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Reading Bridge
River Thames, George Street, Reading, UK
associated engineer
LG Mouchel & Partners
date  January 1922 - September 1923, opened 3rd October 1923
era  Modern  |  category  Bridge  |  reference  SU716741
ICE reference number  HEW 2179
A single span ferro-concrete bridge, claimed to have the world’s longest span of its type when completed. It is located some 500m from Reading town centre and carries the busy B3345 trunk road over the River Thames.
The construction of the bridge was a consequence of the 1911 Reading (Extension) Order, which expanded the borough boundaries of Reading to encompass some adjoining parishes, including part of Caversham. At that time, the only road bridge between Caversham and Reading was the original Caversham Bridge (built 1868, now replaced), which was a little way upstream.
The order required the construction of a footbridge to ease congestion. However, Reading Town Council realised that would be insufficient and, in 1912, sought parliamentary approval for a vehicular bridge 12.2m wide. Charles Marten Powell (1855-1928), a retired medical man and patron of good causes living in Caversham, generously offered to contribute £5,000 towards the cost of its construction.
In 1913, approval was granted and the council opted for a ferro-concrete, or reinforced concrete, bridge with stone parapets. In 1914, L.G. Mouchel & Partners Ltd of Westminster, the company founded by the innovative engineer Louis Gustave Mouchel (1852-1908), was appointed as design engineer but work was deferred on the outbreak of World War I (1914-18).
In January 1922, the Reading Bridge contract was put out to tender and subsequently awarded to Holloway Brothers (London) Ltd. Construction commenced in March 1922.
The completed structure is almost 183m long, which includes the approach viaduct on the Reading (south) side, abutments, wing walls and a 55m span over the River Thames. The river span rises 5.5m above normal water level. The roadway has a rising gradient of 1 in 30 from Reading, peaking at the apex of the arch, and a 1 in 35 falling gradient towards Caversham. The bridge and approach viaduct are 12.2m wide between parapets, comprising a carriageway of 8.2m and two footpaths of 2m.
The southern end of the approach viaduct, originally 43.3m long, sits on mass concrete blocks and is formed by ferro-concrete retaining walls strengthened by counterforts, with a filling of ballast and chalk. The remaining part of the approach up to the south abutment is an arched viaduct carried on ferro-concrete piers. The north abutment's wing walls retain an approach embankment of tipped ballast and chalk.
The abutments consist of trapezoidal blocks of mass concrete 16.2m long, 13.7m wide and 8.8m deep, with stepped foundations sunk into the chalk bedrock. Each has a through archway for pedestrian (and originally also horse-drawn) access. Stairways at the south and north ends of the bridge, near the archways, lead down to paths along the river banks.
The arch consists of four ribs. The two outer ribs are 1.2m wide, 1.4m deep at the springings and 790mm deep at the crown, while the two central ribs are 1.4m wide by 1.4m deep at the springings and 1.1m deep at the crown.
Longitudinal beams, 255mm wide and 510mm deep, run above the ribs, connected to them by spandrel columns every 3m. Each column is 255mm by 610mm in section. The main beams are connected by transverse secondary beams 180mm wide by 360mm deep, set 1.5m apart longitudinally. The whole arrangement is topped by a 190mm thick concrete deck.
Parapets to the arch and abutments are of Portland stone. All other parts of the structure are ferro-concrete. The steel-reinforced construction is monolithic, without joints other than for contraction or expansion.
Reading Bridge was designed to carry Ministry of Transport standard rolling loads, equivalent to a total rolling load of 298 tonnes on the roadway and a dead load of 550kg per sq m on the footpaths. In June 1923, test loading of 300 tonnes was carried out by driving a platoon of steam engines, road rollers and steam lorries onto the bridge — at least 24 vehicles in total.
The bridge was opened on 3rd October 1923 by Alderman John Wessley Martin JP, chairman of Reading’s borough extension committee.
The total cost, including river and approach works, was almost £70,000. However, in 1919, Powell had honoured his promise of contributing £5,000 to the project and with the dividends and interest on his investment, the final sum the council received was more than £6,000.
Resident engineer: J.B. Wilson
Contractor: Holloway Brothers (London) Ltd
Research: ECPK
bibliography
"Reading Bridge" pamphlet to commemorate the bridge’s opening, Reading, 3rd October 1923
www.mouchel.com
reference sources   CEH London
Location

Reading Bridge