Ongoing Safety Issues
Considerable care was taken by all parties to the contract to ensure a safe and robust quality product was delivered to City of Sydney.
It is worth recording a few matters affecting operations that were canvassed during construction:
- There is an ongoing need to prevent intruders to the Prismaflex sign area. The partition doors and walls are robust metal clad steel structures. Preventing intruders is considered easily managed with diligent procedures.
- There is a need to prevent graffiti artists, particularly to the shadow line area or the bottom ledge under the sign.
- Personnel changing graphics need access to the sign area as do maintenance staff who work on the sign. Prismaflex claim the sign is robust and maintenance required is minimal.
- None the less consider a worse case most unlikely scenario that a prism is dropped on the rail track below. According to Prismaflex the prism is light and relatively weak. It would be unlikely to damage a train or interfere with train operation. The length at 3.5m is not long enough to short circuit out two overhead electrical wires which are 6m apart. Prismaflex claim that dislodging a prism is not an issue for them. They claim some 15,000 tri-signs worldwide and also claim Prismaflex signs in hurricane winds in Queensland have recently sustained winds of 180km/hour without any affect on these signs. On balance it would appear that the sign operation and maintenance presents manageable risk. (For the record Goulbourn Street Car Park is the largest Prismaflex sign in the world, but only by a few metres).
Safety Aspects During Construction
- The safety focus and imperatives were different for each phase of the project. Every site worker was inducted before working on site and signed induction papers outlining the main risks for their operations. No work started on site without a relevant approved Safe Work Methos Statement (SWMS). Andersal selected Beaini, AWA and Practicalities to work on site because of their known capabilities and their consistent safety awareness.
- During the initial PE extension, the main risks were the standard risks associated with abseiling and risks of people or objects falling onto the tracks. The site safety instructions emphasised these risks and all site workers had tools that were tied to wrists, ropes or safety harnesses.
- During the demolition of the brick wall (50,000 bricks), the safety emphasis was to prevent dust and concrete or brick chunks falling onto the rail tracks and to minimise interruptions to car park traffic. The bottom net was extended and tightened to minimise shrapnel falling onto the tracks. Temporary opaque partitions were constructed on each floor to separate the car park from the demolition. Conveyor belts were used to transport bricks directly to a dump truck, masonry splinters and dust were systematically swept up and only hand tools were used carefully to loosen bricks. The result: No dust, lumps of concrete or brick fell onto the railway tracks. No conflict with car park personnel occurred. This is attributed to the calm, systematic procedures of Beaini contractors. Note: The 30 by 1 tonne cables were progressively eased during demolition to prevent the cables snapping the bottom concrete slab as the brick removal de-loaded the slab.
- Remove the 10 x 2 tonne spandrels by crane was a challenge because the working drawings did not match the installation on site and extra bolts or pins attached the spandrels to the car park concrete structure. The first scheduled day job was aborted as a safety precaution as the wind was too strong to operate the crane safely. Work proceeded the next day. The important safety considerations were to only lift between train movements, and while road traffic was stopped, and to have adequate extra leveraging and cutting (grinders, oxyacetylene) equipment close to hand in the event the spandrel was safely lifted and stacked in a large dump truck when it was transported for recycling.
- The supply and construction of structural steel work was by Wexford. The concept design was modified by AECOM to reduce beam member size to facilitate construction in that each member was less than 100kg so that it could be manhandled on site without cranes or lifting devices. The main safety concerns during construction were that large steel beams were not dropped with the possibility of piercing the protective net. Each heavy member was therefore check tied till installed. Result: no large steel member was dropped and no incidents of falling bolts or minor steel occurred.
- The construction of the Prismaflex sign was by Prismaflex staff. The tie cables and acro-props prevented all prisms from being installed. All that could be installed were installed prior to the rail closure weekend when cable and acro-props were removed. Then all remaining prisms were installed during rail closure.
- The cladding was installed by Facade Innovation staff. The plan was to complete all cladding that could be completed above the rail corridor while he PE was in place and absolutely finish all cladding above the rail corridor including caulking joints to waterproof during the rail closure weekend. The cladding was completed by working from the platform extensions on each car park floor and from swinging stages at the sides. The main safety concerns were that standard working at heights precautions were observed and the quite difficult final caulking and protective film removal were well planned and totally completed by the end of the rail closure. Result: the tasks were completed without incident.
- Rail closure weekend. The abseiling team was principally responsible (under Andersal direction) to remove the two large protective nets (in three sections) and the thirty 6mm cables each tensioned to 1.8 tonne. They also removed the cable retaining bolts, allowing the re-grouting of these holes and allowing cleaning and Dry Treat application on the first floor slab. They also assisted with cladding protective film removal and waterproof caulking of joints. AWA removed the acro-props and all the steel anchor supports. Prismaflex staff installed all the remaining prisms. The main safety concerns were: people and objects falling onto the tracks and it was imperative that all work would be absolutely completed by the end of rail closure. Result: the weekend proceeded like clock work. Each task was completed 100% without any safety incidents.
- After removal of the PE the main safety concerns were preventing objects and people falling onto the tracks and importantly preventing unauthorised access to the corridor behind the sign (unauthorised personnel could easily dislodge prisms and hurl them onto the tracks). The few site personnel who were doing finishing works were required to wear safety harnesses. The locking off of the enclosure was re-emphasised and extra temporary covered high fences were installed. Installation of the partition wall was accelerated to improve security.
- During construction of the partition wall, the main safety concerns were that each segment of wall was totally complete and abutted the temporary wall securely by the end of each day. Result: there were no known unauthorised entries.
- In all 130 workers were inducted onto the site over a 12 month period. The work was above the fully operating rail corridor and some of the work was quite high risk with stringent time constraints. There were no Lost Time Incidents.