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M5 Widening between Junctions 3 & 8

Probably the decision which has had the greatest effect on the M5 in Worcestershire was to build it to dual 2-lane standard. It has to be remembered that the Gloucester Section (south of junction 8) was dual 3-lane and the section north of Quinton (junction 3) was dual 3-lane. There seemed no sense therefore in building the middle section in Worcestershire to dual 2-lane. Despite repeated representations from Worcestershire County Council, the Police and particularly the County Surveyor of Worcestershire that dual 3-lane standard was appropriate, The Ministry of Transport refused to budge and thus it became a dual 2-lane motorway. The short sightedness of this decision was to be brought home the hard way when it became necessary to widen the Worcestershire section of M5 at a cost of £123 million. The original 28 miles of motorway had cost just £8 million. Every bridge had to be demolished and rebuilt.

The widening and reconstruction was carried out over a period of about 15 years, and included a variety of widening approaches. This included widening within the existing highway boundaries, and new symmetrical or asymmetrical construction.

The section of the M5 between Junctions 4 (Lydiate Ash) and Junction 8 (Strensham) was designed to dual two lane motorway standards which are below those in current use. In layout, as an example, only 18% of the sight distances between Warndon and Catshill meet full current requirements.

When the design brief was started in 1980, the motorway was carrying 38,000 vehicles daily; by the start of construction in 1985 the flow had increased to 42,000 vehicles per day; it is currently exceeding 100,000 vehicles per day on the widened section south of M42.

The expected life of the carriageways was far less than 20 years when measured in current standard axle terms. Thus the reconstruction of the most distressed areas between Junction 6 and Junction 8 was commenced in 1977 and completed in 1983, well in advance of its eventual widening in the early 1990s.

Concurrently the planning of the combined reconstruction and widening of the remaining motorway between Junction 4 and Junction 6 was commenced. This scheme was divided into four Contracts at an estimated cost of £53M. The work involved the demolition of all the overbridges and the construction of replacement structures together with the extension and sometimes replacement of the bridges carrying the Motorway over roads, a railway, rivers and a canal. Improvements were also made to the Motorway alignment as some bends were too sharp and the whole width of the carriageway was rebuilt as necessary. Completing the M5/M42 junction was combined with the adjacent widening contracts.

Widening and reconstruction of 'live' motorway demands pre-planning and advance works far in excess of similar activities on green field sites. The provision of maximum traffic capacity on the motorway, coupled with working space for the Contractor and adequate diversion routes for traffic overspill are essential pre-requisites. As the highway authority for roads, other than motorway or trunk roads, the County Council was uniquely placed to assist the Department of Transport by ensuring that the optimum balance was achieved on the motorway and on the local road network, which carried both Contractors and diverted traffic. To achieve this objective, advance works costing £5m were carried out. These included improving diversionary routes, re-siting Statutory Undertakers equipment, restoring skid resistance to old carriageways, providing street lighting, strengthening hard shoulders, and providing central reservation crossings.

Comparison of the cross-sections showed the dramatic change that had taken place in the build up of motorway furniture. The original empirical design performed extremely well structurally. Although superficially modernised into the intermediate two lane cross section with all the modern aids to movement and safety it still retained inherent weaknesses in alignment, visibility and drainage. Online widening made the updating of these deficiencies difficult but asymmetric widening over 25% of the scheme improved alignment and visibility. Fixed drainage outfalls created problems but drainage was improved considerably to form a more efficient drainage system.

The interpretation of Deflectograph, crack and soil surveys and compliance with DTp recommendations for pavement thickness, presented problems in marrying new to old pavement. The objective to retain as much of the existing pavement as possible was, in many cases, frustrated by the need to break out old hard shoulder, to meet level tolerances at existing underbridges and to produce an acceptable pavement combining both old and new design.

The first widening - Quinton (J3) to Lydiate Ash (J4)

By 1972 traffic flows had reached a level where widening was proposed between Quinton and Lydiate Ash. Widening was carried out within the motorway boundaries. Overbridges were not widened and underbridges either widened or parapets strengthened.

