Preliminary post-tension design support

The biggest structural savings are made before the architecture is fixed. A column moved a metre, a transfer avoided, or a floor-to-floor height set for a PT slab rather than a beam-and-slab floor can be worth more than any later optimisation. Preliminary design support gives the design team PT input at that point.

Typical questions we answer

• Is post-tensioning worth it here, or is a reinforced concrete flat slab enough?
• What slab thickness should be allowed for these spans, loads and fire rating?
• Can the column grid work for both the tower and the car park below, or is a transfer needed?
• What are the approximate concrete, strand and reinforcement quantities for a tender?
• Where should pour strips, construction joints and stressing access be planned?

How it is delivered

Input is based on simplified models and hand checks, enough to set thicknesses and grids with confidence. Findings are given as a short note with sketches, or in a design meeting with the architect. A quick first pass is also available with our free slab thickness estimator.

Preliminary support is not a construction design. Once the scheme is fixed, it continues into the full post-tension design package, so work is not repeated. Contractors bidding PT work can also use the quantities to price a tender, with the design then developed for the approved system.

Please send the architectural plans and sections, the intended use and loading, the authority or code, and any known constraints such as basement levels or height limits. Hand sketches are fine at this stage. We usually reply with questions first, then the scheme note.

Because Iron Axis focuses on design rather than contracting, the advice compares systems on their merits. Where RC is the better choice, we say so.