Ronan Point Collapse Group 1:John Mulhaire David Hatch David Hatch Rob Patterson Rob Patterson Robert Morgan Robert Morgan

Background Housing sector decimated by World War 2 Solution: the construction of many high rise pre-cast buildings. high rise pre-cast buildings. Reasons: Saved land Large numbers of people Large numbers of people Constructed quickly Constructed quickly Cheap Cheap

Perhaps too Cheap!!!

The Building 110 apartments 22 storeys high Construction began on July 25 th & took only 2 years. Cost:£500,000

The method Larsen-Nielsen Developed in Denmark 1948 Walls, floors and stairways were all pre-cast Each floor was load bearing AND supported the floor above……

Collapse The southeast corner of the Ronan Point Tower collapsed on May 16, 1968 at approximately 5:45 a.m Collapse was initiated by a gas-stove leak on the eighteenth floor in apartment ninety Explosion knocked out the opposite corner walls of the apartment Walls were the sole support for the walls directly above, created a chain reaction Floors fell onto level eighteen, which initiated a second phase of progressive collapse.

Domino Effect

Domino Effect

Collapse (cont’d) 4 people died and 17 were injured The lack of fatalities were due to the fact that below floor 18 only the kitchens were destroyed

Layout

Technical aspects Public pressure led to an government inquiry Revealed that strong winds and/or the effects of a fire could also have caused a progressive collapse The building was designed to withstand wind velocities of up to 63mph However a wind of 105mph could be expected at 200 feet above the ground every 60years, within the life expectancy of the building

Technical aspects (cont’d) Building code used for the design of the building were published in 1952 however they weren’t kept up to date In 1963 a new study showed higher than stated winds were likely Fire also would have had a similar effect on Ronan Point It was estimated that fire could so expand and ‘arch’ the floor slab and bend the wall panel 16 years after the collapse architect Sam Webb conducted a fire test which proved this theory

Professional aspects Findings of poor workmanship led to the demolition of the remaining Larsen – Nielson system built towers. Findings of poor workmanship led to the demolition of the remaining Larsen – Nielson system built towers. The collapse initiated changes to the regulation codes Building codes now take in account for the possibility of progressive collapse and of forces from an internal explosion Also require minimum amounts of ductility and redundancy.

Educational aspects An example of what can happen when an alternative load path is not provided The importance of building codes the importance of monitoring construction quality