FEA Based Level 3 Assessment of Deformed Tanks with Fluid Induced Loads
Dismantling of existing ROB, CSB Nagpur, AFCONS
1. 1
Dismantling of Existing R.O.B
CSB-3435
Nagpur
AFCONS Infrastructure Ltd
By:
Rajesh G Rathod, Lalit Garg
ER-02 Er-01
2. 2
Brief introduction to Existing Bridge.
• Length of the Viaduct portion is 207m.
• No of spans -21 No’s.
• No of stone masonry piers-4 No’s.
• No of piers-20 No’s.
• ASSUMPTION
• The bridge is a composite structure made of open web steel girders enclosed in concrete.
7. 7
• Bituminous (overburden) removed by excavator/breaker.
• Removing Foot path by using jack hammer/ boxer
• LG-01/02 marching to its final (pylon) location center of the bridge.
• The crane is moved over the LG1 and LG2 girder to avoid direct loading on span and the load is transferred to
columns of the existing bridge.
• slab cutting as well as Parapet wall using floor saw. (horizontal cut)
• Parapet wall cutting using wall saw (vertical cut)
• Parapet wall cantilever beam (haunch portion)cutting using wire saw
• Individual beams are cut by using two wire saw machine at both end.
• The cut beams are lifted by hydraulically operated crawler crane (136MT) capacity.
Reised animation_of_dismantling_bridge_v007.mov
Working sequence.
9. 9
Crawler Crane
• Crawler crane is of 136MT capacity with 18.29m boom length
having crawler length of 7.42m.
• We have utilized it for lifting 22MT that is 84% at maximum radius
of 15.24m where its safe lifting capacity is 26.1MT
• Average weight of components of bridge.
• Parapet wall: 15MT/19.5MT (Mumbai/Delhi) side.
• External beam: 22MT
• Internal beam: 10MT
• Longitudinal girder shifting.mp4
11. 11
• Floor Saw: Equipment name it self indicates the purpose for which it
is being used.
• It can accommodate an blades of
Dia. 800mm -240mm depth cutting
Dia.1000mm. -400mm thickness.
11HP Electric motor is used in this equipment.
• Equipment costs -1.8Lac .
• Efficiency of blade -100 to 120sqm varying upon the density of steel
in concrete.
• floor saw cutting.mp4
Floor Saw.
12. 12
Equipments.(wall saw)
• Wall saw: The Pentruder CBK is equipment
manufactured by Tractive AB Sweden used for cutting
walls (vertical cuts)
• It is light weight equipment
24kg for saw head
18kg of 22KW motor.
• Track weight - 6.95kg/m
• Distance in between two brackets should not be more
than 2m.
• It is hydraulically operated(Using remote)
• Requires 0 to 160bars pressure for cutting. Water hose.
Motor Power supply
Forward reverse
Blade UP/DN .
Remote electric
connection cord.
13. 13
Wire Saw
• It is the equipment used for cutting huge cross sections of concrete.
• At cable stayed bridge Nagpur we have wire saw of different Types.
1.CIDIMA MAKE. (German company.)
2.TYROLATE MAKE. (Swiz make. PPPH20)
3.HILTIMAKE.
14. 14
CEDIMA make Wire saw.
1. Dimension of 1950 x 600 x 550.
2. Weight of machine - 180kg.
3. Maximum operating pressure -100 bars.
4. 5 pulley arrangement it has 20.5m wire storage capacity
5. Cost in INR: 36 L
15. 15
CEDIMA Power Pack
Hydraulic power pack HAG-12.20
Electric motor: 15/20KW consumes 400v/ 32 A
Oil flow capacity : 30to 44 l/min
.
Oil quantity in tank: 11 lit.
Operating pressure: 250 bar
Total weight: 130kg
Dimension: 640 x 560 x970 mm
16. 16
1. It is an handy equipment utilized for working in confined
space.
2. Dimension of equipment are 780 x 800 x 1340mm.
3. Minimum requirement of wire is 1.8m to 4.0m & it can
accumulate an wire up to 6.5m depending upon wire guide.
