Structural engineering has enjoyed a brilliant and iconic past. Signature bridges, high-rise buildings, and long-span roofs over sports facilities stand as testaments to the work of structural engineers. However, much of the work of structural engineers is hidden by facade - or otherwise exists so commonly in our experience that we do not notice it. In the example all roof coverings, insulation, veneers, fire protection, non-load bearing walls and furnishings are omitted.
The structural design phase represents one of the most complex and dynamic tasks in the life-cycle of a project, given that structural behavior must be rigorously analyzed in adherence to a series of regulatory provisions, not to mention professional practices. This significance makes the structural design phase an essential component of the generation of the BIM model.
At Vee Technologies, we wondered what the structure would look like if we built the model in Revit using just structural elements. Starting with the foundations on hypothetical poor but flat ground conditions, we built the foundation level using piling, pile caps and a ground beam system to carry the loads including the elevator structure and the stair wells. The number and depth of pile will vary according to the depth of load bearing ground conditions and whether they are end bearing, friction or combined piles. The canopy posts are shown on a more regular reinforced pad base which may be square or rectangular according to design. The ability to resist the punching shear is the governing criteria that determines the depth of the reinforced concrete pad foundations.
The second floor shows the post and beam elements with a composite concrete (either lightweight or normal) on steel decking forming the floor supported by Vulcran joists. Note the cutouts designed for services. There is also an area for more traditional hollow core plank flooring. The access cantilevers are shown as well as post and beam canopy support. The supports can be designed as roller, pinned or fixed as required. Bear in mind that most of this structure would be hidden from the eyes by façade, cladding, other finishes and decoration.
The third floor mimics the second floor with the exception of the canopy paraphernalia.
The fourth and fifth floors show the support required to roof in the lower building while the upper building continues to rise. Support members around the elevator shaft and forward stairwell can enclose an area for mechanicals and other system rooms and machinery.
The upper building continues its rise in the skeleton framework of columns and beams to any suitable height, theoretically without limit - except for budgetary constraints.
The eleventh & roof level shows the post and beam elements with a composite concrete (either lightweight or normal) on steel decking forming the floor supported by vulcraft joists, beams and trusses. The roof trusses are used to eliminate column at the center of the building to maintain a clear space and to withstand mechanical equipment loads. The roof diaphragm is introduced to eliminate mechanical equipment vibration and to increase the stiffness matrix for trusses. Note the cutouts are designed in floor/roof slabs for MEP services and all the cutouts are covered by fire rated dry walls. The vertical bracing and concrete reinforced shear walls (elevator and stairwells) are used to resist lateral and seismic loads to reduce sway in the building.
There is an inherent beauty within structural design and engineering. Some of the best structures ever created still can be seen today. When building the components for a long lasting structure, it's always best to start with a solid foundation.
