# Verification Example - RC One-Way Slab Design

## Description

This verification example represents the analysis and design of a reinforced concrete
one-way slab utilizing Tekla Tedds. This example is based on the One-way Slab
Example 1 of the *ACI Reinforced Concrete Design Handbook, A Companion to ACI
318-19, Volume 1: Member Design *(Pages 46 through 57). Comparisons and contrasts
are tabularized and discussed regarding the results from Tedds and the ACI Design
Example.

## Problem statement

Design the reinforced concrete one-way slab shown in Figure E1.1 of the ACI Design Example. See Figure E1.7 of the ACI Design Example for designed slab reinforcement.

## Tedds calculation

RC one way slab design (ACI318) - Compared using version 1.2.05

## Running the example in Tedds

The Tedds verification examples referenced in this document can be run in Tekla Tedds from the Engineering library index, in the Verification Examples\RC one way slab design (ACI318) folder.

## References

*ACI Reinforced Concrete Design Handbook, A Companion to ACI 318-19, Volume 1:
Member Design*

*ACI 318-19: Building Code Requirements for Structural Concrete and
Commentary*

## Example information

Concrete:

γ_{concrete }= 150 lb/ft^{3}

*f’c* = 5.0 ksi

f_{y} = 60 ksi

` `

Uniform Loads:

Live load, L = 100 psf (assembly load, non-reducible)

Miscellaneous dead load = 15 psf (HVAC systems, ceilings, etc.)

` `

Column dimensions: 24” x 24”

Beam dimensions: 18” wide

Slab thickness: 7” (both at cantilever and main span)

Slab span: 14’ at main span and 6’ at cantilever

` `

Concrete cover to reinforcement:

Top clear cover: ¾”

Bottom clear cover: ¾”

## Notes and assumptions

- Analysis using live load patterning was utilized in the design example per ASCE 7 to determine maximum shears and moments.
- The slab does not contain drop panels
- Lateral loads are resisted by shear walls and moment-resisting frames. The slab is assumed to be braced and any moment effects in the slab caused by lateral loads are ignored.
- Diaphragm design is not considered in this example.
- Governing load combination for slab design: 1.2D + 1.6L
- Negative design moments are taken at the face of the support.
- Shear and moment values were determined in the ACI design example utilizing a software program performing a first-order analysis. Further information regarding the analysis approach can be found in the ACI design example.

Comparison of Results between
Tedds and ACI Example 1 |
|||
---|---|---|---|

Component |
Tedds Result |
ACI Example 1 |
% Difference |

Minimum slab thickness for deflection control |
7.0”(main span) 7.2” (cantilever) |
7.0” (main span) 7.0” (cantilever) |
0.0%^{a}^{} |

Moment and Shear results (from ACI
Design Example 1) |
|||

Governing negative moment in main span,
(M_{u}^{-}) |
6.3 kip-ft | ||

Governing positive moment in main span,
(M_{u}^{+}) |
4.9 kip-ft | ||

Governing negative moment in cantilever span,
(M_{u}^{-}) |
6.0 kip-ft | ||

Governing shear in main span and cantilever, (V_{u}) |
2.4 kip | ||

Required
Reinforcement |
|||

Negative moment steel in main span,
(A_{s}^{-}_{req’d}) |
0.25 in^{2} / ft |
0.25 in^{2} / ft |
0.0% |

Positive moment steel in main span,
(A_{s}^{+}_{req’d}) |
0.19 in^{2} / ft |
0.19 in^{2} / ft |
0.0% |

Negative moment steel in cantilever span,
(A_{s}^{-}_{req’d}) |
0.24in^{2} / ft^{} |
0.25 in^{2} / ft^{b} |
4.2%^{b} |

Required minimum reinforcement, (A_{s,min}) |
0.15 in^{2} / ft |
0.15 in^{2} / ft |
0.0% |

Minimum shrinkage and temperature steel (A_{S+T,min}) |
0.15 in^{2} / ft |
0.15 in^{2} / ft |
0.0% |

Provided
Reinforcement |
|||

Negative moment steel in main span,
(A_{s}^{-}_{prov’d}) |
#5 @ 12” o.c. | ||

Positive moment steel in main span,
(A_{s}^{+}_{prov’d}) |
#5 @ 12” o.c. | ||

Negative moment steel in cantilever span,
(A_{s}^{-}_{prov’d}) |
#5 @ 12” o.c. | ||

Shrinkage and temperature steel (A_{S+T,prov’d}) |
#5 @ 18”
o.c.^{c} |
||

Design Shear
Strength |
|||

Design concrete shear strength, (φV_{c}) |
4.9 kip/ft | 4.9 kip/ft | 0.0% |

## Comparison Notes

** ^{a}**In order to not require deflection checks, the thickness of a
cantilevered slab needs to be greater than L/10 per ACI 318-19 Table 7.3.1.1. For
this example, the slab at the cantilever should be a minimum of 7.2” thick, which
Tedds accurately shows. However, in the ACI design example, 7.2” is calculated, but
a thickness of 7” is used.

** ^{b}**The Tedds calculation determines the required top reinforcement
for the cantilever span, while the ACI example uses the main span top reinforcement
as the same top reinforcement for the cantilever span.

** ^{c}**The ACI Design Example incorrectly shows shrinkage and temperature
steel as #4 @ 18” o.c., when the calculations within the design example accurately
calculates #5 @ 18” o.c. is required. Tedds accurately determines the required
shrinkage and temperature reinforcement.

## Conclusion

Upon reviewing the results above, the design of the reinforced concrete one-way slab within Tedds matches the ACI Design Example 1 (apart from errors and engineering judgement found within the ACI example).