A14. M1 to Felixstowe
When the Bedfordshire sub unit of the Eastern Road Construction Units was established its original design briefs included the M11 Cambridge Western Bypass, the A45 Cambridge Northern Bypass, the A45 Bury St Edmunds bypass and with a lowly priority the A45/A11 bypass of Newmarket. At that time the concept was perceived of a series of local bypasses on the A45. The emphasis to the west of Cambridge was on the improvement of the existing A45 towards St Neots.
The traffic work associated with the M11 and A45 in the Cambridge area however identified a strong demand for better northbound links with the A1 and the Sub Unit were given a brief to investigate the dualling of the A604 County Road between Cambridge and Huntingdon where Stirling Maynard and Partners on behalf of the then Ministry of Transport were developing proposals for a Huntingdon Bypass which would improve the connections to the A1 significantly. The A604 was already a problematic route for the local authority. Substantial commuter flows between Cambridge and Huntingdon caused peak hour delays which were exacerbated following the establishment of the new community of Bar Hill to the north of Cambridge.
Following Traffic Studies and a public consultation, the final decision identified the Green Corridor as the preferred corridor. Shortly afterwards the Bedfordshire Sub unit was appointed to undertake the identification and design of routes within the corridor.
Thus the final piece was put in place and the scene set for the implementation of a strategic trunk route linking the industrial Midlands to the East Coast ports.
The geometric standards have evolved, including those associated with the design of all forms of junctions, from at grade priority junctions to roundabouts and grade separated interchanges. In particular the operational aspects of weaving and merges and diverges are now better set out in the standards.
The applications of the design standards has resulted in a route which has similar characteristics along its length.
Apart from Newmarket and Cambridge Northern bypasses which were designed to Motorway design standards with provision for hardshoulders the rest of the route was designed to trunk road standards. The great majority of the length is a dual carriageway with full grade separation with a design speed of 120kph.
This west-east route, some 127 miles in length, forms part of the Ireland-UK-Benelux Link of the Trans-European Road Network. There are four distinct lengths of what is now the A14.
The M1-A1 Link Road between the M1/M6 junction and Huntingdon
Early in the 1970's traffic studies were carried out over a wide area under the direction of the General Planning Highways Division of the Department of Transport to explore possible corridors for a new west-east route between the M1 and A1. The first public consultation in England for a trunk road was held in 1974. A preferred route emerged as the essential element of a strategic route between the Midlands and the East Coast Ports. The statutory proposals for the Scheme and associated Orders were advertised and concurrent Public Local Inquiries to hear objections and representations about the M1-A1 Link Road and A43 Kettering Northern Bypass were held between 11th September 1984 and 19th June 1985, longest public inquiry into a new trunk road at that time. The objections and representations came from some 1,130 sources and the Inspector completed his report to the Secretaries of State for the Environment and Transport on 2nd July 1986. There was a further considerable period before the decision letter was published and the Orders made. This was not however the finish as Supplementary orders were necessitated with subsequent public inquiries. In particular the objection into the construction of the link road close to Naseby was challenged in a very determined manner by the Society for the Preservation of Naseby Field. The Society took the Department to the High Court and the objection was not abandoned until all avenues had been explored.
The Engineer to all of the contracts was Thorburn Colquhoun, and the complete length of the M1-A1 Link Road was opened to traffic in the Summer of 1991.
The previous A604 between Huntingdon and Cambridge
This length, now part of the A14, was improved to dual two-lane standard in the late 1970's. It caters for the elongated axis of north-south and west-east traffic with a high proportion of heavy goods vehicles, as well as local traffic between Huntingdon and Cambridge, with a daily flow of over 66,000 vehicles, and is increasingly seriously congested.
In December 1999 the Government Office for the East of England (GO_East) announced that a consortium of consultants led by Mouchel Consulting Ltd had been appointed to undertake the Cambridge to Huntingdon multi-modal study. The aim of the study is to recommend plans to address the most urgent transport problems along the Cambridge to Huntingdon corridor
The corridor of the previous A45 between Cambridge and Ipswich
This length of the A14 has been improved as a series of bypasses, combined with on-line improvements, mostly to dual two-lane standard except for the length of Newmarket Bypass which again provides an elongated axis, this time for north-south traffic between Norfolk and London on the A11/M11 and west-east traffic on the A14, currently carrying over 54,000 vehicles a day on the axis.
