Features
Road Work Ahead
By Kathy Borsuk
It’s hard to believe that Leeward Highway, that well traveled stretch of road connecting one end of Providenciales with the other, is almost 25 years old. (Although to those of us who drove its ragged, pot-holed length often over the last decade, its obsolescence comes as no surprise.) Actually, it aged fairly well
when you consider that there were only a handful of cars on the island at its inception and today there are in excess of 5,000 vehicles registered for use within Providenciales.
All of that is in the process of changing as the ambitious, $15 million Leeward Highway reconstruction project has been underway for nine months (since January, 2003.) And if island drivers can muster the patience to put up with the unavoidable detours, delays, dust, lumps and bumps, the end result will make travel by vehicle enjoyable again Ð and do justice to the upscale SUVs, sports cars and luxury sedans that many residents enjoy owning.
Johnston International Ltd. — the contractors who laid the original Leeward Highway from the airport to Club Med in 1981 — are tackling the reconstruction task. A great deal of planning has gone into this project. It was three years ago when Johnston submitted to the TCI Government the first design/build proposal. For some time, the project vacillated between a four-lane and three-lane undertaking. Thanks to forward-thinking government ministers who envisioned Providenciales’ future traffic demands, the final proposal did provide for four lanes along the most-traveled part of the highway.
AN END IN SIGHT
Commencing on January 8, 2003 and scheduled for completion in January 2005, the 9 1/2 mile re-construction project will be completed in three different types of road cross-section and will include eight new roundabouts to improve traffic flows.
The first section, from the Blue Hills junction to Tropicana Plaza, will be a four-lane dual carriageway with a central median, turning lanes and seven of the proposed roundabouts. On the section between Blue Hills and the Market Place there will be raised footpaths on either side of the new highway. The speed limit will vary from 30 MPH (airport to Southwind Plaza) and 40 MPH beyond.
The second section from Tropicana Plaza to Heaving Down Rock at Leeward will have two paved lanes, with a four-foot hard shoulder on either side of the road. The third section will run from the Blue Hills junction through Downtown, along the right turn to Providenciales International Airport. It will include three lanes (center turn lane) from the Blue Hills junction to Airport Inn and a roundabout at the Carib West junction, with raised footpaths on both sides of the road. Two paved lanes will run from Airport Inn to the airport parking lot, with a raised footpath on the south side of the road.
Cobra-style streetlights will be installed along the majority of the highway, placed in the center median wherever possible.
According to Johnston’s Area Manager Simon Cross, there are currently no plans for traffic lights to be introduced to Providenciales under this contract. (However, provisions have been made at road junctions to allow for possible future cable requirements.) Instead, traffic control utilizes round-abouts and T-junctions which, Cross says, “tend to result in a smooth, contant flow of traffic as opposed to lots of ‘stop and go.'” Round-abouts will direct flow at the following junctions:
1. Carib West
2. Blue Hills Road
3. Market Place
4. Suzie Turn
5. Venetian Road
6. IGA Supermarket
7. Beaches Resort
8. Tropicana Plaza
FROM START TO FINISH
In spite of being an impatient and easily annoyed driver, I find myself fascinated by the process of watching a new road unfold where only ruts and rubble existed before. Hoping that understanding would breed patience, I decided to ask Johnston engineers exactly what is going on out there.
I learned that the first step in creating a “modern” highway is to survey the existing roadway — every last lumpy inch. I also discovered that the 100 foot wide swath is actually called the Crown Corridor and had been initially surveyed and identified as the zone for future expansion of the highway 30 years ago.
Local surveyor Theo Durham completed the initial topographical surveys which established the contours of the land. These were entered onto a computer data base, with the new highway alignments mapped over the top of this three-dimensional model using state-of-the-art Eagle Point highway design software.
The design work was carried out by Hightechco of Providenciales, in conjunction with Chris Conway, of the local firm CSE (Civil and Structural Engineering Ltd.). It was their task to “make the road work” within the constraints of the government’s design brief, along with criteria and codes set by the American Association of State Highway and Transportation Officials (AASHTO) and the U.K. Department of Transport. Chris explains, “The new highway will be safer and more comfortable to drive because we have addressed issues such as the proper sight lines and stopping distances required for safety at posted speeds. The highway’s contours are designed to ensure a comfortable ride.”
Future traffic flows were projected based on a detailed schedule of traffic studies carried out by independent specialist consultants engaged by Johnston International Ltd. According to Chris Conway, capacity design elements took into consideration a 6% traffic growth year on year for the next 10 to 15 years.
As design is finalized along each section of the road, the designers work closely with the Government Public Works engineering team of Mack Smith, Chief Engineer, Lyndon Collison and Gordon Sutherland to check for compliance with the original brief. The next step is to create “Plan and Profile” drawings for every 50 feet of road. The purpose of these drawings is to show engineers exactly how much clearing, cutting, leveling and/or filling is required.
