Download - COLLAPSE OF WORLD TRADE CENTRE
-
8/14/2019 COLLAPSE OF WORLD TRADE CENTRE
1/36
K.L.S SAHABANDUSPECIALIST ENGINEER (STRUCTURAL DESIGNS)
CENTRAL ENGINEERING CONSULTANCY BUREAU
THE WORLD TRADE
CENTER DISASTER
-
8/14/2019 COLLAPSE OF WORLD TRADE CENTRE
2/36
At 8:55 a.m
first plane crashes into the North Tower
-
8/14/2019 COLLAPSE OF WORLD TRADE CENTRE
3/36
-
8/14/2019 COLLAPSE OF WORLD TRADE CENTRE
4/36
At 9:03a.m
Second plane
crashes into the
South Tower.
-
8/14/2019 COLLAPSE OF WORLD TRADE CENTRE
5/36
-
8/14/2019 COLLAPSE OF WORLD TRADE CENTRE
6/36
-
8/14/2019 COLLAPSE OF WORLD TRADE CENTRE
7/36
-
8/14/2019 COLLAPSE OF WORLD TRADE CENTRE
8/36
-
8/14/2019 COLLAPSE OF WORLD TRADE CENTRE
9/36
-
8/14/2019 COLLAPSE OF WORLD TRADE CENTRE
10/36
At 9:50 a.m
South Tower begins
to collapse.
`
-
8/14/2019 COLLAPSE OF WORLD TRADE CENTRE
11/36
-
8/14/2019 COLLAPSE OF WORLD TRADE CENTRE
12/36
At 10:29 a.m
North Tower begins to collapse
-
8/14/2019 COLLAPSE OF WORLD TRADE CENTRE
13/36
-
8/14/2019 COLLAPSE OF WORLD TRADE CENTRE
14/36
Remains of the facade of Two World
Trade Centre is all that stands after
Tuesday's terrorist attack
Wednesday, Sept. 12, 2001 in New
York. (AP Photo/Nick Finely)
-
8/14/2019 COLLAPSE OF WORLD TRADE CENTRE
15/36
Fire-fighters work in the rubble of
the World Trade Centre towers in
New York, Wednesday, Sept. 12,2001. The towers collapsed
Tuesday after being struck by two
commercial aircraft's in a terrorist
attack. (AP Photo/Virgil Case)
-
8/14/2019 COLLAPSE OF WORLD TRADE CENTRE
16/36
TYPICAL ARRANGEMENT OF THE
TOWER
-
8/14/2019 COLLAPSE OF WORLD TRADE CENTRE
17/36
TYPICL FLOOR ARRANGEMENT
-
8/14/2019 COLLAPSE OF WORLD TRADE CENTRE
18/36
FLOOR / BEAM / COLUMN
ARRANGEMENT
-
8/14/2019 COLLAPSE OF WORLD TRADE CENTRE
19/36
TYPICAL DETAILS OF COLUMN
FOUNDATIONS
-
8/14/2019 COLLAPSE OF WORLD TRADE CENTRE
20/36
BASEMENT TYPICAL DETAILS
WORLD TRADE CENTER AND
-
8/14/2019 COLLAPSE OF WORLD TRADE CENTRE
21/36
WORLD TRADE CENTER AND
SURROUNDING BUILDINGSDAMAGE STATUS
-
8/14/2019 COLLAPSE OF WORLD TRADE CENTRE
22/36
STRUCTURAL ASSESSMENT
Structural Assessment done on 406 Buildings by 24
teams with total 170 engineers
No structural damages - 382 Nos.
Superficial and non-structural - 19 Nos.
Major structural damages - 5 Nos.
-
8/14/2019 COLLAPSE OF WORLD TRADE CENTRE
23/36
AS BUILT DRAWINGS
WHETHER DEBRIS WOULD SUPPORT CRANES,
WHETHER HEAVILY DAMAGED BUILDING WOULD STAY
STANDING.
WHETHER SURRYWALL WOULD STAND WITHOUT SUPPORT O
THE DEBRIS.
FOLLOWING INFORMATION WERE REQUIRED
ORGINALS STORED IN THE WTC TOWERSHAMPERED THE RESCUE OPERATIONS
-
8/14/2019 COLLAPSE OF WORLD TRADE CENTRE
24/36
RESCUE OPERATION
STRUCTURAL ENGINEERS ROLE
STRUCTURAL ENGINEERS WORKING ROUND THECLOCK ARE QUESTIONED :
CAN THIS PIECE OF STEEL BE REMOVED.
