999-3

Narrative Description of the Project:

This project is located in A?Dakhaliya Region, about 250 km south west of Muscat. The proposed road constitutes the only access to Al Jabal Al Akhdar villages and some camps for the Ministry of Defence. The existing track is about 36 km long and experiences many hair pin bends and steep gradients reaching 22 %, with a difference in levels of 2500 m between its ends. In 1994, the Client has completed design (by another Consultant) of a new alternative route. Due to the high cost estimated for this alternative, the Client has re-tendered the project, limiting the design to the utilize and improve the existing track corridor. The preliminary design and alternative improvements were based on aerial photos and mapping while the final design was made based actual topographic survey. To further reduce the cost of construction and minimize deviation from the existing track, up to 15 % longitudinal grade was accepted in the design and approved by both the police and Client. All necessary elements such as concrete safety barriers, climbing lanes, laybys, stability of high embankments or cut side slopes were considered in the design. The first 5 km of the road lie in a major wadi and required extensive protection and retaining wall to protect the road embankment. All these items were properly designed through a comprehensive hydrology and hydraulic analysis.

Description:

1) Review of previous design of the project
2) Study possible improvement to the existing track using aerial photos, digital mappings, contour maps and site visits
3) Carrying out traffic count and estimate of traffic demand on the proposed road
4) Carrying out comprehensive hydrological study for the road section in Wadi Al Maaidyn and design all necessary protection and drainage structures
5) Preparation of preliminary and detailed design and discussing them with all concerned authorities for their approval
6) Provide construction supervision