Structural Design Codes Directory
Authoritative reference guide to governing structural engineering code provisions and side-by-side international code comparisons across reinforced concrete, structural steel, foundations, and loading analysis.
ACI 318-19 | Reinforced Concrete Design
Building Code Requirements for Structural Concrete (American Concrete Institute)
ACI 318-19 Section 9.6 | Minimum Flexural Reinforcement
To prevent sudden, brittle failure upon cracking, concrete beams must contain a minimum amount of flexural reinforcement. If the beam's moment capacity is relied upon, it must be stronger than the cracking moment of the concrete section.
ACI 318-19 Section 22.5 | One-Way Shear Strength
Concrete beams resist shear forces through a combination of the concrete's intrinsic strength and steel stirrups. The new ACI 318-19 shear provisions account for the size effect in members without shear reinforcement, meaning that deeper beams are weaker per square inch than shallow beams.
ACI 318-19 Section 25.4/25.5 | Development Length
Rebar needs to be embedded deep enough into concrete so that it can reach its yield strength without slipping or pulling out of the concrete. This length is called development length.
ACI 318-19 Section 18.10 | Special Structural Walls (Seismic)
Special structural walls in high seismic zones must maintain their strength during severe earthquakes. This requires confinement elements at the wall boundaries when compression stresses become too high under overturning moments.
ACI 318-19 Section 22.6 | Two-Way Shear (Punching)
Punching shear is the tendency for a heavily loaded column to punch entirely through a concrete slab or footing. The resisting perimeter is located at a distance of d/2 from the column face.
ACI 318-19 Table 21.2.1 | Strength Reduction Factors (φ)
To protect structures against variations in material strength, dimensions, and workmanship, nominal strengths are scaled down by a strength reduction factor (φ). Beams with ductile, yielding steel receive a favorable φ = 0.90, while brittle compression columns are penalized with φ = 0.65.
ACI 318-19 Table 24.2.2 | Maximum Permissible Calculated Deflections
Concrete structures must remain functional and serviceable. Excessive sagging causes cracked drywall, ponding water, and misaligned doors. Table 24.2.2 sets strict span-to-deflection ratios based on what elements the floor or roof supports.
ACI 318-19 Table 20.5.1.3.1 | Specified Concrete Cover for Reinforcement
Concrete cover is the protective distance between outer steel rebar and the concrete surface. Adequate cover protects steel from rusting when exposed to moisture and preserves structural integrity during fires.
ACI 318-19 Section 16.5 | Corbels and Brackets Design
Corbels are short cantilevers projecting from column faces to support precast beams or crane girders with shear span-to-depth ratio (av/d) ≤ 1.0. They behave like deep struts rather than standard flexural beams.
ACI 318-19 Section 24.3 | Crack Control & Maximum Bar Spacing
Even properly designed reinforced concrete will crack on the tension side. To keep crack widths narrow for aesthetic and corrosion protection reasons, the code limits the maximum spacing between individual rebar bars.
ACI 318-19 Chapter 13 | Shallow Foundation Design
Spread footings transfer structural column loads into supporting soil strata. Design requires satisfying two independent criteria: geotechnical soil bearing capacity without excessive settlement, and structural reinforced concrete strength against punching and flexure.
ACI 318-19 Section 23 | Strut-and-Tie Method for Deep Beams
Deep beams have clear span-to-overall-depth ratios (ln/h) <= 4.0. In these deep members, Bernoulli's hypothesis (plane sections remain plane) fails completely. Internal stresses must be modeled as an idealized pin-jointed truss comprising concrete compression struts and rebar tension ties.
ACI 318-19 Section 22.7 | Torsional Strength & Threshold Torsion
Torsion twists a beam around its longitudinal axis. ACI 318-19 models torsional response using a thin-walled tube space truss where diagonal concrete compression struts spiral around the member, equilibrated by transverse closed stirrups and longitudinal bars distributed around the perimeter.
