Structural-safety
Structural-safety incorporating
CROSS and
SCOSS
Structural-safety
incorporating
CROSS
and SCOSS
Alastair Soane
November 2011
Ronan Point 1968
Milford Haven 1970
SCOSS
CROSS
• collects data from public
sources on failures
• collect confidential data on
concerns
• consider whether
unacceptable risk exists
• provide comments in relation
to these concerns
• publishes Alerts
• maintains a data base of
reports and publications
• help to influence changes to
improve structural safety
• promote a positive attitude to
learning from experience
Confidential reporting
Sponsors
Supporters
• Institution of
Structural Engineers
• Institution of Civil
Engineers
• Health and Safety
Executive
• UK Bridges Board
• Highways Agency
• British Parking Association
• Department of Communities
and Local Government
• DRD Northern Ireland
• Local Authority Building
Control
• Scottish Government Building
Standards Division
Pyramid of risk
fatal incidents
HSE or other
authorities
injury
precursors
CROSS
incidents
normal operations
diagram courtesy of ASRS
Precursors should be reported internally and
can be reported to CROSS
Operating system
Reports
• reporting from
firms encouraged
influence
and
change
analysis and
comments
newsletters
and
data base
• reports are
confidential
• identities are
removed
• analysis and
comment by
expert panel
Reporters
Examples from building control
29 defective submissions
14
12
10 dangerous
10
– 9 from sole practitioners
8
– 13 from small practices
6
– 5 from medium sized practices
– 2 were from “top” practices
4
2
0
material
steel
timber
masonry
concrete
Reports by sector
demolition
2%
appointment
2%
design
22%
operation
29%
construction
45%
Fig. 1 Reports by sector
Blind bolts
• Steel frame
collapse
• Staircase
collapse
imported
products
• Winch
failure on
offshore rig
British Waterways
8 tonne
counter
weight
hidden fixings
Pre-stressed tanks
cable
corrosion
Acoustic Ceiling Collapses
fixings
Public art
not enough engineering
Proprietary roof system 2011
more data
needed
failure at
support
River Crane bridge
scour
SCOTCROSS
• fatality due to falling masonry in 2001
• legal recommendation for a survey
• started August 2005 – completed August 2007
• 1,186 reports from 25 LAs
• 12 injuries from falling debris
• abundance of statistical data
Masonry façade degradation
form of construction, age, and weathering
Typical
concerns
Figure 3 Decaying
stonework
Figure 2 Unsafe
pediment
Figure 5 Cracked stonework
age and weathering
Figure 4 Dangerous
slates
Distribution of reports
200
January 2007
180
160
140
120
100
80
60
40
20
0
Aug- Sep- Oct- Nov- Dec- Jan- Feb- Mar- Apr- May- Jun05
05
05
05
05
06
06
06
06
06
06
Jul06
Aug- Sep- Oct- Nov- Dec- Jan- Feb- Mar- Apr- May- Jun06
06
06
06
06
07
07
07
07
07
07
Jul07
Snow load collapses 2010/11
depth of ice and snow
Water ballast
for temporary
structures
Concrete
ballast
reliance on nonstructural
components
Wind turbine in Wyoming February 2011
-48 degrees C
LPS structure demolition 2010
lack of robustness
Exploding concrete
unexpected chemical reaction
Degradation of 1960s MSCP
form of construction,
age, salt, lack of
maintenance
Timber frames during construction
acceptable
risk?
Structural-safety International
• Engineers Australia close to joining the scheme
• Co-operation with ABC Meldpunt in Holland
• BCA in Singapore are interested
• Malaysian authorities have made enquiries
• CEBC are planning an EU wide defects reporting system
and are monitoring CROSS
• concept is for an International Group of organisations who
run similar programmes to share information through a
common data base.
Twente stadium roof 2011
bracing incomplete
Cologne records office
collapse of
adjacent cut
Results from CROSS
• BSI and CFA review of fixing standards
• CIRIA review on major events in construction safety
• Highways Agency have embedded CROSS procedures
• DRD Northern Ireland have followed suit
• Evidence submitted to Building Regulations for England
on robustness and other matters
• Scottish Government’s review of hazards from older
buildings
• BSI looking at snow loading
• BSI looking at shear concerns in concrete
Birmingham TV screen 2006
inadequate temporary structure
Ground supported stage structure
Indiana Stage roof 2011
SCOSS current top concerns
• Falsified documentation
• Quality of some imported steel components
• Temporary stage roofs
• Bolted fixings
• Robustness
• Fire and construction methods
Benefits
• Learn from the experiences of others
• Source of practical information
• Identification of pre-cursors to failure
• Tool for influencing regulations and codes
• Potential for avoiding or reducing failures
• Economically sound
• Ethically sound
The programme depends on receiving reports from
individuals, firms, and regulatory bodies. You can
participate by sending concerns in confidence to:
www.structural-safety.org