PSAD Formulas

Earthquake Period (Approx. in Practice)

Earthquake Period

C_t for Steel MRF

C_t for RC MRF & Eccentric. Braced Frames

C_t for Other Frames

Seismic Base Shear

Maximum Base Shear

Minimum Base Shear

Minimum Base Shear (Zone 4)

F_t (Concentrated Force at the Top of Structure) ; T> 0.7s

Maximum F_t

Vertical distribution of seismic shear force

Simplified Base Shear

Pile Foundation Formula

Critical Section for Wide Beam Shear (Deep Foundation)

Nominal Flexural Strength (Deep Foundation)

Critical Section for Punching Shear (Deep Foundation)

Proportioning (Minimum Dimension for Uplift)

Net / Effective Pressure q_u(net)

Footing Dimensions

Actual Shear: Wide Beam Shear (One-way Shear)

Design Shear Strength: Wide Beam Shear (One-way Shear)

Nominal Shear Stress: Wide Beam Shear (One-way Shear)

Actual Shear: Punching Shear (Two-way Shear)

Shear Capacity: Punching Shear (Two-way Shear)

Nominal Shear Stress: Punching Shear (Two-way Shear)

Notes for Shear Foundation: Circular/Polygonal Column (Convert to Square)

Notes for Shear Foundation: Biaxial Bending

Notes for Shear Foundation: Steel Column w/ Base Plate

N_CB

N_OB

Slab Design: Minimum Thickness (Simply Supported)

Slab Design: Minimum Thickness (One End Continuous)

Slab Design: Minimum Thickness (Both End Continuous)

Slab Design: Minimum Thickness (Cantilever)

Slab Design: Modification Factor (Light Weight, w_c = 1500 to 2000)

Slab Design: Modification Factor (Fy ≠ 415 or 420 MPa)

Floor Load Distribution

Equivalent Uniform Load: One Way Slab

Equivalent Uniform Load: Two Way Slab (Triangular)

Equivalent Uniform Load: Two Way Slab (Trapezoidal)

Gross Moment of Moment of Inertia Modification (Columns)

Gross Moment of Moment of Inertia Modification (Beams/Girders)

Gross Moment of Moment of Inertia Modification (Flat Plates/Slabs)

Gross Moment of Moment of Inertia Modification (Uncracked Walls)

Gross Moment of Moment of Inertia Modification (Cracked Walls)

End Restraint Factors

End Restraint Factors (Constant: Pinned)

End Restraint Factors (Constant: Fixed)

Radius of Gyration (Rectangle) for Compression Members ONLY

Radius of Gyration (Circle) for Compression Members ONLY

Minimum Eccentricity: Tied Column

Minimum Eccentricity: Spiral Column

Interaction Diagram: Geometry Factor

K_n : Normalized Axial Load

R_n : Normalized Moment

Bresler’s Reciprocal Equation

Minimum Steel Ratio (Column)

Maximum Steel Ratio (Column)

Minimum Clear Spacing of Ties (Tied Column)

Maximum Tie Spacing (Tied Column)

Volumetric Spiral Reinforcement Ratio

Minimum Spiral Reinforcement Ratio (1)

Minimum Spiral Reinforcement Ratio (2)

Pitch/Spacing of Spiral

Serviceability Spacing (Spiral Ties)

Spacing Based on Combined (Torsion & Shear)

Maximum Spacing for Torsion

Concrete Shear Strength: Shear and Flexure Only (Simplified Calculation)

Concrete Shear Strength: Shear and Flexure Only (Detailed Calculation)

Concrete Shear Strength: with Axial Tension Only (Detailed Calculation)

Concrete Shear Strength: with Axial Compression Only (Simplified Calculation)

Concrete Shear Strength: with Axial Compression Only (Detailed Calculation)

Concrete Shear Strength: with Axial Compression Only (Detailed Calculation), if M_m (-), not applicable

Circular Column: Cross Section Conversion for Shear

Web Steel Ratio

Values of λ

Nominal Shear Strength

Steel Reinforcement Shear Strength

Minimum Shear Area Reinforcement: fc’ > 31.87 MPa

Minimum Shear Area Reinforcement: fc’ < 31.87 MPa

Theoretical Spacing

Compression Block

Compression Block (Balanced)

Beam Flange Width (T-Beam)

Beam Flange Width (L-Beam)

Coefficient of Resisting Moment

Coefficient of Resisting Moment (Derived from Mn)

Steel Ratio (In Terms of Rn)

Minimum Steel Ratio (fc’ ≤ 31.36 MPa)

Minimum Steel Ratio (fc’ > 31.36 MPa)

Maximum Steel Ratio

WSD: Allowable Stress (Concrete)

WSD: Allowable Stress (Steel)

Cracking Moment

Curvature of Cracking

Modulus of Rupture

Crack Index

Maximum Strain Conditions

Balanced Strain Conditions