13-136-020 Exceptions.

   Exceptions to ACI 318-83 – The provisions of ACI 318-83 shall be subject to the following exceptions for purposes of this Code:

   (a)   The requirements contained in ACI 318-83, Sections 1.1.2, 1.2.3, shall not apply. Instead, the applicable provisions of this Code shall apply.

   (b)   The requirements of Section 1.1.4, ACI 318-83, shall be supplemented as follows:

   Tanks, reservoirs and other hydraulic structures shall be designed by using the alternate design method and complying with the provisions of Sections 8.1.2 of ACI 318-83, or by using the strength design recommendations of ACI Committee 350.

   (c)   The requirements of Section 1.3, ACI 318-83, are modified as follows:

   Items b, e, g and h in Section 1.3.2 shall not apply, instead the following shall be substituted and shall apply:

   Since it is the responsibility of the concrete contractor, who shall be licensed in accordance with the provisions of Chapter 4-376 of the Municipal Code of Chicago, to erect, maintain, and provide for properly designed forms and shores; the concrete contractor shall keep a record which shall cover: form placement and removal; reshoring, sequence of erection and connection of pre-cast members; any significant construction loadings on completed floors, members or walls; and general progress of the work.

   (d)   The requirements of Section 1.4, ACI 318-83, shall not apply. Instead, the provisions of the Municipal Code for materials, methods, or systems of construction shall apply.

   (e)   The requirement of Section 5.4.4, ACI 318-83, “unless approved by the engineer” shall not apply.

   (f)   The requirements of Section 10.2.6, ACI 318-71, are supplemented as follows:

   The relationship between concrete compression strength and strain for all members with fc greater than 8,000 p.s.i. shall be based on the provisions of Paragraph 10.2.7, ACI 318-71.

   The requirements of Section 10.2.7, ACI 318-71, are supplemented as follows:

   For the design of columns with fc greater than 8,000 p.s.i., an investigation shall be made to verify the stress-strain relationship of concrete, or design shall be based on a concrete stress distribution which is defined as follows:

   The concrete stress shall be assumed to vary parabolically with strain from zero to a maximum value of 0.85 fc and then to remain constant until the maximum usable strain is reached. The parabola shall have its vertex at stress of 0.85 fc and its slope at zero stress shall not exceed 1,000 fc or ec, whichever is greater. Any other stress distribution, including that defined in Section 10.2.7, ACI 318-71, may be used for fc greater than 8,000 p.s.i. if the results are consistent with those obtained by the use of a verified stress-strain relationship.

   (g)   The requirements of Section 15.6.1, ACI 318-71, are supplemented as follows:

   By adding the following provision to supplement the first sentence thereof:

or by structural steel column bases with vertical reinforcement welded to the bases, including provision for anchor bolts, if required. Column bases shall conform to the requirements of AISC, 1969, specification Section 1.21 – Column-Bases.

   By adding the following provision to supplement the second sentence thereof:

or by anchor bolts per AISC, 1969, specification Section 1.2 – Anchor Bolts.

   The requirements of Section 15.6.2, ACI 318-71, are supplemented as follows:

   By adding the following sentence:

   The permissible stress above or below the contact area shall be computed in accordance with the provisions of ACI 318-71, Sections 10.3.6 and 7.10.5.

   (h)   The requirements of Sections 17.1.1 and 17.1.2, ACI 318-71, are supplemented as follows:

   Composite structural steel-concrete members used as composite flexural members shall be designed by the alternate design method and shall comply with the provisions of Sections 8.1.2 and 8.10.1, and Chapter 7 “Details of Reinforcement”, ACI 318-71, and other applicable requirements and shall be in accordance with the requirements of the following document: Specifications for the Design Fabrication and Erection of Structural Steel for Buildings (AISC, 1969).

   (i)   The requirements of Appendix A – Special Provisions for Seismic Design, ACI 318-71, shall not apply.

(Prior code § 73-1.1; Amend Coun. J. 11-29-89, p. 8413)