Crsi manual of standard practice. CRSI MANUAL OF STANDARD PRACTICE 27th Edition

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Manual of Standard Practice - CRSI: Concrete Reinforcing Steel Institute - Reinforcing Bar Placing 













































   

 

- Crsi manual of standard practice



 

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Nullam a nisi lacus, non interdum ante. Vivamus ante augue, commodo vel egestas sed, pharetra nec dui. Quisque sed tellus felis. Donec ipsum mauris, sagittis eu accumsan in, aliquam non ipsum.

Vestibulum tempor nunc nec felis scelerisque eget elementum erat dignissim. Ut vel ipsum mollis orci venenatis luctus. Aenean vehicula quam vel quam porttitor ac iaculis elit pulvinar. Proin consequat, ipsum eu venenatis semper, justo turpis posuere tortor, ac placerat metus nisl et lectus. Nulla cursus dui id nunc ullamcorper sed semper nisl lobortis. Aliquam erat volutpat. Smaller finished bend diame- ters are permitted if the bars are stress-relieved. The specification has two classes of zinc coating weights which ae designated as Class I and Class II, Class F coating, which requires a zinc coating weight of 3.

Spiral Reinforcement 1. Welding of Reinforcing Bars 1. Unless otherwise specified on the project drawings or in the project specifications, plain or deformed bars will be furnished.

Weldability is accomplished in the specification by limits or controls on the chemical composition of the steel. One limit is on individual chemical elements, for example, carbon is limited to a maximum of 0.

When the steel is to be welded, a welding pro- cedure suitable for the chemical composition and intended use or service should be used. The CE. Reporting these material properties, should be required in the project specifications so that the Contractor will have the carbon equivalent available for the reinforcing bars to be welded. Consider the use of mechanical splices as an alternative to welded splices. Where arc-welded splices are used, the following are required: a. Adjustment of welding techniques to suit C.

Occasional quality control tests of actual welds removed from the structure when nondestructive test results are unsatisfactory 3.

Chemical analyses are not ordinarily meaningful for rail-steel and axlestee! Welding of these types of bars is not recommended. Unless approved by the ArchitecvEngineer, never permit field welding of crossing bars for assembly and fastening of reinforcement. Reinforcement should be assembled and fastened with tie wire to avoid harming the bars. Grade 40 [] and 50 [] bars are required to have only the first three identification marks.

No grade mark or grade line for minimum yield strength is required. H Bar Size ASTM Specifications Welded wire fabric consists of wires arranged in a square or rectangular configuration. The wires are weld- ed at their intersections. These specifications require tensile, reduction of area and bend tests on the fabric, and shear tests on the welded intersections, A minimum yield strength of , psi [ MPa] is required for plain WWF A and a minimum of 70, psi MPa] for deformed WWE A ASTM A82 plain wire and A deformed wire are companion specifications that pre- scribe the requirements for the wire used for manufactur- ing welded wire fabric.

Welded wire fabric can be produced with high- strength wires of minimum yield strengths to 80, psi [ MPa]. Higher minimum yield strengths allow the use of less material in certain applications. Welded wire fabric can be fabricated to make beam stirrups and column ties. The letter is fol- lowed by a number indicating cross-sectional area in hun- dredths of a square inch [square millimeters. Welded wire fabric is usually shown on project draw- ings with the abbreviation WWF followed by spacings of longitudinal wires and then transverse wires and last by the sizes of longitudinal and transverse wires.

Welded wire fabric is manufactured in the form of sheets and rolls. Rolls are generally stocked in W1. Roll widths vary from 5 to 8 feet[1. Rolls should be straightened. Standard widths of sheets vary between 7 to 10 feet 2. Manufacturers of WWF can, meet specific steel area requirements when ordered for designated projects, or in some localities, may be avail- able from inventory.

Detailing Welded Wire Fabric The quantity of welded wire fabric detailed and sup- plied should include the net area shown on the project drawings or required in the project specifications plus sufficient material to include lap splices.

Overall width is, defined as the width plus side overhangs. Transverse wires may be speci- fied to have a specific overhang or no overhang flush sides. The lengths of rolls vary with the individual manufacturing practices of producers. Sheet or roll length is defined as the length, tip to tip, of longitudinal wires.

