building construction framing heavy construction sky steel rails stair stairs steel construction steps additions alterations angled angles building-construction building-site building-work construction-site construction-work danger development height high industrial metal-work patterned patterns pipes reinforced reinforcing safe safety scaffolding secure security steel-scaffolding tall work colors pattern rod rust rusted rusty spots Steel rods balance climb climbing construction-sites counter-weights crane heights ladder perspectives railing steel-framed straight weight weights work-safe workmen architecture bridge constructions enginering flyover highway motorway road scaffold transport transportation underconstruction cranes build construction site diggers machinery site structure