1           Plan Component

1.1          Design Extract

·         Main grid line

·         Boundary line

·         Basement line

·         Building outline, lift core wall, major columns, shear walls, void, access, staircases

·         Overall dimension

·         Surrounding public roads

·         Drawing scale, true north direction

1.2          Major Plant

Location of tower crane, passenger hoist, concrete pump, etc.

1.3          Site Access

·         Temporary decking, if any

·         Temporary gate

·         Guardhouse

1.4          Temporary Facilities

·         RE, COW office

·         Contractor, sub-contractor’s office

·         Storehouse

·         Toilet for staff and workers

·         Canteen

·         Steel bending yard

·         Carpenter’s shed

·         Car park

1.5          Temporary Utilities

·         Water supply along perimeters of the hoarding

·         For site surface water control, no direct silt discharge to the public drain will be allowed.  Instead, temporary drains will be constructed along perimeters of the site to flow into silt traps before discharging into the public drain.  Water from washing-bay will also be directed to the silt trap before discharging into the public drain.

2           Site Transportation

2.1          Vertical Transportation

·         Tower crane

·         Passenger hoist

·         Working platform

2.2          Horizontal Transportation

·         Lorry

·         Loader

·         Tipper

3           Tower Crane

3.1          Statuary Requirement

·         PE design is required.  If within airline corridor, there is height limit and the relevant authority approval is required.

·         Normally, the radius shall be limited within boundary line, especially not beyond the public road.

3.2          Type

There are two types of T/C: hammer type and luffing type.  The latter can have more lifting capacity, flexibility and hence, more expensive.

3.3          Jib Length and Counter Weight Length

Normal jib length is:

·         Hammer Type: 40m, 45m, 50m, 55m.

·         Luffing Type: 40m, 45m, 50m

 

Counter Weight Length:

·         Hammer Type: 16m

·         Luffing Type: 8m

3.4          Tip Load

Normal tip load is: 2-ton, 2.5-ton, 3-ton, 3.5-ton, 4-ton

3.5          Points of Arrangement

·         The tip load shall be able to lift the heaviest component, eg. tableform, precast wall.

·         The coverage shall take care whole site area

·         The number of tower crane shall consider the working load.  For example, precast structure, steel structure needs more lifting capacity compared to normal RC structure.

·         The neighbouring tower crane shall maintain certain safety distance so that the jib of one T/C will not hit the other T/C’s mast.  The height of the two neighbouring T/C shall maintain different.

·         Foundation of T/C shall avoid the location of the facilities, for example, sump room, substation room, etc.

·         Timing to construct the foundation of T/C shall be concurrent with the main structure.  There is always a time lag when the job site starts excavation and the T/C has not yet been installed.  Mobile or crawler crane is therefore needed for this period.

3.6          Standing Height and Tie-Back

·         Maximum self-standing height: about 40-m (about 10 storey)

·         Tie back to the structure: every 4 or 5 storey

3.7          Dismantle

3.7.1          Dismantle Timing

·         About 2 months after completion of roof structure and installation of M&E equipment on roof

 

3.7.2          Dismantle method

·         Self lower down.  This method requires the space for the jib to lower down

·         Use of mobile crane / derrick crane to help dismantle it.  This method requires about 3 x 10-m space for an mobile crane to launch dismantling work

4           Crawler Crane and Mobile Crane

·         Crawler Crane: 35-ton, 50-ton, 70-ton, 80-ton, 100-ton.  For 50-ton, the maximum height is 58-m

·         Mobile Crane: 20-ton, 30-ton, 50-ton.  For 50-ton, the maximum height is 50-m.

5           Passenger Hoist and Working Platform

While tower crane is mainly for the structural construction, the passenger lift, goods hoist and goods platform are generally used for architectural and M&E works.  Usually, when the building is more than 10-storey and 4-units per block, the use of hoist is economical.  Otherwise, only steel platform is to be used.

 

Whether using hoist or not, platform is always required for transporting wet trade material such as bricks, sand, cement, etc. to the floor.  Passenger hoist is mainly for transporting workers and dedicated material such as tiles, marbles, pipes and M&E fixtures.

When to install

When the structure goes to 4th or 5th storey, the wet trades are going to catch up.  And the vertical transportation is required.

6           Estimated Rental Cost (2001)

6.1          Tower Crane

Take a 10 Storey building for example.

·         Hammer Type: S$8,000/month

·         Luffing Type: S$10,000/month

6.2          Crawler Crane

Take 50-ton crawler crane for instance: S$5,800/month.

6.3          Mobile Crane

Take 30-ton mobile crane for instance: S$450/day.

6.4          Passenger Hoist

Take twin-cage, 1.2-ton or 1.4-ton and for a 10-storey building for example.  The rental is about S2, 400/month.  For 2-ton type, it is S$2, 800/month.

7           Access

7.1          Route

The main site access shall normally follow the permanent fire engine access route.  The crusher-run road base is laid for the temporary as well as permanent purposes.  Hoarding is to follow the boundary line.  Temporary utilities (electrical, water supply) follow the hoarding route.

7.2          Gate

·         Facing the main road

·         Have nearby public drain for discharging water from washing bay (after being treated with silt trap)

8           Temporary Site Facilities

8.1          Welfare Facilities

·         A canteen shall be provided if the number of workers exceeds 40

·         Sanitary facilities shall be provided separately for the sexes in the ratio of 1 water closet, 1 shower closet, 1 wash hand basin for every 25 workers.  In addition, a 600-mm urinal shall be provided for every 25 male workers or less.  These toilet facilities shall be connected to a sewer / temporary septic tank with the approval of Sewerage Department.

8.2          Container Office

Standard container office available: 10’ x 30’ (3m x 9m), 10’ x 40’ (3m x 12m)