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Ronan Point Collapse

Group 1: Martin Phelan Michael Grimes Matthew Arnold

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

Ronan Point:Pre-Collapse

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

Example of Larsen-Nielsen Construction

Collapse• 16th May 1968 5.45 am

• Small explosion on 18th floor

• Caused huge structural failure

• Load bearing flank wall blown out

• 4 deaths

• 17 Injuries

Could have been

much more!

“Domino effect”

“flaking like a pack of playing cards”

“I wouldn’t live there rent free"

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

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.

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

Questions?