Structural beams and column design progress

Using CATIA V5 (a sophisticated industry CAD software), I've been designing the structural columns and beams for the World Tech Center's Twin Towers. These images show his current work in progress in preparation for the Finite Element Analysis for structural performance determination.

The vertical columns (my most challenging component to design) consist of 6cm thick steel plates welded into an oblong box shape, with a central 'I beam' in a "+" configuration. The column segment measures 8 metres long and 90 cm wide and deep. The steel is made from ASTM A913 alloy in the 70W grade, a high strength alloy with a yield strength of around 485 MPa while still being weldable at near-room temperature. There has been a re-design and material selection for these columns to balance incredible structural strength with the simplicity of construction on-site. These 'hybrid' columns will be hoisted by crane (like any other) and slide onto doubler plates (on the inner web) of the previous column, where workers would bolt the connection to secure it. Then the side flanges are welded, and then the octagonal ends (used to access the bolt plates) is then welded to cap the column. The column will be then filled with UHPC concrete in two or three stacking intervals, to produce what can be described as a 'super strong and resilient' structural assembly.

The horizontal beams that span the columns on the perimeter are made from the same steel grade. The floor I-beams are made from a different alloy - A992 structural steel with a yield strength of 350 MPa. This steel is readily available in hot-rolled I-beams, which in this case have a web thickness of 4cm, and total beam height of 75 cm. The floor beams measure up to 16 metres long, the perimeter beams 9.1 metres in length. With their I-shape web depth and additional cross-plates to connect the lateral sub-beams, these structural members are designed to be far superior in strength and deflect much more minimally compared to their ancestors on the original World Trade Center - which were lightweight trusses that deflected easily. All structural members will be coated in the latest fireproofing materials with an aspirational 6-hour rating.

The FEA analysis will commence once all parts have been modelled and assembled in CATIA. This upcoming simulation will highlight the structural performance results using complex mathematics. A new drawing has been published that showcases the vertical box column with dimensions shown, with many more to follow.