1. { Ronan Point Collapse Group 1: Martin Phelan Michael Grimes Michael Grimes Matthew Arnold Matthew Arnold

2.  Large number of tower blocks constructed in London during the 1960’s.  High-rise buildings constructed as a quick, cheap and economical solution to the post-war housing crisis.  Built by Taylor Woodrow - Major UK housing provider. Background

3. Ronan Point: Pre- Collapse

4.  Larsen-Nielsen system of construction used.   Precast elements formed off-site, moved into place and connected using bolts and mortar joints.   Minimised on-site construction. This was problematic due to lack of skilled labour at the time.   Each floor supported by load-bearing walls directly beneath. In effect the building was held together by gravity.   Lack of an overall structural frame. Hence lack of alternative load paths and limited structural redundancy.Design

5. Example of Larsen-Nielsen Construction

6. Collapse 16 th May 1968 5.45 am Small explosion on 18 th floor Caused huge structural failure Load bearing flank wall blown out

7. 4 deaths 17 Injuries Could have been much more!

8. “Domino effect” “flaking like a pack of playing cards” “I wouldn’t live there rent free"

9.  The Report of Inquiry into the Collapse of Flats at Ronan Point, Canning Town was published in August 1968.  This report concluded that “a gas explosion had triggered the collapse of a building that was structurally unsound.” Report

10. The design of the building was flawed.  The tower consisted of prefabricated panels without a structural frame.  There was not sufficient redundancy to allow for load redistribution in the event of a localized collapse.  The design wind pressures did not account for the building’s height.  The existing building codes were inadequate.  The Larsen-Nielsen system was extended past the point of safety without testing.  In addition the construction methods were also responsible for the structural failure, in particular quality control of workmanship was severely lacking.

11.  The collapse of Ronan Point led to the development of new regulation codes.  Immediately following the original report the government agreed to a dual standard for system-built flats, with all new structures being built to resist internal explosions of 35 kPa pressure while existing ones had to be strengthened to resist 17.5 kPa.  They also highlighted the need for ductility and redundancy in the structural design.  The subsequent inspection and demolition of Ronan Point, more than 15 years later, highlighted the extent of the poor workmanship in the building.  It is imperative that quality of workmanship is monitored onsite to prevent any abnormal structural loading or safety-issues throughout a building’s design- life. New Building Regulations

12. Questions?