Unless otherwise specified, each end overhang equals one-half of a transverse spacing. All damaged areas of coating on the wires, which occur during manufacture and handling to the point of shipment to the job-site, have to be repaired touched-up with patching material. Side overhangs may be varied as required and do not need to be equal. Longitudinal wire spacing 6 in. W16 [M] Transverse wire size Reinforcing Bars for Masonry Construction 6. The choice of whether to use low-lift or high-lft grouting procedures depends on requirements in the project.

Additional bars, if required, should be shown on the proj- ect drawings or specified in the project specifications. In addition, ewo to four concinu- ous bars usually 4 or 5 [ 13 or 16 are placed in the wall footing and in a bond beam atthe top of the wall. For walls required to provide lateral load resistance, the horizontal masonry joint reinforcement is usually replaced with reinforcing bars.

Both vertical and hori- zontal bars are placed within the cells which are to be filled with grout. The bar size and spacing should be shown on the project drawings or specified in the project specifications. This agreement should spell out how the reinforcing bars will be detailed and furnished. In many instances, the Buyer will provide the bar lists and no placing drawings are fur nished. If placing drawings are to be furnished, the Buyer should notify the Seller at what height the vertical bars are to be spliced, whether horizontal bars are to be detailed and cut to length or cut to fit from stock, and the maximum length of stock to be furnished.

In general, only reinforcing bars are detailed unless other reinforcement is specifically requested by the Buyer. Prior to detailing the reinforcing bars, the Detailer should verify the type and dimensions of the CMU, whether low-ift or high-lift grouting procedures will be used and where bars will be lap spliced.

Corner bars and stirrups in bond beams and lintel beams are detailed to fit within the con- fines of the block cell dimensions as shown on the project drawings, 6. In many instances, lange vertical bars may be spliced using a mechanical splice. Ties are detailed to be placed in the mortar joint between block courses or detailed to fit within the confines of the cell dimensions, depending on the pilaster dimensions and the size and number of vertical bars encased.

The bar forcing bars for masonry walls are estimated in a similar lengths and lap splice locations are dependent on the manner and method as for reinforced concrete walls. There is a tored method based on linear feet of wall or square feet wide variation in practice in many geographic areas, and of wall area. The Seller of reinforcing steel should contact the Buyer in order to determine the specific manner in which reinforcing bars are to be detailed and supplied.

Special Fabrication 1, See Section 5. Radial Prefabricat For industry recommendations oa racial prefabrica- tion, see Section 5. Spirals 1.

See Sections 5. They are generally shipped with the spacers mounted and spaced. See Table 7. The above discussion applies to a single bar. Bundles of bars occupy a greater space, therefore, the " 2. Extra Work or Materials Any work or materials desired iar addition to that spec- ified in the contract are not furnished until instructions in writing have been issued by the Buyer to the Seller, at an agreed extra cost.

The Buyer is credited, less estimating and detailing charges if any, only for omissions or deduce tions due to changes in contract requirements. The Seller is not required, nor expected, to make the unit prices far additions to, as for deductions from, the same as in the original contract. Special Ser Certain speciahy services are not customarily ren- dered by the Fabricator unless specifically requested.

Accordingly, if the Buyer expects the Fabricator to per- form any services such as the following, they should be so specified. Galvanizing and epoxy coating. Painting, dipping or coating 4. Bending or cutting to special tolerances. Non-standard bends, or end preparation not other- wise defined. Special Items Similarly, the following speciafty items are customari ly supplied by che Fabricator only if specified by the Buyer: 1. Mechanical splices. Anchors or studs 3. Pick-up inserts 4. In tilt-up construction, additional reinforcing steel required at panel pick-up points.

Plain dowels and sleeves. Specialty items for positioning masonry work. All prestressing materials and accessories. Reinforcing bars or studs welded to structural steel or miscellaneous metal. Reinforcing bars for architectural precast concrete.

CING M. Inspections authorized by parties other than the Seller for quality of reinforcing stee! The total ost of fabrication, including any expense for testing, is, borne by the Buyer.

Certified mill test reports are sup- plied on request. Bending 1. Reinforcing bars should be fabricated accurately to the dimensions shown on the bending details, within tolerances given in this chapter. Bars should be bent cold, unless otherwise authorized, and should not be bent or straightened in a manner that will injure the material.

See Section 5. Groups of varying bar lengths or marks bent that will be placed adjacent may be bundled together 7. Shop lifts generally are units of reinforcing bars, as loaded for shipment. Field lifts generally are units of reinforcing bars as required for field handling by the Contractor.

