Cold-Formed Steel Beam Design_Manual

8/11/2019 Cold-Formed Steel Beam Design_Manual

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Index

About BeamDesign .......................................................................................... 3

Installing BeamDesign ..................................................................................... 5

Main Window .................................................................................................... 7

Materials Window ............................................................................................. 8

Section Edit Window ........................................................................................ 9

BeamDesign Window ....................................................................................... 14

Options Window ............................................................................................... 23

Technical Considerations ................................................................................. 24

Appendix .......................................................................................................... 27



About Cold-Formed Steel BeamDesign

Cold-Formed Steel BeamDesign is a friendly and powerful software for the design of

flexural members of Cold-Formed Steel, following AISI 2001 and 1996/99 Specifications.

The principal aim is to analyze a simple or continuous beam (2 to 4 equal spans) and to

determine the permitted load (Uniform or Concentrated Load allowed) carrying capacity,

while varying the span length (L). Also you can compare one section and two different

steels, or two sections with the same steel.

In this new version user is able to know the load-carrying capacity value for a specific span

length, being displayed these values in the “References” window.

ASD or LRFD approaches, determine Wall (W-allowable) or Wu (W-ultimate), showed by

Envelope Curves and Tables, or optionally their respectively seven Wi simple components

and Weq (Equivalent to Construction Load).

As efficient coefficients (W/Weight), for ratio between Load-Carrying Capacity and Full

Sectional Weight are giving by Envelope Tables, users can optimize designs, by choosing

their proper Section, Steel and restrictions.

Fourteen different sections are allowed (CS, CU, ZS, ZU, LS, LU, HU, RB, SB, IC, CC, IU,

TS, and TU), with selected Steels (14 ASTM Referenced Standards Steels are provided as

a guide). BeamDesign comes with the section dimensions from the AISI Manual for eachshape, and also user can create new section dimensions. In this new version we add tables

for the following manufacturers: Dietrich, Marino-Ware and SSMA.

Another feature from BeamDesign is you can calculate Geometric and Effective Properties

for provided sections and also for sections created by user.

All Curves and Tables are available for printing with the complete information on headers.

Besides engineers and other professionals, teachers and students also may be able to

profit the versatility of our sofware, changing optional parameters to obtain different curves

and tables or studying the Nominal Flexural Strength for Lateral Buckling Moment (Mnb)

versus L (Span Length) for different Shapes and Steels, or comparing “CS” and “ZS” curves

with AISI Design Manual Charts.



Highlighted Options

Supported Specifications

• 2001 AISI - US (ASD and LRFD)

• 2001 AISI - Canada (LSD)

• 1996/1999 AISI (ASD and LRFD)

Fya: increasing Fy (Virgin Yield Strength) value, due to cold work of forming.

Sections with Web Holes (only CS, CU, ZS, ZU, IC, IU and CC Sections).

Gravity or Uplift loads.

Uniform and Concentrated Load (L/2).

Fastened Flanges: Top, Bottom, both Top and Bottom or Unfastened Flanges.

Fastened to Support Flanges.

Bracings: Against lateral displacement and/or twisting.

One Flange Fastened to a Standing Seam Roof System.

Bearing Supports: Interior Laps; variable Widths and Web Stiffeners for

intermediate, end and/or interior Supports.

Variable Maximum Deflection Limit.

Beam Spacing.

Cb: Bending Coefficient for increasing Critical Buckling Strength.

Reference Span Length and Load Required can be modified by user.

Wi values are displayed for all curves, for required span length.

Units available in American Units and International Units. Units in feet and inches for Span Length.

Units for Uniform and Concentrated Load.

Calculate Geometric and Effective Section Properties.

Dimensional Limits for each Section.

Messages are given for exceeded limits such as b/t, d/t and h/t.

Curve Notes and Error Messages advise for correct AISI employment.

Databases for the following manufacturers: Dietrich, Marino-Ware and SSMA.



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Units of Table for Sections

Units of Table for Steels

Virgin Yield Strength (Fy)

Virgin Ultimate Tensile Strength (Fu)

Fu / Fy ratio

Editable Fields

1) Section Name (ID)Dimensions

2) A’= “Depth of Section”

3) B’= “Flange Width”

4) C’= “Overall Depth of Lip”

5) t’= “Section Thickness>= 0.89mm (35mils)” (Also available Gage units)

6) Ri= “Inside Bend Radius”

7) ga= “Angle between a Flange and its edge stiffener”

