INLAND ROAD BRIDGES.

Kaikoura Star, Volume LXIV, Issue 61, 7 August 1944, Page 2

INLAND ROAD BRIDGES.

ESTIMATED COST £16,000. The Alain Highways Board representative on No. 13 Highways Council (Air D. AL Grant), in reply to the Kaikoura County Council’s letter of April 26, set out the following details: This matter was brought up again by the Kaikoura County Council, who wrote to me on December 16 last stating that as the ratepayers of a portion of the Conway Riding south of the Lynton Stream, on the KaikouiaAVaiau Alain Highway had petitioned the Kaikoura County Council to impress upon the Main Highways Board the urgency of bridging the Kahautara, Linton and Humbug rivers, the Council would like to be supplied with a rough estimate of the cost of these bridges. To this 1 replied that it would be somewhat difficult to give an estimate without survey, but that the matter would be looked into when possible. The matter was then the subject of a deputation from the Kaikoura County Council to the Hon. Minister of Public Works at the opening of the South Island Main Trunk Railway at Kaikoura Railway Station on March 11 last, when the Council asked that they be given an idea of the probable cost of these bridges to enable them, to take any steps necessary to raise their share of the money, so that there would be no delay in the construction of these bridges when conditions again became such that construction could be carried cut. The Alinistcr instructed me to look into the matter and provide the estimate of cost as early as possible.

As Air Southern and 1 had some doubts as to siting, 1 asked, through the Aerodrome Branch, for some aerial photographs which Air Prichard took in passing, and also I recently flew over the area with Mr Prichard, and was thereby enabled to eliminate quickly the various possibilities as to siting. With Air Southern I inspected the sites on the ground, and 1 forward herewith photographs showing the proposed bridge sites. This main highway lacks five bridges, one in the Amuri County over the Ala son River, and four in the Kaikoura County—viz.. Greenburn, Kahautara Linton and Humbug. Greenburn River Crossing.

There would appear no alternative but to build a bridge approximately 6(i feet long on the site of the present road ford. The roadway giving access to this bridge site is very winding and or comparatively steep grades, and fron the air it would appear that bettei alignment and grading might be pos sible on the other side of the spur, bul as this would involve five or six miles of road deviation, for which there would not appear any justification foi very many years, if at all, the bridge should undoubtedly be built at the pre sent ford. The estimated cost is: 60fi bringing in reinforced concrete, two way 24ft width, at £3O per foot, £lBOO approaches and protection £200; total £2OOO. If the bridge were built in timber and steel this estimate cculd be reduced to £l5OO. Kahautara River Crossing.

The proposed site of this bridge is as shown on the aerial photograph herewith. It was thought that there might be some cheaper bridging by grading down and crossing the three streams separately where they leave the hills, but from my aerial reconnaissance it would appear that the total of bridges required for this purpose would be in excess of the proposed site near the present bridge ford. As the whole of the stream could conceivably come down on either side of the island or even through the island, it will be g necessary to bridge from bank to bank This entails a bridge 500 ft in length based on rook at one end and on reasonably protected ground at the other end. This is estimated to cost: 500 ft of reinforced concrete bridging on abutments and R.C. pile piers, 12ft width, with a passing place in the middle, at £l6 per foot, £8000; approach formation and protection, £1000: accommodation and miscellaneous, £300: total £9300. Linton River Crossing.

It is proposed to bridge the Linton in the place shown on the aerial photograph herewith, which from an aerial and subsequent land inspection, is the best available bridge site within reasonable reach of the existing road line. The estimated cost of a one-way bridge 120 ft long, with a considerable length of river protection at the south end and on the upstream side of the road, as proposed, is: 120 ft bridging in reinforced concrete on R.C. pile piers at £l6 per foot, £1920; formation work and river protection approaches, £880; accommodation and miscellaneous £200; total £3OOO.

Humbug River Crossing. This stream is a much smaller one but flows down the road, itself causing considerable inconvenience and trouble. The best permanent solution for the Humbug would appear to be to deviate the road on the northern side to follow along the foot of the hill to a good bridge site, almost at right angles to the stream bed, where it is well established, and to continue on across the flat to join the present road as shown in the aerial photograph. The estimated cost is: 40ft bridging, two-way, 24ft width, in reinforced concrete, at £25 per foot, £1000; 20 chains of road formation, £300; fencing 40 chains at £3 £120; approach protection, £100; land compensation, legalisation and survey, £80; accommodation and miscellaneous, £100; total £l7OO.

The bridging on this highway is a much required work and undoubtedly should be put in hand as soon as the war is over, should the County ami Main Highway finance be available for the purpose. ' I take it that subsidy will be on the usual Highways Board basis of £3 for £l, in which case it will be necessary for the Kaikoura Countv to find approximately £4OOO towards the cost of the Greenburn (estimated cost £2000), Kahautara (estimated cost £9000), Linton (estimated cost £3000), and Humbug (estimated cost £1700), a total estimated cost for Kaikoura ‘County bridges of £16,000. It is noted that Kaikoura County omitted the Greenburn River from their letter, and they may not wish to proceed with this in’the initial programme. You will note that in general I have provided for one-way bridges only, as

the traffic density on this road is very light and not likely to increase to any great extent, and the land is not agricultural, so that 1 do not think any but very short bridges should be constructed as two-way. All existing birdges ot any length on this road are one-way only.

This letter was supplied to the Main Highways Board, Wellington, by Air Grant, Acting-District Engineer, Christchurch, and a copy forwarded from Wellington to the County Council. In discussing the letter, Cr Armstrong said a plan should be obtained of the Humbug Creek and permission obtained to proceed with the work. He moved that a letter be sent to Air E. I’. Aleachen, ALP., to ascertain the possilbe date w.ieis the w r orks outlined could be done.

The Chairman said it wculd be necessary to ascertain the opinion of the ratepayers, and suggested that the subsidy should be on a £4 for £1 bas : The motion was seconded ' anti rie dunanimously.