Post-Tensioned Concrete Design: Engineering Process and Costs

I ask the team to define the grids, spans, loading, geometry, materials, foundations, construction stage, and desired deliverables before discussing a fee. The responsible structural engineer then determines the analysis and detailing scope. Post-tensioning affects slab thickness, deflection, punching shear, tendon forces, anchorage zones, reinforcement, diaphragm behavior, openings, and construction sequencing, so it should be treated as an integrated system.

• Gravity, lateral, serviceability, and construction-stage analysis
• Tendon forces, profiles, anchorages, stressing zones, and losses
• Punching shear, transfer conditions, openings, edges, and penetrations
• Reinforcement, calculations, plans, sections, details, and specifications

Architectural revisions, geotechnical assumptions, MEP sleeves, embeds, slab openings, unusual edges, transfer elements, and contractor sequencing can materially change post-tensioned work. Existing slabs may require records, scanning, testing, or field verification before alteration. I prefer to expose these dependencies in the proposal rather than quote a generic square-foot rate that ignores who owns tendon detailing, shop drawings, observations, and field changes.

• Current plans, loads, grids, elevations, and design criteria
• Geotechnical recommendations and foundation assumptions
• Openings, sleeves, embeds, MEP routes, and construction tolerances
• Submittals, RFIs, site observations, stressing records, and revisions

For early budgeting, a small and well-defined new design may fall in the low-thousands to tens-of-thousands of dollars in engineering fees, while complex commercial, transfer, retrofit, or phased work can exceed those bands. They are not quotes and exclude construction. The AHJ may require calculations, drawings, special-inspection information, or clarifications, while the contractor, stressing supplier, inspectors, and design team must coordinate field execution.

• Separate design fees from concrete, tendons, stressing, and inspections
• Confirm whether specialty tendon detailing and independent checks are included
• Define plan-check responses, submittals, RFIs, and observation services
• Carry contingency for changed loads, geometry, openings, and concealed conditions