Structural elements calculators
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Reinforced concrete integrated T-beam, girder, and 1-way slab calculator

Jonathan Ochshorn

An older reinforced concrete design calculator that computes required steel area for T-beams and 1-way slabs can be found here.

This calculator finds rebar sizes and spacing for beams, girders, and 1-way slabs for a particular type of reinforced concrete floor system consisting of a regular grid of columns supporting a hierarchical arrangement of girders, beams, and 1-way slabs for which "moment values" can be used. The beams and girders are assumed to be integral with the slabs and are designed as negative- and positive-moment T-beams. All dimensions and material properties are user-defined; the calculator computes steel bar sizes and spacing, while checking for "bar fit."

Directions: Enter values in the yellow fields. Scroll down to the bottom for some definitions and commentary. More detailed explanations and examples of reinforced concrete beam and slab design can be found in my text, available at no cost.

Note that the strength design method is used, per ACI-318-19 (2019 edition). Positive-moment T-beams where the compressive zone is not entirely within the "slab" portion of the T-beam (a very rare occurance) are not considered.

moment value diagram
Figure 1. Moment value coefficients (denominators) for continuous beams and slabs, subject to the criteria outlined below. Image adapted from my text

1. The units for uniformly distributed design load, wu, are typically lb/ft or kips/ft (or equivalent metric units); the units for clear span, L, are feet (or equivalent metric units); and the resulting moment value, Mu is in ft-lb or ft-kips (or equivalent metric units) depending on the units chosen for the distributed load. These moment values are valid only for continuous reinforced concrete beams or slabs when the following conditions are met:

2. The negative moment (at the face of support) can be taken as wuL2 / 12 for slabs with clear spans no greater than 10 ft, and for beams framing into relatively stiff columns (see text for details).

The user-controlled parameters in this calculator (shown in the yellow fields) are defined as follows: