The Iconic Road Engineering Masterpiece Engineering Essay

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The M1 is the Great Britain's first ever, modern road built by using modern road-engineering technology. It is also the first ever, full-length motorway in the whole of British Isles.1 This arterial motorway is the main road going out from the north of London and entering the East Midlands, Yorkshire before touching the north-south section to the A1 (M) just near Leeds. The entire motorway is about 311 km long and it consists of four different phases. Major parts of the motorway were opened for traffic in 19592 while the southern and northern ends were extended in 1977 and 1999 respectively.

It first section runs from St Albans to Rugby. At the time of its opening, it was a great road-engineering feat. Today, the M1 is a legendary landmark in the entire island and it holds well on its class and quality even after 50 years3. Earlier, the traffic density was calculated to be around 15,000 vehicles per day. However, today more than 150,000 vehicles ply on this entire road. To meet the rising traffic demands, the government is adding more and wider junctions while another lane is planned to supplement the present ones.

Brief history

Most of the sections of the bridges were completed in late sixties. In the year 1955, the permission was granted to build this road. The construction started with the construction of the first 53.5 miles of the road. More than 150 over and under bridges helped the traffic flow smoothly throughput the entire motorway4. The road engineers who designed the road were was Sir Owen Williams, Owen Tudor Williams and Thomas Vandy. To manage road land acquisition, roadwork engineering and overall supervision, the engineering firm Owen Williams & Partners opened an office at Welton Station that lies on the northern edge of the road.

Survey and design issues

The survey work included areas from the north end of the proposed St.Albans By-pass to another locality called Doncaster. It also included a spur (M45) to the intended Dunchurch By-pass. The total length was about 150 miles5. In July 1955, the permission was granted for the actual construction of southern tip of the project that is a total length of about 53 miles. At that time, the survey work was performed with manual levels, tapes, chains and there were no advanced survey equipments6. Most of the survey work took place at the sites of the proposed junctions and bridges.

Mapping adjustments were needed because county series ordinance maps were available at that time. To rectify the anomaly, engineers had to adjust the map at the county boundaries to fit the grid used for that county. The use of so-called "Railway Curves" was used to define the vertical and horizontal curve forms. The eventual alignments assigned contained many long straight stretches along the proposed road. Master pegs at each fence or hedge line defined the actual line on the ground while additional pegs integrated at many tangent points provided a blueprint for the geometry of the road. Overall alignments were possible by making local adjustments to the road decks.

Road engineering

The whole project was split into four different sub-schemes7. This allowed unlimited flexibility to the people who working on the project. These contracts were labelled as A, B, C & D as below:

Herts and Bed area near Slip End to Ridgmon Beds with a total length of 12.3 miles and 28 major and minor bridges

Ridgmont to Gayhurst with a total length of 11.9 miles and 31 bridges

Gayhurst to Kislingbury with a total length of 12.3 miles and 31 bridges

Kslingbury to Watford and the M45 spur to Dunchurch with a total length of 15.9 miles plus 38 bridges.

Finally, John Laing & Son Ltd bagged the contract because they quoted the most favourable prices and work schedules. The total outlay of the entire project was £1500000. The contractors had to make readjustments in the entire project schedule suiting the four different parts of the contract. The site arrangements were made possible by tackling each phase of the project on an individual basis. Site inspection was carried out with several teams who coordinated their share of their work by keeping constant touch with other teams.

The site conditions were horrible during the rainy days as the ground used to become soggy and wet. The most difficult conditions lay at the southern end of the project where the ground materials consisted of a mixture of chalk and clay8. Other areas where the road passed contained a number of soil types like rock, silt, boulder clay and quicksand. Underground seepage meant continuous wet conditions that eventually posed problems for excavation.


The selected specification for surfacing was dry-lean concrete with black top surfacing9. The construction process consisted of 6" of granular sub-base covered and sealed with a coat of tar spray, 14"dry lean concrete, applied in two intermediate layers, 2½" hot rolled asphalt base course and 1½" hot rolled asphalt wearing course9.

The asphalt mixture used contained lot of stones and it did not possess any coated chippings that could be rolled on to the surface. The carriageways were very important; engineers edged it with haunches and 14-inch trapezoidal concrete strips later topped with 4" thick 12" wide strips and a top coating of white concrete that formed the flush edge lines. The granular sub-base materials used was gravel and it provided an enough base for the traffic required to lay the next level. The initial haunches were laid on the dry lean surface without a leeway for the drainage.

In fact, this design process was very effective during the construction period. Soon after the rolling process, the entire surface was sprayed with tar or bitumen to protect it from excessive sunshine during curing and from traffic that passed during the construction. The asphalt layers laid were conventional in type. However, continuously wet under surface resulted in breakages of the layer which demanded relaying at certain sections of the roadway10.

Eventually, an 8-feet wide hard shoulder was formed with a convenient 4½" gravel sandy-loam seeded mixture and then sprayed with liquid bitumen to speed germination process. The surface stabilization was carried out by using soil stabilization and replacement of stones with thin surfacing. The central reserve areas were filled with high quality op soil and it was mounded with a concrete drainage canal. However, they were replaced at a later stage with other drainage designs.


