River Crossing

DSA was involved in the design of 200 km of GRE pipe installed as part of the Santos GLNG project. One specific section of this pipeline required a river crossing. Due to time and environmental constraints, it was not possible to build an elevated pipe bridge, nor was it possible to install the pipe on the river bed.

DSA’s solution was to pull the GRE pipe under the river. Directional boring was used to install a DN500 steel liner under the river. Then over 500m of GRE pipe was pulled through the steel liner.

This elegant solution required detailed analysis and calculations to ensure that the pipe could successfully be pulled while bending as it was drawn through the curved radius of the steel liner. FEA was used to model the frictional forces and enable all stresses to be analysed. The output from the FEA was used to then design the pulling head, which attached directly to the GRE pipe.

This lateral thinking resulted in a 3 months installation task being condensed into 2 weeks of site installation.