N.J. Admin. Code § 19:6-2.37

Current through Register Vol. 56, No. 11, June 3, 2024

Section 19:6-2.37 - Capping and bracing of piles

(a) Capping of piles rules are:

1. Embedment: Tops of all piles shall be embedded at least three inches in concrete caps. Such concrete shall extend at least four inches beyond the edge of all piles. Cap plates will not be required for steel H piles embedded in a reinforced concrete cap.

2. Uplift: Where piles are subject to uplift, they shall be anchored into the cap to resist at least 1-1/2 times the amount of such uplift without exceeding the basic allowable stresses.

3. Reinforcement: Reinforcement shall be placed to provide at least three inches of clear cover, measured to the surface of the pile cap that is in contact with the ground. All reinforcement adjacent to timber or concrete piling shall have a minimum of one inch of concrete protection. Reinforcement shall extend to within four inches of the edges of the pile cap.

4. Design: Except as modified in this subsection, concrete pile caps shall be designed in accordance with the requirements of this subchapter.

(b) Except for short piles as described in subsection (c) of this section, every pile shall be laterally braced to conform with one or more of the following provisions:

1. Rigid cap: Three or more piles connected by a rigid cap shall be considered as being braced provided that the piles are located in radial directions from the centroid of the group not less than 60 degrees apart (within a tolerance of three inches in location of the pile). A two-pile group, in a rigid cap, shall be considered to be braced along the axis connecting the two piles.

2. Brace beams: Piles may be braced by use of brace beams or ties rigidly connecting to at least two other piles in radial directions not less than 60 degrees nor more than 120 degrees apart. Concrete brace beams shall have minimum dimensions of 1/20 of the clear distance between the pile caps, but not less than eight inches. All brace beams shall be proportioned to resist a maximum axial load equal to three percent of the total axial load capacity of the piles that are to be braced by that beam, plus the moment due to any eccentricity between the centroid of the pile group and the line action of the applied load. Where underlain by soil of class 9-65, 10-65 or 11-65, brace beams shall be proportioned to support the weight of soil, slab-on-ground, and live load on the slab-on-ground that is contained within vertical planes projected upward from the lateral limits of the brace beam. The design of brace beams to resist these loads shall conform to the provisions of this subchapter.

3. Concrete slab-on-grade: A continuous concrete slab or mat on grade, that is six inches or more in thickness and reinforced, and that extends at least three bays in each direction and is anchored to the pile caps (or in which the piles are embedded at least three inches), may be used in lieu of brace beams for bracing of pile caps providing that the slab is supported on material having an allowable bearing pressure of 1-11/2 tons per square foot or better and such material is not underlain by nominally unsatisfactory bearing materials.

4. Other means: Piles may be braced by anchors, anchor wall, or other means acceptable to the chief engineer.

5. Floor system: Single-pile or two-pile groups or a single line of piles may be considered to be adequately braced if connected to, and braced by, a self-supporting floor system provided:

i. That the details and dimensions of the floor and the wall or pier are of adequate strength to resist lateral displacement of the pile cap under conditions of maximum eccentricity of the applied load; and

ii. That the wall or pier is braced until connection of the floor framing is made and the flooring (or slab) is in place.

6. Special requirements for bracing batter piles: The provisions of paragraphs 1 to 5 of this subsection shall apply. In addition, provisions shall be made to oppose the lateral thrust resulting from the pile inclination.

(c) Rules concerning bracing of short piles are:

1. All pile caps supported by piles that penetrate less than ten feet below cutoff level or less than ten feet below ground level shall be braced against lateral movement. Such bracing may consist of connection to other pile caps that encompass piles embedded more than ten feet below those levels; the use of suitable anchors, connection to a slab-on-grade or the floor system as described in this section, or by other equivalent means. The heads of the piles shall be fixed in the cap.

2. Where the embedded length of piles located near a lot line would be reduced to less than ten feet by excavation of the adjacent site to a depth of ten feet below the nearest grade, the provisions of paragraph 1 of this subsection shall apply.

N.J. Admin. Code § 19:6-2.37