Hong Kong's Road Engineering Fea Quality Control Testing in Construction Is Essenti Interior Design: Manila Hotel's Rebirth
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Hong Kong's road engineering fea Quality control testing In construction is essenti Interior design: Manila Hotel's rebirth -Ait HK'S FIRST HIGH-CAPACITY RURAL HIGHWAY TUEN MUN is one of the three new towns being developed in Hong Kong's New Territories. It is 17 km west of another new town Tsuen Wan and 32 km by existing roads from the commercial heart of the territory Tsim Sha Tsui, Kowloon. By 1986 Tuen Mun will have nearly half-a-million people. From the early planning stages of the new town, it was clear that the existing tortuous Castle Peak Rd would prove an inadequate link between Tsuen Wan and Tuen Mun. A high-capacity road link was con• sidered an essential prerequisite to the development of Tuen Mun. The Hong Kong Government commissioned a firm of consultants to prepare a report on a new road between the two towns and, follow• ing its acceptance, to design and supervise construction. Tuen Mun Rd, as it is now called, is Hong Kong's first high-capacity, limited- access rural highway. It is being constructed in two stages. First carriageway Construction of the US$57.1 Mun Rd will form part of Route 2 Aerial view of Tuen Mun Rd which million initial stage commenced in which will provide continuous dual- links Tuen Mun New Town with Tsuen Wan New Town. It is Hong October, 1974, and involved com• carriageway travel from Tuen Mun Kong's first high-capacity, limited- pletion of the first carriageway of to Kowloon. access road and, when completed in what will eventually be a dual, During the initial site reconnais• 1980, it will form part of Route 2 three-lane road some 17 km long. sance for the design of Tuen Mun which will provide continuous dual- carriageway travel from Tuen Mun Also included was the formation Rd, records were made of topo• to Kowloon. (Hong Kong Public works for the second carriageway graphical and surface geological Works Department photograph). over about 7.3 km of its length and features, drainage systems and land the complete construction of the use. This was augmented by stereo• proximately 100 m intervals along two intermediate interchanges. scopic study of available aerial the road alignment. Construction of the US$17.8 photographs. The information ob• Tests were carried out on the million second stage will commence tained was used for planning the soil samples recovered to classify soon after the first carriageway is detailed ground investigation. them and to determine their streng• opened to traffic this month (May, Some 170 boreholes were locat• th, consolidation and permeability 1978). ed at probable bridge foundation characteristics. In addition, surveys When completed in 1980, Tuen sites, in Tai Lam Bay and at ap- were made of the jointing visible in ASIAN BUILDING & CONSTRUCTION, MAY 1978 the rock outcrops and of the occur• investigation was augmented as part from aerial photography under• rence of groundwater. of the construction work. taken in 1963. A flying height of Although for most of its length The Crown Lands and Survey 549 m and photographic scale of Tuen Mun Rd is aligned through Office of the Public Works Depart• 1/3 600 had been used. granite rock and its overlying de• ment have established a fully co• Information from the aerial sur• composed mantle, the eastern 2 km ordinated survey network including vey was verified and the maps up• lies on decomposed volcanic rock. triangulation stations, traverse sta• dated by a limited ground survey The most prominent rock outcrop• tions and bench marks covering the undertaken by the Highways ping occurs at Brothers Point where whole of Hong Kong. A detailed Office, PWD. TUEN MUN ROAD extensive adverse sheet joints were survey based on aerial photography For construction purposes, sur• observed. at a scale of 1/1 200 now covers vey stations were established along Results of the investigations most of the land area of the New the route to enable the road and its were used in the design of cuttings Territories. This survey scale was structures to be set out. Accurate 1.50 m 1.50 m 10.05 m 2.50 m 10.05 m 1.50 m TUEN MUN ROAD CARRIAGEWAY CROSS SECTION and embankments, structural used for preliminary alignment and survey was particularly important foundations, marine works and the engineering studies of Tuen Mun for Tuen Mun Rd as considerable carriageway pavement. The rock Rd. lengths of the road are situated in level determined from the bore• For the detailed design work relatively inaccessible hillside with, holes was also used for providing that followed, plans at the larger in places, heavy vegetation. setting out information for the cut• scale of 1/500 were considered es• Because of the topography tings. sential. These were prepared by a through which Tuen Mun Rd Subsequent to commencing private firm in 1973 by machine passes, a particular effort was made work on site, the pre-tender ground plotting to 2 m contour intervals to minimise the cost of earthworks. 