8) do / dh: Diameter (do) or Depth (dh) of Web Hole. do/h <0.7. (h= Depth of FlatPortion of the Web).Circular Hole: (C)9/16in (14mm) < do <= 6in (152mm).Square Hole: (S)dh <= 4.25in (108mm),Diagonal <=6in (dimensions fit within an allowable circular) - corner radius>= 2t.Rectangular Hole: (R)Diagonal <= 6in (152mm) (dimensions fit within an allowable circular) – cornerradius>= 2t”

Dimensional Limits

Flange (b/t)= “Flat-width-to-Thickness Ratios”

Lip (d/t)= “Lip-width-to-Thickness Ratios”

Web (h/t)= “Flat-depth-to-Thickness Ratios”

Section Properties Calculated

A= “Full Sectional Area”

Ix= “Full Mom. of Inertia X”

Iy= “Full Mom. of Inertia Y”Ixy= “Product of Inertia”

Xr= “Distance X to C.G. (Centroid)”

Yr= “Distance Y to C.G. (Centroid)”

Xo= “Distance (C.G.-S.C.) Shear Center to Centroid”

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Je= “Parameter for Elastic Critical Moment”

Cw= “Warping Constant”

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BeamDesign Window

BeamDesign analyzes a simple or continuous beam and determines the permitted Uniform

Load (W) or Concentrated Load (P) Carrying Capacity, while varying the span length (L). By

default W units are (kips/ft) or (kN/m).

Calculated values (W, L) or (P, L) are represented by Curves and Tables.

Select Sections

Menu allows selecting ten (10) possible sections for curves and tables:

CS, CU, ZS, ZU, HU, BR, BS, IC, IU, TS, TU, CC.

Analysis Method (AISI 2001 and AISI 1996/99)

ADS Approach: Allowable Design Strength for Allowable Loads (Wall).

LRFD Approach: Load and Resistance Factor Design for Ultimate Loads (Wu).

LSD Approach: Limit States Design for Ultimate Loads (Wu).

For LRFD and LSD see “Options” windows with suggested Load Factors. By default,

for Construction Load (g= 1.4) and for Deflection (g= 1.6).

Units

Uniform Load

t/m, kg/m, KN/m, N/m, t/cm, kg/cm, KN/cm, N/cm, kip/in, kip/ft, lbf/ft (plf), lbf/in

Concentrated Loadtn, kg, kN, N, kip, lbf

Holes

Check “Holes” for Central Web Holes allowed for seven sections: C, U, Z, ZU, IC, IUand CC. “Holes” button is available if the hole diameter was previously changed inthe “Section Edit” window.

Clear Distances between Holes >=18 in. (457mm)

Clear Distances between First Hole to Edge Support>= A' (A'=Depth of the Section).

See Editable Fields (8) at “Section Edit” for more information.

Envelope and Simple Curves

Check “Envelope” for Uniform Load Beam Capacity (Wall. or Wu.) versus SpanLength (L).

Otherwise program draws Simple Load Curves W (1 to 7) and Curve (8*) Weq.

Curve (9*) Mn will be drawn only if was checked in Options

Load Capacity Due to:



“Bending Only”

“Bending for lateral Buckling”

“Shear Only for End Reaction”

“Shear” or “Shear + Bending for Interior Reaction”

“Web Crippling (W.C.) for End Reaction”

“W.C.” or “W.C. + Bending for Int. Reaction”

“Maximum Deflection”

8*) “Equivalent to Construction Load”

9*) “Curve Mnb= Nominal Flexural Moment”

Compare Sections

If you select 1 Section, Curves 1 and 2 are drawing for Steels 1 and 2.

If you select 2 Sections, Curves 1 and 2 are drawing with Steel 1

Checking “AS”, program show all dimensions for all sections in the listbox. So you

can compare a C-Section dimension with a U-Section dimension.

Otherwise program show only dimensions for the selected section.

Use Fya

Check Fya due to cold work of forming, for increasing Fy value.

Fya (Average Yield point of Steel in the full section).

Steel Menu

Select Steel 1 for Curve 1.

Select Steel 2 for Curve 2.

Disable Steel 2 (Steel 2 for Curve 2 = Steel 1 for Curve 1).

Selecting Span number

From 1 to 4 Spans of a Continuous Beam.

Fixing Cb Value

Fix Cb Value= 1

Otherwise Cb>= 1 is calculated. Cb is a Bending Coefficient dependent on FlexuralMoment Gradient that increases Critical Buckling Strength.

Beam Deflection

If Deflection is Considered, input Maximum Deflection Limit= ratio Length /MaximumDeflection.

Default value = 240.

Beam Spacing

If Beam Spacing<> 1m (ft), Load Carrying Capacity Units (Wall or Wu) are kN/m2 orkips/ft2.



