Major Groundworks project consisting of 600m2 floor space in Slough Berkshire, to construct a four-storey residential building.
THE CHALLENGE
The main challenge in this job has been the complexity of the design of the ground beams almost looking like something from one of a Leonardo Da Vinci’s sketches.
This resulted in having to implement a complex panel formwork system, which took longer than anticipated to implement and also meant closer cost monitoring.
The second main challenge was that the structural engineer had designed the ground floor as a block beam floor, which the main contractor had installed so as to enable him to start the main brick and blockwork. This however resulted in having to work out and answer the question if the block and beam floor could hold the propping for the first-floor shuttering to support the 25 tonnes plus of reinforcement and the concrete over an area of 130 square metres.
We approached various formwork temporary work companies to help address this problem and the replies we received were mixed with some suggesting very costly and complex solutions. However, after working closely with our own temporary works engineer’s and Mabey Hire engineer’s we came up with a solution that allowed us to prop off the block and beam floor without the need for additional floor spreader plates and beams. The system we eventually used was their KwikStage propping system. Mabey Hire provided a complete design of the system and also, they provide our operatives onsite training with one of their engineers to ensure that we assembled the kit and placed it correctly.
Once this was done, we successfully completed the shuttering that allowed for the steel fixers to complete the reinforcement work.
THE SOLUTION
The scope of our works was to design the foundations of the building, the reinforced concrete ground beams and the construction of the concrete frame and the floors of the building.
Obtaining information from the geotechnical ground survey report and the structural engineer’s loading calculations we designed a foundation solution that involved continuous flight auger piling to a depth of twenty metres. The diameter of the reinforced piles was 450mm.
The party wall agreement specified that the foundation work next to the neighbouring existing building be done using a reinforced concrete cantilever beam.
The design was unusual in the respect that the first-floor reinforcement was in excess of twenty-five tonnes, which needed to be propped and then concreted.
THE RESULT
The KwikStage propping as supplied and assisted by Mabey Hire worked exactly as they specified. The work was completed successfully with the first-floor concrete floor concrete poured containing the steel reinforcement.
The job has proceeded to the remaining floor with the brick and work block work commencing on the first floor, once this is complete the propping process with continue to construct the second and the third floors.
This job provided us with a major learning point, that no two answers are the same. We are very fortunate to have a team of people that support us well and give us the right information to enable us to do our work safe and successfully.