Жаңа Оңтүстік Уэльстегі Хампден Көпірі

Bridge in New South Wales, Australia

Hampden Bridge is a heritage listed single span suspension bridge that carries Moss Vale Road (B73) across the Kangaroo River, in Kangaroo Valley, in the City of Shoalhaven local government area of New South Wales, Australia. The bridge was designed by Ernest de Burgh and built by Loveridge and Hudson. The property is owned by Transport for NSW. It was added to the New South Wales State Heritage Register on 2 August 2019. Opened on 19 May 1898, the bridge is named in honour of Lord Hampden, the Governor of New South Wales from 1895 to 1899.

Hampden Bridge was designed by Ernest Macartney de Burgh, the colony's Assistant Engineer for Bridges, to replace the decaying timber truss bridge which originally spanned the Kangaroo River. The bridge was opened on 19 May 1898, just six days before floods washed the old bridge away. Construction was by Thomas Loveridge and Herbert Hudson and began in 1895. At the conclusion they formed a partnership, Loveridge and Hudson. A public holiday was declared in Kangaroo Valley for the bridge opening. The bridge was opened by the Minister for Public Works, J. H. Young.

Kangaroo Valley region is within the Dharawal/Thurawal clan country, a language group extending generally from the "Cowpastures" (Camden/Appin) east along Georges River then to the south of Jervis Bay and west to Braidwood. The Wodi Wodi and Wandrawandian, Dharawal sub groups from the Illawarra Shoalhaven area accessed the valley year round. Local Dharawal names are still used such as "Noggarah", a big gully and "Parronrah", suitable camping areas on the river side flats. Kangaroos and other wildlife abounded and the valley was considered a refuge or game reserve, sometimes used as a meeting place for the various family groups to replenish on their journey to the "Cowpastures" around the Camden/Appin area, where larger gatherings took place with neighbouring clans such as the Gundungurra from the Blue Mountains, to trade and conduct ceremony. Quite often disputes were also addressed through a formal process. European settlement of the valley began in the late 1810s, with Richard Brooks sending cattle into the valley from the already settled districts of Berrima and Sutton Forest in 1817 and then taking up a grant in the valley in 1820. Others moved into the valley from Sutton Forest to occupy land around Brogers Creek. Cedar getting also commenced in the first half of this century, with Kangaroo Valley known for its red cedar. Kangaroo Valley was surveyed by Hoddle in 1831. Several areas were selected for cattle stations in the 1830s, but the 1841 census showed only seven men inhabiting the valley. Farm amalgamations in the twentieth century have reduced the population greatly, and hobby farmers and retirees are increasingly attracted to the valley. Otherwise, the character of the township has not changed significantly in the last 130 years with a number of heritage buildings remaining. The valley is now a popular tourist destination with a range of accommodation choices available, including bed and breakfasts. The bridge forms an important landmark and an attraction, as well as to this day being still the main access across the Kangaroo River. The bridge is well known to those who reside in the valley, and to the wider public of Sydney and the South Coast region. that was opened to traffic in 1892. It was built as a timber deck suspension bridge with steel cables and ornate sandstone turreted towers by private developers to promote future residential development to the north. The original suspension bridge was constructed with a 500 feet (152 m) main span that was supported by steel cables and hanger rods. The deck was stiffened by an undertruss which was pin connected at the centre of the span. The steel cables were supported on sandstone towers and anchored into bedrock at each end of the gorge. The wooden deck contained two traffic lanes plus two tram tracks and pedestrian footways. This elaborate form, and the relatively sophisticated structural design of the span, reflect the importance of this river crossing at the time of construction: the Cambewarra Road (now the Moss Vale Road) was then a major route from Sydney to the south coast of NSW. The deck is stiffened by timber side trusses which are hinged at midspan. The bridge, with a clear main span of , a sag in the cables of , sandstone tower height of and height above water also of , is an impressive structure in the local landscape and has been a landmark icon of the region for more than 100 years. The bridge is a single lane for vehicular traffic, with two narrow pedestrian walkways; with a maximum truck load of , and no more than one truck on the bridge at a time. and is the oldest and only timber suspension bridge still carrying vehicular traffic still in operation within Australia. In 2012 the bridge underwent a major A$3 million renovation by Roads & Maritime Services, after many years of lobbying by local resident Bruce Ramsay, who agitated for the preservation of this iconic structure.

