# Reinforced concrete beam and 1-way slab calculator

Jonathan Ochshorn

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Directions: Enter values for design (factored) moment, beam "stem" width, bw, effective depth, d, span, spacing, and slab thickness (not all parameters are used for all calculations). Note that design moment for slabs is calculated on a typical 1-ft wide section of the slab. Press "update" button.

The required reinforcement area, As, will be calculated (for slabs, the required spacing of a selected bar size is calculated). More detailed explanations and examples of reinforced concrete beam and slab design can be found in my text.

Note that the strength design method is used; moments must be computed based on factored loads.

Calculator works for rectangular beams, positive-moment and negative-moment T-beams, and 1-way slabs, as shown in the sections below:

Fig. 1. Reinforced concrete beam sections: a) positive-moment rectangular beam; b) negative-moment rectangular beam; c) negative-moment T-beam; and d) positive-moment T-beam

 Mu units d (in.) f'c (ksi) fy (ksi) ft-kips in-kips ft-lb in-lb 3 4 5 60 beam type As (sq in.) rectangular beam T-beam (positive moment) T-beam (negative moment) slab No. 3 No. 4 Effective width: Checks: based on ACI 318-14 based on ACI 318-08 errors: rho must be <= rho max slab spacing must be 2" min. d must be >= slab thickness for beams beam span must be > 0 stem width must be > 0 effective depth, d, must be > 0 centerline spacing must be > stem width "" warning: ""