CHAPTER 2 CODE COMMENTARY Stirrup Reinforcement used to resist shear and torsion stresses in a structural member; typically bars, wires, or welded wire reinforcement either single leg or bent into L, U, or rectangular shapes and located perpendicular to or at an angle to longitudinal rein- forcement. (The term "stirrups"is usually applied to lateral reinforcement in flexural members and the term ties to those in compression members See also Tie Strength, design- Nominal strength multiplied by a strength reduction factor o. See 9.3 Strength, nominal- Strength of a member or cross Strength, nominal- Strength of a member or cross section section calculated in accordance with provisions and calculated using standard assumptions and strength equa- assumptions of the strength design method of this tions, and nominal(specified)values of material strengths code before application of any strength reduction fac- and dimensions is referred to as"nominal strength."The tors, see 9.3 subscript n is used to denote the nominal strengths; nominal axial load strength Pn, nominal moment strength Mn, and nominal shear strength Vn."Design strength"or usable strength of a member or cross section is the nominal strength reduced by the strength reduction factor o The required axial load, moment, and shear strengths used to proportion members are referred to either as factored axial loads. factored moments and factored shears or required axial loads, moments, and shears. The factored load effects are calculated from the applied factored loads nd forces in such load combinations as are stipulated in the code(see 9.2) The subscript u is used only to denote the required strengths; required axial load strength Pu required moment strength Mu and required shear strength Vu, calculated from the applied factored loads and forces The basic requirement for strength design may be expressed as folle Design strength 2 Required strength 中Pn 中Mn≥Ma For additional discussion on the concepts and nomencla ture for strength design see commentary Chapter 9. Strength, required- Strength of a member or cross section required to resist factored loads or related internal moments and forces in such combinations as are stipulated in this code. See 9.1.1 Stress- Intensity of force per unit area licene with Acl oduction of networking permitted without loene from H ACI 318 Building CoNot fos gesaer 12e2oo5 1820415 st
34 CHAPTER 2 CODE COMMENTARY ACI 318 Building Code and Commentary Stirrup — Reinforcement used to resist shear and torsion stresses in a structural member; typically bars, wires, or welded wire reinforcement either single leg or bent into L, U, or rectangular shapes and located perpendicular to or at an angle to longitudinal reinforcement. (The term “stirrups” is usually applied to lateral reinforcement in flexural members and the term ties to those in compression members.) See also Tie. Strength, design — Nominal strength multiplied by a strength reduction factor φ. See 9.3. Strength, nominal — Strength of a member or cross section calculated in accordance with provisions and assumptions of the strength design method of this code before application of any strength reduction factors. See 9.3.1. Strength, nominal — Strength of a member or cross section calculated using standard assumptions and strength equations, and nominal (specified) values of material strengths and dimensions is referred to as “nominal strength.” The subscript n is used to denote the nominal strengths; nominal axial load strength Pn , nominal moment strength Mn, and nominal shear strength Vn. “Design strength” or usable strength of a member or cross section is the nominal strength reduced by the strength reduction factor φ. The required axial load, moment, and shear strengths used to proportion members are referred to either as factored axial loads, factored moments, and factored shears, or required axial loads, moments, and shears. The factored load effects are calculated from the applied factored loads and forces in such load combinations as are stipulated in the code (see 9.2). The subscript u is used only to denote the required strengths; required axial load strength Pu, required moment strength Mu, and required shear strength Vu, calculated from the applied factored loads and forces. The basic requirement for strength design may be expressed as follows: Design strength ≥ Required strength φ Pn ≥ Pu φ Mn ≥ Mu φ Vn ≥ Vu For additional discussion on the concepts and nomenclature for strength design see commentary Chapter 9. Strength, required — Strength of a member or cross section required to resist factored loads or related internal moments and forces in such combinations as are stipulated in this code. See 9.1.1. Stress — Intensity of force per unit area. Copyright American Concrete Institute Provided by IHS under license with ACI Licensee=Black & Veatch/5910842100 No reproduction or networking permitted without license from IHS Not for Resale, 11/28/2005 18:20:15 MST --`,,`,````````,,`,,`,,``,`,,,`-`-`,,`,,`,`,,`---