Default value= 1m (ft), Load Carrying Capacity Units (Wall or Wu) are kN/m orkips/ft.

Specific Span Length for a Beam

In this new version user is able to know the load-carrying capacity value for a

specific Span Length.

In the “References” box are displayed the values of the required load and the Wivalues of the load-carrying capacity corresponding to desired span length.

Inside the “Curves” window the Wr is displayed through a triangle. For making the

comparison between Wr and Wi, the triangle icon has three states:

Green: the required load by the user is lower than load-carrying capacity for the two

steels (Section verifies - OK).

Yellow: the required load by the user is lower than load-carrying capacity for one

steel. (Section doesn’t verify for steel 1 – Section verifies for steel 2)

Red: the required load by the user is higher than load-carrying capacity for the twosteels. (Section doesn´t verify – NOT OK).

These values are also displayed in the “References” window (Sr and Wr).

Reference Span Length

Write a desired Span Length.

Required Load

Write a desired Load.

Span Length Range

From: Initial length value for drawing curves and calculating tables.

To: End length value for drawing curves and calculating tables.

Show range in inches and feet.

Load Cases

Uniform Load

Concentrated Load (L/2)

Gravity (Beam Weight Included)

Suction (UpLift) - (Beam Weight Included)

Fastened Flange

Free Flange

Top Fastened Flange (See different advices with Curves)

Bottom Fastened Flange (See different advices with Curves)

Both Fastened Flanges

Stiffeners



Check “Es”, “In” or/and “Is” for Web Stiffeners, against Web Crippling, for increasingLoad Carrying Capacity.

Es: Web Stiffener at End Support.

In: Intermediate Web Stiffeners.

Is: Web Stiffener at Interior Support.

Notes: advice the Span Length Limit for economical Stiffener use.

Bracings

Check “y” for Lateral Bracings (Against Lateral Deflection) – “y” Direction isperpendicular to Load Direction.

Check “t” for Rotational Bracings (Against Twisting)

For “Fix Point” button disabled:

Case 1 - Number : Number of Bracings for each Span (Recommended <= 3)

For “Fix Point” button enabled:

Case 2: Instead of Number, Spacing Length will be specified for several Bracings.

(Use full for One Flange Fastened to a Standing Seam Roof System, see AISISpecification Section C3.1.4).

Using Laps

Check Lap on Interior Supports for increasing Load Carrying Capacity.

External Lap Length (ELL) = % of Span Length.

Internal Lap Length = 1.5xELL - (for 4 spans, Central Lap Length = ELL).

Check “Fastened to Support” (Only for AISI 2001)

Support Width

Ne: End Support Width: minimum 1.5 in (38 mm) - (Increase width Against WebCrippling).

Ni: Interior Support Width: minimum 3 in (76 mm) - (Increase width Against WebCrippling).

Buttons

“Graph”

Updates Curves with selected options

“Table / Curves”

Switches between Table Forms or Curve Drawings

“E” (Zoom for W curves)

Switches among:

(E) Envelope, maximize scale to show Envelope curves.

(R) Reduced, maximize scale to show all simples curves.

(F) Fit, maximize scale to show simples curves selected.



Menu

“Print”

The program shows Page Setup Dialog and selects the Paper size and orientationand margins.

Table Forms: select Vertical orientation

Curve Drawings: select Landscape orientation

“Options”

Open the “Options” window.

“Sections Table” and “Materials Table”

Open the Sections and Materials window (You can not make changes in this tables,it is only for consult).

“User’s Guide”

Open the User´s Guide in Adobe Acrobat Reader (Keyboard Shortcut is F1).

“Check for Updates”

Check if there are new versions of BeamDesign available for download.

Contextual Menu

Show/Hide:

References

Beam Icon

Section IconChange Curves Line Thickness

References Lines – Wr

Change Color Curves

Call windows:

Options

Print

Advises wi th Curves

Users must fulfill the Following Conditions for:

“Laps at Support Not Convenient (For Economy)”.

“Tension Fastened Flange: See Appendix A (9 to 15)”.

“End Support Member Thickness>= 3/16 (4.76mm)”.

“Interior Support for two Nested Z: See Appendix B”.

“Web Stiffener at End Support: B 6.1 (all)”.



“Web Stiffener at Interior Support: B 6.1 (all)”.

Headers for Curves and Tables

First Line: Type of Curve, Specifications, Approach Method, Load-Length and Units,

Section name and/or Steel (Fy/Fya), for Simple or Envelope Curve, respectively.

Second Line: Span Number, Loads (Presion or Uplift), Laps Length (%L), Beam

Spacing, Flanges (Free or Fastened), Bracings.

