Sheet piles and combi wall systems are shaped steel and tube sections with interlocking edges (or clutches) which are driven into the ground for earth retention and evacuation support. They are often installed with vibratory hammers.

When handled correctly, sheet piles can be used and re-used, whereas combi walls tend to be used in permanent applications.

CLL have brought sheet piling and combi wall systems to projects ranging from basement developments, tunnel portals, protective barriers, and in marine contexts of riverbank protection, seawall, and cofferdams.

Our design and engineering experts have the knowledge and tools to bring cost effective sheet piling and combi wall systems into appropriate situations.

Combi wall systems like the clutched tube system (see clutched tubes) provide a strong slender permanent wall option which requires no second stage wall in front to finish. The clutches in the permanent case are welded to provide 100% waterproofing and the tubes themselves may be drilled out and onto depths for the formation of piles sufficient for the compression and uplift loads required by the building.

This is a very definite advantage when space is at a premium and waterproofing is high risk. The program is shortened as the temporary retention becomes the permanent wall without any second stage operation. Shear wall loads if additional to the capacity of the combi wall may be taken into the wall using steel bracing or cast in situ walls in front as required.

CLL has brought into NZ a fleet of leader rigs with German built high performance, high and variable speed and variable moment vibrators which add a magnitude of accuracy not possible with crane and excavator mounted vibrators.

Additionally, the computer-controlled variable speed and moment technology on the vibrators eliminates random resonance in the surrounding environment which makes the vibratory technique applicable in many built up areas where previously the technique was ruled out. The installation and removal of sheets with leader rigs is more accurate and therefore sheets suffer much less wear and tear so where in the past we were able to count on reusing sheets 5 times we commonly now achieve significantly more.

Over the last 15 years CLL has successfully imported into NZ more than 35,000 tons of sheet and combi wall. We use SGS for our import QA compliance validation. We have never experienced any issues with receiving steel into NZ from the valuable manufacturers we have developed relationships with.

Alan Ford