ACI 314R-11 Guide to Simplified Design for Reinforced Concrete Builidings PDF

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Guide to Simplified Design Buildin

(For Buildings of Limited Size and Height,

“Essential Requirements for Reinf

Reported by ACI C JoAnn Browning,* Chair Kenneth B. Bondy Iyad M. Alsamsam

James R. Cagley Lila Gabriela Mendez Florez D. Cardona JaveedOmar Munshi W. Muste Gene Corley T. George Om P. Dixit David A. Fanella Santiago Pujol Yosef Farbiarz Luis E. García* Jose M. Izquierdo-Encarnación† E. Kamara Jorge I.H.Mahmoud Segura Rolfe Jennings James JasonS.J.Lai Krohn Lionel A. Lemay Andres Lepage Robert F. Mast Adolfo B. Matamoros

ICONTEC and AIS. The initial drafting of ACI IPS-1 (2002) was motivated by frequent worldwide discussions that reinforced concrete codes might be unnecessarily sophisticated for some applications, such as small, low-rise buildings. Current knowledge

Sergio Shuaib John E Juan P John C

comm on reinforced concrete behavior obtained through experimentation and experience, and its status and dissemination as a structural material used worldwide, made developing a simplified design and construction guide feasible. This guide used ACI IPS-1 (2002) as a basis, with information derived from the following: ACI 318-11, ASCE 7-10, and IBC 2009. This guide presents simplified approaches to assist engineers in designing low-rise buildings within certain limitations. This guide is a design aid and educational tool, but not a code. It does not fully satisfy the requirements of ACI 318-11, ASCE 7-10, and IBC 2009. There are many options within these standards that are not considered in this guide, such as the use of supplementary cementitious materials in concrete mixtures. It is the licensed design professional’s requirements of the local jurisdiction. This guide provides simplified design information that is interdependent, and aa user shoulddesign not employ only responsibility to ensure structure’s satisfies the alegal portion of this guide and disregard the remainder. This guide

David Bilal H Neil M Werne Kennet James James Dov K Richar Leslie Jack P Vilas S James Basile Julio A Mete A Richar James Min-H *

FOREWORD provides adequate design information when used as a whole and for Guide structures within its scope. Itis isderived unsafefrom: to use only information presented selected 1.sections of Code this Requirements guide or forfor structures its 2 “Building Structuraloutside Concrete Many 2.of “Minimum the tables, charts, values in this Designand Loads forincluded Buildings and Other (ACI scope. guide are drawn from information in the reference standards, Struc but are modified or reorganized to be more conservative, to Engin (2002 match design process flow or better support the holistic 3 “International Building Code (IBC 2009) ” by the Inter-J S

CONTENTS C

be

Chapter 3—Structural system layout, p. 15 Chapter 2—Notation and definitions, p. 8

gi

Chapter 4—Loads, p. 17

w be

C commonly available steel grades and medium-strength concrete that can be site mixed. Foreword, p. 2 Preface, p. 2 Chapter 1 General p 4

8. re 8. 8. C 8.

in most 12.6—Shear cases, more detailed procedures prescribed in the

This guide is intended for the planning, design, and 12.8—Core walls 1.2—Purpose floor finish to floor finish, should not exceed 13 ft (4 m). rise buildings of restricted occupancy, number of stories,

10.7—

Chap

11.2—Interaction elementsstructo produce, when properly with used,nonstructural a reinforced concrete

guide provides a licensed design professional with theThe guide to attain the intended margin of safety, the guide 12.2—Loads supporting codes and standards listed inat1.4 . 12.7—Calculation of reactions foundation a low-rise building with the limits set in 1.3. Design rules

Chap

set forth in this guide are simplifications that, when used reference14.2—Allowable standards listed soil-bearing in 1.4. capacity 14.3—Settlement criteria 1.3—Limitations 14.4— Dimensioning foundation members 13.2—Small water tanks (for water storage) concrete members that comprise the potable structural framing of

Chap

This guide 14.5—Spread is only footings meant for buildings meeting all the limitations 14.6—Wall set forth footings in 1.3.1 to 1.3.10. 14.8—Piles and caissons to the collective experience of the original drafting committee

