Where integrated girders are used, pre-fabricated hollow-core beam floor slabs are positioned between girders, not on top of the steel structure. This achieves thinner flooring thicknesses that lead to significant savings especially in multi-storey buildings. Integrated girders are cast in situ together with the hollow-core floor slabs, which means that they also have a higher fire-resistance. Additional fire-resistant coatings can be applied very easily and technical plant mounted very simply thanks to its flat bottom flange. A logistical advantage is also gained because girders are produced from hot-rolled steel strips and plate. Availability of these standard materials is far higher and customers are not limited to standard trade dimensions. Union Steel Structure Material Co., Ltd. can produce virtually any size of girder to customer specifications subject only to the limitations of its welding machinery. After welding operations, attachments and openings can be incorporated, as well as any anti-corrosion treatment required for the construction phase.