4. Total weight of equipment Is 65kg.
5. It creates an noise level up to 75dB.
Tyrolit make Wire saw.
17. 17
Tyrolit make Wire saw
1. Power pack used is PPH20. 20KW electric motor.
2. It has an oil pressure of 33l/min at 260bar
& 40l/min at 210bar for wire saw.
3. Power consumption is 32A.
4. Dimension 420 x 470 x 980mm & weight 140kg.
18. 18
Wire Rope
• Wire saw: It is an rope 8mm dia. having diamond bits 12mm
dia. & 7mm thick . at alternate spacing of 18mm.
• Life of rope is 1 sqm cross-sectional area per running meter
length of rope, with dense reinforcement.
• Cost per running meter of rope is 18000-14000 INR.
19. 19
Challenges
• Availability of power and traffic block from railways.
• Unknown structure behavior of every element of bridge.
• Working above live over head electric traction lines & handling of equipments after last beam is being
dismantled.
• Continuously motivating people & ensuring to work them with all safety precautions and creating awareness
at every available railway block time.
• Water line on Delhi side parapet wall which is being dismantled by us.
• Parapet wall -Dismantling cantilever haunch beams using wire saw which took time of 2hrs 30mins. We have
simplified it by using wedge hammering near to haunch portion which takes approximately 15mins.
• Resting of parapet wall on ground after dismantling.
• Continuous water supply is required for operating all dismantling equipments which would require
46,000liters/per span excluding pier.
• Pier dismantling simplified . By improvement at various stages in execution. Earlier it was planned to
demolish by breaking using jack hammer that would have taken 4 days per pier along with traffic and power
block. Whereas we have used wire saw and dismantled it in 12hrs.(3days)
• Longitudinal girders locking arrangement is more critical and time consuming and therefore simplified by
counter weights.
24. 24
Intermediate beam dismantling.
Pier diaphragm dismantling
Cross-section of column after wire saw
Removing of water pipe line above
OHE.
Last intermediate beam dismantling.
26. 26
1. Pier diaphragm dismantling.
2. Tyrolit column wire saw machine setup.
Site photos of masonry Pier diaphragm dismantling.
27. 27
Planned methodology. Improved / Methodology
1. Parapet wall-All cantilever haunch portions in parapet
wall to be dismantled using wire saw. Time required
for dismantling 4hrs 40mins, requires mega power block
for dismantling.
All cantilever haunch portions dismantled using wedge and
hammer time required maximum of 3hrs. Fastest completed
in 2hrs. Resulted in achieving 3hrs block from Nagpur
division or else for mega block we need to approach Mumbai
office.
2. Water-Initially water was planned to be
purchased from external party which was costly as
water requirement for dismantling of each span is 46000
liters.
We have utilized our bore well water. We have just laid a
flexible pipe line of 250m length and bear electricity charges.
Water was available at any movement when it was required
at site.
Innovations
Cantilever haunch beams
Cantilever haunch beams dismantled using
wall saw &wire saw
Water tank
28. 28
Planned methodology. Improved / Methodology
3. Pier dismantling-
It was proposed manually by using jack hammers. The
debris generated from this has the chances to fall on
Railway tracks and the same is to be shifted manually
from Railway premises to dumper by crossing the
electrified track endangering the workers and is costly &
more time consuming.
In contrast to the above we have dismantled the piers using
wire saw cutting and core cutting machines. The pier
diaphragm is dismantled in only three parts and the 4 pier
columns in 4 parts separately. This required a total Railway
power block of 12hrs (9hrs+03hrs). The dismantled pieces
are directly loaded in trailer with the help of crane & finally
shifted to dumping yard. Thus the site was clean free from
debris and the work was completed much earlier.
Innovations
1 of 3 pieces
dismantling
29. 29
Planned methodology. Improved / Methodology
4. Longitudinal girder locking-The longitudinal girders
were supposed to be locked at pier location by means of
8nos 16mm dia TOR steel at every pier location by drilling
50mm dia 1.00 m through the slab into the pier and grouting
the same to prevent the LG’s from uplifting. This drilling and
grouting procedure is time consuming and not cost effective.
