Documents

Ch05_Design_Code_and_Commentary_Approved_Version_Revised_13-01-18.pdf

Description
Description:
Categories
Published
of 17
All materials on our website are shared by users. If you have any questions about copyright issues, please report us to resolve them. We are always happy to assist you.
Related Documents
Share
Transcript
   ACI 318-14 Chapter 5 Code & Commentary, Approved Version, Revised 2013-01-18 1 NOTES: This version of Chapter 5 includes the following: 1 1. Approved version of 27 July 2011. 2 2.   Changes approved for ACI 318-11. 3 3.   Technical changes approved under CA 116. 4 4.   Editorial changes approved under CA 115. 5 5.   Commentary as approved on 318 LB 12-4. 6 6.   Technical changes as approved under CA 120. 7 7.   Section renumbering changes to make the chapter consistent. 8 9 CHAPTER 2 (partial) – NOTATION AND TERMINOLOGY 10 11 2.2 – Notation 12 13 f  cm  = measured average compressive strength of concrete, psi 14 15 f  ct  = measured average splitting tensile strength of lightweight concrete, psi 16 17 18 19 CHAPTER 5 — CONCRETE: DESIGN AND DURABILITY 20 REQUIREMENTS 21 22 5.1 — Scope 23 24 5.1.1 —  The provisions of this Chapter shall apply to the design properties and 25 durability requirements for concrete. <~> 26 27 5.2 — Concrete design properties 28 29 5.2.1 -- Specified compressive strength 30 31 5.2.1.1 —  The value of f’ c  shall be specified in contract documents and 32 shall be in accordance with (a), (b), and (c): <1.1.1> <4.1.1> <19.3.1> 33 <21.1.4.2> <21.1.4.3> <22.2.3> <5.1.1> 34 (a) Limits in Table 5.2.1.1; 35 (b) Durability requirements in Table 5.3.2.1; 36 (c) Structural strength requirements. 37 38   ACI 318-14 Chapter 5 Code & Commentary, Approved Version, Revised 2013-01-18 2 Table 5.2.1.1 — Limits for f  c   39  Application Concrete Minimum f  c , psiMaximum f  c , psi   General Normalweight and lightweight 2500 None Special moment frames and special structural walls Normalweight 3000 None Lightweight 3000 5000*   *The limit is permitted to be exceeded where demonstrated by experimental evidence that members made with lightweight concrete provide strength and toughness equal to or exceeding those of comparable members made with normalweight concrete of the same strength. <21.1.4.3> 40 5.2.1.2 — The specified compressive strength shall be used for mixture 41 proportioning in 22.4 and for testing and acceptance of concrete in 22.5. 42 <5.1.1>   43 44 5.2.1.3 — Unless otherwise specified, f  c   shall be based on 28-day tests. If 45 other than 28 days, test age for f  c  shall be indicated in the contract 46 documents. <5.1.3> 47 48 R5.2.1 – Specified compressive strength 49 50 Requirements for concrete mixtures are based on the philosophy that concrete should provide 51  both adequate strength and durability. The Code defines a minimum value of  f   c  for structural 52 concrete. There is no limit on the maximum value of  f   c  except as required by specific Code 53  provisions. <R5.1, Code 1.1.1> 54 55 Concrete mixtures proportioned in accordance with 22.4 should achieve an average compressive 56 strength that exceeds the value of  f   c   used in the structural design calculations. The amount by 57 which the average strength of concrete exceeds  f   c  is based on probabilistic concepts. When 58 concrete is designed to achieve a strength level greater than  f   c , it ensures that the concrete 59 strength tests will have a high probability of meeting the strength acceptance criteria in 22.5. The 60 durability requirements prescribed in Table 5.3.2.1 are to be satisfied in addition to meeting the 61 minimum  f   c of 5.2.1. Under some circumstances, durability requirements may dictate a higher  f   c 62 than that required for structural purposes. <R5.1.1> 63 64   ACI 318-14 Chapter 5 Code & Commentary, Approved Version, Revised 2013-01-18 3 For design of special moment frames and special structural walls used to resist earthquake 65 forces, the Code limits the maximum specified compressive strength of lightweight concrete to 66 5000 psi. This limit is imposed primarily because of a paucity of experimental and