The towers, constructed mainly from sandstone quarried on the site are of Victorian Gothic style, similar to the (former) suspension bridge at Northbridge in Sydney. Each tower has two columns, joined by an elliptically arched crossbeam above traffic height. As described by The Kangaroo Valley Times of April 1896, "These towers will be about 42 feet (13 m) high, built on concrete blocks resting on the present sandstone formation, the masonry to towers being Each pair of towers will be connected by a wall containing an arched doorway 18 feet (5 m) high, and as the top sides of the centre walls and heads of towers will be finished with battlement tops, the whole will present the appearance of a structure similar to the famous "Traitor's" gate of the Tower of London ". In section, the towers are formed by a solid mass concrete core and finished with sandstone blocks. They sit on mass concrete which in turn was cast onto excavations to solid sandstone. Immediately below the roller saddle bearings supporting the cables, the mass concrete is surmounted by bedstones composed of the rarely found hard trachyte weighing 3 tonnes and quarried at Mount Gibraltar at Bowral. The cables enter the towers through openings close to the battlement height of the cross wall, and each tower is then topped with an enlarged battlement. The finish of the sandstone is a combination of smooth ashlar battlement details and rock faced finish on the main column faces. The original design incorporated drainage gratings in the floor of the upper battlements. Extending out from the base of each tower are sandstone parapet walls framing the approaches to the bridge. These are rubble filled, and topped with footpaths, kerbs and drainage grates on each side of the roadway. The parapet walls connect the towers to the cable anchorage structures. These consist of a shaft sunk some 25 ft into sound sandstone. At the bottom of each shaft is an enlarged chamber where riveted steel beams transfer the tensile forces from the cables to upthrust in the sandstone above. At the surface there are cast iron shoulder castings which turn the cables from inclined to vertical. The thrust forces from these are transferred into the sandstone bedrock via further 5 ton trachyte thrust blocks set in concrete. Each anchor pit is surmounted by a small crenelated turret, with an access cover adjacent. This allows access to the bottom of the pit via a full height access ladder. One of the significant construction tasks was the excavation of drainage tunnels for the pit. On the Nowra side, the main drainage drive was some 100 feet (30 m), opening to the northeast of the abutment, with a cross cut to the western pit. On the Moss Vale side the main drive was 60 feet (18 m) long. These tunnels were excavated by drilling and blasting.

The main cables of the bridge on each side, consist of fourteen 36mm diameter steel wire ropes, each with a specified tensile strength of The fourteen ropes are grouped into two cables of seven ropes each, and each rope consists of six strands, each having seven wires. They are anchored vertically in pits at either end of the bridge and have facility for length adjustment. Each rope has its own anchorage yoke around which it passes and is then fastened back to itself using six U bolt clips. The fourteen yokes are connected by links and bolts to three anchorage girders using a pattern of 4 6 4, and these girders bear against the top of the anchorage pits. From the anchorage, the ropes run upwards, over a shoulder casting which bears on the thrust block, leave the sandstone pilaster, run directly to the tower where they turn again on turning saddles which have roller bearings, and cross the span with a low point approximately one metre above deck level. In plan the cables angle inwards from the anchorage pits till they leave the towers, and then form a curve back to the tower on the far side of the bridge. This curve is created by the plane of the suspension hangers. The maintenance files on the bridge, describe that in 1970 the cables were coated with Davidsons X3016 Anticorrosive primer, BA77 Lumatint and Line 176 Black Finish.

