Farm Buildings Top tips for safe and e ective use of pre-stressed concrete panels

of three tonnes, you cannot a ord to underestimate any possible risk.”

However, he added: “Concrete is a fantastic material and performs extremely well when in compression and steel performs very well in tension – hence the combination of the two provides an extremely strong structural component.”

Not appreciating the design, installation and designed use of pre-stressed concrete panels in any building could introduce problems, warns Mark Allen, director of Johnstruct Ltd.

“Fundamentally, understanding how pre-stressed concrete panels (PSCP) are made and ensuring they are used as designed, may make you rethink what you do to the panels in your steel frame building,” he explained.

Civil engineer Mark has been using pre-stressed concrete components for all sorts of engineering and practical applications over the years –however, PSCP can come with a health warning. Mark explains: “Far too often, we ignore what we can’t see. Inside the commonly used PSCP are a series of pre-stressed/high tensile steel wires running through the concrete panels themselves. Dependant on the supplier/ manufacturing method and design, many of the lifting points rely on these internal strengthening wires to provide adequate or additional mechanical ‘lifting’ support strength. With some panels weighing in excess

Should any one of these internal pre-stressed wires become compromised or damaged, or are not installed during manufacturing, then the overall panel structural strength and/or its lifting capability could be majorly reduced. Mark advises buying from a reputable manufacturer with good quality assurance processes, that o ers a consistent quality product – rather than buying the cheapest PSCP available or even pre-used panels.

“We occasionally see panels damaged during transit or handling/ loading. Whilst this damage tends to be mainly cosmetic, with evidence of small chunks or aking of the concrete, or small bits missing from the panel edges, generally the PSCP integrity and strength is not compromised. Checks still need to be made though,” Mark continues.

More concerning is damage, whether accidental (e.g., from a vehicle impact with evidence of steel wire exposure or large cracks), or ‘man-made’ (e.g., from a neat ventilation duct being cut through the panel). This can have a signi cant impact on how the panel performs. Mark has seen panels with holes hacked out of them or disc cut to form an opening. The structural integrity will have been signi cantly reduced. It should also be noted that not all PSCP are designed to be double loaded; these are more prone to issues if damaged and the user is not aware of any design limitations. If your panels have been compromised in some way (or are being used in a way not originally intended), take care when loading the panel, whether it is to be used as a soil/ earth retaining wall or for your grain store walling, Mark concludes.

Johnstruct Ltd. covers Bedfordshire, Cambridgeshire, Essex, Hertfordshire and Su olk. Farmers Guide readers are o ered free initial advice on planning, supply and installation of all aspects/turnkey solutions for all types of steel frame buildings. FG