Prior efforts

The first attempt to build a crossing below Northam Bridge began in 1833.^[3] The plan for a 17-arch swing bridge was stopped by the Admiralty over concerns on the effects it would have on navigation.^[3] Instead the Woolston Floating Bridge was built which opened in 1836.^[4]

In 1926, in the context of the construction of the Queensway Tunnel under the River Mersey, Southampton council hired Basil Mott to investigate the various options for building a fixed crossing across the lower River Itchen.^[5] Along with providing costs for a tunnel and a high level crossing he recommended a low level opening span bridge.^[5]

Another planning effort was undertaken in 1936.^[6] The full report took two years to compile and included sinking boreholes into the Itchen.^[6] Again a low level crossing with a swinging section was the preferred option.^[6] Attempts to raise funds for this bridge were delayed by the need to carry out work on Northam Bridge and then by the outbreak of World War II.^[7] During World War II the construction of a pontoon bridge was briefly considered but the decision was made that the floating bridge was adequate.^[8]

A further plan for a low level bridge was produced in 1947 but again work on Northam Bridge took priority.^[9]

In 1955 with the work on Northam bridge complete R. Travers Morgan and Partners were commissioned to produce a report on a new bridge.^[10] Two reports were produced over the following two years recommended in fixed structure with a dual carriageway and 55 feet (17 m) feet of headroom or another with 80 feet (24 m) of headroom.^[10] An act authorising the bridge was obtained in 1960.^[10] However, in 1961 Ministry of Transport announced it would not be providing financial support for the bridge which again put the project on hold.^[10]

Planning

In the mid-1960s it became clear to the council that some form of action would have to be taken.^[11] The floating bridges were reaching the end of their life requiring an expensive refit or replacement and the compulsory purchase powers under the 1960 Act would expire in 1973.^[11] With no possibility of funding from the Ministry of Transport the council started to look into the possibility of constructing a toll bridge.^[11] The council requested a formal report on the possibility of a toll bridge from the city Engineer and Surveyor in October 1969 and the report was delivered on 12 March 1970.^[12] It recommended a two lane high level bridge with 80 feet of head-space to allow ships from the dockyards upstream to pass under it.^[12] A bridge with an opening span was rejected on the basis of the disruption it would cause to traffic every time it had to open.^[12] With a toll bridge having been decided upon, it was decided it could also be used to control traffic levels over the bridge to avoid the need to significantly upgrade local roads.^[13] This was unpopular with motoring organisations who opposed the council's attempt to get a bill through parliament to authorise the toll bridge.^[13] This opposition was overcome after debate at parliamentary committee level and the council obtained its act of parliament in July 1973.^[13]

The contract for building the bridge was then put out for tender and was awarded to the lowest bidder, Kier Group (then Kier ltd), at a price of £5,710,630.^[14]

Construction

The ceremonial start of construction took place on 22 March 1974 with the Mayor of Southampton driving the first pile.^[15] Along with basic site preparation, the first job was the construction of two jetties, one from each bank, to the position in the Itchen where the two piers in the river would be built.^[16] The jetty from the east bank was built first with the one on the west bank being delayed by the need to fill in an area of shallow water known as the Chapel Inlet.^[16]

Once preparation was complete 100 feet (30 m) long piles were driven into the ground.^[17] Transport limitations meant the piles had to be brought in 50 feet (15 m) sections before being welded together onsite.^[17] The piling process on the east bank of the Itchen was delayed by the piles hitting the remains of a jetty which had to be partially removed.^[17] Meanwhile, on the west side delays were caused after construction disturbed a poorly documented system of sewers.^[17]

Once the piling was complete pile caps were added and the bridge supports constructed on top of them.^[18] From the top of the bridge supports cantilevered arms were then constructed outwards.^[18] They were constructed symmetrically in both directions at once in order to keep the weight on the supports balanced.^[18] Once the cantilevered arms were complete the sections that spanned the gap between them were cast from concrete in the form of box beams on top of the arms before being moved into place on hydraulic bogies suspended from girders.^[19] In order to balance the weight large concrete blocks were placed on the opposite arm.^[19] During this period work was slowed by the 1976 British Isles heat wave and subsequent rains.^[19]

Opening

The original plan was for the bridge to open on 1 May 1977 but construction fell behind schedule and instead it was opened 1 June 1977.^[20]

Before opening to motor vehicles it was decided to hold a pedestrian only day for people to examine the bridge.^[21] This was held on Tuesday 31 May 1977.^[21] The first member of the public across was the then 69 year old Mrs Edith Parks at around 13:30 with a general opening at 14:00.^[21] The bridge opened to motor traffic the following day, 1 June, at 10:30 with the mayoral car leading the way.^[21] Former Southampton MP Horace King, Baron Maybray-King decided to celebrate by being driven across in a horse-dawn Landau.^[20] Southampton's bus routes started using the bridge on 12 June.^[22]

The bridge was named by Princess Alexandra, The Hon Mrs Angus Ogilvy on 13 July 1977.^[21] This had originally been planned as an opening ceremony but this was changed when the bridge was completed before that date.^[21]

Maintenance and changes

In 2011 the bridge lighting was switched to white LEDs with Blue LEDs placed on the uprights.^[23]

As part of the bridge's maintenance eight expansion joints were replaced in March 2016.^[24]

In February 2022, the city council announced a bridge strengthening programme that would see work carried out on the bridge in 2023 and 2024 at a cost of around £3.8 million.^[25] In February 2024, the city council announced that the bridge would be closed to vehicular traffic for eight weeks for maintenance and improvements. The works are to include improvements to the drainage on the bridge as well as resurfacing.^[26]