ROAD AND RAILWAY BRIDGE
Provision For Combined Structure At
RECOMMENDATION that the proposed
new combined rail and road bridge at Bridgewater be proceeded with under the original plan, except that the necessary railway superstructure be not erected until required, was made by the Director of Public Works when giving evidence before the Parliamentary Public Works Committee yesterday. The Director pointed out that if the paper pulp works in the Derwent Valley commenced operations it would be necessary to proceed with the scheme as originally planned.
There were present: Mr. C. E. Culley (Chairman), Messrs. C. J. Eady and A. Lillico, Ms.L.C., G. G. Becker and N. Campbell, Ms.H.A., and the secretary (Mr. C. K. Murphy).
The Director (recalled) stated that he had been asked to report on the following suggestions: (1) That a new road bridge be constructed to the east of the existing road bridge with the same conditions as to the width of the opening span as originally proposed by the Department. (2) That a new railway bridge be constructed at the end of the life of the existing bridge, either alongside the new bridge or alongside the existing railway bridge.
The Director stated that there was a location to the east of the existing road bridge which would give a considerably shorter bridge but would entail considerably longer road and rail connections. Should a road bridge only be constructed on this location and a new rail bridge be built later alongside the existing rall bridge, it would involve two separate opening spans only 600ft apart. The Harbour Master had been consulted and he had strongly advised against such an arrangement. The ebb tide set strongly against the eastern shore at that point and he was of opinion that a big ship could easily get into trouble, for if it got off its course after passing the first opening, it would not have sufficent room to straighten up to make the next opening, there being only two ship lengths in which to manoeuvre. This opinion forced the department to consider constructing both load and rail bridges on the new location which would involve additional railway
construction of one third of a mile, the removal of the Bridgewater station, and the resumption of four properties. An estimate of the cost of a combined bridge at this location was made and the amount involved was £99,000. Allowing 5 per cent for contingencies would bring the total cost to £104,000 or practically the same figure as at the originally proposed site. It could therefore be accepted that any combined bridge in the vicinity would cost from £103,000 to £104,000. Regarding the committee's difficulty in making a recommendation for the construction of a combined road and rail bridge while the present rail bridge had an alleged life of 15 years. If it was not desired to proceed with the railway half of the structure until it was required the matter could be solved by omitting the railway portion of the combined bridge but utilising the south- ern channel of the existing railway swing span instead of the northern channel.
Although the railway portion could be omitted for the time being it was very desirable that the common substructure be erected at the one operation. He therefore made the following
(1) Construct the whole substructure of the combined bridge on the oiiMml location
(2) Construct the superstructure of the load poition on the plate girder spans and the lift and flanking spans to the full width for road and rail
(1) Omit the supetsti uctttre of the nil poition on the plate girder spans
(4) Iea\c the railwaj on the exist
ln" tail bridge for the present until a
larger opening Is required, or until the existing rail bridge is due for re- newal through decaj or economic
(5) Piovide a liver steamer channel through the new opening span and the southern channel of the rall swing Illidge and construct piled sheathing where noccssnrj demolish the exist- ing load blidge and transfer the rall vvHV blidge to the new blidge when debited
The Dliector ¡stated that the savings that would lesult fiom this proceduie would lie about X10 nu» Under this pio posal the cost of the fli st installation would be £104 000 and the completed bridge £123 000
To Mr Campbell Ills pioposnl was that the combined bridge be erected on the oilglnallv chosen site without the lailvvav superstincture for the time being Until it was required for rail pin posés the saving would he £11000 and the annual savings of Inteicst sink- ing fund, nnrl maintenance chaigcs would be £810 '
In answer to Mr Eadv the Dliector said lie understood the Railway Depart- ment estimated that It would have to spend £0 000 In niaintenance during tho estimated life of tho present bridge, which would led nee the saving to £10 000 If the paper pulp vvotks were started in the Dei went Valley It would bo necessaiv to proceed with the original scheme at a cost of £121 000, and In the event of the works com- mencing when the Construction of the bridge with the common substiuctuio for road and rall, was under way, It would be possible to proceed with the completed scheme w hen desired
In answer to the Chairman the Director stated that a 15 per cent lise in labour costs had been allowed for In the estimate of the scheme
The committee adjourned