14.9—Footings on piles (ICONTEC-AIS). Buildings within this scope are expected to have a14.10—Foundation normal rectangularmats footprint with simple standard 4

10.4— 14.11—Retaining walls geometries and member dimensions in both plan and vertical 14.12—Grade beams (foundation beams) directions. Such buildings also depend primarily on reinCHAPT 10.5— 14.13—Slabs-on-ground forced concrete structural walls for lateral load resistance. details for was seismic zones and area.11.1—Special Although thereinforcement information presented developed ture with an appropriate margin safety, guide and is not Observing these limits justi fies theof simpli fiedthis analysis Chap

spans should be at least 80 percent of the larger span, except F-2

Heavy industries using heavy m

G r o health hazard

N

O miscellaneous

stage YES

R-1 Hotels having an assembly room with c R-2 Apartment buildings and dormitories R-3 Houses

YES

R-4 Residential care and assisted-living fac S-2 Storage of light materials

merican Concrete Institute Copyrighted Material—www.concrete.o

beams, and slab-column systems, measured center-to-center

of the supports, should not exceed 30 ft (10 m). two-story buildings if the span length does not exceed 15 ft (5 m).

A-1 Fixed-seating theaters, television, and A

2

1

F

all str

quality products. 6 and 8 H

J

11 and 12

IDesign of the stairways, ramps, small potable

D

LThe structure is built complying with merican Concrete Institute Copyrighted Material—www.concrete.o KProduction of the structural drawings

at all sections at least equal to the demands calculated for the combinations of factored loads described in Chapter 4. chapter

S AVerification that the limitations for us

6, 7, and 9 Related

(a) General structural program, as defined in Chapter 3;

(b) Description of the system; be furnished and included asstructural part of the structural drawings

6 GIf lateral load, such as earthquake, wind, or lateral earth pressure, is beyond

member becomes unfit for service and is judged to be unsafe

shoul

or no longer useful for its intended function. The designer

perfo

11

RS

2 2

n

(1.8.1b)

in be a se

merican Concrete Institute Copyrighted Material—www.concrete.o

no φ. ul cr

where the required strength is U = γ1S1 + γ2S2 + ... Flexure, without .............................. axial load sh Axial tension and axial tension Axial compression and axial c Columns with ties and reinf

Columns with spiral reinforc

awd=ist

(a) Long-term environmental effects, including exposure ds

o=utside diameter of spiral reinforcement, in. (mm) (b) Dimensional changes due to variations in temperature, (c) Excessive cracking of the concrete;

D

d=ead loads or related internal moments and loads

dcdistance = from extreme tension fiber to centroid of e

y

Aae=ffe

Ab=are =eccentricity, measured in y-direc As u Ava=rea

eHe=ccentricity of resultant applied to footing in e Be =ccentricity of resultant applied to footing in E=seismic loads or related internal moments and loads E = odulus concrete, psi for (MPa) b cm o of perimeter =elasticityofofcritical section two-way shear fbBcw′= strength concrete, psi f s=hort horizontal footing, w = ebspecified width of compressive section, or dimension wall width,ofof in. (mm) in. (mm)

b= widt bcw = id bfw = id 8

recom cc c′ =square root of = least distance from surface of of reinforcement √f specified compressive strength C s u w = ind surface pressure coefficient Cp = component, or cladding, wind surface pressure Cvx = coefficient defined in 4.11.4 for design of seismic and c relativ fcr ′=required (d) Excessive deflections; and of concrete average vertical compressive strength

M M h overall = depth or thickness of member, or height of Fsection ui,Fux = factored lateral force applied to wall at level i or x of member, or outside diameter of circular M section, in. or ft (mm or m) M M hb vertical = distance measured from bottom of M fa supporting girder to bottom of supported beam, ft g acceleration = due to gravity, 386 in./s2 ( 9 M (m) hc =depth of column, or dimension of column in M direction parallel to girder span, and for punching M shear evaluation the largest plan dimension of capital, drop panel, pedestal, or thickness change in stepped footings, in. (mm) hf= flange thickness, in. (mm) hg t=otal depth of supporting girder, in. (mm) hi, hx height = above base to level i or x , respectively merican Concrete Institutedistance Copyrighted Material—www.concrete.o h n clear = vertical between lateral supports of ncn

lb (kN) Ko a=t-rest soil pressure coefficient Fs u equivalent = static wind force acting normal to windKp passive = soil pressure coefficient

