The Infinity Bridge is a public pedestrian and cycle footbridge across the River Tees in the borough of Stockton-on-Tees in the north-east of England. The bridge is situated one kilometre downriver of Stockton town centre, between the Princess of Wales Bridge and the Tees Barrage and it links the Teesdale Business Park and the University of Durham's Queen's Campus in Thornaby-on-Tees on the south bank of the Tees with the Tees Valley Regeneration's £320 million North Shore development on the north bank.^[1][2]

Built at a cost of £15 million^[3][4] with funding from Stockton Borough Council, English Partnerships and its successor body the Homes and Communities Agency, One NorthEast, and the European Regional Development Fund^[5] the bridge is a major part of the North Shore Redevelopment Project undertaken by Tees Valley Regeneration.

The bridge had the project title North Shore Footbridge before being given its official name Infinity Bridge, chosen by a panel made from the funding bodies, using names suggested by the public.^[6][7] The name derives from the infinity symbol formed by the bridge and its reflection.^[5]

Design

Initial investigations for the footbridge were done by the White Young Green Group^[8] who with English Partnerships produced a brief for an international architectural design competition organised with RIBA Competitions^[2][8][9] and launched in April 2003. The brief was for a "prestigious" and "iconic" "landmark" footbridge at North Shore Stockton, to cross the River Tees which is 125 m wide at that point.^[10]

There were more than 200 entries to the RIBA Competition but this was slimmed down to a shortlist of five. The successful competition design was by Expedition Engineering and architect Spence Associates.^{[10][11][12][13]}

The subsequent design was led by Expedition Engineering assisted by^[14] Arup Materials, Balfour Beatty Regional Civil Engineering, Black and Veatch, Bridon, Cambridge University, Cleveland Bridge UK,^[15] Dorman Long Technology,^[15] Flint & Neill,^[16] Formfab, GCG, GERB, Imperial College,^[17] RWDI, Spence Associates, Speirs & Major, Stainton, and William Cook while White Young Green were project managers.^[18]

English Partnerships appointed Flint & Neill Limited to carry out a category III independent check of the bridge design including loading, wind tunnel testing, and investigation of failure modes, a number of aspects of which fall outside current standards.^[16] The bridge has a 120-year design life.^[10]

Description

The bridge is a dual, tied arch bridge or bowstring bridge. It has a pair of continuous, differently-sized structural steel arches with suspended precast concrete decking^[2][4][9] and one asymmetrically placed river pier. The tapering arches with a trapezoidal box section are fabricated from weathering steel plate.^[10] The arches both bifurcate within the spans to form a double rib over the river pier.^[19][20][21] A reflex piece between the two arches holds them together^[10] making the two arches one continuous curve. No other bridge is known to have quite the same design.^[2][4]

The offset river pier is to accommodate water sports and leisure craft to one side.^[22] The river pier is supported by a 11.5 m square by 2.5 m thick pile cap on sixteen 1&np;m diameter hollow steel pipe piles.^[10] On the pile cap beneath the water line are four 3 m cylindrical concrete legs onto which are bolted and welded the four inclined grey steel legs visible above water.^[10][22][23] Riprap covers the river bed around the river pier for scour protection^[7] against the large flows when the Tees Barrage downstream discharges. Each of the two concrete riverside piers are supported on four 500 mm hollow steel piles and a pile cap.^[10]

The bridge as initially proposed was to have been some 272 m long.^[24] It was originally designed with a northern approach 38 m long and a southern approach of 54 m^[25] however the design of the north side of the bridge was later simplified and the bridge's northern approach shortened. The design of the southern approach is largely unaltered and has a staircase connecting it directly to the river frontage.^[25] The bridge deck is 5 m wide^[7] and 4 m between its handrails.^[10][26][27] The main arch of the bridge is 120 m long, weighing 300 tonnes, 32 m tall with its top 40 m above the Tees and the short arch is 60 m long and 16 m tall.^[2][3][9] The hangers (droppers) are spaced 7.5 m apart^[16] and are made from 30 mm diameter high strength locked coil steel cable.^[10]

^{Sumber : http://en.wikipedia.org/wiki/Infinity_Bridge}