From the cables, suspension rods of varying length hang in an inclined plane at 6 feet (2 m) centres to support the deck. Anchorage on the suspension cables is by way of suspension clips which have a U bolt to support the eye at the top end of the hanger rods. They terminate through crossbeams which were originally timber, but are now boxes of galvanised steel formed by welding channel sections together. The hangers terminate with wedge shaped washers, nuts and lock nuts to allow adjustment of vertical profile. Deck Sitting on the cross beams, the current deck consists of longitudinal timber stringers supporting transverse decking of timbers topped by longitudinal timber sheeting, with a bituminous seal. The stringers are of varying depth to provide a camber to the deck. As part of that work and to compensate for the loss of lateral and torsional stiffness of the new deck, a steel undertruss was installed. This connected to the abutment at each end and, by so doing, changed the manner in which the bridge was designed to articulate. It has since had a history of connection failures. Packed above deck level to allow drainage, there is a timber kerb on each side giving a clearance of 18 feet (5 m) between kerbs. In its current configuration, plastic flaps are fixed approx 1m in from each kerb to provide pedestrian access to the bridge, leaving approximately carriageway for traffic.

A suspension bridge is inherently a very flexible structure, with its vertical geometry (referred to as a funicular polygon which approximates a catenary shape which applies when the load on a cable is completely uniform) varying to balance the loads at each node. Stiffening of a minor nature is provided by the deck, but this is insufficient to prevent large vertical movements for heavy vehicles. To control this effect, this bridge is provided with stiffening trusses along each side of the deck. Each truss is pinned at the abutment and at the centre of the span. The truss form is of the Pratt truss configuration with timber top and bottom chords and timber verticals, with steel rod crossed diagonals. This configuration allows the truss to transfer loads from where it is applied in both directions to the elastic supports provided at each node by the suspension cables. The top and bottom chords consist of pairs of horizontal timber whilst the verticals are single timbers. Splices in the chords have been affected with steel side plates, some of which may be original and some replaced. The original mild steel diagonal rods have been replaced with high strength steel rods (presumably grade 8.8 steel with an ultimate tensile strength of 800 MPa). These bear on galvanised steel thrust plates which are either original or similar to the original detail. To assist with durability, the chords and vertical tops have been capped with galvanised steel flashing. Bearings and Centre Hinge The bottom chords of the side trusses terminate at mid span at a pin joining the two truss halves, and at the abutments in bearings. The northern bearing and centre pin are of fixed pin type whilst the southern bearing is of a swing link style, detailed to allow longitudinal movement. This movement is a combination of thermal and geometric due to articulation of the suspension system. Materials used in the bearings and other ferric components include cast and wrought iron and also cast and wrought steel. In addition, the bridge consists of a number of other features of a secondary nature. This includes lighting which illuminates the towers. These are in vandal resistant boxes mounted outside the approach parapets. Downpipes and drainage was installed to remove water ponding in 1974 works. Galvanised wire mesh grillesare provided to prevent bird access to the suspension cable saddle areas on each tower. Security grilles are provided to prevent entry to the anchor pit drainage tunnels. A mesh grille was added as a nut catcher at the end of each steel truss diagonal. A maintenance gantry is suspended from the underside of the bridge. The gantry is a lightweight steel truss structure supporting a personnel platform which can be skidded from the upstream to the downstreem side of the bridge. Utility pipes include a water main on the eastern side at the roadway level and two PVC conduits on the western side of the bridge. A number of plaques and historical markers are present either on the bridge or in its vicinity.

As at 5 July 2018, the bridge and its various components are in a good condition due to regular maintenance and upkeep. The bridge is highly intact and retains a high degree of integrity.

As at 10 July 2018, Hampden Bridge is of state significance as the second major suspension bridge in NSW, and as the only surviving timber decked vehicular suspension bridge constructed in the nineteenth century (1898). The bridge is associated with engineer Ernest Macartney de Burgh, and builders Loveridge and Hudson. Hampden bridge has the capacity to represent some of the key characteristics of a small class of Australian suspension bridges, both vehicular and footbridges; many of which do not survive, or do not survive in their original form. The Hampden Bridge also has historic significance because it facilitated the agricultural prominence of the Kangaroo Valley area in the first decades of the twentieth century. The form of the bridge, its sophisticated structural design and elaborate tower castellations, reflects the cultural importance of this crossing at its time of construction, on what was then both a major route to the south of the state, and an area of emerging prosperity. The bridge now facilitates the growing importance of the area as a tourist destination. It is readily viewed and interpreted from the surrounding recreational areas and is held in high esteem by the local and wider community for its historic, aesthetic and technical qualities. Hampden Bridge was listed on the New South Wales State Heritage Register on 2 August 2019 having satisfied the criteria.