Construction World July 2016

COVER STORY

FRANKI SHOWS ITS MARINE EXPERTISE

and test phase, the jet grout operations began and, after some initial hiccups with Franki Cape Town coming to the rescue with their experience in jet grouting, we were able to source the faulty parts from Europe and continue with a productive and successful operation,” Pearce says. There have been a few significant chal- lenges on this job with the first, as expected, having to work in tidal conditions and being exposed to the moods of the ocean. The Franki crew worked around the clock to accommodate tidal movement and, operating when they could; they lay down a high-spec working platform for the piling rigs. “This was an exacting job to say the least,” says Pearce, “but when it was complete we were able to work with the sea being kept at bay and the biggest risk to our operation allayed.” The second challenge from a piling perspective was the positioning and tol- erance of the piles in relation to the jet grout columns. “It was critical to get the positioning spot on to ensure a vertical face to the quay wall,” Pearce says. “Our works depart- ment came up with a very innovative idea in the manufacture of special guides and frames to assist us in placing the piles in accordance with the fine tolerances and this worked perfectly.” Piling challenge number three – to increase our piling production rates – was A panoramic view with the South lead-in jetty being dismantled (on the left), the North lead- in jetty completely dismantled and existing piles cut off at low water mark. In the centre are grid-lines C and D with the capping beams and decking in progress (done by Haw & Inglis), and on the right Franki is busy installing casings on the 15 th bay on grid-lines A and B.

Introduction Geotechnical work in the marine environment demands creative solutions to complex chal- lenges. That’s the nature of the game and there is no one better at it than Franki Africa, which has developed a reputation throughout Africa for its innovative and cost-effective solutions. It is interesting that in both the marine projects below, one of the common themes is great teamwork – a perennial Franki skill. 230 no. x 900 mm diameter CFA piles 24 m deep; 180 no. x 800 mm diameter jet grout columns 16 m deep; 180 m long x 5 m high quay wall capping beam; 1 500 m x 63 mm diameter tie bars; 80 000 m³ dredging and excava- tions; 6 000 m² new dock yard surface with services. Pearce says that Franki is concluding installing the capping beam and are currently busy hanging the facial panels on the quay wall. “This has been a chal- lenging project but we are proud of our ability to work in marine conditions – a skill that we have acquired throughout the company over many years. Apart from knowledge and expe- rience, the most important ingredient for jobs of this nature is teamwork and we had that in abundance on this job,’ concluded Pearce. Quantities on the Dormac project

Project 1: Dormac Quay Wall The first project is the construction of a 180 m-long, 16 m-high (4 m above water and 12 m under water) quay wall for marine engineering company Dormac’s new floating dock at their marine works facility at their Bayhead, Belfast Road site in Durban. Ship- ping is renowned for tight schedules and high operational costs and this project is subject to the same pressures in order to meet the schedules of the future users of the dock. Franki Africa’s Paul Pearce says that this has been a complicated, multifaceted contract. “Although it is one structure, it has required many highly specialised geotech- nical skills for a successful outcome,” he says. One of these skills was specialised jet grouting using a rig from Franki owner Keller’s German division. “In fact the co-operation between Franki and Keller Germany was most helpful,” says Pearce, “and confirms the supreme advantage that we have being part of the Keller network and able to tap into the best technology and equipment in our industry.” He adds that the jet grouting was a highly technical and complicated ope- ration requiring top-end management, opera- tors and support. “After a three-week training 1. Exposed CFA piles and jet grout in-fill columns. 2. Quay wall face panels around north mooring pawl position. 3. Overview of site showing dredging and CFA piling in progress.

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CONSTRUCTION WORLD JULY 2016