Precast Hollow Core Slab Design

Request a Hollow Core Slab Design

We carry out the structural design of prestressed precast hollow core slabs across the full range of depths we produce, typically from 150 mm to 500 mm. Our calculations cover the slab from the moment of strand release through transport, erection and the in-service condition, verifying strength, serviceability and handling for the specified spans and superimposed loads.

3D model of a 200 mm thick precast hollow core slab spanning 6.26 m on a supporting beam.

The design checks we perform

Prestress force and losses: We establish the jacking and transfer force and calculate short- and long-term losses (elastic shortening, relaxation, shrinkage and creep) to obtain the effective prestress used in every subsequent check.
Stress limits at transfer and in service: We verify concrete fibre stresses against the allowable tension and compression limits at transfer and under service load, so the section stays uncracked where required.
Ultimate flexural capacity: We confirm the factored moment capacity of the prestressed section against the design moment, including strand stress at ultimate.
Shear capacity: We check web-shear and flexure-shear strength to ACI 318-19, allowing for the absence of shear links in standard hollow core sections and the contribution of the prestress.
Deflection and camber: We calculate transfer camber and long-term deflection under sustained and live load, and confirm they are within serviceable limits for the span.
Bearing and end support: We verify bearing length and end-zone stresses at the supports, including any transmission-length effects near the slab ends.
Lifting and handling: We check the clutch / sling arrangement and slab stresses during demoulding, stacking and erection.

Flexure Check at Final Service (ACI 318-19)

Flexure design-check chart for a precast hollow core slab to ACI 318-19, comparing factored moment with design moment capacity along the span.

Hollow Core Slab Cross-Sections

Cross-sections of 270 mm and 405 mm precast hollow core slabs showing void geometry and prestressing strand layout with dimensions.

Hollow Core Slab Floor Layout

Governing standards and how we apply them

ACI 318-19: Primary code for flexural and shear strength, serviceability stress limits and detailing of the prestressed section.
PCI: We follow PCI design practice for prestressed hollow core members, including handling, camber and bearing recommendations.
BS EN 1168 / EN 1992: Used where European practice is specified, with EN 1168 covering the precast hollow core product and EN 1992-1-1 the prestressed concrete design.

This page covers the structural design calculations for hollow core slabs. For automated placement, opening, shop drawing and quantity production we also offer our in-house HollowCoreSlab plugin for AutoCAD.

Why choose Precasterz for hollow core slab design

Full depth range: We design the complete range of hollow core depths and adapt the strand pattern to the span and loading rather than forcing a standard layout.
Strength and serviceability together: Every section is checked for ultimate capacity and for the stress, camber and deflection that determine real-world performance.
Production-aware output: Our design ties directly into fabrication — strand layout, lifting and bearing details are issued ready for the casting bed.