Drain shall be excavated
besides road shoulder at 100 mm spacing from the existing guardrail post. The width and depth shall be as specified in
the drawing. The length of excavation
shall be as specified in the bill of quantity.
Gradient of excavation is checked against the
requirement. Upon approval from the
Engineer, lean concrete at thickness of 50 mm is laid along the drain.
The pre-cast blocks are then
laid properly as per drawing, ensuring the profile and layout to follow the requirement.