CHAPTER 2 CODE COMMENTARY Structura/ concrete- All concrete used for structural purposes including plain and reinforced concrete Structural walls- Walls proportioned to resist combi- nations of shears. moments and axial forces induced by earthquake motions. A shearwall is a structural wall Structural walls shall be categorized as follows Intermediate precast structural wall-A wall complying with all applicable requirements of Chap ters 1 through 18 in addition to 21.13 Ordinary reinforced concrete structural wall-A wall complying with the requirements of Chapters 1 through 18 Ordinary structural plain concrete wall-A wall complying with the requirements of Chapter 22 Special precast structural wall-A precast wal complying with the requirements of 21. 8. In addition, he requirements of ordinary reinforced concrete structural walls and the requirements of 21.2 shall Special reinforced concrete structural wall-A cast-in-place wall complying with the requirements of 21.2 and 21.7 in addition to the requirements for ordinary reinforced concrete structural walls Tendon- In pretensioned applications, the tendon is the prestressing steel. In post-tensioned applications, the tendon is a complete assembly consisting of anchorages, prestressing steel, and sheathing with coating for unbonded applications or ducts with grout for bonded applications. Tension-controlled section-A cross section in which the net tensile strain in the extreme tension ste at nominal strength is greater than or equal to 0.005 Tie- Loop of reinforcing bar or wire enclosing longi- tudinal reinforcement. a continuously wound bar or wire in the form of a circle, rectangle, or other polygon shape without re-entrant corners is acceptable. See so Stirrup Transfer- Act of transferring stress in prestressing steel from jacks or pretensioning bed to concrete member Transfer length-Length of embedded pretensioned strand required to transfer the effective prestress to the concrete Unbonded tendon- Tendon in which the prestress ing steel is prevented from bonding to the concrete and licene with Acl o reproducion of networking permitted without loene from H ACI 318 Building Nor censee-Black veatch ot for Resale. 11/28/2005 a
CHAPTER 2 35 CODE COMMENTARY ACI 318 Building Code and Commentary Structural concrete — All concrete used for structural purposes including plain and reinforced concrete. Structural walls — Walls proportioned to resist combinations of shears, moments, and axial forces induced by earthquake motions. A shearwall is a structural wall. Structural walls shall be categorized as follows: Intermediate precast structural wall — A wall complying with all applicable requirements of Chapters 1 through 18 in addition to 21.13. Ordinary reinforced concrete structural wall — A wall complying with the requirements of Chapters 1 through 18. Ordinary structural plain concrete wall — A wall complying with the requirements of Chapter 22. Special precast structural wall — A precast wall complying with the requirements of 21.8. In addition, the requirements of ordinary reinforced concrete structural walls and the requirements of 21.2 shall be satisfied. Special reinforced concrete structural wall — A cast-in-place wall complying with the requirements of 21.2 and 21.7 in addition to the requirements for ordinary reinforced concrete structural walls. Tendon — In pretensioned applications, the tendon is the prestressing steel. In post-tensioned applications, the tendon is a complete assembly consisting of anchorages, prestressing steel, and sheathing with coating for unbonded applications or ducts with grout for bonded applications. Tension-controlled section — A cross section in which the net tensile strain in the extreme tension steel at nominal strength is greater than or equal to 0.005. Tie — Loop of reinforcing bar or wire enclosing longitudinal reinforcement. A continuously wound bar or wire in the form of a circle, rectangle, or other polygon shape without re-entrant corners is acceptable. See also Stirrup. Transfer — Act of transferring stress in prestressing steel from jacks or pretensioning bed to concrete member. Transfer length — Length of embedded pretensioned strand required to transfer the effective prestress to the concrete. Unbonded tendon — Tendon in which the prestressing steel is prevented from bonding to the concrete and Copyright American Concrete Institute Provided by IHS under license with ACI Licensee=Black & Veatch/5910842100 No reproduction or networking permitted without license from IHS Not for Resale, 11/28/2005 18:20:15 MST --`,,`,````````,,`,,`,,``,`,,,`-`-`,,`,,`,`,,`---
