Concrete Paving For Central City Footpaths

Press, Volume C, Issue 29516, 18 May 1961, Page 14

Concrete Paving For Central City Footpaths

Concrete slabs would be used to reconstruct the footpaths in the central business area of the city, the City Council agreed last night. A loan of £300,000 to £350,000 would be needed, the City Engineer (Mr E. Somers) told the council. The work would take five or six years at least, Mr Somers said. Because of the generally bad condition of the paths and their steady deterioration, renewal should be faced with little further delay.

“The city paths were originally constructed of tarred asphalt many years ago—probably 50 or 60," Mr Somers said. "For many years they were maintained by topdressing with tar (swept on> and sand or fine grit with patching as required. By 1930. considerable deformation had taken place, and over the following few years a large proportion was corrected with a hot mix sand carpet. This was laid with varying thickness Much of this carpet has now worn off or has hardened and is disintegrating slowly. “The chief deforming agent is, of course, trenching. All the city paths have been opened up repeatedly. Reinstatement has generally been well carried out, but slow consolidation of fill in the trenches takes place over years. This shows frequently not only as sharp subsidences over the trench, but also as shallow sinkages over extended ar'eas, giving extensive shallow pools. Similar depressions are caused by the consolidation of undisturbed ground, particularly where all vegetable matter was not removed before the original path construction. Paths Breaking Up

"In addition to the unevenness, the paths are J breaking up, pot-holing and crazing because they have, in effect, lived their Dives." Mr Somers continued. “The binder, particularly the tar in the original formation, has slowly oxidised until it has become completely brittle, with no plasticity or binding quality. That they have continued to function so long is a tribute to the quality of the tar used, the workmanship and the maintenance of early years.” There was no "way by which the paths could be repaired satisfactorily, he said. The best cheap job would be again resurfacing with a fine hot mix sand carpet after renaming the worst part of the base. This would not be very satisfactory. • It would build the path too high in places, probably move over recent patches and fail on a faulty base elsewhere. Of the types of materials for. replacement. Mr Somers said there were only two worthy of consideration for city work— concrete slabs and bitumen The former were used almost universally overseas, one exception being the extended use of bituminous paths in Sydney, Concrete slabs provided a satisfactory path in most respects. They were not unduly expensive, and properly made and laid had a long life. Those in front of the MED. in Manchester street had given 25 yeari’ service. Their great virtue was that

they could be lifted and relaid at a low cost when path opening W’as necessary. That was important. Mr Somers said, and would remain so with underground services such as water supply, gas. telephone and electricity.

Opening For Sendees Openings for replacement* and new services would always be necessary. Slabs must be cast on the site around the multiplicity of utility service boxes and covers, and generally a strip of concrete was necessary along a building to make up the odd inches where slabs did not fit exactly Well-laid bituminous paths had a long life. They were softer to walk on than concrete slabs and if in firstclass condition rather easier to clean But they involved much more expense and inconvenience when path opening was necessary. Mr Somers said there was still much trenching of paths to be done in the city. The M.E.D. was slowly putting its reticulation underground. This year the work would be completed around Victoria square, in Gloucester street from the river to Manchester street and in Colombo street from the square to Armagh street. At this rate it would

take many years « compete the business area. The Post Office was carrying out similar work at a rattier more ' 4 ?t d wmifid be advisable to work first in areas where underground utilities had been installed, Mr Somers said.

Kerbs and Channels Along with the path the kerbs must be considered, and in some cases channels, he continued. Kerb* were showing old age clearly, and replacements were required in many area*. Rather a separate but related problem was the elimination of dished channels. This problem was generally <>e»t handled with the roadway, rather than footways. To determine the cost or the replacement of paths would require fairly extensive schedules and examination of existing condition*. Mr Somers »aid. The area under consideration was the whole of the central business area and would include generally Moorhouse avenue from Lincoln road to Madras street and the area to the north, running out about Kilmore and Peterborough streets, but with extensions along Victoria street to the north and Colombo street to the south. “Our side channel® are worse than our pavements, and we may be putting the cart before the horse,” said Cr. G. D. Griffiths. "Every time we have a few spots of rain our side channels are flooded." he said. “The Drainage Board is endeavouring to raise a loan to take care of underground drains, but it is not providing for the inner part of the city. It is a disgrace that certain properties have been flooded becau*e of inadequate underground stormwater drainage.”