Kingston Bridge, London, UK, is a strategic crossing point over the River Thames in South West London. It carries a total of approximately 50,000 vehicles per day with some 2000 vehicles per hour crossing in each direction at peak times.
There has been a crossing of the river at Kingston since Roman times. It is believed that the first bridge of timber construction was built in AD43 following the Roman invasion of England. Over the centuries it was rebuilt and repaired on several occasions.
The wooden bridge was eventually replaced in 1828 by a masonry arched bridge, Figure 2, which was widened on the south side in 1914. Spanning the river are five elliptical arches with Portland stone facades with a bold cornice and balustraded parapet. Semi-circular cut waters carry flat panelled piers surmounted by balcony projections that form recesses in the balustrading. Above the springings the 1914 bridge is separated from the 1828 bridge by a small gap which can only be seen from the river. The façade of the 1914 bridge is a replica of the 1828 original using similar Portland stone and ornamental features.
The nearest alternative road crossing points are at Richmond, 7 km downstream, and Hampton, 4 km upstream.The bridge is part of the national heritage and in 1951 was granted listed status. This places extra control on any work that is carried out to maintain the structure and also any alterations.
The bridge is an integral part of the road network serving Kingston town centre, the wider area of south west London and beyond. It is therefore essential that any work on the bridge does not disrupt the flow of traffic and if unavoidable should be carried out only during off peak times.
The river at the bridge is non-tidal with flow being controlled at Teddington weir 4 km downstream. The west bank of the river lies within the Thames flood plain so ground levels in this area cannot be increased because of the risk of flooding elsewhere during high flow conditions. Although no longer used by any significant commercial traffic, the river is a valuable amenity used by pleasure craft particularly in the summer season. Navigation must be maintained whilst carrying out any maintenance work to the bridge
The areas surrounding the bridge are environmentally sensitive with parkland on the west side and the historic market town of Kingston on the east. Restaurants and cafes overlook the river on the Kingston side. Both sides have riverside footpaths and are within designated conservation areas recognising their historical and visual importance with the bridge acting as a focal point.
The bridge carries numerous services including electricity and telecommunication cables. A majority of these are located in the south side footway.
Kingston Bridge has been the responsibility of The Royal Borough of Kingston Upon Thames since 1986. In September 1993, consulting engineers Travers Morgan were commissioned to inspect the condition of the bridge and carry out a load assessment.
Prior to carrying out the load assessment detailed inspections were undertaken to examine the bridge's condition. The inspections revealed numerous defects including:
Displaced and cracked brickwork in the hidden voids over the piers.
Lack of effective drainage and waterproofing causing penetration of water through the bridge fabric.
Open joints, loss of mortar and minor cracking to the brickwork arches.
As a result of the inspections, exceptionally heavy vehicles (over 38 tonnes) were prohibited from crossing the bridge and a programme of regular inspections instigated to monitor its condition.The subsequent load assessment identified a number of elements of the bridge with a reduced load bearing capacity.
The imposition of a permanent 3 tonne weight limit was rejected due to the severe disruption it would cause to traffic, local businesses and the community as a whole. Access to Kingston town centre by public transport would also be severely restricted if buses were banned from crossing the bridge. It was therefore decided to carry out investigations to identify methods of strengthening the bridge. Whilst the investigations were being undertaken the bridge would continue to be monitored.