CHAPTER 2 CODE COMMENTARY is free to move relative to the concrete. The prestress- ing force is permanently transferred to the concrete at the tendon ends by the anchorages only Wall- Member, usually vertical, used to enclose or Welded wire reinforcement -- Reinforcing elements consisting of plain or deformed wires, conforming to ASTM A 82 or A 496, respectively, fabricated into sheets in accordance with astma 185 or A 497M respectively Wobble friction- In prestressed concrete, friction caused by unintended deviation of prestressing sheath or duct from its specified profile Yield strength- Specified minimum yield strength or yield point of reinforcement. Yield strength or yield point shall be determined in tension according to appli cable ASTM standards as modified by 3. 5 of this code licene with Acl oduction of networking permitted without loene from H ACI 318 Building Co Not fos gesaer 12e2oo5 1820415 st
36 CHAPTER 2 CODE COMMENTARY ACI 318 Building Code and Commentary is free to move relative to the concrete. The prestressing force is permanently transferred to the concrete at the tendon ends by the anchorages only. Wall — Member, usually vertical, used to enclose or separate spaces. Welded wire reinforcement — Reinforcing elements consisting of plain or deformed wires, conforming to ASTM A 82 or A 496, respectively, fabricated into sheets in accordance with ASTM A 185 or A 497M, respectively. Wobble friction — In prestressed concrete, friction caused by unintended deviation of prestressing sheath or duct from its specified profile. Yield strength — Specified minimum yield strength or yield point of reinforcement. Yield strength or yield point shall be determined in tension according to applicable ASTM standards as modified by 3.5 of this code. Copyright American Concrete Institute Provided by IHS under license with ACI Licensee=Black & Veatch/5910842100 No reproduction or networking permitted without license from IHS Not for Resale, 11/28/2005 18:20:15 MST --`,,`,````````,,`,,`,,``,`,,,`-`-`,,`,,`,`,,`---
CHAPTER 3 CHAPTER 3- MATERIALS CODE COMMENTARY 3.1- Tests of materials R3.1-Tests of materials 3.1.1- The building official shall have the right to order testing of any materials used in concrete construction to determine if materials are of quality specified 3.1.2- Tests of materials and of concrete shall be made in accordance with standards listed in 3. 8 3.1.3-A complete record of tests of materials and of R3.1.3-The record of tests of materials and of concrete concrete shall be retained by the inspector for 2 years should be retained for at least 2 years after completion of after completion of the project, and made available for the project Completion of the project is the date at which inspection during the progress of the work he project or when the certificate of occupancy whichever date is later. Local legal requirements may require longer retention of such record 2-Cements R3.2-Cements 3.2.1-Cement shall conform to one of the following specifications :(a)"Standard Specification for Portland Cement" ASTMC 150 (b)"Standard Specification for Blended Hydraulic Cements"(ASTMC 595), excluding Types S and SA which are not intended as principal cementing con- stituents of structural concrete (c)"Standard Specification for Expansive Hydraulie Cement"(ASTMC845): ( d)"Standard Performance Specification for Hydraulic Cement(ASTMC 1157) 3.2.2 -Cement used in the work shall correspond to R3. 2.2-Depending on the circumstances, the provision of that on which selection of concrete proportions was 3.2.2 may require only the same type of cement or may based. see 5.2 require cement from the identical source. The latter would be the case if the sample standard deviation. of strength tests used in establishing the required strength margin wa based on a cement from a particular source. If the sample standard deviation was based on tests involving a given type of cement obtained from several sources the former inter licene with Acl oduction of networking permitted without loene from H ACI 318 Building Nor censee-Black veatch ot for Resale. 11/28/2005 a
