Chapter 19 — CONCRETE

(Matrix Adoption Tables are nonregulatory, intended only as an aid to the code user.

See Chapter 1 for state agency authority and building applications.)

Adopting agency	BSC	BSC- CG	SFM	HCD			DSA			OSHPD						BSCC	DPH	AGR	DWR	CEC	CA	SL	SLC
Adopting agency	BSC	BSC- CG	SFM	1	2	1/AC	AC	SS	SS/CC	1	1R	2	3	4	5	5	5	5	5	5	5	5	5
Adopt entire chapter
Adopt entire chapter as amended (amended sections listed below)	X			X	X				X		X	X			X
Adopt only those sections that are listed below
Chapter / Section
1901.1.1									X		X	X			X
1901.1.2									X		X	X			X
1901.1.3									X		X	X			X
1901.1.4									X		X	X			X
1901.3.1											X	X			X
1901.3.2											X	X			X
1901.3.3											X	X			X
1901.3.4											X	X			X
1901.3.4.2											X	X			X
1903.2											X	X			X
1903.4											X	X			X
1903.5											X	X			X
1903.7											X	X			X
1903.8											X	X			X
1905.1.2	X
1905.1.3	X
1905.1.8	X
1906											X	X			X
1907.1.1				X
1908.1											X	X			X
1908.3											X	X			X
1908.5											X	X			X
1908.7											X	X			X
1908.9											X	X			X
1908.10.2											X	X			X
1908.11											X	X			X
1908.12											X	X			X
1909									X
1910											X	X			X
1911											X	X			X

The state agency does not adopt sections identified with the following symbol: The Office of the State Fire Marshal’s adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.

Copyright © 2019 ICC. ALL RIGHTS RESERVED. Accessed by Kevin Day (kevin.day@dgs.ca.gov), (California Building Standards Commission) Order Number #100735044 on Jul 24, 2019 03:54 PM (PDT) pursuant to License Agreement with ICC. No further reproduction or distribution authorized. Single user only, copying and networking prohibited. ANY UNAUTHORIZED REPRODUCTION OR DISTRIBUTION IS A VIOLATION OF THE FEDERAL COPYRIGHT ACT AND THE LICENSE AGREEMENT, AND SUBJECT TO CIVIL AND CRIMINAL PENALTIES THEREUNDER.

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212 2019 CALIFORNIA BUILDING CODE Copyright © 2019 ICC. ALL RIGHTS RESERVED. Accessed by Kevin Day (kevin.day@dgs.ca.gov), (California Building Standards Commission) Order Number #100735044 on Jul 24, 2019 03:54 PM (PDT) pursuant to License Agreement with ICC. No further reproduction or distribution authorized. Single user only, copying and networking prohibited. ANY UNAUTHORIZED REPRODUCTION OR DISTRIBUTION IS A VIOLATION OF THE FEDERAL COPYRIGHT ACT AND THE LICENSE AGREEMENT, AND SUBJECT TO CIVIL AND CRIMINAL PENALTIES THEREUNDER.

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CHAPTER 19

CONCRETE

Italics are used for text within Sections 1903 through 1905 of this code to indicate provisions that differ from ACI 318.

User notes:

About this chapter: Chapter 19 provides minimum accepted practices for the design and construction of buildings and structural compo- nents using concrete—both plain and reinforced. Chapter 19 relies primarily on the reference to American Concrete Institute (ACI) 318, Build- ing Code Requirements for Structural Concrete. Structural concrete must be designed and constructed to comply with this code and all listed standards. There are also specific provisions addressing concrete slabs and shotcrete.

Code development reminder: Code change proposals to this chapter will be considered by the IBC—Structural Code Development Commit- tee during the 2019 (Group B) Code Development Cycle. See explanation on page ix.

1908.4 Reinforcement.¶

Reinforcement used in shotcrete construction shall comply with the provisions of Sections 1908.4.1 through 1908.4.4.

1908.4.1 Size. The maximum size of reinforcement shall be No. 5 bars unless it is demonstrated by preconstruction tests that adequate encasement of larger bars will be achieved.

1908.4.2 Clearance. Where No. 5 or smaller bars are used, there shall be a minimum clearance between parallel reinforcement bars of 2 ¹ /2 inches (64 mm). When bars larger than No. 5 are permitted, there shall be a minimum clearance between parallel bars equal to six diameters of the bars used. Where two curtains of steel are provided, the curtain nearer the nozzle shall have a minimum spacing equal to 12 bar diameters and the remaining curtain shall have a minimum spacing of six bar diameters.

Exception: Subject to the approval of the building official, required clearances shall be reduced where it is demonstrated by preconstruction tests that adequate encasement of the bars used in the design will be achieved.

1908.4.3 Splices. Lap splices of reinforcing bars shall utilize the noncontact lap splice method with a minimum clearance of 2 inches (51 mm) between bars. The use of contact lap splices necessary for support of the reinforcing is permitted where approved by the building official, based on satisfactory preconstruction tests that show that adequate encasement of the bars will be achieved, and provided that the splice is oriented so that a plane through the center of the spliced bars is perpendicular to the surface of the shotcrete.