N

ss =spacing = of transverse samplereinforcement, standard deviation, stirrups, psi (MPa) or ss k s=pacing of skin reinforcement, in. (mm) su=shear strength of undrained cohesive soil, lb/ft2

S= snow load or related internal moments and loads Sa v=alue of elastic acceleration design response

Pc p Pdu=nf Plu=nfa Pnnom =

Pn(max Pon =

Sin=ominal load effect based on load i S D S value = of design earthquake spectral acceleration

Pov =m

tx , ty

Ptnnom =

structural = vertical member cross-sectional

T= cumulative effect of temperature, creep, shrinkage,

Ptufac =

Ti, Tx unfactored = story torsional moment due to lateral

Vcn=ominal shear strength provided by concrete, lb (N)

ql 10

Vi, Vx =unfactored story shear due to lateral loads at story i qo R ubf=asic actored reaction structural puw f=a V= wind speed,from mph,supported corresponding to 3-second sVj bs s=eismic c=enter-to-center spacing design base shear,between lb (kN) parallel joists, in. Viu,Vxu = factored story shear due to lateral loads at story i or

¯ ,γx u=nit y weight ¯ s=toryof lateral stiffness center material or soil, lb/ftcoordinates 3 (kN/m3) in (4.11.3.3) directly to the member, lb/ft (kN/m) W= lb/ft wind(kN/m) loads or related internal moments and loads z s d=epth of building soil, ft (m) W t=otal weight for seismic design, lb (kN) αa=fraction of load acting in short direction in two-way ΔM u = factored unbalanced moment at column-girder joint

ΣM ρv ΣM ΣP φ s=

ΔM u-ad = additional factored unbalanced moment at column- ΣR or wall-girder joint, lb·in. (N·mm) 2. te Wslabs-on-girders u =total factored uniformly distributed design loa βdirections =ratio xof clearand spans in long toin.short y, respectively, (mm) direction of hy αfp=arameter of Eq. (5.11.4.2) an ad merican Concrete Institute Copyrighted Material—www.concrete.o

slabs-on-girders

cr di ce m

reinforcement

de

two-way slabs da us βf ratio = of long side to short side of footing wdf =unfactored dead load per unit member length applied directly to the member, lb/ft (kN/m)

wh agrt ρ φsa

essential facilities—buildings and other structures depth of member, h—distance in a flexural member, bindin essent hydro column—member with a firatio of extreme height-to-least lateral measured from extreme compression ber to the dimen and c tension fiber. comp designcollector load combinations—combinations element—element that actsof infactored axial tension or partic loads and loads. comp a stru forceconcrete—mixture portland cement and any other effective depth of section,of d—distance measured hydra design method, strength—a method of member proporwater concrete mixture proportioning—the proportions of ingred tioning based on ensuring that the design strength obtained able m tudina necessary bracing. prope concrete, specified compressive strength of, f by reducing the nominal strength is larger than the required strength obtained by applying load factors to service loads. from extreme compression fiber to centroid of tension required to develop the design of strength of reinforcement development length—length embedded reinforcementat a critical section. development for athebar with asection standard hook— shortest distancelength between critical (where the reinforcement. strength of the bar is to be developed) and a tangent 12 to th eleme outer edge of the 90- or 180-degree hook. in elevation of differential settlement—the lowering bending under normal loads, such as the horizontal portiontions, of the of a verify of the cross section of a simple span T-beam.

m

of (w

gration and abrasion of rock or processing of weakly bound conglomerate; and a slab-like shape with or without depressions or openings. a

main

structural

member

often

supporting

m react or

consisting of a continuous concrete slab, placed over native (4.75 mm) sieve and resulting either from natural disinteconglomerate.

ra fa pr sp

elements and content that cause the dead and live loads. tion and abrasion of rock or processing of weakly boundstr tie can be made up of several reinforcement elements each having seismic hooks at both ends. A continuously wound

concrete structure, usually a vertical plane, at a designed location such as to interfere least with performance of the strucfib ture, yet such as to allow relative movement in three direc- be t i o n s re beam,through usuallywhich at ground stiffens thelim and all orlevel, part that of strengthens the bonded orreinforcement lo other beams or girders. See also beam. interrupted.

