Method Statement for Drainage System

METHOD STATEMENT FOR DRAINAGE SYSTEM PRECAST U-DRAIN 600mm x 600mm 1.

Setting out / Pegging for drainage line shall be established by surveyor.

2.

Excavation for surface drainage shall be carried out to the dimensions of 700mm (w) x 900mm depth.

3.

The precast U-drain shall be in 600mm lengths true to shape, sizes and dimensions as per the drawing.

4.

The drain shall be laid on 100mm thk compacted sands to the proper falls and joined straight true to lines and levels. The joints shall be cement grouted.

5.

RC coping of 100mm thc x 150mm (w) complete with all necessary reinforcement tied to starter bar, formwork and placing in with G30 concrete.

V-SHAPE ROAD SIDE DRAIN 1. Setting out / Pegging Surveyor.

for drainage line shall be established by

2.

Excavation in V Shape trench to a depth of 300mm with sides 300mm width.

3.

Lay fabric reinforcement A6 in single layer raised on chair.

4.

To place in 75mm thc concrete and rough trowel finish

CASCADE DRAIN

1.

Excavation for cascading drain shall be carried out to the dimensions as shown in the drawing.

2.

To compact base and lay fabric reinforcement A7 raised on chair.

3.

To concrete base to a thickness of 125mm and lay half round precast concrete drain in steps.

4.

225mm thick brickwall complete with plastering on both sides of wall.

PIPE CULVERT CLASS 2 (600mm dia – 1800mm dia) 1.

Excavation for pipe culvert shall be carried out to the dimensions and size as shown in the drawing complete with strutting and formwork.

2.

To lay and compact hardcore for bedding and to lay 50mm thc lean concrete.

3.

To lay 150mm thc concrete bedding, the pipes shall than be laid with ends true to lines and gradient.

4.

The annular gap shall be filled with cement sand mortar (1:3) with sufficient water added to ensure adequate workability.

5.

Backfill the pipe culvert with suitable earth stockpiled.

PRECAST CONCRETE BOX CULVERT 1.

Excavation for box culvert shall be in accordance to a depth and size as shown in the drawing.

2.

To lay 225mm granular bedding and leveled.

3.

Box culvert shall be laid as close as possible and the maximum gap in between shall not be more than 20mm and the difference in level not more than 5mm.

4.

The gap shall be filled with cement mortar (1:3) and finished smooth. To ensure uniform bearing, a layer of cement grout shall be spread along the top of the walls to the invert where the lid will sit.

5.

To construct 150mm thc wing wall, compact base with hardcore lay lean concrete, concrete base with reinforcement , starter bar to wall, formwork, install 50dia pvc pipe for weephole and place in vibrated G30 concrete for wall.

6.

Backfill with suitable earth stockpiled and compact the sides.