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PERGAU
H.E.P. - KELANTAN, MALAYSIA
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STORAGE
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On completion of fabrication there was a requirement
to store the STL sections above ground. This
presented a problem with the limited space
available and a system was developed to allow
the sections to be lifted and rotated into
the vertical. The sections were then positioned
on "roller skates" and hauled into
the storage area on steel footplates. |
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INSTALLATION
In addition to the Portal Crane, operating from
the workshop to the Surge Shaft, a system of material
handling temporary works and a 35te capacity main
winch using a two fall rope configuration were set
up to facilitate the installation of the 40 - 50te
STL sections.
Each sections was lowered 120m down the Surge Shaft,
rotated through 90 degree, attached to heavy duty
bogies and lowered 450m down the inclined shaft,
and for the first few sections, also lowered around
the bottom bend and along the horizontal High Pressure
headrace Tunnel.
Access to the workface was via a twin rope manriding
winch and cage down the Surge Shaft and a similary
configured manriding winch and car down the inclined
shaft.
A multi level welding platform with independent
winching capability was installed for use in the
inclined shaft.
Intensive safety procedures were adhered to at every
stage of the works to ensure safe working, as well
as achieving an efficient productivity level.
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SPECIAL
CONSIDERATIONS
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| SHAFT/
TUNNEL GEOMETRY |
In order to accommodate a change in geometry
in the high pressure headrace tunnel a rail
turnable was introduced to enable the sections
to be moved into position.
At handover it was also indentified that the
inclined shaft geometry deviated from the
planned configuration which presented addtional
problems with the installation of the STL
sections and the winch rope management.
Mitres were incorporated at several in-situ
weld seams to adjust the line of the STL in
the relation to the shaft geometry and lobsterback
bend at the bottom of the inclined shaft was
rotated in-situ with the aid of hydraulic
jacks.
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| RETRIEVAL
OF TEMPORARY WORKS |
After each section had been lowered into position
the associated temporary works needed to be
retrieved ready for use on the next section.
The heavy load installation/ light load retrieval
problem was solved by ballasting and moving
the load points during retrieval and a simplified
system of dismantling and re-building the
temporary works was developed. |
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