seismic hook—a hook on a stirrup, or crosstie having a

tensil

and loads in specified load combinations. specifi shall have a bend not less than 90 degrees. Hooks shall have 1.6.3. a 6d b (but not less than 3that, in. [75 mm]) that enga project drawings—drawings along withextension the project sand— plain reinforcement—reinforcement without surface and almost entirely passing the No. 4 (4.75 mm) sieve and

the ap

the2.longitudinal andpassing projectsthe intoNo. the4interior That portionreinforcement of an aggregate (4.75 mm) bend not less than 135 degrees, except that circular hoops the material that composes the member.

specifi where concr requir

service load—all loads, static or transitory, imposed on a param (withoutreinforced load factors). concrete—structural concrete reinforced with settlement—downward movement of the supporting soil. no les shear—an internal force tangential the documents planecaused onnwhich r eof the ito member, f self-weight—weight structural by specify project specifications—written that it acts. shear reinforcement—reinforcement designed to resist shell concrete—concrete outside the transverse reinforce-

reinfo prestr concr

ment conreinforcement—deformed fining the concrete core. steel bars, wire, or wire mesh, shores—vertical or inclined support members designed to embe 14

carry thestructural weight of the formwork, a given function, or both. concrete, and construction piles. concr loads above. reinforcement, compression—reinforcement designed shrinkage and temperature reinforcement—reinforcerequired strength—strength of a member cross plain concrete—structural concreteorwith nosection reinforce- to car 1. Granular material passing the 3/8 in. (9.5 mm) sieve defor ment provided to resist shrinkage stresses positive reinforcement—steel reinforcement to resist reinforcement, deformed—metal wire, or fabric predominantly retained on the No.and 200temperature (75 bars, μm) sieve, and

stresses in a structural member; typically bars, wires, or

scope of work, materials to be used, method of installation, bent into L, U, or rectangular shapes and located perpendicular to or at an angle to longitudinal reinforcement. The

co sh A sp

force, for seismic-resistant design.

co

term “stirrups” is lateral usuallydimensions applied to than lateral in pa concrete, larger in the reinforcement column or yi welded wire fabric (plain or deformed) either single leg or

calculated in accordance with provisions and assumptions of See also tie.

as th de ca 3.

the strength design method of this guide before application of any strength reduction factors. in structural design; a number less than 1.0 by which the

be by sy

story to the floor finish of the story below. strength reduction factor φ.

do nominal strength of a structural member or element in terms m of load, moment, shear, or stress is required to be multiplie to determine design strength capacity. horizontal structural member or such as a slab, joist, beam, or

w f

girder, measured center-to-center of support. sponding to the appropriate distribution of the base shear design of members of a structure and based on a factor of

wh in

(4) Use of internal spaces of the building, its subdivision,

3.2.1 Architectural program—A general architectural (5) Minimum architectural clear height in all floors; (6) Location and dimensions of stairways, ramps, and licens follow

(3) Type of roof, its shape and slopes, the type of eleva wate and m (8) Locations of ducts and shafts for utilities such as powe detec (9) Architectural features that may reduce effective concr tectur 3.2.2 Structural program—Based on the general architectural being

follow (1) Intended use of the building; 16

(2) Nominal loads related to the use of the building; Fig. (16) 3.3.1—General General (3) Special and loads local structural sustainable defined layout by the construction in plan. owner; practices. Fig. 3.3.2—Typical (4) Design floor seismic structural loads, layout. if the building is located 3.3—Structural layout and dimensions of all building floors; (1) Plan geometry

ramp in a begin seism

that are continuous from floor to floor;

ad

correspond to the center-to-center span lengths of the floor system; and

4.

p

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o

f

e

(

F

i

g

.

s

s

i

o

lo n fo

3

.

3

. sim

strips for slab-column systems; fa us supporting beams and girders. should defin e

a

T

g

h

e

op m gse

e

co n

to distance from floor finish to floor finish; Re

horizontal dimension and are either free standing, supported nonstructural per unit area elements horizontal are surface located. or Inhorizontal determining projection, thethe deadflat applied to theof corresponding zones or areas where loads of flat nonstructural elements, the actual weight of be used. As guide,...