This PPT explains about a building in UK, which has a weird history

1. Ronan Point Apartment Tower Collapse
Course Instructor:
Dr. Sri Kalyana Rama Jyosyula
Department of Civil Engineering
Presented by
Vigneshwar S (SE22MCIE003)
Syed Tariq S (SE22MCIE002)
Md. Mustafa Ahmed (SE22MCIE004)
CE5022 TALL BUILDINGS
PRESENTATION – 4
20-03-2023 1

2. • Ronan point was a 22-storey tower
block in canning town in London.
• Precast panels without structural frames.
• Partial collapse
• 4 – killed /17 – injured
• Flaw in both design and construction
Source: https://engagedscholarship.csuohio.edu/
INTRODUCTION

3. WHAT HAPPENED…!
May 16, 1968, the occupant of
apartment 90 on the 18th floor of the 22-story
Ronan Point apartment tower lit a match for
her stove to brew her morning cup of tea.
1. Gas explosion blew out the walls of her
apartment, and initiated a partial collapse.
2. Displacement of walls initiated a
progressive collapse upward and then
downward.
https://en.wikipedia.org/wiki/Ronan_Point

4. STRUCTURAL SYSTEM
One of many identical high-rise
precast concrete flat-plate structures
constructed during this time.
• Larsen–Neilsen system
• Gravity loads only through LBW
• The wall and floor panels fitted in slots
• Joints –dry pack mortar.

5. COLLAPSE
• The collapse sheared off the living room
portion of the apartments, 17–22,
• These walls were the sole support
collapse propagating upward.
• The four floors fell onto level 18, which
initiated a second phase of the collapse.
• This sudden-impact loading on floor 18
caused it to give way, smashing floor 17
and progressing until it reached the
ground.

6. INVESTIGATION
• The nut was previously fractured by overtightening, causing the gas to have
accumulated at the ceiling
• The explosion was not significant in magnitude. The resident’s hearing had not
been damaged < 70kPa.
• The Building Research Station and Imperial College of London - 19.3 kPa.
(Interior walls 1.7 kPa / Exterior walls - 21 kPa).
Ultimately, the collapse of Ronan Point was due to its lack of structural redundancy.
Its design did not incorporate fail-safe mechanisms, and provided no alternative load
paths for the upper floors should a lower level give way

8. TECHNICAL ASPECTS
• The investigation revealed that strong winds and the effects of a fire in the
building could also have caused a progressive collapse.
• Ronan Point was designed to withstand wind velocities of only 100 kph (63
mi/h), but later research indicated that for buildings of that height higher wind
velocities could be expected.
• It was noted that “the structure had been designed to comply with fifteen-year old
wind load codes”. The building code (1952).
• According to the inquiry, “the suction effect of the pressures applied by such
winds, in particular the opening of the joints as the tower block bent in the wind,
would have similar effect to the explosion.
• “It is estimated that fire could so expand and ‘arch’ the floor slab and bend the
wall panel, as to displace or rotate a joint to a dangerous degree

9. SAM WEBB, WHISTLEBLOWER
There would be gaps between walls and floors through which smoke would pass …
you’d be able to hear people and their televisions on different floors
The building was not demolished in the traditional fashion. Instead, Ronan Point was
dismantled floor-by floor so that the joints could be studied. The site was an “open site” for
anyone interested.
“I knew we were going to find bad workmanship—what surprised me was the sheer
scale of it. Not a single joint was correct”.
Structural integrity against progressive collapse, or “robustness,” should be taught in
engineering schools.
Collapse illustrated a lack of provisions for general structural integrity in existing building
codes and led to changes in the United Kingdom, the United States, and Canada.

