Sydenham Station, Sydney

Arenco contracted Mann Group to complete the total demolition of the overhead concourse spanning over the railway lines. The building in its entirety was reduced to the concourse level whilst the rail lines remained active. Accordingly the concourse level bridge configuration spanned over 6 railway corridors and platforms; this also was successfully demolished and removed through a combination of track possession shut downs and working whilst live below. This rail shut down works where continuous works over 48 hours i.e. 3 x 8 hour shifts continuous over two days with a least a crew of 35-40 personnel working at one time. Upon successfully working through the demolition scope and meeting all programme millstones and safety requirements, Mann Group where given the opportunity to tender for the civil works package and subsequently was awarded the works. This involved detail excavation of lift shafts, pad and strip footings on all platforms.

The following challenges and constraints where resolved in consultation with Mann Group senior management, Arenco, Railcorp, Sydney Airport Corporation Limited (SACL), Crane Specialist and various engineers are as follows:

Working over live railway corridors
This was an extremely safety sensitive issue when working over live rail lines- especially whilst conducting demolition. Mann group through close consultation with Arenco developed a system and sequence that would enable to complete the successful demolition of the buildings above the lines in a safe manner. Structural catch decks where installed in-between the flanges of the ‘I’ beams to the underside of the concourse- this enabled Mann to demolish and remove the RC concourse slab. The remainder of the buildings where wrapped in non-conducting scaffold engineered specifically for the application. The above controls which were implemented allowed Mann group to conduct all the necessary works required through normal working hours whilst the tracks below remained live.

Working in the flight corridors with cranes
Mann group contracted their crane experts to assess the lifts/segments to be removed along with all the necessary engineering required. The maximum size segments for the lifts was the key target- as this would minimise crane and programme time. Controls where put in place to negotiate all the aviation constraints as the work site was in the middle of a major flight path. The crane was given a maximum RL for the mast height, slew restrictions to the north and the south from State Rail, RTA restrictions to the south due to the proximity of the bridge and engineering restrictions from the retaining walls within close proximity of the crane outrigger positions. With all these restrictions Mann group and the team implemented and monitored all the necessary controls required to complete the works in a safe and timely manner.

Technical sequencing for crane lift study
As the maximum size segments to be removed was the key objective, Mann group and the team sequenced and engineered all the respective lifts with precision. All the concourse floor beams where structurally braced together and welded on site which simply made a series of beams composite and reducing from approximately 45 singular lifts down to 8 key lifts only. This was a major hurdle that was successfully achieved and completed safely.

Materials handling
One of the key points to this job was the materials handling aspect. A number of techniques where successfully and safely used throughout the job itself-

  • Forklifts with rotators and 2m3 bins
  • Manito telescopic handlers
  • Engineered steel gantries with winch attachments to lift off platforms 6m below
  • Crane with certified 10m3 lifting bins
  • Bobcats with high rail tipping trucks
  • High rail tilt trays
  • High rail rubber tyred dumpers
  • Wheel barrows and otto bins

HAZMAT Removal
Given the age of the building it was inevitable that asbestos was evident. All HAZMAT removal was conducted through normal working hours within the work zones. All the removal works where conducted by Mann group’s licensed personnel in a safe manner in accordance with the strict Workcover guidelines.

Excavation
Managing the bulk/detail excavation was again limited to the access constraints. Some platform excavations could only be conducted in track possessions by loading spoil via 10m3 crane bins. Another platforms spoil was removed via an engineered steel gantry purpose built on ground level with a 2t winch attached to lift off the platform 6m below. Accordingly the remainder of the platforms spoil where removed via the aid of a 4t forklift with rotator attachment which was used to traverse 2m3 bins to a designated dumping compound situated outside the work zone.
In all the above cases, the works where successfully completed injury/incident free and on programme.

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