CASE STUDY OF SEONGSU BRIDGE
Presented by:
DAVESH SADOTRA(18BCE1083)
AJAY KUMAR(18BCE1114)
Project Guide: MRS. SHALIKA
MEHTA
Department of Civil Engineering
Introduction
The Seongsu Bridge is a bridge over the Han River in Seoul, South Korea. It
links the Seongdong and Gangnam districts. The cantilever bridge was
completed in 1979 and its total length is 1160 m.
Collapsed bridge in 1994
The original bridge collapsed early on the morning of October 21, 1994, when
one of its sections broke off due to failure of the supporting truss, caused by a
faulty weld. A total of 32 people died and 17 were injured in the accident. In
the aftermath of the event, authorities planned to repair the bridge,[by whom?]
but its structural weaknesses made a repair unfeasible and it was eventually
dismantled and replaced. The new design was finished on 15 August 1997, and
is similar to the original design.
BRIDGE COLLAPSED
The central region of Seongsu Bridge over 48m in length which was built in Han
River of the capital city Seoul city in Korea suddenly collapsed, while the bridge
was in service. Bus and passenger car in use fell to the Han River about 20m
below, since it was the commuting time in the early morning, and 32 persons
died and 17 persons got injured. From the investigation after the accident, the
actual condition of many "omission" became clear.
At 07:40 on October 21 (Fri), 1994, 48m of the central region of Seongsu Bridge
suddenly collapsed, which across Han River running Seoul the capital city of
Korea, urban bus and 6 passenger cars that driving down the bridge fell in river
about 20m below one after another. The fallen bridge girder which is upper part
of pavement part did not sink in the underwater, since it was the dry season and
the water depth was 3-5m, and urban bus and passenger cars which fell in the
top wrecked and they became rolling big disaster. The victims were 17 day girls
who on the bus and almost the other were workers driving to the office.
CAUSES FOR THE COLLAPSE OF BRIDGE
1) Bad welding of the suspension which member of the I-type cross section which was
hanging the suspension digit of the center from the steel truss seems to be a main
caus.
(2)There was visibility cuting corners between surface and splice plate of the fillet
welding, so construction management and inspection method in the construction of
Seongsu Bridge seemed to be remarkably slipshod.
(3)Calcium chloride, which was scattered in order to prevent the road surface freezing,
chloride ingress was up pued for the cracks by poor weld or stress corrosion, and so
that the corrosion of steel product might be promoted.
(4)There is a possibility to produce unexpected partial cracks in the steel surface
because in the cross-sectional shape of suspension steel product, the cone angle ( the
relaxation curved surface ) for easing stress concentration was insufficient.
(5)Though there is no error at the content for the design, there was some possibility
that the immature construction level wasn't sufficiently assumed.
(6)There were no technical standards on in-service maintenance repair of Seongsu
Bridge.
(7) Because of the fiscal resource constraint ( budget ) of Seongsu Bridge while
it was in service, the periodic check was not possible.
(8) There were no survey about the actual situation and the inspecting
standard on the change ( increase ) of traffic load.
(9) There was no technology ( inspection ) standard on maintenance and
welding of the bridge.
(10)
There was no tender contract system which accurately selected the
contractor.
(11)
There was a social trend that however basic road of Seoul city facilities
should be constructed quickly.
PHYSICAL DAMAGE
48m of the central region of Seongsu Bridge suddenly collapsed, fallen bridge
girder upper part pavement part was not sinking in the underwater, urban
bus and passenger car which fell in the top wrecked and they became rolling
big disaster.
COUNTERMEASURES
At this opportunity accident of Seongsu Bridge , the Korea nation got angry and
demand countermeasure to omission construction which spread in Korea.
It was decided that President Kim Young-sam ordered general checkup of national
roads and bridges and appointed the foreign special enterprise on the Korea
government for some main civil engineering works.
A consultant in the United Kingdam, Remdell Palmer oand Triton (RPT) Co. made
successful bid the contract on integration and technical advice of the remedial
work of Seongsu Bridge.
And, it was redesigned ( that existing concreate floor system is exchanged for the
steel plate floor, etc. ) in order to suit the design load that removes and increased
the suspension digit part in the center after the accident-generation of Seongsu
Bridge for the inspection, in May, 1995, the modern construction received order
at about 22 hundred million yen, and the construction began, and Seongsu Bridge
was opened in July, 1997 again for service.
Objectives/Hypothesis
• Learn various type of loads which real life bridge is subjected to.
• Understand how bridge structure works to carry the loads placed on
bridge
• Understand how the different type of bridge can fail.
• Learn what modification can be done to increase strength.
• Relate the bridge modal to real life.
• From this disaster we can learn that while building you should make sure
that the welding and other part of the structure are ready to use and will
not end with collapsing when in use.
• There will be proper cure for bridge.
Methodology-Research Design
Bridge design is a very delicate matter.
As a conceptual study of seangsu bridge for a cantilever bridge we aim to
get good design notions, that is the we need to follow in order to project a
pleasant and safe bridge
The second part of thesis is more objective using case studies we will see
how that bridge fails and what was the major reason for disaster.
By the end of the work, we will have developed a critical analysis towards
bridge in terms of achieved design, and also distinguish what should be in
mind while constructing bridge.
With this thesis we hope we could enlighten a bit more the subject of
bridge design and cure.
Methodology-Research Process
Construction of bridges decks involves different type of resources that intract in
a cycle manner. Constructors have to select the construction method that suits
project constraints including condition, technical, financial etc.
Once we selected a case, develop our problem statement we provided new
insight to the subject, open up new directions for future research.
We build a theoretical framework. And collected data from different research
paper and magazines.
We find that the improper work on any part of structure can cause a disaster
like in this case.
And research about different modification that can be done.
Bibliography or References
http://science.howstuffworks.com/bridge4.htm
The honsu-shicoku bridge authority
www.hsba.go.jp
super bridge(1998) nova online
www.pbs.org
en.m.wikipedia.org
mashahiko kunishima www.shippai.org
Thank you