Work finally started on 20 November 1978 when a tender, in the sum of £3.639M, was awarded to A Monk & Co. This was before the days of lane rental but tenderers had been asked to price for both 56 and 72 week Contract periods. The shorter tender period was accepted.

The scheme was 8.4 km long. Carriageways were widened symmetrically about the existing central reservation and the works were contained within the existing motorway boundaries. Continuity of hard shoulder was maintained over the nine widened underbridges but not at the eight unwidened overbridges.

Advance Works to this Contract were necessary and were carried out by direct labour prior to the main Contract so as to keep the main Contract period and traffic disruption to a minimum. These works included -

1. improvement to Quinton Junction to improve traffic flow;
2. removal of the existing and erection of the new permanent traffic signs (this was possible because there was no land take);
3. hard shoulder strengthening for contraflow;
4. re-siting of the communications cable from the verge to the motorway boundary.

The central reservation had to be narrowed over a short distance to accommodate the extra lane at Carters Lane overbridge near Quinton and the northbound carriageway had to be lowered to give adequate bridge headroom when the slope of the hard shoulder was reversed.

Fortunately the majority of bridge headrooms were adequate to allow a 100 mm overlay on existing carriageways. The concentration of work was therefore at the old hard shoulder/new nearside lane and the new hard shoulder.

In cuttings, the slopes of the hard shoulders on the low side of superelevation had to fall towards the carriageway to save under-cutting the toe of the slopes which were relatively unstable in this area. On embankments, a large edge beam or verge wall had to be used to provide stability for the back of the hard shoulder.

Lydiate Ash (J4) to Catshill (J4A)

This contract, let to A Monk & Co, had five existing overbridges and two underbridges. The overbridges were totally replaced, whilst the underbridges were modified and extended.

Unlike the previous two contracts, a substantial proportion of the length of this scheme, including the section containing the underbridges, was widened asymmetrically. Using construction methods developed previously, this meant that 2 + 2 traffic working was possible at all times except for two short periods, to enable construction of widened carriageway under Lydiate Ash junction.

Overbridge structures were generally single span and extensive use was made of steel for deck spans, with girders being lifted in during overnight closures of the motorway, enabling the contractor to continue work on deck construction with minimal disruption of traffic. However, the side road structures at the southern end of the scheme spanned both the M5 carriageways and M42 slip roads. This resulted in longer than normal span lengths and the need for two span structures with central piers and hence "island site" working.

Construction of these centre piers was completed in conditions of limited access and working space and extensive use was made of precast concrete safety barriers in these locations to protect the working area.

Demolition of some of the existing bridges was carried out using tried and tested methods; footbridge decks at Claypit and Woodrow Lane were lifted off in one piece at night and broken up at ground level, whilst Clockhouse Bridleway bridge was brought down using controlled explosives. The size of the structures at Rocky Lane and Stourbridge Road along with the proximity of adjacent property, however, required the use of new methods specifically suited to these environmentally sensitive areas. These post-tensioned concrete structures were 'cut' into longitudinal slices using a recently developed machine mounted saw. The sections were then removed during overnight possessions of the motorway.

In addition to replacement and modification of the existing structures, two standard DTp design sign gantry structures were erected to carry advanced warning signs and matrix signals, whilst a third gantry structure was designed as an integral part of the footbridge at Claypit Lane.

Catshill (J4A) to Rashwood (J5)

The 8.5km contract, M5/2, from Catshill to Rashwood was completed in time for Christmas 1986, in 85 weeks, thus cutting the Contract period by some 28 weeks. This early completion provided three lane motorway on M5 ready for the opening of M42 southern turn which was connected to M5 at Catshill on the 18th March 1987. Work continued throughout the winter of 1985/1986 with the anticipated suspension of earthworks and asphalt laying as determined by weather and temperature; although the use of EVA in the wearing course did facilitate working which otherwise would have been impossible. The Contractor was A Monk & Co.

100,000 tonnes of recycled cement bound granular base (CBGB) and blacktop, taken from superseded sections of the scheme, were incorporated into the new pavement structure as a capping layer on this contract.

