit by a mixture of shot fired nails and proprietary drilled in sockets. The strap top was bent over at 900 to allow the fixings to be made through the horizontal part and consequently the fixings were subject to direct load and bending.

 

Some of the fixings pulled out in one of the auditoria (both shot fired nails and drilled in fixings) setting up a cascade reaction such that the whole ceiling fell down. Inspections were carried out in the adjoining auditoria and it was found that the fixings there had partially failed. The collapse occurred at night so no one was injured.

Comments

 This and other similar reports demonstrate a concerning trend of progressive collapse mechanisms in public buildings where there is a high probability of casualties in the event of failure. In each case there has been a fault, or a combination of faults, in the design, selection or installation of fixings, and a lack of appreciation of the magnitude of the dead loads from acoustic ceilings. These would have been compounded because it is not usually possible to inspect the fixings after installation. The danger of falling ceilings is not new; there is old cinematographic legislation that was brought in because of failures with lath and plaster ceiling fixings. The Home Office document ‘Recommendations on Safety in Cinemas 1955’, and which is still relevant says: “Ceilings shall be in such a condition as not to cause a danger to persons visiting the premises”.

 There are other examples where the failure of a single component must not compromise the whole; for example cable stayed bridges are designed so failure of one stay does not cause the bridge to come down. Similarly what is needed for heavy ceilings is a robust design with a sensible appreciation by designers of the importance of what might appear to be trivial structural detail. There must be a sound design tracing load paths back to a solid platform with a responsible person in charge. It may be that guidance there should be provided in Part A of the Building Regulations in a similar manner to the existing guidance on cladding systems.

 SCOSS has been concerned about ‘fixings’ of various kinds for some time and these collapses illustrate very well the ‘3Ps’ promulgated by SCOSS to illustrate the wide causes of failure:

 

People	Those involved exhibiting a lack of structural engineering competence such that the safety critical implications of the work were not recognised.
Process	Lack of attention given to the procurement of the work and in particular to ensure that one competent party is responsible for the overall design. A failure to appreciate that these support systems are just as important as primary structural members. Lack of supervision and checking of installations.
Product	Specification (or choice) of the wrong product i.e. not fit for purpose.

 Fixing failures such as the 1981 Hyatt Hotel walkway collapse in which 114 people died demonstrate the magnitude of tragedies that can unfold. 

Back