Preconstruction is the work done at a desk before any digging starts on a building site: the design is drawn, the materials are counted and priced into a bid, and the schedule and budget are set. It is the first of the two zones of construction technology.
Design comes first. Architects and engineers draw a building in BIM software. BIM, or building information modelling, means that every wall, pipe and beam in the 3D model is an object with a size, a material and a cost. Roads, bridges and railways are drawn in civil infrastructure design software instead, because they follow the ground for many kilometres. Specialist engineers then design their own systems inside the building. Security system design software places the door readers and cameras. AV design software places the screens and speakers in meeting rooms and halls.
Next, contractors price the design. Construction estimating software counts the materials and labour that the design needs, multiplies each item by a rate, and adds everything up into a bid. Counting the items from the drawings is called a quantity takeoff. Quantity takeoff software now does much of this counting with AI. For a government project, the bid answers a government tender, a formal invitation to bid in which fixed rules choose the winner.
Some owners run many projects at once, and they need software of a different kind. Say a city corporation is building 40 flyovers, schools and drains over five years. Capital project management software tracks the budget, approvals and progress of every one of them. A company that must put EV chargers at 800 petrol pumps has a similar problem. Multi-site rollout management software tracks the permits, crews and progress at each pump.
Why spend so much effort before digging? A wall moved on screen costs almost nothing. The same wall moved after the concrete is poured can cost lakhs of rupees and weeks of time. When the work moves to the site, the drawings and the budget pass to construction management software. The work on site itself is covered in construction site management.