The scheme included sixteen existing structures, six overbridges, six underbridges and four culverts. The overbridge spans (two side roads, three farm access and one footbridge) were all too short and the under bridges too narrow to accommodate the proposed widened motorway.

The essence of the design philosophy was the simplicity of structural form, to minimise disruption to traffic and bridge users and also allow the Contractor to carry out key operations during the limited carriageway possessions available.

To achieve these aims the new structures were built alongside the existing which remained in use until the new work was complete. The new overbridges are of steel/concrete composite construction, five being of single-span configuration and one a two-span structure crossing both M5 and M42 slip road. The plate girders with spans up to 49m were manufactured by Fairfield Mabey at their Chepstow Works. Foundations were generally spread footing founded on sandstone at the northern end of the scheme or marl at the southern end, although Upton Warren overbridge was founded on bored cast in-situ piles.

During overnight possessions of the motorway, the new deck girders were lifted into position in the form of braced pairs. These were 'boarded out' to allow the Contractor to continue construction of the new deck the following morning over the live motorway.

Demolition of the existing structures was also carried out during the night-time possessions. The single-span farm overbridges were demolished using controlled explosives, whilst the four-span side road bridges were 'cut' and lowered to the ground on jacks or broken up using machine mounted hydraulic breakers.

Underbridges were generally widened symmetrically using a similar form of construction to the existing. Some of the existing decks were strengthened by over stabbing and in two cases completely replaced. As with the overbridges, foundations were generally spread footings with the exception of the two most southerly bridges where bored cast in-situ piles were employed. Although at face value less spectacular than the overbridge structures the design and construction of the underbridges did pose a greater challenge and great care was taken to ensure the new extensions did not impart additional load to the existing structures.

In addition to replacement and extension of the existing structures, three new sign gantries were required to carry advanced direction signing for the proposed M42 junction at Catshill. These structures have been fabricated to standard Department of Transport designs.

Archive information

M5. Widening between Junctions 3 & 8

The full archive for this scheme is stored at the Northamptonshire CC Record Office. Click to see details of this record office, then delete the pop-up window to return. Its reference number is: MA/M/M5(W)

Document Number	Document Description & Author	Publisher	Date
1	The widening of the M5 Motorway. Environmental Statement.	DTp (W.M.R.O.)	Jun-89
2	M5 Widening, Warndon - Strensham Official Opening Brochure. Laing /Howard Humphreys.	DTp, M.W.U.
3	A Decade of M5 Widening. Paper by G. Stapleton and A. Whitfield.	IHT	Sep-89
4	Moss and the M5 Widening. Paper by Robin Mules.	H&W.C.C.	Jun-88
5	Timetable of M5 Widening in Worcestershire. 1984-1993. J.M. Carrington.		Jul-01
6	M5 Widening Warndon - Lydiate Ash. Paper by G. Stapleton. (Many useful facts).	IHT
7	M5 Widening and Reconstruction. Paper by P.E. Mortimore.	IHT	Apr-88
8	Motorway Maintenance in Worcestershire. Paper by G. Stapleton.	IHT
9	Site Visit with Associated Documents.	IHT	Jun-86
10	M5 Widening Warndon - Lydiate Ash. Official Opening Brochure.	DTp, H&W.C.C
11	Project Organisation for M5 Widening (J 5 - 6)	I.C.E.	Jun-05
12	Motorway Widening. Notes by G. Stapleton.	MAT	Nov-97
13	M5 Warndon, Catshill SRO	Dot WHRO	Aug-84
14	M5 Rashwood Junction Connecting Roads Scheme	Dot WHRO	Mar-83

Key Dates

M5. Widening between Junctions 3 & 8 Statistics

Section	Construction started	Work completed
Quinton to Lydiate Ash (J3 to J4)	November 1978	December 1979
Lydiate Ash to Catshill including M42 Northern Turn (J4 to J4A)	June 1988	December 1989
Catshill to Rashwood (J4A to J5)	May 1985	December 1986
Rashwood to Warndon (J5 to J6)	December 1986	November 1988
Warndon to Strensham (J6 to J8)	July 1991	May 1993