What is AASHTO HL-93 loading?

HL-93 (standard highway loading) is the design truck (72 kip) + design lane (0.64 kip/ft) in each lane. Also check design tandem (2×25 kip axles at 1.2m spacing) + lane. Use governing combination for each element.

How is live load distributed to bridge girders?

Distribution factor g = S/D for simple span (S = beam spacing, D = empirical constant). AASHTO LRFD uses more complex equations including S, span length, depth, and stiffness parameters for interior/exterior beams.

What is the multiple presence factor?

Multiple presence factor m: 1 lane = 1.20, 2 lanes = 1.00, 3 lanes = 0.85, 4+ lanes = 0.65. Accounts for probability that all lanes are simultaneously fully loaded decreasing with more lanes.

Bridge Live Load Distribution Calculator

Calculate live load distribution factors for AASHTO LRFD bridge design. AASHTO HL-93 truck loading. Distribution factors for moment and shear in interior and exterior beams. Multiple presence factors.

2D stress state at a point. All stresses in MPa.

σx — Normal Stress X (MPa)

σy — Normal Stress Y (MPa)

τxy — Shear Stress (MPa)

⚙ Mechanical Note: Results are based on standard textbook formulas and ISO/AASHTO references. Always verify critical designs with applicable codes (ISO 898, AASHTO 1993, AISC, Eurocode 3) and a qualified engineer.

How to Use

Enter the values for the patient or scenario you are assessing. Calculate live load distribution factors for AASHTO LRFD bridge design. AASHTO HL-93 truck loading. Distribution factors for moment and shear in interior and exterior beams. Multiple presence factors. Use the bridge live load result to inform your clinical assessment.

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Frequently Asked Questions

What is AASHTO HL-93 loading?

How is live load distributed to bridge girders?

What is the multiple presence factor?