THE HUTT ROAD

Evening Post, Volume CX, Issue 38, 13 August 1930, Page 12

THE HUTT ROAD

PROPOSED WIDENING

ESTIMATED COST £21,300

THORNDON TO NGAHAURANGA

A proposal to widen the Hutt load, from 26ft to 40ft from Thorndon to Ngahauranga, by using a liinch bituminous concrete wearing a 6-inch concrete base, was before the City and Suburban Highways Board to-day. The cost of the actual widening is estimated at £15,600, but adjustments to crosssection, replacement of wooden culverts by concrete pipes, and the laying down of concrete docks on the Kaiwarra and Ngahauranga bridges Bring the estimate to £21,300.

On a number of occasions tho City and Suburban Highways Board has discussed the widening of the Hutt road, ljut it was not till quite a recent meeting that a majority of the board agreed ■that the road should be widened, but only from. Thorndon to JNTgahauranga. The fact which swung the views of mejn^ bers who had previously opposed widening to a widening policy was that the edges of tho road were showing very marked signs of traffic damage. Though the board was in agreement in widening as far as Ngahauranga, it was necessary %o obtain tho sanction of the Main Highways Board, and application was made accordingly, as well aa application, in respect of Seaview road and 'Branda. Pass. To-day's proposals are also to be submitted to tho Main Highways Board. ENGINEER'S REPORT. In his report, the City Engineer (Mr. G. Hart) said that he had included an alternative proposal for carrying out the work in which 1-Kn bituminous concrete wearing course- would be placed in a. Cmi minimum Portland cement concrete base. The estimate of the work was £15,600, against £13,110 for the original specification of 4*in bituminous concrete. The engineer said he had to recommend the adoption of the alternative proposal for the following reasons:— (1) Present indications are that the edges of the existing pavement aro showing signs of incipient failure due to lack of lateral support, and . this will become more apparent with increasing traffic. The proposed concrete foundation and kerb will completely deal with' this trouble. ■■■ (2) The slower moving heavy traffic will gravitate to the edges of pavement, even if it is not found necessary to regulate ' them to use „ these outer lanes to facilitate movement of the faster traffic. This factor alone warrants the consideration of a higher type of pavement than that at present in use! (3) In casting the cement concrete foundation, a concrete margin eau be vast integral with it, thus affording a white edge "which will render the pavement safer for, night travel and encourage traffic to utilise its full width. . "If the alternative proposal is adopted," he added,. "I recommend that tenders be called for the concrete foundation: only, and tliat the bituminous concrete wearing surface be placed by the corporation's own staff in conjunction with the correcting work to the existing pavement referred to below. My reasons for making this recommendation are that the quantity of bituminous concrete is relatively small, and that the contracting firms most likely to give the best prices for cement concreting work will have had little or no experience with bituminous concrete. In connection with either type of construction, it will be necessary to correct the shape of the existing pavement, which is constructed on a ■parabolic curve in order to avoid excessive cross-fall on. the new widening, and to comply with the the Main Highways Board's requirements. This work is difficult to estimate, but will probably cost in the neighbourhood of £1000, and should be carried out by the corporation's own staff.

"There are two other matters which require consideration on this length of road prior to carrying out the paving work. These are: —(a) The replacement of sonic 1520 linear feet of liimber box culverts in from fair to bad order by concrete v pipes at an estimated cost of £1700; (b) the, replacement of the timber decks on the Kaiwarra and Ngahauranga bridges with reinforced concrete slabs at an estimated cost of £3000.". HIOHWAY BOARD ATTITUDE. The chairman of the Main Highways Board, Mr. F. W. Furkert, in his letter to the board under date- of 20th June, stat(|d, inter alia: — "The Main Highways Board is agreeable to paving Seaview road, which, according to the estimate supplied, will i-.ost £4485, and to the widening of the pavement on the Hutt road to 40 feet from Thorndon to Ngahauranga, estimated to cost £13,110, but it regrets being unable to agree to the paving of Branda Pass road and ths paving of the cycle track on the Hutt road out of the funds which can be borrowed in accordance with the conditions of the Wellington City and Suburban Highways and Hutt Eoad 'Acts. if There yet remains tb be paved three sections of road included in the schedule to the City and Suburban Highways Act. The three sections to which I refer are: — (a) 34 chains deviations between ffohnsonvillo and Porirua, £2475. . (b) Johnsonville Town District, . £990. (c) Taita Gorge section, estimated to cost £10,560. Total, £14,025. "The Main Highways Board, when the time arrives for these works to be ■done, and when finances can be made available, will pay a subsidy of £ for & towards the cost, as has been done oa other portions of main highway, so that the amount payable by the Wellington City and Suburban Highways Board will be £7012. '•No reference is made to these works in your letter, and the Main Highways Board would be glad to know Jiow the Wellington City and Suburban Highways Board proposed to provide finance for them." THE FINANCIAL ASPECT. The City Engineer reported as follows — "I have to comment as follows upon the points raised by the Main Highways Board: "Items (a) and (b) in the Public Works schedule are provided for under the existing loan of £05,400. Item (c) is partly covered in tho £65,400 loan, and the balance is provided for by withholding £4600 of loan authorisation In Taising the additional loan for the now works*now proposed ear-marking same for this work. "(g) Curtailment of schedule: In View of.the Main Highways Board's etfrtaJlment of tho /board's programme,

I have to submit the following amendment for the board's consideration: £ (a) Paving Seaview road .. 4,-185 (b) Widening Hutt road, from Thorndon to Ngahauranga (cement concrete foundation) 15,600 (c) Adjustments to cross section existing Hutt road pavement (Thorndon to Ngahauranga) 3,000 (d) Replacement of wooden culverts, Hutt road (Thorndon to Ngahauranga) 1,700 (c) Concrete decks on Kaiwarra and Ngahauranga bridges 3,000 Total £25,785 CAUTION FIRST. In referring to the proposed construction of tho road, tho Mayor (Mr. G. A. Troup) said that in view of tho failure of certain experiments that were made in tho past by a former engineer with regard to putting down what he called "bitumen carpets," he was not prepared to recommend the board to go in for any extensive experiment until It had been tried out on a smaller scale in the first place. Any departure from their practice in the past should be tried out on small sections. Ho had a doubt whether tho proposed 1-} inches of bitumen on concrete would prevent the "creeping" which took place in the "carpet" system which was tried before, and which proved such a failure. He was not averse to an experiment, but ho idid not want to see tho board spend £15,000, and then find that a considerable portion, of the work would have to be done again. If the engineers assured tho board with an experiment that would justify the work, ho would not object. Ho thought the board should walk warily witli experiments. What he was afraid of was the continual hammering of a soft- material on a harder, with the traffic all going in one direction. He was afraid they would get that "creeping." If the traffic was coming and going, it would be dif-

ferent. Mr. D. R. Hoggard said he would like to have an opportunity of considering the engineer's report before a decision was reached.

The Mayor remarked that there was 'no need to come to a decision to-day. It would be two or three months before they could start. The Mayor said there was no doubt about tho strength of Gin of concrete and liin of bitumen. It was just the question of the "creeping." The City Engineer said that hundreds of miles of that formation had been laid in Great Britain. In regard to the replacement of the wooden culverts, the board was agreed that the work would have to be done in any case. They approved of the_ renewal work, provided the Main Highways Board agreed to tho amended scheme.' If the Main Highways Board agrees to the scheme, the renewal of the culverts is to proceed immediately.