1908.4.4 Spirally tied columns. Shotcrete shall not be applied to spirally tied columns.

1908.5 Preconstruction tests.¶

Where preconstruction tests are required by Section 1908.4, a test panel shall be shot, cured, cored or sawn, examined and tested prior to commencement of the project. [OSHPD 1R, 2 & 5] a precon- struction test panel shall be shot, cured, cored or sawn, examined and tested prior to commencement of the project for all shotcrete work. The sample panel shall be representative of the project and simulate job conditions as closely as possible. The panel thickness and reinforcing shall reproduce the thickest and most congested area specified in the structural design. It shall be shot at the same angle, using the same nozzleman and with the same concrete mix design that will be used on the project. The equipment used in preconstruction testing shall be the same equipment used in the work requiring such testing, unless substitute equipment is approved by the building official. Reports of preconstruction tests shall be submitted to the building official as specified in Section 1704.5.

1908.6 Rebound.¶

Any rebound or accumulated loose aggregate shall be removed from the surfaces to be covered prior to placing the initial or any succeeding layers of shotcrete. Rebound shall not be used as aggregate.

11.9 -¶

Foundation walls. Horizontal reinforcing of concrete foundation walls for wood-frame or light-steel buildings shall consist of the equivalent of not less than one No. 5 bar located at the top and bottom of the wall. Where such walls exceed 3 feet (914 mm) in height, intermediate horizontal reinforcing shall be provided at spacing not to exceed 2 feet (610 mm) on center. Minimum vertical reinforcing shall consist of No. 3 bars at 24 inches (610 mm) on center.

Where concrete foundation walls or curbs extend above the floor line and support wood-frame or light- steel exterior, bearing or shear walls, they shall be doweled to the foundation wall below with a minimum of No. 3 bars at 24 inches (610 mm) on center. Where the height of the wall above the floor line exceeds 18 inches (457 mm), the wall above and below the floor

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line shall meet the requirements of ACI 318 Section 11.6 and 11.7.

1909.3.2 ACI 318, Section 12.7.3. Add Section 12.7.3.4 to ACI 318 as follows:

12.7.3.4 – At least two No. 5 bars in diaphragms having two layers of reinforcement in both directions and one No. 5 bar in diaphragms having a single layer of rein- forcement in both directions shall be provided around openings larger than 12 inches in any dimension in addition to the minimum reinforcement required by Section 12.6.

1909.3.3 ACI 318, Chapter 14. Plain concrete is not per- mitted.

1909.3.4 ACI 318, Section 18.10.6.5. Modify ACI 318, Section 18.10.6.5 by adding the following:

Where boundary members are not required by ACI 318 Section 18.10.6.2 or 18.10.6.3, minimum reinforcement parallel to the edges of all structural walls and the boundaries of all openings shall consist of twice the cross-sectional area of the minimum shear reinforce- ment required per lineal foot of wall. Horizontal extent of boundary element shall be per ACI 318 Section 18.10.6.4 (a), (b) and (c).

1909.3.5 ACI 318, Section 18.12.6. Add Section 18.12.6.2 to ACI 318 as follows:

Collector and boundary elements in topping slabs placed over precast floor and roof elements shall not be less than 3 inches (76 mm) or 6 db thick, where db is the diameter of the largest reinforcement in the topping slab.

1909.3.6 ACI 318, Table 21.2.2. Replace Table 21.2.2 as follows:

TABLE 21.2.2 STRENGTH REDUCTION FACTOR φ FOR MOMENT, AXIAL FORCE, OR COMBINED MOMENT AND AXIAL FORCE

CONCRETE

pressive strength tests shall be taken for each class of concrete at the beginning of the concrete work or whenever the mix or aggregate is changed.

1909.4 Shotcrete.¶

1909.4.1 General. Shotcrete shall also conform to the pro- visions of ACI 506.2. The specified compressive strength of shotcrete shall not be less than 4,000 psi (27.6 MPa).

1909.4.2 Preconstruction tests. A test panel prepared in accordance with Section 1908.5 is required. Approval from the enforcement agency must be obtained prior to performing test panels.

1909.4.3 Aggregate. For structural walls, when total rebar in any direction is more than 0.31 in ² /ft. or rebar size is larger than No. 5, shotcrete shall conform to course aggregate grading No. 2 in accordance with Table 1.1.1 of ACI 506R.

1909.4.4 Surface preparation. Concrete or masonry to receive shotcrete shall have the entire surface thoroughly cleaned and roughened by a suitable method, and just prior to receiving shotcrete shall be thoroughly cleaned of all debris, dirt and dust. Concrete and masonry shall be wetted before shotcrete is deposited, but not so wet as to overcome suction.

1909.4.5 Joints. The film of laitance which forms on the surface of the shotcrete shall be removed within approxi- mately two hours after application by brushing with a stiff broom. If this film is not removed within two hours, it shall be removed by thorough wire brushing or sand blasting. Construction joints over eight hours old shall be thor- oughly cleaned with air and water prior to receiving shot- crete.

