McConnell Dowell Constructors has used Trimble's SPS851 GPS+GLONASS receiver, SPS551H heading receiver and HYDROpro Construction software during construction of a 256 m long wharf extension at Cape Lambert Port, Western Australia.
Extension of the wharf, which is operated by Robe River Mining, required the precise positioning of the pile clusters as pre-formed concrete sections would be placed on top of them. If the piles were not in the correct position the preformed sections would not fit.
While positioning the vertical marine piles was difficult, the marine raked piles were an even greater as the direction, inclination and height, as well as the horizontal positioning all had to be monitored. Developed 12 years ago specifically for such tasks, Trimble's HYDROpro Construction software allows the operator to take control of the rig and pile positioning tasks without the need for surveyors.
At Cape LambertPort a jack up rig was used to install the piles. Its stable platform, which remains unaffected by the tide, allowed for accurate positioning of the piles.
Using Trimble's solution McConnell Dowell Constructors positioned the rig to within 1 m. The SPS851 GPS+GLONASS receiver then allowed for centimetre positioning accuracy.
The SPS851 was connected to the secondary SPS551H heading receiver and together they provided centimetre positioning, as well as heading to a precision of 0.05°. A Trimble SPS851 base station was onshore sending corrections to the jack-up to ensure the centimetre accuracy was maintained.
The GPS data was fed to the Trimble HYDROpro Construction PC software, which presented the guidance information in an easy to understand display, which allowed for immediate guidance of the rig and piles.