SECTION 9 (SI): DECKS AND DECK SYSTEMS 9-7
9.7 CONCRETE DECK SLABS
9.7.1 General
9.7.1.1 Minimum Depth and Cover C9.7.1.1
Unless approved by the Owner, the depth of a For slabs of depth less than 1/20 of the design span,
concrete deck, excluding any provision for grinding, consideration should be given to prestressing in the
grooving, and sacrificial surface, should not be less than direction of that span in order to control cracking.
175 mm. Construction tolerances become a concern for thin
decks.
Minimum cover shall be in accordance with the Minimum cover requirements are based on traditional
provisions of Article 5.12.3. concrete mixes and on the absence of protective coating on
either the concrete or the steel inside. A combination of
special mix design, protective coatings, dry or moderate
climate, and the absence of corrosion chemicals may
justify a reduction of these requirements provided that the
Owner approves.
9.7.1.2 Composite Action C9.7.1.2
Shear connectors shall be designed in accordance with Some research efforts have dealt with wood beams
the provisions of Section 5 for concrete beams and composite with concrete decks and steel beams with
Sections 6 and 7 for metal beams. stressed wood decks, but progress is not advanced to a
point which permits codification.
9.7.1.3 Skewed Decks C9.7.1.3
If the skew angle of the deck does not exceed 25°, the The intent of this provision is to prevent extensive
primary reinforcement may be placed in the direction of cracking of the deck, which may result from the absence of
the skew; otherwise, it shall be placed perpendicular to the appreciable reinforcement acting in the direction of
main supporting components. principal flexural stresses due to a heavily skewed
reinforcement, as shown in Figure C1. The somewhat
arbitrary 25° limit could affect the area of steel as much as
ten percent. This was not taken into account because the
analysis procedure and the use of bending moment as a
basis of design were not believed to be sufficiently
accurate to warrant such an adjustment. Owners interested
in making this refinement should also consider one of the
refined methods of analysis identified in Article 4.6.3.2.
Figure C9.7.1.3-1 Reinforcement Layout.
© 2007 by the American Association of State Highway and Transportation Officials.
All rights reserved. Duplication is a violation of applicable law.
