Analysis and Design of Slabs — Worked Examples
These examples separate prescriptive thickness screening from explicit analysis and keep every load, depth, and reinforcement calculation consistent with the selected slab geometry.
One-Way Slab Prescriptive Thickness Explorer
Screening rule only — not an analytical deflection or strength verification.
Controls
Prescriptive calculation
The displayed adopted value rounds the equation result upward to the next 5 mm for a practical teaching selection.
Prescriptive minimum
Raw equation value: 200.0 mm. Use only when the slab end rotations are not restrained by continuity in the design direction.
Example 1: Prescriptive Thickness of a Simply Supported One-Way Slab
Problem: A nonprestressed one-way solid slab has an applicable span and is simply supported. Using the lesson's normal-weight-concrete screening rule with , determine the prescriptive thickness that permits omission of a separate detailed deflection calculation.
Step-by-Step Solution
0 of 2 Steps CompletedExample 2: One-Way or Two-Way Behavior from Supports and Aspect Ratio
Problem: A slab panel is supported by beams on all four sides. Classify its principal slab action using the lesson's aspect-ratio screening rule.
Step-by-Step Solution
0 of 2 Steps CompletedExample 3: Coherent One-Way Slab Design after the Thickness Check
Problem: Design a representative strip of a simply supported one-way slab spanning . The live load is and superimposed dead load is . Use , , normal-weight concrete at , clear cover, and trial bars. Use the lesson's prescriptive thickness route rather than an independent deflection calculation.
Step-by-Step Solution
0 of 6 Steps CompletedExample 4: Direct Design Method Total Static Moment
Problem: A qualifying interior panel is being checked for DDM in one direction. The factored uniform load is , the transverse panel dimension is , and the applicable clear span is . Calculate the total static moment before any prescribed positive-negative or strip distribution.
Step-by-Step Solution
0 of 2 Steps CompletedExample 5: Punching-Shear Critical Perimeter Geometry
Problem: An interior square column is and the slab effective depth at the connection is . Determine the simplified critical perimeter located from the column faces.
Step-by-Step Solution
0 of 1 Steps CompletedExample 6: Complete DDM Applicability Screening
Problem: A flat-plate floor has three continuous spans in each direction. Panels are , successive spans are equal, columns are on the panel centerlines, loading is gravity-only and uniform, dead load is , and live load is . Determine whether the lesson's listed DDM screening conditions are satisfied.
Step-by-Step Solution
0 of 3 Steps CompletedExample 7: Yield-Line Mechanism Interpretation
Problem: Two admissible yield-line mechanisms for the same idealized slab give collapse-load estimates of and . What should be concluded from the upper-bound interpretation of yield-line analysis?
Step-by-Step Solution
0 of 2 Steps CompletedExample 8: When a More General Slab Analysis Is Required
Problem: A two-way floor has two continuous spans in one direction, a large irregular atrium opening beside a column line, significant nonuniform equipment loads, and the slab participates in the lateral-force-resisting system. Should DDM or a basic gravity-only EFM idealization be treated as sufficient by default?