Structural Design and Detailing
CoGri USA structural designs are generally in full accordance with guidance given in The Concrete Society’s Technical Report 34, 4th Edition, which in general is compliant with Eurocode 2.
Where the slab loading or support is more complex or ‘non-standard’ we also have the facilities and expertise to design slabs using Finite Element Analysis software.
Although our primary focus is the slab, our in-depth knowledge of structures and construction allows us to fully evaluate how the floor ‘fits’ within the building, enabling us to design the slab with consideration to all interfaces, allowing us to highlight early any potential issues with other designed elements reducing the risk of delays on site.
We will consider and advise on any ground floor slab design, but generally they would fall into one of the following categories:
Ground Supported Slabs
Bearing directly onto a sub-base, typically mesh reinforced and with formed joints at nominal 40m ctrs and sawn restrained-movement joints at nominal 6m centers. Jointless, steel fibre reinforced design options can also be provided.
Ground floor slabs can be constructed using a variety of methods; large pour, wide bay or long-strip.
Pile Supported Slabs
Where ground is poor, the slab is laid over a grid of dedicated support piles at nominal 3.5m ctrs. The slab would typically be of ‘jointless’ construction reinforced with steel fibres at a dose of 45kg/m³. Formed joints would typically be installed at 35m ctrs, with no sawn restrained-movement joints.
CoGri USA can work with the Contractor to optimise pile spacing to ensure that the most economical solution is found.
Chiller / Freezer Slabs
As the temperature in Chiller / Freezer chambers can be as low as -29°C the construction is split into three defined zones. A base slab is laid at formation level, with a rigid insulation placed over this prior to casting of the wearing slab. Design of the construction details is particularly important, due mainly to the insulated wall panels passing through the Wearing slab and onto the base slab.
Specialist Storage / Retrieval Systems
As technology progresses, there is a natural trend to move towards more complex storage systems. CoGri USA Ltd have extensive experience with such systems and keep informed with the latest industry developments. These include :
- Automated Storage and Retrieval (ASRS)
- High Bay Warehousing
- Adjustable and Mobile Pallet Racking
- Live Storage Systems
- Drive-in and Push-back Racking
- Clad Rack Structures
- Automated Guided Vehicles (AGV’s)
External Slabs
Typically ground supported, laid in either strips or large-pour. Special consideration must be given to thermal expansion and contraction that is not usually a factor in an Internal slab. Detailing of the joints and interfaces with other construction elements and services is vital in external slabs.
Bonded Topping Slabs
With a minimum depth of 100mm, the topping is mechanically anchored to the base slab with shear connectors. These bars are installed to sit over the mesh reinforcement, providing a fully bonded and fully restrained topping slab
Bonded topping slabs can be installed over existing ground floor slabs or over multi-level elevated slabs. Where the structure is often provided by pre-cast concrete units.
