Lean Construction Ireland Annual Book of Cases 2021 24 Case 6 This case study is based on a new Dublin city-centre office development of approx. 250,000 square feet.The building superstructure is a 7-storey reinforced concrete frame over a double-storey basement, and the concrete slabs are designed to be post-tensioned. Our goal was to complete a 19,500 square feet slab pour of a nominal 250mm thickness in one shift using 2 placing booms, 1 static pump, and a spider pump extended to reach all corners of the C-shaped slab.The plan was to break each slab into 4 separate pours.Because we chose to use Jump Form formwork to construct the cores, the use of placing booms was restricted. For this reason, we used spider pumps to reach areas around the rear of the two central cores.A second significant constraint was the working time restrictions imposed by the Local Authority which meant that we were restricted to working between the hours of 06:00 and midnight. Company Overview SISK johnsiskandson.com Overview & Background to the Lean Initiative Rorie Considine Author Define The first slab pour commenced on schedule and in line with the out of hours working arrangements we had agreed with the Local Authority. All local residents had been notified of the pour 48 hours in advance.Placing booms had been set up from the evening before and the spider pump was also in position. The concrete supply all morning was in line with the planned delivery rate.We hit our first milestone mark on schedule and started to ramp down for the placing boom line clean-out and swapover.The planned timeline for the swap-over was 45 minutes, but on the day of the pour it took over 2.5 hours from the time placing boom 1 stopped pumping to starting again with placing boom 2. This was the main cause of the knock-on delays to the second half of the pour and completion of the overall schedule,which ran much later than planned. It also meant that we were not able to get the quality finish to the last 30% of the slab as planned because we had to complete all floating work within the working hours imposed by the Local Authority. Measure The steps involved in the process are outlined in Figure 1.We created this process flow to detail the steps involved, ensuring any critical milestone activities were tracked. Setting up the placing booms the day before and ensuring all equipment was in full working order were key. Figure 1. As-Is Process Map The costs incurred because of the late finish included: • Fifteen resources tied up working out-of-hours at a cost in the region of €3,700.Had we not developed the solution we did, this figure would be multiplied by 19 pours on-site for the duration of the superstructure, equating to €70,000 in overtime costs. • Where the slab could not be finished completely, the knockLean Initiative Undertaken – Lean Thinking, Tools, Techniques John Sisk & Son Ltd. (Sisk) is an innovative engineering and construction company employing over 1,800 people in Ireland, the UK, and Europe. Sisk has the track record, scale, and capacity to successfully undertake large, complex,multi-disciplinary programmes, and we are recognised by our global customers as world leaders in sustainability and safe delivery. Sisk is a progressive business and Ireland’s No. 1 ranked provider of construction services.Operating since 1859,we have built many iconic buildings and landmark pieces of infrastructure.Our continued success is due to: • Our ability to collaborate with customers and supply chain to provide technical and delivery solutions in an open and can-do way. • Safety, innovation, quality, efficiency, and value are integral to everything we do. We deliver projects in key sectors such as Data andTechnology, Pharmaceutical and Life Sciences, Infrastructure,Transportation, Healthcare, Commercial, Residential, Retail, Industrial, Leisure, Education,Water, and Energy.
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