The Ipswich By-pass is an important addition to the trunk road network which will have benefits for the national and regional economy as well as for local travel. At the strategic level the By-pass offers a more efficient route and shorter journey times for traffic between the ports of Ipswich, Felixstowe and Harwich and the industries of London and the Midlands. Locally, it removes through traffic from Ipswich, reduces the problems of road congestion in the town centre, and improves access for communities on both sides of the Orwell estuary.
The opening of the By-pass marks the successful achievement of a ten-year programme of planning, design and construction, which has included the necessary stages of consultation and public inquiry. Throughout the programme, work on each of the completed sections of the By-pass has remained on schedule.
In its final form the By-pass provides three sides of a trunk road box around Ipswich. The first sections to be built (now the A14) formed a route to the south of the town, from the London to Gt Yarmouth road (A12), across the River Orwell to an interchange with the former A45 (now A14), the road from Felixstowe to the Midlands, and the A12. The remaining sections link the route with A14 on the western side of Ipswich and with A12 to the east of the town.
The By-pass is an all-purpose trunk road with dual two-lane carriageways 7.3m wide. It has been built to near motorway standards and its engineering features include access via two-level interchanges for traffic joining and leaving it. The route has been designed throughout to blend acceptably with the landscape. C H Dobbie & Partners were the consulting engineers for the south western and south eastern sections of the By-pass. Sir William Halcrow & Partners were the consulting engineers responsible for the Orwell crossing.
South western section
Construction of the 5km south western section started in May 1981 with a separate contract, carried out by Biwater Shellabear Ltd, for an advance embankment on the approach to the Orwell crossing. The main contracts for the section were undertaken by Cementation Construction Ltd, and started in July 1981. This work included three reinforced concrete bridges, one composite steel and concrete rail bridge, culverting and substantial earthworks.
From the A12 the route crosses the valley of the Belstead Brook, which has been diverted into a new channel and runs under the By-pass in a multiple flood arch culvert. The route then passes over Grove Hill and through the embankment of the London/Norwich railway line to an interchange with A137 at Wherstead, which leads it to the approach embankment of the Orwell crossing. Northward from the Wherstead interchange, A137 has been diverted (under a separate Suffolk County Council contract) to provide a direct link between the By-pass and the entrance to Ipswich Port Authority's new West Bank Container Terminal.
For most of their length the carriageways are built of concrete laid in the form of a 280mm thick unreinforced slab over a cement stabilised sub-base. The remainder has a 100mm hot rolled asphalt surface and a 210mm roadbase over the sub-base. The rail bridge, which was designed under a separate contract for British Rail by White Young, Consulting Engineers, has a 32m composite welded steel beam and concrete deck.
The earthworks for the south western section amounted to over 700,000 cubic metres of excavation and over 500,000 cubic metres of fill. Much of the excess excavation has been used to landscape the western approach embankment of the Orwell crossing and to disguise its height.
The centrepiece of the By-pass is the high-level bridge which carries the road across the Orwell valley. The bridge has a length of 1287m (about four-fifths of a mile) and is 24m (80ft) wide. At 190m (623ft) its central span is the longest single span of prestressed concrete in the UK. There are more than 100,000 cubic metres of concrete in the bridge and its foundations. The superstructure consists essentially of two prestressed concrete box girders, each of which carries one carriageway of the road. The girders are continuous throughout the length of the bridge, and the only expansion joints are at each end of the bridge. The superstructure is supported by 19 sets of reinforced concrete piers which range in height from 20m at the ends of the bridge to 45m at the central span. The piers rise from groups of concrete piles 1 m in diameter formed in the valley bed to a maximum depth of 40m.
A bridge was selected for the crossing because it would cost less than a tunnel and could be built more quickly. It had the further advantage that it could be constructed in a way which allowed the shipping activity of the port to go ahead unhindered while it was being built.
In order to make the least intrusion on the landscape of the Orwell estuary, while achieving the highest transport benefits, the route of the By-pass was located as close as possible to the southern edge of Ipswich, so that it adjoins the industrial development of the port, container terminal and power station. The actual line of the bridge was set at an angle to the river so as to gain the best relationship to the surrounding terrain.
