Inspire : Public Works May Jun 2013
49 structural lining that will last in excess of 100 years. The smooth inter nal fnish provides enhanced hydraulic fow, delivering increased discharge velocity despite a reduction in diameter. The concrete can be un-reinforced or reinforced with traditional steel bars, mesh or fbre, as required. Moreover, the Tunneline system can be adjusted to ft tunnels and culverts of many shapes (i.e. box, brick arch or ovi-form) and has successfully lined culverts as small as 900mm and structures as large as twin track rail tunnels. NO TRAFFIC DISRUPTION Following a successful tender proposal, the Queensland TMR engaged ITS Trenchless to design and install a fully structural, stand alone lining to the existing Funkers Creek culverts without affecting the fow of traffc. This included a full structural design to Australian Codes & Standards AS 5100, the design of shutters, hydraulic gradient calculation, concrete mix design, and reinforcement scope and design. For the design of Tunneline liners, ITS Trenchless uses an independent third party design engineer, and each cell is considered separately and designed strictly in accordance with loadings dictated under the relevant design code. In this case the design confor med to AS5100-2, which called for a 200mm thick reinforced concrete liner, to result in a fnal diameter of 2050mm. Work commenced on 14 December 2012 and followed the three essential stages of the Tunneline process. The frst stage saw the crew install reinforced steel to all three cells, as per the design drawings. Then, in the second stage the pre-designed shutter system was installed in 10m sections. The crew then installed the formwork in the morning, ready for a concrete pour later that day. The concrete was poured in the afternoon once the formwok was installed, formed and sealed. Once the concrete had been pumped, the crew cleaned the site to complete their shift. On the following day the formwork was removed and set up on the next section for a repeat of the three-stage process. All three cells were completed on time by 17 January without incident, and the use of the Tunneline system resulted in substantial time and cost savings over conventional lining systems. There was also no impact to the operation of the busy highway above the culverts. ••• CONTINUE THE CONVERSATION Have your say on this story. Go to http://goo. gl/XPzj7 to comment on this article. A few easy steps breathe new life into culverts under a highway.
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