For this we proposed counterweights for the same so that
uplifting of LG’s could be prevented in consultation with our
design team. After due analysis for upliftment of LG during
the movement of crawler crane, counterweights of 4MT on
each side of LG opposite to overhang portion was permitted.
This has resulted in safe working and expediting the work
Innovations
Trak
Counter weights
30. 30
Planned methodology. Improved / Methodology
5. Transportation-
Shifting of beam was to be done using minimum two
no's of tailors and one crane of 100MT at dumping
yard
We have used just one flat bed tailor and hydra for shifting
of all dismantled materials. Since each beam was made
two piece so can be loaded by hydra. This helps in saving
trailer and 100T crane hiring charges for 5 months.
6. Track Creation- Cutting of parapet wall could not be
achieved in straight line. Due to this the dismantled
piece could not be lifted safely because of the
unbalanced weight and moreover the cut beams also
got stuck with adjacent sides while lifting.
Since the diameter of wheels of floor saw is 60mm and
therefore we had fabricated a Track of channel at site track
with ISMC75 which was anchored with the deck slab by
means of 20mm dia. and 50mm long anchor bolts. The
floor saw machine can be operated on this track easily and
vertical cutting can be achieved in a straight line. With this
we were able to lift up the cut pieces vertically without any
jerks and can be handled with crane safely
Innovations
Track
Handling with hydra
31. 31
PLANNED TIME VS ACTUAL TIME
Activities Parapet wall dismantling
Pier & beam haunch
dismantling
Longitudinal girders
locking
Planned time (Days) 63 88 84
Actual Time (Days) 26 60 0
Difference (Days) 37 28 84
TOTAL TIME SAVING (Days) 149
35. 35
1. Considering safety point of view & convenience for execution (Lifting of beam) All external and
intermediate beams were cut inclined by 60 degree. Such that it acts as a wedge arresting the free fall of
beam once the total cutting is completed and further reduce the sudden impact on crane holding the
beam.
Safety precautions implemented.
36. 36
Safety precautions implemented.
1. As we all are aware that Existing bridge which has being dismantled was above 25 railway tracks of
most busiest station of central INDIA is NAGPUR. Out of these, 20tracks were having over head
electrical traction lines & 5 tracks for maintenance & washing purposes etc.
2. Before starting any activity safety tool box talk was taken and special training was given to manpower
working on dismantling about overhead electrical traction lines awareness.
3. All PPEs were used by all including all visitors , safety nets were provided & barricading were provided
during block hrs on platform. Ropes & soft barricading were provided on span after each beam
dismantling
4. Wooden ladder was used in OHE portion as an access to Pier for Dismantling
5. Rigid Barricading was provided on every cut span to avoid fall of debris over OHE lines and Track
during pier dismantling.
6. Not even a single drop of water was being spelled out on live traction lines throughout completion of
dismantling.
7. Not even a single first aid event occurred through out the dismantling activities
37. 37
CONCLUSION
• This case study presented herein indicates the use of modern technology i.e. wire saw and floor saw cutting
that can be adopted for any kind of dismantling works. More pro-activeness and meticulous study on
ongoing works and methods can simplify the things which can bring a lot of change with respect to time
and cost.
• Major achievements from dismantling of Railway over-bridge (100 yrs old) at Nagpur, Railway Station are
as follows:
1) Reduction in Railway power & traffic blocks from 588 hrs to 278hrs.
2) Reduction in 149 working days due to adoption of simplified method for pier dismantling, LG locking
arrangements and parapet wall dismantling.
3) Cost saving of Rs 80, 37,486 due to reduction in working days & simplified methodologies adopted at site.
• Hence we have reduced required number of railway power and traffic blocks to half, indirectly contributed
towards railway passenger’s convenience and got appreciation from Client (MSRDC). These
methodologies can also be helpful for dismantling in other projects
