Frame Girder Span Calculator (L1 & L2)

🧮 Beam BBS Calculator (ACI Fig. 5 – Standard Bar Arrangement)

Input dimensions in mm. L1 = center span, L2 = side span (each).

Center span L1 (mm) Side span L2 (mm) Beam size b×D (mm) Column size C×C (mm) Main bar diameter db (mm) Stirrup bar diameter dt (mm)

📌 BBS Result — ACI Fig. 5 Logic

Bar lengths are based on 0.25L1, 0.3L1 / 0.3L2 (greater) and 2D confinement zones as shown in ACI Detailing Manual-2004, Fig. 5.

Longitudinal Bars

Bar mark	Description	Formula (mm)	Length (mm)

Stirrups & Shear Reinforcement

Item	Value / Rule

📐 Auto Drawing — ACI Fig. 5 Style

EXT. END – CENTER – INT. END – END zones, 0.25L1, 0.3L1 or 0.3L2 (greater), 2D confinement zones, and S1 spacing per ACI.

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