CHAPTER 3 37 CODE COMMENTARY ACI 318 Building Code and Commentary 3.2 — Cements 3.2.1 — Cement shall conform to one of the following specifications: (a) “Standard Specification for Portland Cement” (ASTM C 150); (b) “Standard Specification for Blended Hydraulic Cements” (ASTM C 595), excluding Types S and SA which are not intended as principal cementing constituents of structural concrete; (c) “Standard Specification for Expansive Hydraulic Cement” (ASTM C 845); (d) “Standard Performance Specification for Hydraulic Cement” (ASTM C 1157). 3.2.2 — Cement used in the work shall correspond to that on which selection of concrete proportions was based. See 5.2. R3.1.3 — The record of tests of materials and of concrete should be retained for at least 2 years after completion of the project. Completion of the project is the date at which the owner accepts the project or when the certificate of occupancy is issued, whichever date is later. Local legal requirements may require longer retention of such records. R3.2 — Cements CHAPTER 3 — MATERIALS R3.2.2 — Depending on the circumstances, the provision of 3.2.2 may require only the same type of cement or may require cement from the identical source. The latter would be the case if the sample standard deviation3.1 of strength tests used in establishing the required strength margin was based on a cement from a particular source. If the sample standard deviation was based on tests involving a given type of cement obtained from several sources, the former interpretation would apply. 3.1 — Tests of materials R3.1 — Tests of materials 3.1.1 — The building official shall have the right to order testing of any materials used in concrete construction to determine if materials are of quality specified. 3.1.2 — Tests of materials and of concrete shall be made in accordance with standards listed in 3.8. 3.1.3 — A complete record of tests of materials and of concrete shall be retained by the inspector for 2 years after completion of the project, and made available for inspection during the progress of the work. Copyright American Concrete Institute Provided by IHS under license with ACI Licensee=Black & Veatch/5910842100 No reproduction or networking permitted without license from IHS Not for Resale, 11/28/2005 18:20:15 MST --`,,`,````````,,`,,`,,``,`,,,`-`-`,,`,,`,`,,`---
CHAPTER 3 CODE COMMENTARY 33-— Aggregates R33一 Aggregates 3.3.1--Concrete aggregates shall conform to one of R3.3.1- Aggregates conforming to the AsTM specifica the following specifications tions are not always economically available and, in some instances, noncomplying materials have a long history of (a)"Standard Specification for Concrete Aggre- satisfactory performance. Such nonconforming materials gates"(ASTMC 33 are permitted with special approval when acceptable evi- dence of satisfactory performance is provided. Satisfactory (b)"Standard Specification for Lightweight Aggre- performance in the past, however, does not guarantee good gates for Structural Concrete"(ASTM C 330) performance under other conditions and in other localities Whenever possible, aggregates conforming to the desig- xception: Aggregates that have been shown by spe- nated specifications should be used. cial test or actual service to produce concrete of ade- quate strength and durability and approved by the building official 3.3.2- Nominal maximum size of coarse aggregate R3.3.- The size limitations on aggregates are provided to shall be not larger than ensure proper encasement of reinforcement and to minimize oneycombing. Note that the limitations on maximum size (a)1/5 the narrowest dimension between sides of of the aggregate may be waived if, in the judgment of the forms, nor engineer, the workability and methods of consolidation of (b)1/3 the depth of slabs, nor the concrete are such that the concrete can be placed with- ut honeycombs or voids (c)3/4 the minimum clear spacing between individ ual reinforcing bars or wires, bundles of bars, individ lal tendons bundled tendons or ducts These limitations shall not apply if, in the judgment of the engineer, workability and methods of consolidation re such that concrete can be placed without honey combs or voids 4- Water R3. 4- Water 3.4.1- Water used in mixing concrete shall be clean R3. 