A field lift may consist of single bundles or two or more smaller bundles tied together. A shop lift may consist of one or more bundles, the same as field lifts, orconsist of two or more field lifts. Straight and bent bars, will not be combined in the same lift.

Ties are generally spaced 10 to 15 feet [3 0 4. Identification tags should show the grade of steel, num- ber of pieces, size, and mark or length of bars. Special Bundling and Tagging 1. Special tagging will include any provisions additional to Section 7. Unless otherwise agreed to by the Buyer and Seller, contracts will include standard bundling and tagging only. Standard Fabrication All fabricating tolerances will be in accordance with Figures and , unless otherwise agreed to by the Buyer and Seller.

General Reinforcing bars should be accurately placed in the positions shown on the placing drawings, adequately tied and supported before concrete is placed, and secured against displacement within the tolerances recontmended in Section 8. Surface Condition of Reinforcing Bars At the time of concrete placement, all reinforcing bars should be free of mud, oil, or other deleterious materials. Reinforcing bars with rust, mill scale, or a combination of both should be considered as satisfactory, provided the minimum dimensions, weight, and height of deforma- tions of a handswire-brushed test specimen are not less than the applicable ASTM specification requirements 8.

Bars with kinks or improper bends should not be used. Those reinforcing bars as shown on the project draw- ings or permitted by the ArchitecvEnginecr, 8. Groups of parallel reinforcing bars bundled in con- tact, assumed to act a8 4 unit, noe more than four in any fone bundle may be used only when stirrups or ties enclose the bundle.

Reinforcing bars larger than 11 [ 36] should not be bundled in beazas or girders. Individual bars in a bundle cut off within the span of flex- ural members should terminate at different points with at least 40 bar diameters of stagger.

Where spacing lintita- tions and minimum concrete cover are based on bat size, a unit of bundled bars should be treated as a single bar of a diameter derived from the equivalent total area. Splices of reinforcing bars should be made only as required or permitted on che project drawings or in the project specifications, or as authorized by the ArchitecEngineer. Lap splices of bundled bars should be based on the lap splice length recommended for individual bars of the same size as the bars spliced, and such individual splices within the bundle should not overlap each other.

The length of lap should be increased 20 percent for a S-bar bundle and 38 percent for a 4-bar bundle. Bars spliced by moncontact lap splices in flexural members should not be spaced sransversely farther apart than one-fifth the required length of lap nor 6 inches [ mm]. AWS DL4 , 8. Bottom bars in, slabs or joists should extend into the support to the limn- its of the specified concrete cover or 6 inches [ mm], whichever is less. Generally, in one-way continuous construction, unless otherwise called for on the project drawings or in the project specifications, the top reinforcing bars should extend into adjacent spans to 0.

Generally at discontinuous ends, top bars should extend imo we span at least 0. See Section 14 in Chapter 4. Tolerances in Placement Unless otherwise specified, reinforcing bars shoutd be placed within the following tolerances: 1. Concrete Protection for Reinforcing Bars The following minimum concrete cover should be provided for reinforcing bars. Concrete Cover; in, [mm] Concrete cast against and permanently exposed to earth.

Concrete Cover, in. Such pro- visions should specify free time if any allowed for unloading. Seller can reserve the right to charge interest on delinquent payments, Seller may include the right at all times to decline to make any ship- ments, deliveries or perform any work except upon receipt of payment or security or upon terms and condi- tions satisfactory to the Seller.

The cost of any additional testing should be specifically allocated in the contract between the Buyer and Seller. Under commonly accepted practice, Buyers, assume the cost of any testing in addition co the certified mill test reports 9. Generally, the Seller has the obligation of replacing all nonconforming material and assuming any necessary transportation charges.

Buyer's remedies, unless specifi- cally provided for or waived in the contract, are set forth in detail by the Uniform Commercial Code. Seller should caution Buyer to recover through carri- cer for any loss or damage in transit, except when Seller is supplier of the transportation mode.

Buyer must take proper exceptions at time of delivery. Such guarantees, if presented, may be limited; for example, to the materials furnished.

In those states that have adopted the Uniform Commercial Code, statutes spell out warranty rights in considerable detail and should always be consulted. Other members Min. Regarding flame-cutting, tests have shown that any effect of flame-cutting is localized to the end-cut surfaces.

Hardness testing was used 0 evaluate the effects of flame-cutting on the tensile properties of the bars. From the tests it was concluded that flame-cunting had no adverse effects. Flame-cutting of epoxy-coated reinforcing bars is not recommended. Preface 9. Material Supply Contract 9.

