What EI value should I use for steel beams?

E = 200 GPa for steel. I from section properties (cm⁴). For W200×59 (W8x40): I = 60.8×10⁶ mm⁴. EI = 200,000 × 60.8×10⁶ = 12,160 kNm². Deflection formula must use consistent units.

How do I use superposition for multiple loads?

Calculate deflection from each load separately using standard formulas, then add algebraically. Valid for linear elastic behavior (small deflections, no yielding). Works for any combination of point loads and UDL.

What is the difference between elastic and total deflection?

Elastic (immediate) deflection occurs under short-term loads. For concrete beams add long-term creep deflection (λ_Δ factor from ACI 318, typically 2× elastic for sustained loads). Total δ = δ_immediate + δ_creep.

Simply Supported Beam Deflection Calculator

Calculate midspan deflection: central point load δ = PL³/(48EI), UDL δ = 5wL⁴/(384EI). Maximum deflection at midspan for symmetric loading. Superposition for multiple loads. EI stiffness database for steel sections.

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 midspan deflection: central point load δ = PL³/(48EI), UDL δ = 5wL⁴/(384EI). Maximum deflection at midspan for symmetric loading. Superposition for multiple loads. EI stiffness database for steel sections. Use the beam deflection result to inform your clinical assessment.

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Simply Supported Beam Deflection Calculator

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Frequently Asked Questions

What EI value should I use for steel beams?

How do I use superposition for multiple loads?

What is the difference between elastic and total deflection?