To minimise construction time and ensure successful delivery of the project within the small allocated time frame for the culvert replacements, VEC chose a design that was 100% precast.
The open culvert area has been increased for every site during the design to ensure the capacity of the culverts are greater than the redundant structure. As a by-product of this feature, backfill over the culverts has reduced, resulting in a quicker construction process.
All of the culverts were designed to Queensland Rail 300A Load rating.
The culverts are located in the secure rail reserve, which resulted in limited access to the project sites.
The culverts were to be replaced during client nominated closures of tight time scales. This meant the VEC project team and work crew had to program construction works to fit into a schedule that had limited closures. This was, in some instances, as few as 30 hours per closure.
Each closure was for the replacement of 2 culverts at different locations.
Due to the nature of the work, the VEC crews were required to work in 12 hour shifts day and night to deliver the culverts within the programmed schedule. This required stringent Fatigue Management regiments to ensure the crew were able to perform the tasks safely.
Each closure required 4 work crews to support the replacement of the 2 independent sites.
The closures occurred sporadically; in October, November and February. This resulted in it being difficult to maintain an experienced work crew over such an extended timeframe.
All of the construction sites are on the electrified line and therefore all works were conducted below the overhanging asset.
With the project sites being located over an area of 221.02km, mobilisation of the crew, plant and equipment were also challenges the team had to overcome.