DEMOLITION OF THE TWO OLD LADIES OF CAPE TOWN,

BY THE CONTROLLED USE OF EXPLOSIVES.

PRESENTER, DICK GREEN.

ABU DHABI

AMMAN, JORDAN

RAMAGUNDAM, INDIA

DUBAIGREECE

PORTUGAL

SOME PAST PROJECTS

Texas Stadium, Dallas

Rydges Hotel, Qatar

2 x 175m Chimneys, UK

2010

ATHLONE COOLING TOWERS, CAPE TOWN

SEWAGE PIPE

ELECTRIC CABLE & WATER PIPE

N2 Motorway

PUMPING STATION

LIMITATION AND CONSIDERATIONS

1, Contractor to be responsible for all safety issues and safe access and egress from towers.

2, Minimum disruption to the area. (Demolition could not take place during world cup, and FIFA stipulated N2 route must stay open)

3, Major sewage pipe within 10m of towers must not be damaged

4, Electric cables and Water pipes running within 20m of towers must not be damaged.

5, Vibration and noise to be minimised during blow down

COLLAPSE DESIGN

Cooling towers because of their design are relatively simple to demolish with explosives.

Other methods of demolition

Crane and ball. Cheap, fast, uncontrolled

Deconstruct. Expensive in time, labour and materials, men working at height. Scaffold

Hanging Hydraulic shear, Expensive in time, equipment.

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Explosives Method (Telescoping)

Removal by explosives of 2/3 legs

formation by explosives of slot 2/3 circumference in shell by explosives

A near vertical collapse of a structure, caused by inducing enough compressive stress at the base to make the disintegration at the bottom a continuous process as the structure descends.

Explosives causes sufficient movement after which gravity takes over.

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PREPARATION WORKS

Make site safe

Drill Holes for charges

Test Blast

Place protection (at source)

Remove and clear packs

Charge structure

Protect services

Explosives used in shell

PE BUSTER GEL

WATERGEL

25mm x 200mm

Medium energy (excellent fragmentation)

VOD 3400m/s

Can be used in wet holes

External Protection works

BLOWDOWN