A majority of the structures built along the motorway were reinforced concrete without any pres-stressing10. A few of the bridges constructed along the way were precast especially the ones that passed over railways. The British Rail constructed three pre-cast steel bridges over the motorway and they carried rail tracks over the motorway.

Structures built were very simple and followed standardized design patterns so that it became easy to use shuttering and to quicken the speed of construction. Another reason to use normal reinforced concrete structure was its established long shelf life. The deployment of mass-concrete structures for under bridges provided much simpler road geometry and brought down the requirements for reinforcing steel10.

Accommodation bridges built on the way were either portal frames or four spans RCC slabs that sit on circular columns. On the contrary, the under bridges were of two main categories- RCC portal frames or mass-concrete 3-pinned arches. Railway crossings were designed by using pre-cast concrete cantilever and slab system. The parapet walls were of RCC in design that saved money in maintenance work like painting. Bridges constructed provided a solid look while the appearance was neat and stable. General conditions of all these structures were11:

No movement joints

Provision of massive columns and abutments

Robust concrete parapets

Joints at the portal haunches

Longitudinal section joints

The over bridges constructed were of the following types:

the two-span one described,

a four-span continuous slab design and

railway over bridge

The under bridges constructed were of the following types:

single span portals

mass concrete arches, and

railway under bridges

The important bridges followed a common shape and pattern with strong and low vertical walls supported by inclined tapering haunches that curve over top the reinforced deck slabs. Both the thickness and of the deck and the number of reinforcing bars changed according to the span type and skew of the bridge. On the contrary, under bridges were of single span type with sturdy walls. Circular columns supported over bridges at the mid span areas. Those bridges that crossed rivers and streams were plain unreinforced concrete 2 and 3 pin arches with moving shuttering that was rolled along the length of the bridge. On the other hand, the bridges that passed over the rail tracks caused minimum disruption to the system. Abutments were set away from the rails where lines of columns were constructed very close the rails and they supported all pre-cast sloping members11.,

Finishing and utilities

A high-speed motorway will be complete only when there is an efficient surface deck. The numbers of utilities that go along with it are also very important for the success of the bridge. During the time of construction, steel guardrail system were scantily available. Overhead roundabouts needed strong parapets with robust railings. The bridge construction team decided to use an innovative wooden barrier to protect the parapet. This system consisted of timber beams mimicking railway sleeper of the 1950's. It was mounted on wooden posts that were overlapped with a scarfed joint along the length of the travel. However, these guardrails have been replaced with steel guards in the late 1970s.

MM1 used a large numbers of signboards all along the motorway. To erect signs, the bridge engineers used a large numbers of concrete tapered posts for larger signboards with many grooves set along the sides to hold the clamps and the signboards in place. Lighted signboards were the newest inventions created by engineers. M1 motorway was one of the first highways to use emergency telephone posts along the way. These telephones are connected to the local police station to provide emergency services.

Service areas were established at an interval of 12 miles. Most of them were utility areas that were suitable for picnics. Heavy transport vehicles used these areas extensively. Landscape planning and eco system protection were the top most priority for the project. Various trees, plants, flowering shrubs, annuals and green lawns were the mandatory utilities that the authorities insisted. The road geometry ensued landscape designed was non-obtrusive and inconspicuous.

Safety features

The safety features and systems provided throughout the motorway were exemplary for the time. The bridge engineers provided a central reservation with a continuous crash barrier and a central separation corridor. Of late, M1 has been using concrete and steel barriers in the central reserve area. Side barriers used are made of steel. To ensure safety top passengers as well vehicles, the road transport department has stipulated many conditions like:

Reduced roundabouts unless there are sections with heavy traffic

Provision of hard shoulders; incidentally, M1 bridge provides only hard shoulders along the way.

Motorway interchanges on M1 provide ancillary road connections and not anywhere else.

All M1 junctions are numbered for easy recognition and referencing

M1 does not allow stationary vehicles and traffic needs to moving all the time unless there is a traffic jam caused due to an accident or emergency.

The minimum speed limit is 80km/h

Both the nearside edge and offside edges is marked with a solid white line. The number of lanes on the road surface is marked with white dashed lines.

The lane near the hard shoulder signifies normal and steady driving while other adjacent lanes are reserved for overtaking or passing slower vehicles.

M1 recommends the use of nearside lane that is free of traffic.

The M1 motorway is a safe drive zone. There are many junctions with four slip roads, two on each side of the motorway, to either enter or exit. A flyover accompanied simple crossroads or roundabouts; such structures exist in only bigger towns.

Road transport statistics

According to road-traffic, statistics provided the Department of Road Transportation (The UK), the maximum flow of traffic that plied across the northern section of M6 junction was 103,000 while the south section displayed a traffic flow of 107,000 vehicles per day. M1 has contributed a lot to the economy of England and Northampton's in particular. Being an arterial road running through major counties of England, M1 motorway has transformed Great Britain's image as a pioneer road builder who has the ability to construct roads of highest international standards. Even with many rounds of expansion, this road remains a model and an enduring standard for all future road engineering and design both in the Great Britain and elsewhere.