ACI 318-19 Section 22.4 | Axial Strength & P-M Interaction of Columns
Concrete columns carry simultaneous axial compression and bending moments. Because minimum accidental eccentricity is always present in real construction, ACI 318-19 caps the maximum usable axial capacity at 80% of pure squash load Po for tied columns (85% for spiral columns) and evaluates combined capacity across a continuous P-M interaction curve.
ACI 318-19 Section 7.3 & 7.6 | One-Way Slab Thickness & Reinforcement
One-way slabs bend primarily in a single direction across the shorter span. To avoid tedious deflection calculations on routine floors, ACI 318-19 Table 7.3.1.1 provides span-to-depth ratios (such as l/20 for simply supported and l/28 for both ends continuous) along with minimum temperature and shrinkage reinforcement.
ACI 318-19 Section 8.10 | Two-Way Slab Direct Design Method (DDM)
Two-way slabs transfer floor loads in two perpendicular directions simultaneously. The Direct Design Method (DDM) first computes the total static moment Mo across the clear span, splits it into negative support moments and positive midspan moments, and then apportions those moments laterally between the stiffer Column Strip and softer Middle Strip.
ACI 318-19 Section 6.5 | Approximate Moment & Shear Coefficients
For regular continuous beams and one-way slabs where adjacent spans do not differ by more than 20% and live load does not exceed 3 times dead load, ACI 318-19 Section 6.5 permits engineers to use envelope moment coefficients (wu ln² / C) that automatically account for pattern live load placement.
ACI 318-19 Chapter 17 | Anchoring to Concrete (Breakout & Shear)
Anchor bolts embedded in concrete can fail either by the steel rod snapping or by pulling a 35-degree pyramid-shaped cone of concrete out of the foundation (Concrete Breakout). Edge distances, group overlapping cones, and concrete cracking heavily influence breakout capacity.
AISC 360-22 | Structural Steel Buildings
Specification for Structural Steel Buildings (AISC 360-22 LRFD & ASD)
AISC 360-22 Chapter F | Flexural Strength of Steel Beams
Steel beams fail in bending either by local buckling of their flanges/web, yielding across the whole section, or by twisting sideways (Lateral-Torsional Buckling). The unbraced length determines which failure mode controls.
AISC 360-22 Chapter G | Shear Strength of Steel Members
Shear in a steel member is carried almost entirely by its web. Depending on the web's slenderness (depth-to-thickness ratio), it may buckle before it yields in shear.
AISC 360-22 Table J2.4 | Minimum Size of Fillet Welds
If a weld bead is too small relative to the thickness of the steel plates being connected, the heavy steel pulls heat out of the weld too quickly (quenching). This makes the weld brittle and causes cracking along the weld toe. Table J2.4 establishes mandatory minimum weld leg sizes.
AISC 360-22 Chapter E | Compressive Strength of Steel Columns
Steel columns under compression fail either by yielding or buckling. Short stocky columns fail by inelastic crushing, while long slender columns buckle elastically at much lower stresses according to Euler's classic column formula.
AISC 360-22 Chapter J | Bolt Shear and Bearing Strength
Bolted steel connections transfer load either by direct shear across the bolt shanks or by the bolt pressing against the edge of the steel hole (bearing and tearout). The weaker mechanism controls the connection strength.
AISC 360-22 Chapter H | Combined Axial Force and Flexural Bending
Steel members in building frames rarely carry pure axial load or pure bending alone. AISC 360-22 Chapter H provides piecewise bilinear interaction equations that govern beam-columns carrying simultaneous compression and bi-axial moments.
AISC 360-22 §J8 & Design Guide 1 | Steel Column Base Plates
Steel columns concentrate immense axial forces over a small steel cross-section that would crush supporting concrete foundations directly. A steel base plate spreads the column load over a larger bearing footprint while resisting upward cantilever bending around the column flanges and web.
