Glebe Island Silos

Client: Cement Australia

Location: Glebe Island, Sydney

Task: To strengthen 4 silos to enable them to be filled with cement. The existing silos were designed for grain only strong enough to be half filled.

Andersal Site Supervisor: Eddie Issa

Facility Manager: Sydney Ports Corporation

Design Check: Maunsell

Structural Design: Connell Wagner

Special Challenge

  • Cement Australia run a very tight OH&S regime because of the inherent safety risks in working in an operating industrial cement storage facility.
  • The silos had to be cleared of existing compacted cement and cement dust prior for personnel working internally in the silos.
  • An access door had to be cut into the silos above the concrete new base to allow access for the steel fixers, form workers and concreters.


Main Silos

  • Jacques Calluaud designed a special “helicopter” to air blast the silos from top to bottom to remove compacted cement from the silo walls.
  • We manually shoveled 50 to 100 tonne of dry contracted cement powder from each silo.
  • We used a Cement Australia crusher to break up the hardened lumps so the product could be recycled.
  • We removed the 16 air slides from the base of each silo to clean them and to prevent damage.
  • We cut a door sized access hatch into the silo and erected an access platform.
  • We then had the tasks of constructing a 4m high x 300mm thick reinforced concrete ring internally in the base of each silo.
  • The new ring was anchored to the existing by dowels epoxied into the existing. These dowels then had 2 layers of s16 circumferential and vertical steel reinforcement installed followed by form work and pouring of the internal annulus.
  • Following concrete cure the form work was removed and the access opening reinforced using rebar continuity couplers and then concreted up.


  • We constructed 2 new footings per silo.
  • We reinforced 8 existing footings with 6 layers of Carbon Fibre. Each layer gave the equivalent strength of 50mm of concrete.
  • We also repainted the area above the site access to restore it to its heritage conformity.
  • We completed 4 silos in 6 months. There are another 8 that may be reinforced in the next few years.
  • In total about 200 cubic metres of concrete was used.