LocationOman Middle East
Developing a dual-carriageway highway in Oman
All our work on Bidbid-Sur Project was followed closely by His Excellency Dr. Ahmed Mohammed Salem Al-Futaisi, Minister of Transport and Communications, and his team, to ensure that Oman’s national objectives were being met. The final result was a project that met two sets of high standards, Oman’s and Dar’s.
Widening a road can seem like a straightforward task.
However, the Bidbid-Sur Road in Oman presented significant design, construction and follow-up challenges.
Dar recently expanded a road that connects two towns in Oman: Bidbid, an inland town west of Muscat, and Sur, the main town of the Sharqiya South Governorate. Although a road had already existed, Dar’s team widened it and, in several stretches, provided bypasses to sensitive urban and natural areas.
Bypasses, interchanges and flyovers:
A look at the road section
The Bidbid-Sur Road project was divided into two sections, with our input covering the first section (Section 1). This section was divided into two packages: 1-A and 1-B.
Package 1-A covers the first 40 km, starting from the town of Bidbid. It included two major bypasses, three interchanges and a flyover bridge.
Bypasses | Two major bypasses were introduced:
- The first bypass avoided a critical flood plain and the town of Surur.
- The second bypass circumvented the Wadi Al Uqq area, notorious for its winding alignment and accident history. The bypass crossed a mountain range where cut and fill heights exceeded 100 m in some locations.
Interchanges | Apart from expansion works on the existing interchange, three interchanges were added:
- Semi cloverleaf interchange with overpass bridge (at Luzugh) Dumbbell interchange with underpass bridge (at Samail Prison)
- Diamond dumbbell interchange with underpass bridge (at Dahiyah).
Service road length | Six-km long service roads were used to segregate long-distance traffic from local traffic.
Flyover | A flyover bridge was introduced to cross an area with oil and gas pipelines. Dar constantly coordinated with the Petroleum Development Oman and Oman Gas Company to achieve this part of the road.
Package 1-B covers the last 75 km of Section 1. It included one major bypass, one minor bypass and nine interchanges.
Bypasses | One major and one minor
- The major bypass avoided the populated urban area of Ibra, with a length of approximately 13 km.
- The minor bypass is 6 km in length and designed to improve on the alignment.
Interchanges | Nine interchanges of various types were introduced.
- They included diamond, dumbbell and trumpet designs.
- The final interchanges provide for all movements as well as service road connections and access to existing facilities and structures.
Service road length | Fifty km-long service roads were used to segregate long-distance traffic from local traffic.
Reserve lanes | A modification in design took place right after at the beginning of the works. Initially, the plans were for a 2x2-lane cross-section road with a wide central reserve for future additional lanes. However, before construction works began, the client requested that the reserve lanes be introduced from the start. The result was a 2x3-lane cross section road.
Service roads | The project’s service roads are two-way single carriageways. They maintain the circulation of local traffic and its connectivity with the new dual carriageway through right-in-right-out junctions, underpasses and overpasses.
Additional road features
The works also included the following:
- Retaining walls
- Barriers and miscellaneous road furniture
- Signage and road marking
- Street lighting for the entire road stretch and interchanges
- Weigh station for trucks
- Ambulance and police stations
- Police layby pockets on the road
- Traffic count stations
Utilities | Dar made provisions for the relocation or protection of existing utilities. This was done in full coordination with the utility owners.
The following issues made this “typical” project more
challenging than normal:
Crossing sensitive areas
The road crosses a mixture of natural, archaeological and socially sensitive areas. Bypasses that were supposed to overcome these sensitivities faced technical issues, such as crossing old cemeteries on the Ibra bypass and a very rough mountain range adjacent to Wadi Al Uqq.
Planning for future developments
Future development plans by Oman’s Ministry of Housing (MOH) posed another challenge. Service roads had to be constantly extended to cover new, vacant areas. MOH plans had to be respected down to the tiniest detail in order to ensure that road elements, especially at interchanges, did not conflict with access requirements for the future plots.
The entire design process had to be constantly coordinated with, and approved by, several stakeholders including the Royal Oman Police, local authorities, utility owners, the MOH, and the
Planning Authority (formerly known as the Supreme
Committee for Town Planning).
Managing earthwork volume
Earthwork volumes, especially with regard to Wadi Al Uqq bypass, had to be kept at manageable scales. The fact that the project was divided into two packages made it more difficult to balance the earthwork quantities along the entire road. Each package had to be considered separately in that respect.
Preparing for exceptional flooding
With the outburst of Cyclone Phet, hydrology took on a vital aspect. Drainage structures had to be designed to deal with the rush of water. While wadis in Oman are dry most of the time, the ensuing floods proved to be quick and devastating. Culverts had to be converted to bridges and protection works increased, measures that are not always justifiable in normal hydrological calculations.
Since the road preserved its role as a link and continued providing service to vast areas, safe traffic had to be maintained in parallel with the heavy construction activities.
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