The Solihull Section of M42 is one of the four sections of the M42 Birmingham to Nottingham Motorway which was added to the Trunk Road Preparation Pool in 1968 and was the first to be completed, in 1976 - nine years before the next section.
The Solihull Section of M42 is one of the four sections of the M42 Birmingham to Nottingham Motorway which was added to the Trunk Road Preparation Pool in 1968 and was the first to be completed, in 1976 - nine years before the next section. The route of the M42 was planned to commence at a junction with the M5 near Bromsgrove, south-west of Birmingham, skirting the southern and eastern sides of the West Midlands conurbation, joining the M6 near Coleshill and then proceeding in a generally north-easterly direction to join the M1 to the south-west of Nottingham. When the contract was let in 1974, it was one of the largest ever let by the Department of Transport. The contract consisted of the construction of 10 miles of dual 3-lane motorway, one motorway to motorway junction, 3 interchanges and over 50 bridges. Despite earthwork and piling problems the contract was completed on time.
The preparation of the M42 Birmingham to Nottingham Motorway was the responsibility of the Department of Transport's Midland Road Construction Unit and the task of the detailed design and supervision of the construction of the Solihull Section was carried out by the Unit's Warwickshire County Council Sub-Unit. Messrs E W H Gifford, Consulting Engineers, gave assistance in the detailed design work by designing 8 of the 52 bridges - two of which were associated with the M6 Interchange and were constructed in advance of the main work.
Warwickshire County Council prepared the detailed design for two accesses to the National Exhibition Centre. The costs of the National Exhibition Centre access and the works in the area of the A41 interchange were shared with the former Birmingham City Council and the Solihull Borough Council respectively.
The route of the 8 mile long M42 Solihull Section commences on the A34 at Monkspath (about 8 miles south-east of the centre of Birmingham) and runs in a generally north-easterly direction ending east of Birmingham on the M6 at Coleshill. (The construction works contract also includes a short length of the Tamworth Section to the north of the M6 which was not opened to traffic until the M42 was extended to Curdworth).
The opening of the Solihull Section of the M42 Motorway marked the first important step in the fulfilment of the objective to provide for a south-west/north-east motorway across the Midlands and thereby facilitated the distribution of traffic between the Birmingham conurbation and the M5 and the M6, provide relief for villages in the area for through traffic as well as being well placed to serve the needs of the National Exhibition Centre. The roundabout on the A452 at Packington and the link with the A446 were opened in January 1976, just prior to the opening of the National Exhibition Centre. Changed circumstances, additional works and difficulties encountered during the Contract made it necessary to extend the contract period by 3 months to February 1977. In the event, the Scheme was available to traffic in early November.
The M42 had a multi-purpose function in the national strategic network. It connected the North with the West Country and South Wales by linking the M1 at Nottingham to the M5 south of Birmingham and, via the M5, the M50 at Strensham Interchange. When the M40 Oxford to Birmingham Motorway and its junction with the M42 at Umberslade were completed, the M42 and the M40 linked directly the north-east and north-west with the south-west and south-east.
The main contractor for the Works was Messrs R M Douglas Construction Ltd, whose staff on site were headed by a Project Manager. For the management of the works, the Contractor established 3 geographical sections and a mainline section each controlled by an agent supported by sub-agents, engineers and works for staff. During the peak construction period, the Contractor's staff and labour force on site numbered some 650 and peripheral labour involvement by suppliers and manufacturers was of similar magnitude. At this time an interim payment of £2.1 million was paid to the Contractor for work carried out during 1 month thus indicating the level of productivity is achieved.
British Rail designed and supervised the construction of the Paddington/Birmingham railway bridge which was constructed by Messrs Lehane, McKenzie and Shand Ltd, as an advanced contract.
The twobridges associated with the M6 Interchange were commenced in advance of the main works and were constructed by Messrs Gallifords Ltd, under the supervision of E W H Gifford and Partners, Consulting Engineers, Southampton.
Extensive landscaping was undertaken, including the planting of about 100,000 young trees and shrubs on the side slopes of cutting and embankments of the motorway as well as on the mounded areas near to it and contained within its interchanges.
Over and above the environmental treatment, an assessment of the change in noise levels on all properties affected by the works was made and double glazing and other noise insulation measures were provided where necessary.
The length of the contract includes 52 structures, mainly of reinforced or prestressed concrete construction. Apart from the 19 bridges associated with the four major interchanges of the. A34, A41, A45 and M6 motorway the route exhibits a variety of structures such as two railway bridges, eight river and two canal crossings, three farm accommodation structures and three footbridges.
A considerable number of the bridges passing the existing side roads either over or under the motorway are of a similar form of construction incorporating standardised components. Those crossing over the motorway are generally of two-span design whilst those carrying the motorway over side roads are single-span structures. In both cases the bridge decks have been constructed with the aid of standard factory-made precast pre-tensioned beams. Certain of the bridge sites posed particular problems both for the designer and contractor and a number of the more interesting are described below.
Ground conditions varied from sands and gravels to marls with running sand occurring in places and 11 of the bridges required piled foundations, the majority being concentrated at the northern end of the route. One of these was the four-span bridge carrying the M42 over the existing M6 which had to span two slip roads as well as the motorway itself. Construction here was difficult, especially when building the supporting trestles, positioned in the central reserve of the motorway and between the main carriageways and slip roads, as it was necessary to keep open at least four lanes of the M6 during the contract apart from the special closures needed for lifting the deck beams into position. Erection of the beams was carried out during night closures, each span requiring a complete possession of the affected carriageway on four successive nights with two-way traffic operating on the other carriageway.
