gt retrieval

8/2/2019 GT Retrieval

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ACCIDENT OF GT (FR9 Fa+) & ITS

RETRIEVAL

INCIDENT REPORT:-

The Contract for Marine Cum Inland Transportation from US Port to Pipavav site for FR9fa(+)

Gas Turbine was finalised by BHEL ROD, Mumbai on Shipping Corporation of India. SCI inturn, engaged M/s J M Baxi for the inland transport. The Consignment was dispatched fromMundra Port on 30th July09 which fell into Shetrunjay River at Talaja, near Bhavnagar due to the

failure of the span of the Bridge on 8th August09. Weight of the Consignment was around 280

MT. The trailer was a brand new 132 Tyre Hydraulic Trailer of Volvo Make and it was carrying its

first consignment. The rear side of the trailer kept hanging with broken slab of bridge after collapse(Refer view 1 & 2). The 250m long bridge had 10 spans, each span being 25m long. The third span

totally collapsed as the Bearing over which RCC Girder and RCC Slab were resting snapped. The

bridge also failed from the middle of the span. GT was submerged in water. Though a part of Inlet,Combustion and Exhaust chambers could be seen. 5 Casualties were observed.

RETRIEVAL PLAN:-Retrieval plan was made by BHEL Hyderabad in association with BHEL Officials at Pipavav Site.Civil works near the GT prior to lifting the GT was a major challenge which was overcome by

preparing a Coffer Dam around the work area and Preparation of a Steady & solid working

Platform made from rubble masonry & plumb concrete for heavy lift crane movement. A plan for

lifting the GT, Shifting it to a working platform and dismantling it there itself over the platformwas prepared thereafter.

CIVIL WORKS PRIOR RETRIEVAL:-Survey was done for an access road from Highway to the place of fall (River bank) submersed in

water. Through talks with concerned officials water of the River was stopped at the Dam near to

the bridge. To prevent water logging, a coffer dam was prepared around the GT area. Anexcavation of 5 m was done and a strong platform was built using Random Rubble Masonry for a

height of 4.5 m. Platform was strong enough to bear the load of GT and the Crane Movement. An

access road of 7m width was prepared from the Highway to the place of fall.


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INITIAL SITUATION

The trailor was removed

prior the land preparation

for GT-Retrieval.

LAND DEVELOPMENT :

(Initial Stage)

The loose black cotton soil

was removed first after the

removal of trailor.

APPROACH ROAD

An approach road of 7mwidth was prepared from

the main road to the place

of fall (River bank) for the

movement of crane and

vehicles


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PLATFORM FOR CRANE

MOVEMENT AND

DISMANTLING OF GT POST

RETRIVAL

COFFER DAM

CONSTRUCTION

Coffer Dam was constructed

to avoid seepage of water to

the work-area.

Still, heavy de-watering of

River Water was required.

SALVAGING OPERATION:

After the fall, GT got stabilized in a position almost perpendicular to

the position of the base. Thus, first the GT was tilted by 90 o i.e. to a

position where its all 4 Lifting Lugs were easily accessed by the slings

so that the crane could easily lift it. Structure beams and other

supporting members required for the tilting operation were designed

by BHEL Hyderabad. After tilting, GT was shifted to the platform

prepared. The GT was dismantled there itself before sending it back to

the concerned Unit/Service Station.


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OVERALL SITE VIEW AFTER MOBILIZATION OF HEAVY LIFT

CRANES LIFTING THE GT


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TILTING OPERATION OF GT BY CRANE (600MT)

SALVAGING OPERATION OF GT

PROBLEMS FACED DURING SALVAGING

Entire bed was to be prepared with Random-Rubble masonry &Plumb Concrete which could bear the weight of a 650 MT

Capacity crane and 280 MT GT with other small cranes.Constructing such platform over a river bed became a herculeantask.

Even after taking all possible precautions water seepage couldntbe stopped and thus continuous dewatering was done.

The behavior of GT while tilting, though was calculatedthoroughly, but was still unpredictable.

The casings of the compressor chamber were just 35mm thick,

thus care was taken while designing the beams used to tilt theGT.

CONCLUSION

The Gas Turbine was successfully removed from the River and was

placed over a platform adjacent to the river bed. It was dismantled


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there itself so it could be sent back to the Unit safely. The Inlet

Chamber, Compressor chamber and the exhaust chamber were sent to

Hyderabad unit and the Rotor assembly and the nozzles were shipped

to Singapore to get them checked through GE.

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