Holdfast Training Services Trial Blog

The Airport East project has displayed the importance of management of stakeholder relations to ensure the smooth running of a site.

Roads and Maritime Services (RMS), Australian Rail Track Corporation (ARTC) & Sydney Airport Corporation Limited (SACL), are the three biggest stakeholders on the Airport East site and known affectionately as the three amigos.  The contract is construct only and a number of clarifications are submitted to RMS daily, which in turn do lead sometimes compensation claims. SACL own the land but also impose tight restriction on operations due to the proximity of the E-W runway.  ARTC operate the main freight line which runs to Port Botany which dissects the site and is also being upgraded as part of the project to dual lines, they also impose tight restriction and limit access to the rail corridor.

During installation of reinforcement for Span 1 of the Canal Bridge, RMS were still changing their minds right up to 3 hours before the pour of where they wanted to locate conduits for traffic lights and lighting for the bridge.  Retrospectively fitting conduits into slab reinforcement is a time consuming process.  This is a lesson I will be taking forward for when the ducts are fitted into the Rail Bridge for post tensioning.  It is key reinforcement is staged with conduits or ducts being fitted prior to the B layer of reinforcement being placed.

Figure 1 – Conduits for traffic control systems run through the cast-in-situ bridge deck of Span 1 of the Canal Bridge 

One of the most exciting yet exhausting tasks I have been package manager for on site has been the installation of sixty precast pretensioned bridge beams for Span 2 of the Canal Bridge.  I have taken this process from competitive tender, standard subcontract and award, through to installation.  The tasks leading up to their installation involved; authoring the activity method statement, excavation and removal of the temporary piling platform in the canal, checks to stressing calculations for the bridge beams, quality inspections of the prestressing yard, application to SACL for a week long closure of the E-W runway for 220T telescopic crane, design and validation of the crane platform, oversized load permit for delivery to site of the beams, organisation of haulage, medium risk lift plan for installation, and being lead engineer co-ordinating the landing of each beam onto temporary bearings. Choreographing their installation over 4 days, involved 15 being delivered per day, a truly rewarding task once they were all secured in place.

Figure 2 – The one of sixty precast bridge beams is lifted into position for Span 2 of the Canal Bridge

During installation I received a telephone call from SACL, the wind had picked up so for safety reason they needed to reopen the E-W runway.  15 minutes after the crane was lowered, the photo in Figure 3 was taken as an A380 passes over the site, showing the reason for the imposed height restrictions.  This delay forced installation operations to cease until that evening when the Airport closed between 2300 – 0455hrs.

 Figure 3 – SACL reopen the E-W runway of Sydney Airport during installation of the beams forcing installation operations to be postponed to the night.

My relationship with ARTC will grow as I move onto Project Engineer for the Rail Bridge and Underpass this month.

I would appreciated peoples thoughts on the below issue I have encountered on site.

ISSUE: The steel frame erection is generally progressing well on site with approximately 90% of the steel work now erected. Unfortunately a recent site inspection highlighted that some of the secondary steel beams to level 02 had developed a twist in the member (see below). Level 03 above is a cantilevered deck which is currently temporarily supported through diagonal bracing.

The tolerances for the steel work on the project are laid down in the Structural Steel work Specification developed by Ramboll. These are in addition to the requirements of the National Structural Steel work Specification (NSSS). However, establishing the tolerances for the twist has proved more difficult than first thought. The steel contractor is currently attempting to determine a root sum squared answer from the fabrication and erection tolerances. In the meantime the visual distortion has been enough to instigate further investigation.

An as-built survey conducted by the steel work contractor confirmed the following ‘out of tolerances’ for three of the beams highlighted on site.

OPTIONS: The two options as I see it are to either leave it as it is, or to release the members and conduct remedial works as necessary. In both situations an evaluation of the significance of the twist is required to be made.

1. Assess the structural significance of the twist. If not significant then do nothing and except the visual impact.

2. Assess the structural significance of the twist. If not significant then do nothing, but weld a plate to the bottom flange in order to mitigate the visual impact.

3. Assess the structural significance of the twist. If significant, release the connection. Relocate fin plate on primary beam to accommodate altered position of the secondary.

We are currently finding that, possibly due to the consequences, neither the structural engineers nor the steel subcontractor are willing to comment on the structural implications of the twist to the members and subsequently commit to a strategy moving forward. We are due to remove the temporary bracing in the near future. It is hoped that this along with the erection of the cladding will counteract the twist, however it is unlikely to counter it to the extent required.

It would be interesting to hear the thoughts of others with regard to the issue and potential remedial options? I would have thought that this issue must have been encountered previously through the experience of others? Any feedback is appreciated. Cheers, Al.