CONVENTIONAL MANHOLES

Extensive concrete used

Minimal concrete used

8-10 days work per manhole

2 - 3 days work per manhole

Labour intensive

Modular construction

STEP

ACTIVITY

DURATION

STEP

ACTIVITY

DURATION

1

Dewatering, excavation and side support

Min 2 days, dependent upon depth required.

1

Dewatering, excavation and side support.

2 days, dependent upon depth required.

2

Concrete base  installation and curing

1 - 3 days.

2

Insert precast concrete slab and mount manhole with cement base.

1 day

3

GRP liner placement and pipe installation. Establish formers.

1 day

4

Build concrete surround and Curing

2 - 3 days.

3

Dewatering, excavation and side support.

2 days, dependent upon depth required.

5

Backfill and re-establishment of surface level. Backfilling  requires pouring concrete grout in layers and compacting without any lumps or debris.

1 day