1908.1.9 ACI 318, Section 18.11.

Modify ACI 318, Section 18.11.2 to read as follows:

18.11.2.1 – Special structural walls constructed using precast concrete shall satisfy all the requirements of Section 18.10 for cast-in-place special structural walls in addition to Section 18.5.2.

1908.1.10 ACI 318, Section 18.13.1.1.

Modify ACI 318, Section 18.13.1.1, to read as follows:

18.13.1.1 – Foundations resisting earthquake-induced forces or transferring earthquake-induced forces between a structure and ground shall comply with the requirements of Section 18.13 and other applicable provisions of ACI 318 unless modified by Chapter 18 of the New York City Building Code.

1908.1.11 ACI 318, Section 24.2.3.5.

Add the following to Section 24.2.3.5:

When calculating M a , consideration shall be given to loads imposed during construction.

Section BC 1909: Structural Plain Concrete

1909.1 Scope.

The design and construction of structural plain concrete, both cast-in-place and precast, shall comply with the minimum requirements of ACI 318, as modified by Section 1908 of this chapter.

   Exception: For Group R-3 occupancies and buildings of other occupancies less than two stories above grade plane of light-frame construction, the required footing thickness of ACI 318 is permitted to be reduced to 6 inches (152 mm), provided that the footing does not extend more than 4 inches (102 mm) on either side of the supported wall.

Section BC 1910: Minimum Slab Provisions

1910.1 General.

The thickness of concrete floor slabs supported directly on the ground shall not be less than 3 1/2 inches (89 mm). A 6-mil (0.006 inch; 0.15 mm) polyethylene vapor retarder with joints lapped not less than 6 inches (152 mm) shall be placed between the base course or subgrade and the concrete floor slab, or other approved equivalent methods or materials shall be used to retard vapor transmission through the floor slab.

   Exception: A vapor retarder is not required:

      1.   For detached structures accessory to occupancies in Group R-3, such as garages, utility buildings or other unheated facilities.

      2.   For unheated storage rooms having an area of less than 70 square feet (6.5 m 2 ) and carports attached to occupancies in Group R-3.

      3.   For buildings of other occupancies where migration of moisture through the slab from below will not be detrimental to the intended occupancy of the building.

      4.   For drive ways, walks, patios and other flat work that will not be enclosed at a later date.

      5.   Where approved based on local site conditions.