Reinforced concrete beam and 1-way slab calculator

Jonathan Ochshorn

© 2009 Jonathan Ochshorn.

Directions: Enter values for design (factored) moment, beam "stem" width, b_w, 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, A_s, 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
Checks:
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:
""

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Disclaimer: This calculator is not intended to be used for the design of actual structures, but only for schematic (preliminary) understanding of structural design principles. For the design of an actual structure, a competent professional should be consulted.

First posted Sept. 4, 2009 | Last updated Sept. 21, 2009