ASCE 7-22 | Minimum Design Loads & Hazards
Minimum Design Loads and Associated Criteria for Buildings (ASCE 7-22)
ASCE 7-22 Section 2.3 | LRFD Load Combinations
Buildings must be designed to withstand simultaneous, probable extreme loads. Because a record earthquake is unlikely to hit exactly during a 500-year snowstorm, load combinations scale down loads when they act together.
ASCE 7-22 Chapter 26 | General Wind Load Requirements
Wind exerts a dynamic pressure against a building based on the wind's speed, the terrain roughness, and the height above the ground. Taller structures in open terrain attract much higher wind pressures.
ASCE 7-22 Chapter 12 | Seismic Design Requirements
During an earthquake, the building's own mass generates inertial forces against acceleration. The total force at the base of the building (v) depends on its spectral acceleration and its ability to absorb energy (R factor).
ASCE 7-22 Table 1.5-1 & 1.5-2 | Risk Categories and Importance Factors
Not all buildings are equally critical. A grain silo (Category I) carries lower risk than a standard office building (Category II), an auditorium or school (Category III), or an essential hospital / fire station (Category IV). Essential structures must be designed for higher design loads so they remain operational after disasters.
ASCE 7-22 Chapter 7 | Flat and Sloped Roof Snow Loads
Snow accumulates on roofs differently than on the ground due to wind blowing snow off flat surfaces, heat escaping through the ceiling, and roof slopes causing snow to slide. The design roof snow load translates ground snow into actual roof pressure.
ASCE 7-22 Chapter 30 | Components & Cladding (C&C) Wind Pressures
Individual roof panels, windows, mullions, and purlins do not feel the smoothed average wind load of the whole building. Localized wind vortices curling around roof corners generate intense suction pressures that strip panels off buildings.
Geotechnical & Shallow Foundations
Bearing capacity equations, footing settlement, and soil-structure interaction
Meyerhof's General Bearing Capacity Equations | Shallow Foundations
Meyerhof's bearing capacity equation computes the ultimate pressure a shallow footing can apply to soil before undergoing shear failure. It expands Terzaghi's classical formula by introducing empirical factors for footing shape, foundation embedment depth, and inclined load angles.
IBC Chapter 18 & Rankine Theory | Retaining Walls & Deep Piles
Cantilever retaining walls hold back soil wedges that exert horizontal Rankine active earth pressure against the stem. Under IBC Section 1807.2.3, retaining walls must achieve a minimum Factor of Safety of 1.5 against both overturning about the toe and horizontal sliding along the base, while deep piles transfer load through shaft skin friction and end bearing.
International Code Comparisons (US vs. Eurocode & CSA)
Side-by-side guides comparing safety factors, material grades, and formulas
ACI 318-19 vs. Eurocode 2 (EN 1992-1-1): Concrete Design Guide
How safety factors, concrete cylinder strengths, and flexural stress blocks translate between US and European concrete codes.
Punching Shear Compared: ACI 318-19 (§22.6) vs. Eurocode 2 (§6.4)
Why ACI checks punching at 0.5d from the column face while Eurocode checks at 2.0d—and how longitudinal steel changes the outcome.
One-Way Beam Shear: ACI 318-19 (§22.5) vs. Eurocode 2 (§6.2)
The 45-degree Vc + Vs model in ACI versus Eurocode's variable angle truss model—explained without the headache.
AISC 360-22 vs. Eurocode 3 (EN 1993-1-1): Structural Steel Guide
Comparing section classification (Compact vs. Class 1–4), column buckling curves, and lateral-torsional buckling between US and European steel codes.
ACI 318-19 (US) vs. CSA A23.3 (Canada): Concrete Design Differences
Why Canadian concrete design uses material resistance factors (φc = 0.65, φs = 0.85) and Modified Compression Field Theory for shear.
US (ASTM) vs. Canadian (CSA) vs. European (Metric) Rebar Conversion Guide
How to substitute reinforcing bar sizes, adjust bar spacing, and account for yield strength differences across international drawings.