12 ASIAN BUILDING & CONSTRUCTION, MAY 1978 CONSTRUCTION The time involved in testing the various detailed vertical and hori• zontal alignments to determine the most economical design was con• siderably reduced by the consul• tant's extensive use of computer programmes. By the use of computer facilities a complete set of 1/250 scale machine-drawn cross-sections at 20 m intervals along the road was pre• pared. The chosen alignment of the EMBANKMENT 17 km road meets standards shown SLOPE in Table 1 (pg. 14). At its eastern end (see map), the chosen route of the Tuen Mun Rd connects with the Castle Peak Rd at a signal-controlled junction. When the Tsuen Wan By-pass is construct• ed, this connection will become one SAFETY FENCE of the slip roads in a three-level interchange. CARRIAGEWAY EDGE COVERED DRAINAGE CHANNEL The road climbs to a high point SUB-SOIL DRAIN CARRIAGEWAY SURFACE AND SUB-SURFACE built on the waterfront. An inter• .. Because of the massive rock change with Castle Peak Rd serves formation at Brothers Point, at the the traffic needs of this developing eastern side of Tai Lam Bay, the YOKES village. Tuen Mun Rd passes the new road has been constructed village on a high-level viaduct be• close to the shoreline with the fore climbing for an another 2 km existing Castle Peak Rd being re• PLATFORM through sparsely populated aligned on reclamation. Tuen Mun countryside. Rd descends rapidly to this shore• line before crossing the bay on a causeway with a bridge built to JACKING RODS allow for the discharge from Tai Lam Chung Reservoir. The enclosed area of the bay is expected to be reclaimed eventually. A second CONCRETE DISCHARGED intermediate interchange is located ON TO PLATFORM COLUMN SLIPFORMING at the western side of the bay and near Ting Kau giving a panoramic provides access to nearby villages view of the harbour and islands. and the Lok On Pal desalter. The natural slope of the ground in The chosen route cuts inland this area is very steep, so the road is and follows a succession of ridges carried on a viaduct constructed HANGING and cultivated valleys for the next 3 SCAFFOLD' just below an existing catchwater. km. The road then runs through The road crosses two deep valleys broken land separating army bar• before it descends to Sham Tseng. racks from their training grounds to Sham Tseng is a large village the north. At its western end, Tuen separated from the sea by Castle Mun Rd connects directly into the Peak Rd with a bakery, chemical centre of Tuen Mun over a reclaim• works, brewery and textile factory ELEVATION ed section of the Castle Peak Bay. ASIAN BUILDING & CONSTRUCTION, MAY 1978 Table 1 - Alignment standards Tuen Mun Rd will have two when the final stage of the road is Minimum sight distance three-lane carriageways separated completed the maximum climbing for stopping 90 m by a central reserve and bounded gradient will be 6%. Minimum (absolute) by relatively narrow verges and The road pavement has generally horizontal curve radius 130 m Minimum vertical crest curve radius 1 000 m Minimum vertical sag curve radius 2 000 m Maximum gradients: The Sham Tseng Viaduct (left) Ascending 6% during construction. Descending 8.3% (Hong Kong Public Superelevation: absolute Works Department maximum photograph). A view of the Telford Absolute maximum 10% Bridge (below). In Desirable maximum 7% all, 10 road bridges, three footbridges and 15 Table 2 - Tuen Mun Rd box culverts have been constructed carriagev^ay along the Tuen Mun Cross section Rd. (Scott Wilson Kirkpatrick & Part• Three-lane carriageway ners photograph). width (normal) 10.05 m Three-lane carriageway width (on sharp curves) 10.95 m Hard strip 1.50 m Verge to embankment width 1.50 m hard strips. Until the second been formed with 250 mm of Verge to cut width carriageway is opened, the first crushed stone sub-base, 150 mm of (minimum) 1.20 m carriageway will carry two-way bituminous macadam base and 100 Minimum clearance to traffic. Details of the carriageway mm of asphaltic concrete surfacing. bridge piers 1.00 m cross section are given in Table 2. Where formation is rock, the sub- Minimum headroom 5.10 m In designing the road the nature base has been omitted. Almost Central reserve width of the terrain dictated the use of 125 000 tonne of sub-base and (minimum) relatively steep gradients. However 135 000 tonne of bituminous sur• facing have been used. Hong Kong's average annual rainfall is about 2 200 mm, most of which is concentrated in the sum• mer months.