Two other basic design factors were the height and width of the central span of the bridge above the main navigation channel into the port of Ipswich. The dimensions of this span had to give adequate clearance for the largest vessels to use the port, both now and in the future. The higher the bridge, the more emphatic would be its impact on the estuary environment. Following discussions with the Port of Ipswich Authority and other relevant interests, the lowest height consistent with navigational requirements was adopted. As a result, the central span provides a clearance of 39m (128ft) above high water spring tides. The width of the span (190m) also was determined by shipping requirements.
Since it was essential that port activities should not be disrupted, the engineers recommended a form of construction which would enable the part of the bridge above the river to be built at high level and without interfering with shipping movements. The method involved constructing the navigation span and adjacent anchor spans by a system of balanced cantilevers, so as to build them out progressively in corresponding sections on either side of a pier. The piers and .the spans were to be formed from concrete cast on the spot. This form of construction, using concrete box girders, secured a high degree of rigidity at an economic cost.
To ensure that the bridge could be built as cost-effectively as possible, its design was based on modular principles which standardised the size and shape of the largest structural elements and allowed construction to proceed in a regular cycle of operations.
As well as possessing an efficient and functional structure, the bridge had to be designed with an eye to its setting within the landscape of the Orwell valley, and particularly its effect on views along the estuary. The aim was to achieve a form that was both simple in its outlines and sympathetic to the valley contours. Frederick Gibberd Partners were commissioned to provide the necessary specialist advice on the architecture of the bridge and the landscaping of its approach roads. Their advice helped to refine the shape and proportions of the piers and superstructure and to retain the continuity of the long views downstream and across the valley. The resulting design received the approval of the Royal Fine Art Commission.
Before the bridge contract went out to tender, the consulting engineers undertook site investigations involving over 70 boreholes to obtain information on the characteristics of the chalk which underlies the alluvial soils of the valley. In addition, a test pile contract was carried out in advance of the main bridge contract to indicate to bridge tenderers which construction techniques were likely to be successful.
The contract to build the bridge was won by Stavin Construction B.V., who started work in October 1979. The project took 38 months: the first year involved work on the bridge foundations; in the second year, the foundations were completed and the piers and western part of the bridge were built; the third year saw the construction of the longer eastern part of the bridge and the completion of the detailed superstructure. At the peak of the construction work, the contractor's labour force totalled about 300, almost all of whom were recruited locally.
Putting in the foundations of the bridge required the formation of piles in the tidal mudflats flanking the navigation channel. The contractor solved this problem by piling the main piers on each side of the channel inside cofferdams and building a dike to enclose the remainder of the piers, which are all on the eastern side of the river. The water was removed from the area within the dike and so a dry site was created for piling and pier construction.
The piers that stand in the river are skirted by beaches clad with precast concrete tripods which will protect the pier from collision if a vessel were to run off course. The design of the beaches was based on tests undertaken specifically for this project at the Hydraulics Research Station, Wallingford.
Construction of the main spans progressed on a weekly cycle of operations. From a 12m long 'hammerhead' formed at the top of each main pier, specialised bridgebuilding equipment was used to cast new sections of concrete, adding them alternately on either side. The sections were then stressed back to the main structure. Large steel tubes acted as temporary supports during concreting and cantilevering.
The approach viaducts were built in a cycle of operations which produced one completed span every four weeks. For these parts of the bridge, the contractor had a specialised type of gantry designed, which supported the deck while each span was cast. When the concrete had gained strength, it was stressed and became self-supporting, and the gantry was then moved forward to make the next span.
All parts of the bridge structure have been designed to ensure easy access for routine inspection. The box girders, which are hollow, contain works utilities such as power, telephone and lighting. The girder which carves thewestbound carriageway also conveys a 711 mm water main of the Anglian Water Authority across the Orwell valley.
South eastern section
Work on the south eastern section of the By-pass began in July 1981, at the same time as the main contract for the south western section. Costain Civil Engineering Ltd were the main contractor for this part of the By-pass, which is about 6km long and includes five reinforced concrete bridges and a rail bridge.