The interchange with the M6 alone involved the construction of eight separate bridges, two of which were built in advance of the main contract in order that various slip roads could be re-aligned as early as possible and minimise the total contract period.
Similar careful construction programming was involved where the M42 crossed the electrified London to Birmingham railway. Apart from the normal phasing of the construction procedures with the available railway possessions, the site was complicated by the presence of nearby CEGB high tension cables and placing the deck beams of the two-span bridges required a simultaneous possession of the railway itself and cut off of the power supply to the overhead cables.
Certain of the bridges were completed early in the contract to ensure that adequate access was available for the opening of the National Exhibition Centre, one of these being immediately adjacent to the A45 interchange. At this site, an in-situ form of construction was chosen as opposed to the precast beam type. To span both the new slip raids and motorway a three-span structure was adopted, the deck being a continuous in-situ post-tensioned prestressed concrete box beam 113 yds long supported on reinforced concrete leaf piers.
Another site which dictated the final form of the bridge was on the new dual carriageway road linking Solihull to the A41 motorway interchange near Berry Hall. At this location the roads both over and under the bridge were curved and a structure with an open appearance was considered the most appropriate; this led to the selection of a four-span in-situ reinforced concrete voided slab deck supported on discrete circular columns.
The part of the motorway immediately west of the A41 interchange known as the "Solihull Gap" is in cutting. Due to the poor ground conditions in this section, and the need to restrict the overall width of the motorway due to adjacent houses, high-pressure gas sub-station, and a CAB electricity pylon the sides of the cutting were reduced to a 45-degree slope by means of an inclined retaining wall. The vertical height of the structure varies up to a maximum of 16 ft and is surmounted by a vertical wall 4 ft high which, combined with the vertical sound deflecting properties of the sloping wall, provides an effective visual and noise barrier.
Crossing the Solihull Gap is the Warwick Road footbridge situated on the line of the old section of the A41 road. The bridge spans both the motorway and slip roads of the adjacent interchange. A two-span post-tensioned prestressed concrete deck with curved soffit rigidly connected to the central supporting leaf pier was selected for the main spans and to reduce land take and access problems the approach ramps were constructed in a spiral form.
The A34 Interchange was 2 level with a roundabout above the motorway. Only the northern slip roads were constructed with this scheme; the southern slip roads formed part of later contracts.
The A41 Interchange was also 2 level with a roundabout above. The works include a 3-mile diversion of the A41 to dual carriageway standards at the southern end of the Solihull Town Centre Relief Road. A bifurcation provides a link back to the A41 for local traffic.
The A45 Interchange is at 3 levels, with the dual carriageway A45 passing over one leg of the roundabout and under the other to achieve better harmony with the topography. The motorway is at the lowest of the 3 levels through the interchange.
The M6 interchange provided some "free flow" motorway/motorway links. The additional main manoeuvres were not made available until the Water Orton Contract was carried out. The roundabout forming the original intersection was extended by building two bridges to carry the roundabout over the link road connecting the M6 northbound with M42 southbound.
Throughout the construction of the Works, it was necessary to maintain traffic flow, not only on the major roads where interchanges were provided but also on the several minor roads which were realigned over or under the motorway. This required close liaison with the 4 Highway Authorities and 4 Police Divisions whose area the scheme traversed and had a major effect on the programming of the Works.
The M6 Interchange was the most difficult area in this respect. During construction, at least two lanes on each carriageway of the M6 were kept open to traffic during weekdays. Placing the beams on the bridge carrying M42 over the M6 and the erection of 3 sign/signal gantries was carried out at night and at weekends by closing a complete carriageway to traffic and by operating a contra-flow system on the other carriageway. Traffic was also maintained on the A446 roundabout over the M6 during the construction of the two bridges carrying the extended roundabout over one of the links between M6 - M42. The only exception to this was for 2 days when the eastern portion was closed for concreting of one of the bridge decks.
At the A41 Interchange, the motorway Works through the 'Solihull Gap' could not proceed until the mile section of the Solihull Town Centre Relief Road was opened as part of the works, thus freeing the existing A41 from traffic and allowing the construction of the retaining walls and footbridge to proceed.
At the A45 Interchange at Bickenhill, 2 traffic lanes in each direction were maintained at all times on the heavily trafficked A45.
At Packington, the normal procedure of two way traffic on one half of a partially completed roundabout was adopted for the construction of the A34 Interchange and the roundabout over the motorway at the A452 which forms part of the northern access to the National Exhibition Centre.
With the motorway crossing 3 main radial roads into Birmingham the re-routing or strengthening works to many services was necessary before construction of a carriageway over them. With the major apparatus serving the Gas, Water and Electricity Boards and the Post Office, some of these re-routing works took over 9 months; careful programming was needed by the main Contractor who was responsible for coordinating the activities of the Statutory Undertakers.
In addition, main 132KV and 440KV overhead power lines are in the motorway corridor and some of these had to be resited. Wherever possible, these and major gas pipelines were resited in advance of the main contract. The cost of these advance works was approximately £600,000 and in addition, a further £1.2M was spent on service diversions within the contract.
