Flat slabs design is appropriate for most floor situations and is also suitable for irregular column layouts, curved floor shapes, ramps etc. The benefits of choosing flat slabs include a minimum depth solution, speed of construction, flexibility in the plan layout (both in terms of the shape and column layout), a flat soffit (clean finishes and freedom of layout of services) and scope and space for the use of flying forms. The flexibility of flat slab construction can lead to high economy and yet allow the architect great freedom of form.
For many years, CIRIA Report 110 has been the standard document for the design of reinforced concrete flat slabs. Over that time analysis methods have changed and new construction methods have been developed. In the past few years there has been a significant increase in the use of finite element software packages both for the analysis and design of flat slabs. However, there is very little supporting information to allow engineers to understand the whole design process or verify the results of FEA. The publication of Eurocode 2 introduced changes in the design methods for flat slabs especially for punching shear. In addition the Designer is required to take greater responsibility for the Health and Safety implications of the method of construction. Many flat slabs are designed in an environment where the contractor should be involved. In the light of these various factors, The guidance in the spreadsheet is in accordance with Eurocode 2 (BS EN 1992) and the National Structural Concrete Specification.