From the eastern embankment of the bridge, the route passes the southern perimeter of Ipswich Airport and crosses over Nacton Road, where an interchange provides access to the airport and adjacent industrial development. The route then continues beneath the Felixstowe branch railway line and the existing line of A45 before reaching the two-level Seven Hills interchange near Bucklesham. Here it connects with the new line of A45 and the eastern section of the By-pass.
The Levington scheme, a separate 4km long contract let by Suffolk County Council to Costain Civil Engineering Ltd, is a continuation of the By-pass which improves the existing A45 between the Seven Hills interchange and the start of the Timley By-pass.
The rail bridge, built under a separate contract, is similar in form to its counterpart in the south western section, and is a 29m composite welded steel beam and concrete deck, designed by British Rail. The branch rail line was diverted around the site of this bridge during the construction period.
Because the ground water level on this part of the By-pass alignment is very close to the surface, it was originally intended that the route should be carried over both the railway and the existing A45 on an embankment. Following the public inquiry, at which concern was expressed over the environmental impact of these works, British Rail agreed to raise the track sufficiently to allow the By-pass to run beneath the railway line without going below ground water level.
The earthworks for the south eastern section required 560,000 cubic metres of excavation and 540,000 cubic metres of fill. The main earthworks were at the 14m high approach embankment to the Orwell Bridge, where an old landslip had been identified. The problems of building the embankment on top of this landslip were overcome by using a combination of deep gravel drains, drainage blanket and carefully monitored construction.
What is the future for the A14 route? The route as built is already a victim of its own success and lengths are being investigated for improvement. These include the section between Thrapston and Brampton where proposals are being developed to eliminate all crossings of the Central Reservation. Several lengths were identified in Roads for Prosperity for widening but these proposals have now been put on hold. On a more encouraging note the Highways Agency have commissioned Babties to carry out a Route Strategy Study into future management arrangements for the entire length of the A14.
One factor will remain constant, the improvements associated with the A14 in East Midland region have brought considerable traffic and environmental benefits to a wide range of communities and businesses throughout the region.
|Ml/M6 Junctions||Tarmac (now Carrilion Construction)||Thorburn Colquhoun|
|M1 to Rothwell||Tarmac (now Carrilion Construction)||Thorburn Colquhoun|
|Rothwell to Kettering||May Gurney||Thorburn Colquhoun|
|Kettering Southern Bypass||Balfour Beatty||Thorburn Colquhoun|
|Kettering to Thrapston||Budge||Thorburn Colquhoun|
|Thrapston to Brampton Contract 7||Tarmac (now Carrilion Construction)||Thorburn Colquhoun|
|Thrapston to Brampton Contract 8||Henry Boot||Thorburn Colquhoun|
|A1 to Brampton||Tarmac (now Carrilion Construction)||Thorburn Colquhoun|
|Huntingdon Bypass||A Monk||Stirling Maynard & Parts|
|Bar Hill to Huntingdon||Alfred Mc Alpine||Bedfordshire SU|
|Bar Hill Interchange||Jackson Civil Engineering||Bedfordshire SU|
|Girton to Bar Hill||Jackson Civil Engineering||Bedfordshire SU|
|Cambridge Northern Bypass||Bovis||Bedfordshire SU|
|Cambridge to Newmarket||A Monk||Cambridgeshire CC|
|Newmarket Bypass||Wimpey||Bedfordshire SU|
|Ipswich By-pass - SW section||Cementation Cons Ltd||CH Dobbie & Parts|
|Ipswich By-pass - Orwell crossing||Stevin Construction BV||Sir W Halcrow & Parts|
|Ipswich By-pass - SE section||Costain Civil Eng Ltd||CH Dobbie & Parts|
|Seven Hills to Timley By-pass||Costain Civil Eng Ltd||Suffolk CC|
|Click on a section name to see a map|
Rothwell to Kettering
Kettering to Thrapston
Bar Hill to Girton
Cambridge to Newmarket
Newmarket to Bury St Edmunds
Stowmarket to Ipswich Bypass
Ipswich Bypass - Orwell Bridge
M1 to Rothwell|
Kettering Southern Bypass
Thrapston to Brampton
Huntingdon to Bar Hill
Cambridge Northern Bypass
Bury St Edmunds to Stowmarket
Bucklesham to Felixstowe