INDOT 67-3.02 Usage
Highway Grade Specifications: Preferably use thin walls or frame bents with multiple columns. The aesthetics of the pier should be considered. Special surface treatments using form liners or other means should be investigated, especially for the wall pier.
INDOT 67-3.03 General Design Considerations (INTERIOR SUPPORTS)
Cap Reinforcement: Multiple layers of negative moment reinforcement are permitted in caps to minimize cap dimensions.
Cap Extension: The width of caps shall project beyond the sides of columns. The
added width of the cap shall be a minimum of 2 in on the outside of the column. This width will reduce the reinforcement interference between the column and cap. The cap should preferably have cantilevered end to balance positive and negative moments in the cap.
Compressive Steel: Compressive steel tends to buckle when the cover is gone or when the concrete around the steel is weakened by compression. The criteria in the LRFD Specs, Article 220.127.116.11 or 5.10.11 for ties and spirals should be rigidly adhered to.
67-3.04(01) Extended Pile Bents (INTERIOR SUPPORTS)
1) Cap Beam: Extended piles always need a cap beam for structural soundness, which may be an integral part of the superstructure.
2) Cap Design: The minimum reinforcement for the concrete bent cap shall be #5 bars at 1 ft spacing on all faces and shall satisfy Article 18.104.22.168 of the LRFD Specs. The cap shall be designed as a continuous beam.
INDOT 62-3.24 The following presents specific design details which represent typical INDOT practices for the design of integral caps in conjunction with reinforced concrete slab superstructures.
1) INDOT's standard pile cap dimensions are 2.5 ft in width and a depth of 1.5 ft plus the slab thickness.
2) For skewed structures, the 2.5 ft dimension is measured perpendicular to the skew.
3) All transverse reinforcement (stirrups) in the caps is placed perpendicular to the skew.
4) Minimum concrete cover for the cap reinforcing steel is 2.0 in.
5) Standard pile embedment into the end bent and interior bent caps is 1.0 ft
6) Support bars and coping stirrup bars are used to provide support for the top steel in the slab. Stirrup bars shall be placed parallel to the skew.
7) A 0.8in, half-round drip bead shall be located under the deck, 6.0 in from the face of coping.
The following applies to the level or sloped profile for the bottom of the bent caps:
1) Either a level or sloped profile of the bottom of the bent caps can be easily formed by contractors.
2) The profile of the bottom of the bent cap can be made level if the difference in top-of-slab elevations at the left and right copings, along the centerline of the bent cap, is 3.0 in or less. For a difference greater than 3.0 in, slope the bottom of the cap from coping to coping.