WILL THIS STRETCH OF RUBBLE SUPPORT ACRANE.
CAN PEPOLE WORK UNDERNEATH THE FACADEOF BUILDINGS WHERE HUGE PIECES OF STEELDEBRIS PROTRUDING FROM THE CLADDING.
-
8/14/2019 COLLAPSE OF WORLD TRADE CENTRE
25/36
PROBLEMS ASSOCIATED WITH
REMOVAL OF DEBRIS
STABIL I TY OF THE DIAPHRAGM WALL
During construction supported by Tieback Anchors.
After construction propped by basement slabs.
(Tiebacks are disconnected )
During the collapse of towers propped basementslabs were destroyed by fallen debris and wall was
restrained by well packed debris.
-
8/14/2019 COLLAPSE OF WORLD TRADE CENTRE
26/36
Removal of debris was not possible which
would destabilize the wall.
* Endangering the adjoining buildings
* flooding of the basement .* flooding of the under ground tunnels.
New anchor system was foreseen to stabilize the
slury wall.
-
8/14/2019 COLLAPSE OF WORLD TRADE CENTRE
27/36
POSSIBLE REASONS FOR
PROGRESSIVE COLLAPSE
Impact of the planes - No.
Lost of load bearing elements during the crash ofplanes.
Fire softening of steel load bearing elements andthe impact of collapsing of the top part of the tower
on to the bottom part.
-
8/14/2019 COLLAPSE OF WORLD TRADE CENTRE
28/36
FIRE SOFTENING OF LOAD BEARING
ELEMENTS
SOFTENING OF FLOOR MEMBERS.
* Collapsing of floor.
* Buckling of columns due to increase
of unsupported height.
SOFTENING OF COLUMNS.
-
8/14/2019 COLLAPSE OF WORLD TRADE CENTRE
29/36
SOLUTIONS TO MINIMISE THE
DAMAGES
OBJECT - Not to save the Building.
But to save human lives.
Improvement of fire ratings (five to six hours )and
robustness of the structure.
Improvement of evacuation methods.
Solutions for services , ventilation and access routes in
crisis situation.
-
8/14/2019 COLLAPSE OF WORLD TRADE CENTRE
30/36
STRUCTURE
Safety of the structure ( to complete the total evacuation)
* Higher fire rating for the structure
* Reliable fire protection system.
* Designing a level of structure every 10 floors to carry the weight of
nine collapsing floors above.
* Compartmentalizing buildings using a secondary structure as a fall
back if the main structure fails.
(i.e having concrete core able to stay after loosing the floors
and perimeter frame.)
-
8/14/2019 COLLAPSE OF WORLD TRADE CENTRE
31/36
EVACUATION
Present philosophy - Partial evacuation.
Future Aim - Total (Simultaneous)evacuation.
Emergency access / stair case arrangements* Ventilation
* Lighting
* New method of evacuations
# Use of helicopters
# Use of parachutes
Time Requirement for evacuation.
-
8/14/2019 COLLAPSE OF WORLD TRADE CENTRE
32/36
SERVICES
Artificial ventilation.
Artificial lighting.
Sprinkler system and water for fire fighting.
* Reliability - In question
* Solutions
# Passive means of fire protection.# Natural ventilation and lighting.
-
8/14/2019 COLLAPSE OF WORLD TRADE CENTRE
33/36
7thInternational Conference on
INSPECTION, APPRAISAL, REPAIR ANDMAINTENANCE OF BUILDINGS ANDSTRUCTURES
1113 September 2001At The Nottingham Trent UniversityUnited Kingdom.
DAMAGE ASSESMENT AND REPAIRTECHNIQUES USED IN BOMB AND FIRE
DAMAGED CENTRAL BANK BUILDING INSRI LANKA
-
8/14/2019 COLLAPSE OF WORLD TRADE CENTRE
34/36
K.L.S. Sahabandu, an expert in
blast and fire damage from SriLanka at the conference,told The
Structural Engineer, It was the
fire,not the impact of the planes
that caused the progressive
collapse. We need to the review the
fire resistance and services of such
structures, and the evacuation
plans,in future.
-
8/14/2019 COLLAPSE OF WORLD TRADE CENTRE
35/36
-
8/14/2019 COLLAPSE OF WORLD TRADE CENTRE
36/36
THE END