PROGRESS OF NEW BRIDGE AT BRIDGEWATER - The Mercury (Hobart, Tas. : 1860 - 1954) - 14 Mar 1939 (original) (raw)

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Tue 14 Mar 1939 - The Mercury (Hobart, Tas. : 1860 - 1954)
Page 7 - PROGRESS OF NEW BRIDGE AT BRIDGEWATER

PROGRESS OF NEW BRIDGE AT BRIDGEWATER

SECTIONS of the new bridge un der construction over the River Derwent at Bridgewater. The existing wooden bridge is shown in the background. Help

SECTIONS of the new bridge under construction over the River Derwent at Bridgewater. The existing

wooden bridge is shown in the background.

Having completed the difficult pre-

liminary work, steady progress is being

made with the erection of a new bridge

over the River Derwent at Bridgewater.

The new bridge will carry rail, road, and

foot traffic, and special preparations

are being made for a wide opening span

on the main river channel to permit of

the passage of sea-going vessels.

About 50 men are employed on the

bridge work. The chief work has been

done on the concrete piers, commencing

from the Granton side of the river.

There are eight sets of piers, and at

each set 20 special piles have been

driven. Each wooden pile has been

fitted with a concrete sleeve from a

point where it enters the mud on the

river bottom, and the Junction with the

concrete pier. It is the first time

composite wood and concrete piles

have been used for bridge construc-

tion in Tnsmania, and the experiment

promises to be highly successful in pre-

serving the wood, which, without the

concrete sleeve, would be exposed to

the action of the water and borer pests

above the point where the piles enter

From the Granton end a start has

been made with the application of the

concrete road deck. Steel girders have

been placed in position for seven spans

of the bridge, and in a short time it

is expected that the concrete decking

will be extended almost half way across

the river. Because of the bad condi-

tion of the existing wooden bridge, the

work on the new bridge is being expe-

dited, and although provision hass been

made for the railway line on the up-

stream side of the new traffic bridge,

the work of laying the rails probably

will not be done until the road bridge ls

well on the way towards completion.

Provision is being made on the road

bridge for a section for pedestrians, and

there will be nearly 30 feet of roadway

on the bridge for vehicular traffic.

The most difficult part or the work

above the water level will be on the

section to provide an opening for steam-

ers on the main river channel. A huge

tower will he erected on each side of the

opening span, and the bridge sections

will be raised high into the air to pro-

vide the necessary opening. The pro-

vision of concrete cylinders in the deep

part of the stream as a foundation for

each corner of the opening span has

presented a difficult task. The cylin-

ders have been got down to an average

depth of about 86ft., and it is expected

that the work on them will be completed

shortly. A huge steel crane hns been

built on the Bridgewater side of the

river to convey girders from the rail-

way siding to the deep water, and this

arrangement of handling the heavy

steelwork is proving satisfactory.

At one stage, when all the work was

being done below the water level, it ap-

peared that the Derwent bridge at Ho-

bart would he completed before the

Bridgewater structure, but if the pre-

sent rate of progress is maintained it

is likely that the Bridgewater bridge

will be the first of the two structures in