field data on 67 the behavior of members made with lightweight concrete subjected to displacement reversals in 68 the nonlinear range. <R21.1.4> 69 70 71 5.2.2 — Modulus of elasticity   72 73 5.2.2.1 — Modulus of elasticity, E c , for concrete shall be permitted to be 74 calculated as (a) or (b). <8.5.1> 75 76 (a) For values of w c   between 90 and 160 lb/ft 3 77 78 E c  = w c 1.5 33 √ f’ c   (in psi) (5.2.2.1.a) 79 80 (b) For normalweight concrete 81 82 E c   = 57,000 √ f’ c (in psi) (5.2.2.1.b) 83 84 R5.2.2 – Modulus of elasticity 85 86 Studies leading to the expression for modulus of elasticity of concrete in 5.2.2 are summarized in 87 Reference 5.1 where  E  c  was defined as the slope of the line drawn from a stress of zero to a 88 compressive stress of 0.45  f’  c . The modulus of elasticity for concrete is sensitive to the modulus 89 of elasticity of aggregate and mixture proportions of the concrete. Measured elastic modulus 90 values can range from 80 to 120 percent of calculated values. ASTM C469 5.2  provides a test 91 method for determining the modulus of elasticity for concrete in compression. <R8.5.1> 92 93 5.2.3 — Modulus of rupture 94 95 5.2.3.1 — Modulus of rupture, f  r  , for concrete shall be calculated by: 96 <9.5.2.3> 97 98 f  r    = 7.5 λ√ f’ c  (5.2.3.1) 99 100 where the value of  λ  is in accordance with 5.2.4. <~> 101 102 5.2.4 — Lightweight concrete 103 104 5.2.4.1 — To account for the properties of lightweight concrete, a 105 modification factor  λ  is used as a multiplier of √ f’ c  in all applicable 106 provisions of this Code. The value of  λ  shall be based on the composition 107 of the aggregate in the concrete mixture in accordance with Table 5.2.4.1 108 or as permitted in 5.2.4.2. <8.6.1> <22.5.6.1> 109   ACI 318-14 Chapter 5 Code & Commentary, Approved Version, Revised 2013-01-18 4 110 111 Table 5.2.4.1 — Modification factor  λ   112 113 Concrete Composition of aggregates  Λ    All-lightweight Fine: ASTM C330 Coarse: ASTM C330 0.75 Lightweight, fine blend Fine: Combination of ASTM C330 and C33 Coarse: ASTM C330 0.75 to 0.85* Sand-lightweight Fine: ASTM C33 Coarse: ASTM C330 0.85 Sand-lightweight, coarse blend Fine: ASTM C33 Coarse: Combination of ASTM C330 and C33 0.85 to 1.00† Normalweight Fine: ASTM C33 Coarse: ASTM C33 1.00 *Linear interpolation from 0.75 to 0.85 is permitted based on the absolute volume of normalweight fine aggregate as a fraction of the total absolute volume of fine aggregate. †Linear interpolation from 0.85 to 1.00 is permitted based on the absolute volume of normalweight coarse aggregate as a fraction of the total absolute volume of coarse aggregate. <8.6.1> 114 115 5.2.4.2 —  If the measured average splitting tensile strength of lightweight 116 concrete, f  ct , is used to calculate  λ , laboratory tests shall be conducted in 117 accordance with ASTM C330 to establish the value of f  ct  and 118 corresponding value of f  cm and  λ  shall be calculated by: <5.1.4> <8.6.1> 119 120 λ  1067  ct' c  f  . . f    (5.2.4.2) 121 122 NOTE: replace  f’  c  with  f   cm  in this equation. 123 124 The concrete mixture tested in order to calculate  λ  shall be representative 125 of that to be used in the work. 126 127 R5.2.4 — Lightweight concrete  128 The modification factor  λ  is used to account for the lower tensile-to-compressive strength ratio of 129 lightweight concrete compared with normalweight concrete. For design using lightweight 130 concrete, shear strength, friction properties, splitting resistance, bond between concrete and 131

tax

Oct 7, 2019
Search
Similar documents
View more...
Tags
Related Search
We Need Your Support
Thank you for visiting our website and your interest in our free products and services. We are nonprofit website to share and download documents. To the running of this website, we need your help to support us.

Thanks to everyone for your continued support.

No, Thanks
SAVE OUR EARTH

We need your sign to support Project to invent "SMART AND CONTROLLABLE REFLECTIVE BALLOONS" to cover the Sun and Save Our Earth.

More details...

Sign Now!

We are very appreciated for your Prompt Action!

x