Last edited 06 Jun 2019

Falsework

Falsework is '...scaffolding or other temporary structures used to support construction components until the construction is sufficiently advanced to allow the structure to support itself'. Ref The HS2 London-West Midlands Environmental Statement, Department for Transport, November 2013.

There are three main types of systems used for falsework. These include:

Type 1 - Aluminium support legs with aluminium frames assembled into falsework systems, such as; Ischebeck Titan, SGB GASS or PERI MultiProp.
Type 2 - Individual aluminium or steel props, including either timber header beams or proprietary panels, such as ; PERI Multiflex or Doka Eurex Systems.
Type 3 - Heavier steel falsework, such as; RMD Kwikform System Shoring or A-Plant Acrow Props.

The design philosophy behind falsework differs from that of permanent works. They are highly stressed, usually to 90% of their capacity over short periods of time and involve reusable components. Props are rarely tied down and rely on their self-weight and supported load for lateral stability.

The design of the falsework must make allowances for erection tolerances and take into account that the components are re-used many times.

Falsework capacities are provided by the manufactures and permanent, imposed and environmental loads must all be taken account of in their design.

As with general construction, stability is often identified as the main cause of collapse. BS 5975 (BSI, 2011; clause [IP address hidden]) recommends that all falsework is designed for 2.5% of the vertical load acting horizontally as a tolerance for workmanship during erection.

Workmanship and inspections play key roles in the design and installation of falsework, as attention to detail is particularly important.

NB BS 5975: Code of practice for temporary works procedures and the permissible stress design of falsework, was revised in 2019. It provides guidelines for the design, specification, construction and removal of falsework.

Ant Burd, BSI head of built environment, said: “This is a significant revision of an important standard that seeks to reflect changes in working practices and health & safety regulation within temporary construction and falsework. It offers procedural guidance to all organizations and personnel involved, to ensure competence in construction projects, from Principal Contractors and clients through to designers and trainers. The standard gives clear instructions and guidance to help companies be properly prepared for site investigations and compliant with current regulation.”