PCA Australia is featured in the July/August issue of DFI magazine for the successful implementation of their foundation retrofit design on a Northeast Australia transmission line. Quanta Subsurface (QS) teamed with PCA on the project, providing critical design support. The solution was delivered on time, at a tenth of the cost of more traditional methods. It was also the recipient of the 2017 ISM World Cup, for which the International Society of Micropiles recognizes outstanding projects.
PCA had been working with Powerlink Queensland to develop a cost-effective foundation replacement system, and extend the life of aging power infrastructure by up to 50 years. The final design involved an efficient, patent-pending steel bracket connecting hollow bar micropiles to existing lattice towers.
QS provided finite element analysis (FEA) of the steel brackets, as well as structural design for the hollow bar micropile casing. Constructability challenges included inconsistency in existing structure and foundation types. Micropile spacing in the retrofit designs needed to accommodate the foundation variability, and the pile spacing directly affected the steel bracket design. A two-pile layout combined with five different steel bracket configurations were required to successfully accommodate all foundation and structure types. Additional challenges included minimizing the thickness of the steel plate for cost and weight purposes.
The project served as a trial for the solution, which has since been implemented on additional alignments. Read the article →