10. " SKYLINE PLAZA – CASE STUDY "
04-06-2023 10

11. SKYLINE PLAZA - INTRODUCTION
• Large complex located in Bailey’s Crossroads, Virginia.
• It contains eight apartment buildings, six office buildings, a hotel, and
a shopping center.
• It was designed as a 26 story apartment complex with a four-storey
basement and a penthouse.
• Structural Engineer: Heinzman, Clifton, and Kendro
• General Contractor: Charles E. Smith Construction
• Concrete Subcontractor: Miller & Long Construction (Ross 1984)

12. DESIGN PARAMETERS
• Flat plate type slab.
• Floor slab Thickness – 8”. Floor to floor height – 9’
• Length of building – 336’.
• Each floor slab poured in four sections
• The design strength of the concrete columns and floor slab is listed
below:
Floor Base to 7th 7th to 17th 17th to top
Column 5000 4000 3000
Slab 3000 3000 3000
Design strength of concrete Columns & Slabs (in psi)

13. CATASTROPHIC FAILURE
• In the midst of construction on March 2, 1973 , the building got
collapsed.
• The incident occurred at around 2:30 PM in the afternoon.
• Death – 14 construction workers.
• Injured – 34 others.

14. CAUSES FOR FAILURE
After conducting FEA, It is concluded that:
• Improper removal of forms supporting the 23rd floor.
• Increased shear force around the columns.
• The recently poured concrete had not yet reached its full
strength capacity.
• Trigger mechanism of the collapse was punching shear
failure around a number of columns on the 23rd story.
• Columns #67, #68, #83, and #84 all experienced shear
stress greater than the shear capacity of the concrete slab.
• This indicates that the partial or complete removal of
forms was a major contributing factor to the collapse.

15. LESSONS LEARNT
• In slab design, it is now encouraged to place rebar continuously
through the slab-column intersection at the top and bottom of the
slab.
• If the slab fails in punching shear, the bottom bars act as a
catenary and prevent the collapse of the slab onto the structure
below.
• Concrete testing must be performed before the removal of
shoring.
• Formwork and shoring needs to be detailed by the contractor.
• Inspections must verify that the contractor is properly shoring
floors above and that poured concrete is meeting its design
strength.

16. IRONY
“So even though the contractor did not comply with the shoring
requirements specified in the construction documents, the collapse
was still found to be the fault of the designers”

17. "The Walkie Talkie Building"
04-06-2023 17

18. INTRODUCTION
•Location – Fenchurch street, London, United
Kingdom
•Architect – Rafael Vinoly
•Height of the building up to tip – 176 m (579 ft)
•Number of floors – 34 + Three storied sky garden
•Floor area – 62,100 sq.m

21. CONCEPT OF SUSTAINABILITY
• A sustainable building should have its environmental impact
minimized over service life.
• One obvious environmental impact of a building is its energy demand.
• To minimize the cooling load inside a building, most modern building
envelops are made of a spectrum selective glass to achieve optimal
energy consumption.
• However, this mechanism may lead to environmental problems such
as discomfort glare and unexpected thermal load on surrounding
areas.

22. A FATAL FLAW

23. CONSEQUENCES
• By the time of the sunlight concentration incident in 2013, the
building had become an iconic volume and shape in the skyline of
London.
• Plastic parts (wing mirror, panels and badge) of a car parked at street
level near the building being melted because of 'death ray'.
• Surfaces exposed to hotspots created by the building were reported
to reach temperatures of up to 91.3◦C.
• The architect of the building at 20 Fenchurch Street told the media
that he knew reflected sunlight could cause problems but that there
was a lack of tools and software to assess and prevent these
problems.

24. Reference: https://www.bbc.com/news/uk-england-london-23930675

25. Reference: https://www.dailymail.co.uk/news/article-2409710/Walkie-Talkie-building-melting-bicycles-
Light-reflected-construction-City-skyscraper-scorches-seat.html

26. Reference: https://www.dailymail.co.uk/news/article-2409710/Walkie-Talkie-building-melting-bicycles-Light-
reflected-construction-City-skyscraper-scorches-seat.html

27. ACTION PLAN - RECTIFICATION
• Large umbrellas and reflective screens as temporary
solution.
• Non-reflective Film Application.
• The new design incorporated horizontal sunshade fins
into the facade.
• Simulations and Testing.
• Installation of Modified Glass Panels.