Changes In Lining Of Road Tunnel Urged By Architect

Press, Volume C, Issue 29643, 13 October 1961, Page 15

Changes In Lining Of Road Tunnel Urged By Architect

cniiirf . of M* e cei,ln K of the Christchurch-Lyttelton road tunnel P l grave noise problems and create dangers, the architect (Mr ' In ® ret report to the Road Tunnel Authority th* Proposed that a way of reducing sun dazzle at the Heathcote end of the tunnel be considered.

The first drawback to a compietely-tiled tunnel would be that it would not be pos sible to estimate the distance of cars by ear as a safety factor, My Beaven said. . Ovei *eas. there had been dissatisfaction with “the hurricane traffic roar’’ in tied tunnels. Complete tiling would make driving me ft dangerous, make heavy freight vehicles even more noisy, and increase panic in an emergency, he said. The tiling of the side walls was desirable for cleanliness and finish, Mr Beaven continued. “ft has been suggested by experts that it may not be practicable to tile prestressed concrete because it has a tendency to creep under the tension, causing the tiles to dislodge.’’ Mr Beaven said. ■There is no proven method of attaching tiles to prestressed concrete, notwithstanding various claims made for patent adhesives. “The danger of tiles dislodging from the ceiling on to passing traffic and the expense and time in constantly renewing Jiles need no comment.” Referring to solutions overseas to noise problems in tunnels, Mr Beaven suggested that tiles be eliminated on the ceiling and acousticallyabsorbent glass wool blanketing be used on the underside of the ceiling panels. Under this would be suspended aluminium performated panels, he said. Sun Dazzle A hazard might be created by sun dazzle at the Heathcote end, Mr Beaven said. The careful provision of brighter illumination at the portals might overcome diffl. culties, but experience would be the only criterion. If there was trouble, the solution found in the Velsen tunnel in Holland might be satisfactory. There, open diamond-shaped grids of prestressed concrete extended from the tunnel portal across the toll plaza. The grid int cepted the direct sunshine. The grid was painted a dark blue near the tunnel exit and graded out through grey to white at the open end. Mr Beaven reported on a lay-out for the toll plaza and the administration and maintenance buildings. He said

| the basic lay-out of the toll i plaza, toll booths and toll canopy of the’ Auckland Harbour Bridge Authority gave a clear guide to the design which could be adopted at Heathcote, although on a smaller scale. Four toll booths would be. sufficient for a considerable time, but provision should be made for easy expansion to six. Building Plan The administration build, ing should be sited on the east side of the toll plaza, where it could command a full view of the plaza, and Mr Beaven suggested that it i be a two-storeyed building half to two-thirds of the size of the Auckland bridge building. The maintenance building should be of about 3000 sq. ft., he proposed. While commending the architect’s report, Mr L. G. Amos said he was surprised at the size of the proposed buildings. “It would appear that we will be up for about £lOO.OOO worth of buildings,’’ he said. In Auckland the administration building was really too small, said the chairman <Mr W. S. Mac Gibbon). “We are building for the growth of traffic. I want things done well and done economically, but I don’t want to build another empire.” The deputy-chairman (Mr R. A. Witbrock) said he had

shared Mr Amos’s views until he had gone to Auckland. “My ideas changed when I saw Auckland,” he said. "We must have ample buildings and ample room.” He suggested that those members who had not seen the Harbour Bridge Authority’s administration should be sent to Auckland by the authority. Mr Heaven’s report was deferred for consideration after Mr Mac Gibbon bad said it was being studied by the Ministry of Works, as the authority’s consultant, but it was agreed that the administration building should be sited to the east of the Heathcote portal and that Mr Beaven should be asked to prepare sketch plans of the buildings.