Posted By Alan Haynes Try googling 'Preflexed Beams' They are just composite steel and concrete beams, where the steel is 'flexed up' a bit at the centre of the span, and concrete added to the beam in the flexed position. When the concrete has set, the beam is taken out of its flex, i.e it as allowed to relax and attempt to go back to its non-flexed shape [flat/horizontal]. This puts the concrete into compression, making the composite beam stronger under load. A demolition involving preflexed beams shouldn't be too problematic - they won't explode or anything. They'll probably suggest breaking out the concrete in situ [if the beams are too heavy to get down to ground level first, or its a complete floor that has ben cast onto the flexed beam], so working at height needs considering. Obviously, if they can, its best to do that after the beams have been removed to the ground, but the structural report will guide you on this. Hope this helps

Posted By Peter MacDonald Cheers guys All options for dismantling/demolition are open and will be based on a structural report. I'm aware of the difficulties in demolition/dismantling post and pre-stressed structures but had never come across Pre-Flex beams before and could only get limited info from google. Received some info from an engineering forum today so have the necessary info. Regards Pete

Posted By Peter MacDonald Alan More or less as you said but with a bit more padding. Cross refrencing that info with the requirements of BS6187 (14.3.7) allows me to be a bit more specific in writing my pre-tender information for that specific piece of work. Pete