1909.4.6 Curing. Shotcrete shall be maintained above 50°F (10°C) during the curing periods specified in Section 1908.9.

1909.4.7 Forms and ground wires for shotcrete. Forms for shotcrete shall be substantial and rigid. Forms shall be built and placed so as to permit the escape of air and rebound.

Adequate ground wires, which are to be used as screeds, shall be placed to establish the thickness, surface planes and form of the shotcrete work. All surfaces shall be rodded to these wires.

1909.4.8 Placing. Shotcrete shall be placed in accordance with ACI 506.2 and ACI 506R. In addition to testing requirements in Section 1908, special inspection and test- ing shall be in accordance with Section 1705A.19.

1909.5 Existing concrete structures.¶

The structural use of existing concrete with a core strength less than 1,500 psi (10.3MPa) is not permitted in rehabilitation work.

For existing concrete structures, sufficient cores shall be taken at representative locations throughout the structure, as designated by the architect or structural engineer, so that knowledge will be had of the in-place strength of the con- crete. At least three cores shall be taken from each building for each 4,000 square feet (372 m ² ) of floor area, or fraction thereof. Cores shall be at least 4 inches (102 mm) in diame-

NET TENSILE STRAIN ε t	CLASSIFICATION	φ
NET TENSILE STRAINεt	CLASSIFICATION	Type of transverse reinforcement	Type of transverse reinforcement	Type of transverse reinforcement	Type of transverse reinforcement
NET TENSILE STRAINεt	CLASSIFICATION	Spirals conforming to 25.7.3	Spirals conforming to 25.7.3	Other	Other
εt ≤ εty	Compression- controlled	0.75	(a)	0.65	(b)
εty <εt < 0.005	Transition1,2	0.75 0.15 ε_t_ ε_ty_ – ε_t_ ε_ty_ – ----------------- + *	(c)	0.65 0.25 ε_t_ ε_ty_ – ε_t_ ε_ty_ – ----------------- + *	(d)
εt ≥ 0.005	Tension- controlled_3_	0.9	(e)	0.9	(f)

For sections classified as transition, it shall be permitted to use φ corresponding to compression-controlled sections. 2. ε t* is the greater of net tensile strain calculated for Pn = 0.1Agf ′ c and 0.005. 3. For sections with factored axial compression force Pu ≥ 0.1Agf ′ c, φ shall be calculated using equation (c) or (d) for sections classified as transition, as applicable.

1909.3.7 ACI 318, Section 26.12.2.1(a). Replace ACI 318 Section 26.12.2.1(a) by the following:

26.12.2.1(a) - Samples for strength tests of each class of concrete placed each day shall be taken not less than once a day, or not less than once for each 50 cubic yards (38.2 m ³ ) of concrete, or not less than once for each 2,000 square feet (186 m ² ) of surface area for slabs or walls. Additional samples for seven-day com-

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CONCRETE

ter. Cores as small as 2.75 inches (70 mm) in diameter may be allowed by the enforcement agency when reinforcement is closely spaced and the coarse aggregate does not exceed ³ /4 inch (19 mm).

1911.2 Crack repair by epoxy injection.¶

Crack Repair of concrete and masonry member by epoxy injection shall con- form to all requirements of ACI 503.7.

1911.3 Concrete strengthening by externally bonded fiber reinforced polymer (FRP).¶

reinforced polymer (FRP). Design and construction of exter- nally bonded FRP systems for strengthening concrete struc- tures shall be in accordance with ACI 440.2R.

Exceptions:

1. Near-Surface Mounted (NSM) FRP bars shall not be permitted.

2. Strengthening of shear walls and diaphragms (including chords and collectors) shall be consid- ered as an alternative system.

Design capacities, reliability and serviceability of FRP materials shall be permitted to be established in accordance with ICC-ES AC 125. Minimum inspection requirements of FRP composite systems shall be in accordance with ICC-ES AC 178.

NET TENSILE STRAIN ε t	CLASSIFICATION	φ
*NET TENSILE* STRAINεt	*CLASSIFICATION*	*Type of transverse reinforcement*	*Type of transverse reinforcement*	*Type of transverse reinforcement*	*Type of transverse reinforcement*
*NET TENSILE* STRAINεt	*CLASSIFICATION*	*Spirals conforming* *to 25.7.3*	*Spirals conforming* *to 25.7.3*	*Other*	*Other*
ε_t ≤ ε_ty	Compression- controlled	0.75	(a)	0.65	(b)
ε_ty <ε_t < 0.005	Transition1, 2	0.75 0.15 ε_t_ ε_ty_ – ε_t_ ε_ty_ – ----------------- + *	(c)	0.65 0.25 ε_t_ ε_ty_ – ε_t_ ε_ty_ – ----------------- + *	(d)
ε_t _≥ 0.005	Tension- controlled3	0.9	(e)	0.9	(f)

1. For sections classified as transition, it shall be permitted to use φ corresponding to compression-controlled sections. 2. ε t* is the greater of net tensile strain calculated for Pn = 0.1Ag f ′ c and 0.005. 3. For sections with factored axial compression force Pu ≥ 0.1Ag f ′ c , φ shall be calculated using equation (c) or (d) for sections classified as transition, as applicable.