One suggestion is for the contract to state that all materials, and services are to be furnished in accordance with the CRSI Manual of Standard Practice current edition. Seller should consider whether its price is firm for the life of the construction project. The type of transportation truck, railroad car or vessel , the point of delivery ie. Seller's vehicle, Commercial Carrier or Buyer's vehicle.

The method of delivery trucks, rail, or vessels should be specified. There should be a time limit given the Buyer for acceptance of the offer. Material Supply and Instal 9.

Final payment should be specified after substantial completion of the work under contract to overcome the possibility of delaying substantial payment until final completion of the project. Seller may reserve the right at all times to decline to make any shipment or delivery or perform any work except upon receipt of payment or upon terms and conditions satisfactory to the Seller. Seller may specify that payment to him will follow satis- factory completion of his work, and not be contingent on the actions of any third party such as payment by the Owner to the General Concractor.

The Buyer should! The contract should clearly state the manner in which the Seller will be compensated for overtime or shift work performed. This clause should specifically out- line the responsibility for supplying hoisting equipment, including the operator.

Generally, the Buyer is to supply hoisting equipment; the wording should be clear as to the size anal type of crane required, at what times the crane will be available to the Seller, and that the crane will be available for lifting, moving or lowering material. Where personnel lifts are required, the Buyer normally shall pro- vide same, to which it should be clearly stated as to any special requirements or needs, who will be responsible for the cost of this service and who will bear the liability for disruption of service.

In most areas, the Buyer is normal- ly required to furnish all grades, lines, levels, elevations, templates, toilet facilities, drinking cups and water, ramps, scaffolds, and space for delivery and storage of materials accessible for truck and trailer delivery adjacent to the point of use.

Where temporary guying is necessary to support reinforcing steel prior to placing of concrete, the Buyer commonly agrees to provide materials for guy- ing, for installation by the Seller, and Buyer commonly agrees to remove guys after use. If deadmen are required to hold guys, the Buyer commonly agrees to furnish, install and remove same. This clause usually requires the Seller to provide the Buyer with 2 certificate of insurance to assure the Buyer that adequate insurance i in effect.

In some cases, the Buyer is required to procure builder's risk insurance to protect Seller's material and equipment at the job-site from loss or damage caused by fire and extended coverage. This clause should also state who is responsible for any per- formance, payment, or other bonds required in the per- formance of the contract. Seller should then consider contract pro- visions which excuse him for any delay in performance due to acts of God, war, riot, embargoes, acts of civil or miliary authorities, fires, floods, quarantine restrictions, mill conditions, strikes, difference with workers, delays transportation, shortage of railroad cars, fuel, labor or materials or any circumstance or cause beyond the con- trol of the Seller in reasonable conduct of its business.

In the event any circumstance causes a delay, the time of completion should be extended accordingly. If arbitration is specified, clearly state method for selecting arbicrators, responsibility for the expense, including attorney fees and court cost. Seller's responsi- bility may be specified to cease at that time. Buyer may be expressly specified to be liable for expense resulting from any subsequent damage by fire, flood, other trades, or any cause other than the work performed by Seller's own employees.

Ifthe Buyer wishes to have placing personnel stand by during the placing of concrete, this requirement should be clearly stated in the contract for reinforcing steel placing services. Parking for the Seller's employees working at the job- site. All reworking of existing reinforcing bars, 8. All drilling or burning of holes in structural steel or miscellaneous iron to pass reinforcing bars.

This obligation of the Buyer should include any situation in which the Seller may be Gited for allowing is employees ta work at the job-site while a violation of the said regulations, chargeable to some party other than the Seller, its agents, employees or subcontractors remains uncorrected.

Both joists and slab are cast in place to form a monolithic unit, integral with the supporting beams and columns. The joists form a characteristic waffle pattern on the underside, and this, construction is often referred to as waffle flat slabs. Ducts and conduits are incorporated in the structural slab, in a separate topping slab, or through the voids created by the forms. Standard size reusable forms help make joist construction economical.

These tables give safe, superim- posed loads in pounds per square foot for various thick- nesses of top slabs and combinations of bars. The load capacity is determined by the most critical design consid- ceration—shear, development length, or flexure.

For joist sizes not listed in the current CRSI Design Handbook, designs can be made following the illustrative examples in the Handbook. The ACI Building Code requirements for permissible shear and minimum web reinforcement will cause some variations in the design techniques.

 


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