Document Name: ACI 3 1 8: Building Code Requirements for Reinforced Concrete CFR Section(s): 30 CFR (d)(1) Standards Body: American Concrete. BY ORDER OF THE EXECUTIVE DIRECTOROffice of the Federal RegisterWashington, Authority of the Code of Federal Regulations. ACI Building Code Requirements for Structural Concrete (ACI ) and MANUAL OF CONCRETE PRACTICE CODE COMMENTARY.
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At cracked sections, the ability of the concrete to resist tension is neglected.
Within these limitations, columns may be offset a maximum of 10 percent of the span, in direction of the offset, from either axis between cen- ter lines of successive columns. The steel takes all the tension due to flexure. The limiting value for shearing stress in slabs and adi, vu, in Sections c and 318-9 shall be: Compressive strength shall be determined by tests 138-92 standard 6 x in.
Such slab shall be reinforced at right angles to the joists with at least the amount of reinforcement required for flexure, giving due consideration to con- centrations, if any, but in no case shall the reinforcement be less than that required by Section Where the actual computed eccentricities at both ends are less than the specified minimum eccentricity, the strength reduc- tion for 318-9 shall correspond to the actual conditions of curva- ture and end restraint.
For special structures, such as arches, tanks, reservoirs, grain elevators, shells, domes, blast-resistant structures, and chimneys, the provisions of this code shall govern so far as they are applicable. Column—An upright compression member the length of which ex- ceeds three times its least lateral dimension.
Elastic shortening of concrete 3. They shall not be used at points of sharp curvature. The equivalent of the bars so interrupted shall be provided by extra steel on all sides of the opening.
SYNOPSIS This code provides minimum requirements for the design and construction of reinforced concrete, or composite structural elements of any structure erected under the 3118-92 of the general building code of which this code forms a part. The radius of gyration, r, may be taken equal to 0.
The pressure test shall be held for 4 hr with no drop in pressure except that which may be caused by air temperature. In columns restrained laterally by struts, it shall be the clear distance between consecutive struts in each vertical plane; provided that to be an adequate support, two such struts 318-922 meet the column at approximately the same level, and the angle between vertical planes through the struts shall not vary more than 15 deg from a right angle.
Bars shall be spaced approximately uniformly across each panel strip, except: The ribs shall be straight, not less than 4 in.
Where adjacent spans are unequal, the extension of negative reinforcement on each side of the column center line as prescribed in Table g 1 shall be based on the requirements of the qci span. Moments ai faces of supports may be used for design of beams and girders.
The reinforcement in the bottom of the slab shall be at right angles to the diagonal or may be of Generated for Mohamed Aly Abdel-razik Moustafa University of California, Berkeley on Balanced conditions exist when, at ultimate strength of a member, the tension reinforcement reaches its yield stress just as the concrete in compression reaches its assumed ultimate strain of 0. The second test loading shall not be made until at least 72 hr after removal of the test load for ack first test.
Shear as a measure of diagonal tension shall be computed in conformance with Section 318-922 In considering the combination of dead, live, and wind loads, Generated for Mohamed Aly Abdel-razik Moustafa University of California, Berkeley on Sections,Chapters 13 and 14, SectionChapter 18, Section aChapter 21, and Section b.
Except as provided in 1, separation of the component elements in the direction normal to the surface shall be prevented by steel ties or other suitable mechanical anchorages. All stirrups so required shall be anchored into the cast-in-place slab, where their area may also be relied upon to provide some or all of the vertical tie steel required in c.
Bends for stirrups and ties shall have zci on the inside of the bar not less than one bar diameter.
Full text of “ACI Building Code Requirements for Reinforced Concrete”
The live load may be considered to be applied only to the floor or roof under consideration, and the far ends of the columns may be assumed as fixed. Reinforced concrete—Concrete containing reinforcement and designed on the assumption that the two materials act together in resisting forces.
Such struts shall be of adequate dimensions and anchorage to restrain the column against lateral deflection. Shear reinforcement consisting of bars, rods or wire shall not be considered effective in members with a total thickness of axi than 10 in.
Building Code Requirements for Structural Plain Concrete Aci 318-92
After proof- stressing, the bars shall conform to the following minimum properties: The center to center spacing of reinforcement shall be not more than three times the slab thickness and the ratio of reinforcement in each direction zci be not less than required by Section Sleeves, conduits, or other pipes passing through floors, walls, or beams shall be of such size or in such location as not to impair aaci the strength of the construction; such sleeves, conduits, or pipes may be considered as replacing structurally in com- pression the displaced concrete, provided they 318-9 not exposed to rust- ing or other deterioration, are of uncoated or galvanized iron or steel not thinner than standard steel pipe, have a nominal inside diameter not over 2 in.
Sleeves, pipes, or conduits of any material not harmful to concrete and within the limitations of this section may be embedded in the concrete avi the approval of the engineer provided they are acci considered to replace the 38-92 concrete.
When a section is controlled by tension, and has reinforce- ment in one or two faces, each parallel to the axis of bending, and all the reinforcement in any one face is located at approximately the same distance from the axis of bending, the ultimate strength shall not exceed that computed by: For symmetrical spiral columns: They shall be properly braced or tied together so as to maintain position and shape.
For contact splices spaced laterally closer than 12 bar diameters or located closer than 6 in. In flanged members, if the centroidal axis is not in the web, the principal tensile stress should be determined at the intersection of the flange and the web.
This moment shall be divided between the columns immediately above and below the floor or roof avi under consideration in direct proportion to their stiffness and shall be applied without further reduction to the critical sections of the columns, c Determination of “c” effective support size 1.
Although they may give somewhat different results in details, the re- sulting floors give reasonable over-all safety factors. The test load shall be applied without shock to the structure and in a manner to avoid arching of the loading materials. Slabs with paneled ceilings may be considered as flat slabs provided the panel of reduced thickness lies entirely within the area of inter- secting middle strips, and is at least two-thirds the thickness of the re- Generated for Mohamed Aly Abdel-razik Moustafa University of California, Berkeley on For 3318-92 similar degree of control, the reauirements of c 2 will be met by an average strength 25 percent greater xci the specified strength.
Calcium chloride or an admixture containing calcium chloride shall not be used. Screw connections shall be prohibited. The metal cores shall aic designed to carry safely any construction or other loads to be placed upon them prior to their encasement in concrete. The shear at sections between the face of the support and the section a distance, d, therefrom shall not be considered critical.