4.1- Almost any natural water that is drinkable(pota- and free from injurious amounts of oils, acids, alkalis, ble) and has no pronounced taste or odor is satisfactory as alts organic materials, or other substances deleteri- mixing water for making concrete. Impurities in mixing ous to concrete or reinforcement water,when excessive, may affect not only setting time, concrete strength, and volume stability(length change ),but 3.4.2--Mixing water for prestressed concrete or for may also cause efflorescence or corrosion of reinforcement concrete that will contain aluminum embedments, Where possible, water with high concentrations of dissolve including that portion of mixing water contributed in the solids should be avoided form of free moisture on aggregates, shall not contain deleterious amounts of chloride ion see 4.4.1 Salts or other deleterious substances contributed from the aggregate or admixtures are additive to the amount which 3.4.3- Nonpotable water shall not be used in con crete unless the following are satisfied amounts are to be considered in evaluating the acceptability of the total impurities that may be deleterious to concrete or 3.4.3.1- Selection of concrete proportions shall be steel based on concrete mixes using water from the same licene with Acl oduction of networking permitted without loene from H ACI 318 Building Co Not fos gesaer 12e2oo5 18020415 Ms
38 CHAPTER 3 CODE COMMENTARY ACI 318 Building Code and Commentary 3.3 — Aggregates 3.3.1 — Concrete aggregates shall conform to one of the following specifications: (a) “Standard Specification for Concrete Aggregates” (ASTM C 33); (b) “Standard Specification for Lightweight Aggregates for Structural Concrete” (ASTM C 330). Exception: Aggregates that have been shown by special test or actual service to produce concrete of adequate strength and durability and approved by the building official. 3.3.2 — Nominal maximum size of coarse aggregate shall be not larger than: (a) 1/5 the narrowest dimension between sides of forms, nor (b) 1/3 the depth of slabs, nor (c) 3/4 the minimum clear spacing between individual reinforcing bars or wires, bundles of bars, individual tendons, bundled tendons, or ducts. These limitations shall not apply if, in the judgment of the engineer, workability and methods of consolidation are such that concrete can be placed without honeycombs or voids. 3.4 — Water 3.4.1 — Water used in mixing concrete shall be clean and free from injurious amounts of oils, acids, alkalis, salts, organic materials, or other substances deleterious to concrete or reinforcement. 3.4.2 — Mixing water for prestressed concrete or for concrete that will contain aluminum embedments, including that portion of mixing water contributed in the form of free moisture on aggregates, shall not contain deleterious amounts of chloride ion. See 4.4.1. 3.4.3 — Nonpotable water shall not be used in concrete unless the following are satisfied: 3.4.3.1 — Selection of concrete proportions shall be based on concrete mixes using water from the same source. R3.3 — Aggregates R3.3.1 — Aggregates conforming to the ASTM specifications are not always economically available and, in some instances, noncomplying materials have a long history of satisfactory performance. Such nonconforming materials are permitted with special approval when acceptable evidence of satisfactory performance is provided. Satisfactory performance in the past, however, does not guarantee good performance under other conditions and in other localities. Whenever possible, aggregates conforming to the designated specifications should be used. R3.3.2 — The size limitations on aggregates are provided to ensure proper encasement of reinforcement and to minimize honeycombing. Note that the limitations on maximum size of the aggregate may be waived if, in the judgment of the engineer, the workability and methods of consolidation of the concrete are such that the concrete can be placed without honeycombs or voids. R3.4 — Water R3.4.1 — Almost any natural water that is drinkable (potable) and has no pronounced taste or odor is satisfactory as mixing water for making concrete. Impurities in mixing water, when excessive, may affect not only setting time, concrete strength, and volume stability (length change), but may also cause efflorescence or corrosion of reinforcement. Where possible, water with high concentrations of dissolved solids should be avoided. Salts or other deleterious substances contributed from the aggregate or admixtures are additive to the amount which might be contained in the mixing water. These additional amounts are to be considered in evaluating the acceptability of the total impurities that may be deleterious to concrete or steel. Copyright American Concrete Institute Provided by IHS under license with ACI Licensee=Black & Veatch/5910842100 No reproduction or networking permitted without license from IHS Not for Resale, 11/28/2005 18:20:15 MST --`,,`,````````,,`,,`,,``,`,,,`-`-`,,`,,`,`,,`---