Structural-safety

Alastair Soane

November 2011

Structural-safety incorporating CROSS and SCOSSStructural-safety incorporating CROSS and SCOSSStructural-safety incorporating CROSS and SCOSS

Ronan Point 1968

Milford Haven 1970

SCOSS

• collects data from public sources on failures

• consider whether unacceptable risk exists

• publishes Alerts

• help to influence changes to improve structural safety

CROSS

• collect confidential data on concerns

• provide comments in relation to these concerns

• maintains a data base of reports and publications

• promote a positive attitude to learning from experience

Confidential reporting

Sponsors

• Institution of Structural Engineers

• Institution of Civil Engineers

• Health and Safety Executive

Supporters• 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

normal operations

incidents

injury

fatal incidents

precursors

diagram courtesy of ASRS

Pyramid of risk

HSE or other authorities

CROSS

Precursors should be reported internally and can be reported to CROSS

Operating system

analysis and comments

Reports

newslettersand

data base

influenceand

change

• reporting from firms encouraged

• reports are confidential

• identities are removed

• analysis and comment by expert panel

Reporters

Examples from building control

29 defective submissions

10 dangerous

– 9 from sole practitioners

– 13 from small practices

– 5 from medium sized practices

– 2 were from “top” practices 0

2

4

6

8

10

12

14

material

steel timber masonry concrete

Reports by sector

Fig. 1 Reports by sector

demolition2%

appointment2%

design22%operation

29%

construction45%

Blind bolts

• Steel frame collapse

• Staircase collapse

• Winch failure on offshore rig

imported products

British Waterways

8 tonne counterweight

hidden fixings

Pre-stressed tanks

cable corrosion

Acoustic Ceiling Collapses

fixings

Public art

not enough engineering

Proprietary roof system 2011

failure at support

more data needed

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 2 Unsafe pediment

Figure 3 Decaying stonework

Figure 4 Dangerous slates

Figure 5 Cracked stonework

age and weathering

Distribution of reports

0

20

40

60

80

100

120

140

160

180

200

Aug-05

Sep-05

Oct-05

Nov-05

Dec-05

Jan-06

Feb-06

Mar-06

Apr-06

May-06

Jun-06

Jul-06

Aug-06

Sep-06

Oct-06

Nov-06

Dec-06

Jan-07

Feb-07

Mar-07

Apr-07

May-07

Jun-07

Jul-07

January 2007

Snow load collapses 2010/11

depth of ice and snow

Water ballast for temporary structures

reliance on non-structural components

Concrete ballast

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