But before any earth moving could start, a somewhat touchy issue had to be dealt with. Over the years since the Crown Corridor had been surveyed, a number of encroachments had been made within its boundaries — most quite unintentionally. These included walls, garden plantings, power poles, water mains and even three small houses. In each case, TCI Government served owners with legal notice that they would have to be moved for the highway widening. Johnston representatives followed up with courtesy calls and visits and found most people to be helpful and understanding when it came time for the bulldozers to move in.
To accurately follow the design plan, it is imperative that the edges of the new highway are precisely set out. Highway engineers use optical instruments called Theodolight Total Stations, which to the layman look like telescopes. These essential pieces of surveying equipment very accurately measure angles and distances.
Massive D-8 bulldozers, front end loaders and dump trucks clear away bush and excavate roadsides and hills, with precious topsoil dropped in the central median for future landscaping wherever possible. Poles and utility boxes are carefully moved, in close coordination with power, telephone, water and cable television companies. The existing sand-seal pavement is scarified using special ripping teeth on the back of a bulldozer prior to the reconstruction process commencing.
As construction proceeds, dump trucks will be seen steadily hauling quarry fill material from the project- designated quarry at the south of the Providenciales International Airport to areas of the highway where embankments are being constructed.
The bulk fill and leveling operations bring the highway embankment up to an approximate level prior to the curb construction. The earthworks operation utilizes a bulldozer, several compaction rollers and a water truck. The fill material is a limestone based substance and is pushed out into layers by the bulldozer then compacted — first with a sheep’s foot roller and then with a smooth cylinder roller. At all times during the process, water is sprayed onto the fill surface. Water helps achieve the high density levels that are required for a firm foundation and has the added benefit of reducing the dust levels. Throughout the process, engineers carefully measure density levels and bearing strengths to ensure that the target parameters are being achieved prior to placing the next layers.
The bulk earthworks are followed by the construction of the curbs using a continuous slip forming process.
Prior to the asphalt operations, the road is finally graded using a road grader and the smooth wheel roller. Once at the final level, the surface is sealed with a bitumen emulsion coating called EPRS. This black primer coat helps ensure good adhesion of the asphalt and protects the top surface from rain prior to asphalt surfacing operations.
The asphalt surfacing is produced in Johnston’s plant next to the Sky King hanger. A precise mixture of 1/2 inch gravel, sand and AC-30 bitumen is fed into the mixer drum, heated to 250 to 300 degrees F and mixed into hot asphalt for road surfacing. This is transported by truck to the project site, where it is emptied into the hopper of the paving machine and slowly fed through onto the road surface. The paving machine uses laser guided sensors to precisely govern the level of the finished asphalt. The asphalt is laid approximately 3 inches thick (compared to 1/2 inch for the original Leeward Highway!), in two layers in some places, and elsewhere 2 inches thick. Cooling and compaction using both steel-wheeled and pneumatic tired finishing rollers ensures a strong, smooth surface. The project will require at least 41,000 metric tons of asphalt to cover the 9 1/2 miles of reconstructed highway, utilizing about one ton per foot of surfacing along the length of the four lane highway!
The white dividing lines are like icing on a cake. These days, they’re not paint but a thermoplastic substance, which is melted in a boiler and poured into the lining machine. Glass beads are then dropped on top of the lines to create a reflective surface. Installing road lights and signage will mark the highway’s completion.
CHALLENGES ON THE ROAD
Although the process itself sounds complicated enough, project engineers and highway workers face additional challenges. First and foremost are the difficulties of working on a busy “live road” on which traffic must be kept steadily flowing and access to roadside businesses remain clear. Simon Cross explains that Johnston is committed to keeping two lanes open at all times, with minimal disruption to businesses and appropriate signage where necessary. “In the event that we can only open a single lane or are building something like a round-about or tie-in, we’ve tried to work in the very early morning or on Sundays to reduce impact to motorists, and we have a flagman directing traffic.” He adds that they work closely with the local police to help ensure safety for both drivers and the work crews.
A second challenge is procuring quality materials. To keep to schedule, a shipload of aggregate (which comes from a quarry in Cuba) must arrive every 10 days. Johnston maintains a full laboratory to make sure materials are up to specification, as well as for testing of concrete and asphalt mixtures.
Amazingly, the entire undertaking only involves about 30 workers, including a handful of experienced highway construction specialists specifically recruited for the Leeward Highway project by Johnston.
It’s probably an understatement to say that Providenciales drivers will notice a big difference when the road is completed. (In fact, the tradition of driving “up the road” on weekends just for fun could make a come-back!) However, a final (and major) challenge will be educating drivers on rules of the road to ensure that the new Leeward Highway is a safe Leeward Highway.
Special thanks to Johnston’s Area Manager Simon Cross and Business Development Manager Simon Odoni for their help in compiling, reviewing and taking photographs for this article.
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