Two workers fell two-and-a-half metres in the incident on 8 July 2011, although both escaped with only minor injuries.
Plymouth Magistrates’ Court heard yesterday (29 October) that the workers were pouring concrete onto a deck to form the floor of a weights area at the dry dive centre. However, no temporary support was used and the combined weight of the two men and the concrete caused it to give way.
An investigation by the Health & Safety Executive (HSE) found that Balfour Beatty Construction Scottish & Southern had failed to ensure that sufficient steps were taken to protect workers during the construction work that led to the collapse.
The contractor did not follow its own temporary works procedure and should have checked that the deck was properly supported before allowing the work to commence.
The company pleaded guilty to a single breach of The Construction (Design and Management) Regulations 2007. It was fined £2,000 and ordered to pay costs of £5,347.
Speaking after the hearing, HSE principal inspector Andrew Kingscott said: "The two workers were fortunate not to have been seriously injured in this incident, which was entirely preventable had Balfour Beatty followed the proper temporary works procedure.
"The correct procedure would have highlighted the need to use a temporary support, such as stronger steel decking, propping or the construction of a temporary wall."