detail of a new customizes prefabricated railing structure, steel carpentry with pillars, steel beams and galvanized steel bolts

industry railing banister banisters balustrade balcony bannister rail galvanized steel zincplated zinc galvanizing precast crossbeam roof beam architectural column nut fastener bolt pillar building activity prefabricated metal iron bolts engineering girder assembly construction rod buildings architecture engineer customizes custom projects prefabrication carpentry metallic structural work components calculating technology detail new structure pillars beams welded bolted flanges flanges