Third Line: Web Stiffeners at Supports (Considered or Not), Hole (Considered or

Not).

Fourth Line: Maximum Deflection Limit (or Not Considered), Cb (Bending

Coefficient).

Complementary Drawings for Curves

Icons for Sections in scale: Drawing Sections, Bracings (“y” and “t”) and Fastened

Flanges (Top and/or Bottom).Beam Diagram View: Span Number, Gravity or Uplift Loads, Laps (if any), Bracings

(if any).

For simple curves, dotted lines indicate that they are not included in envelope

curves.

The possible cases are:

a) W5 - With Web Stiffener at end Support.

b) W6 - With Web Stiffener at interior Support.

c) W7 – Maximum Deflection not considered.d) W8 – Equivalent to Construction Load (always in dotted line).

Display Tables

Envelope

W-env.1 and W-env.2 show values from Curve 1 and Curve 2 respectively.

Simple governing causes (W1 to W7) witch determined the minor Load Carrying

Capacity for each case are given, and efficiencies W-env.1/Wt and W-env.2/Wt ,

and the relative efficiency W-env.2/W-env.1 are so written.

If W-env.1 and W-env.2 values are minor to W8 (Equivalent to Construction Load),

text changes to “Italic Style”.

Simple Curves

Simple Curves and (W8) are also given in tables.

Governing values are all painted to highlight them (green). If some of these values

are minor to W8, color changes (red).



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Technical Considerations

Cold-Formed Steel BeamDesign for flexural members of CFS, was entirely conceived

following AISI 2001 and 1996/99 Specifications.

Certainly, some practical restrictions were introduced:

1. Beams are supposed simple or continuous elements over fixed supports. They will befirmly connected to both the top and the bottom flanges, to prevent from twisting andlateral bending at the ends of each span.

2. “Fastened Flange”, means that these compression flange, (bottom or top), is throughattached to a rigid plane diaphragm (deck or sheathing) over (or under) the flange,(see AISI 96 Section D, for more information), to effectively restrain the flange againsttwisting and lateral bending all along the beam.

3. Beams (C or Z shapes) having the tension flange attached as Section C3.1.3 states(Fourteen conditions), with the compression flange laterally unbraced, are partiallyrestrained against lateral bending. Factors R<1 are specified to reduce Nominal

Section Strength for Bending Only. The program checks first nine conditions. Usersmust fulfill last five conditions.

4. For this Version, the constant Moment of Inertia Ix, based on the full span section wasadopted for a linear analysis of the Continuous beam (2 to 4 spans), instead of thevariable effective Moment of Inertia, due to the different effective areas of thecompression flange and web, along the beam. For C and Z shapes using short laps atinterior supports, exact flexural moments are lightly smaller on spans but lightly biggeron supports. As the moment region between the end of the lap and the inflection point,for lateral buckling is treated as a cantilever with an unbraced free end, conservatively,program increases that unbraced length for calculations, and errors are minimized.(See 7).

5. For Deflection determinations, as eventual Laps are short, (See: Using Laps…) and1999 AISI Supplement, neglects allowed Central Web Holes, a constant EffectiveMoment of Inertia Iex is used for these Version following AISI Design Manual criteria.(Iex is calculated based on the effective span section, at a service load of 60% of Mn,and assuming approximately a maximum compressive stress of 60% of Fya).

6. Program allows optionally, for calculations, to use increased Fya (Average Yield Pointof the Full-Section) in lieu of Fy (Virgin Yield Strength), by effect of cold work offorming, only for “Compact” compression flange, (where the reduction factor Ro,determined in accordance with Section B2 equals unity), with Fu/Fy>= 1.2 and Ri/t’<=7, (section A7.2). For non-symmetric sections, conservatively program adopts for thefull beam, the smallest value between Fya top and Fya bot (calculated for top orbottom compression flange respectively).

7. Cb, Bending Coefficient for Increasing Critical Buckling Strength, is calculated inaccordance with Equation C3.1.2-11 (AISI 96), due to variable shapes of flexuralmoment diagrams within the unbraced segments for compression flanges. At regionswith unbraced length between the inflection point and the interior support (orconservatively the middle of the lap if any), sections are treated as unbracedcantilevers, with a free end, and Cb=1. Users can fix Cb=1 and assumed it for the fullbeam, otherwise program calculates Cb>=1, for all the different segments andchooses for all the beam, the worst combination of Cb with it respective bendinglength. Maximum Cb=2.3 (adopted).



8. Load Carrying Capacity Wall or Wu are calculated by ASD or LRFD Method. Wall.gives the envelope Allowable Uniform Load, for six nominal design strengths,(additionally a seventh limitation, for beam deflection is considered), divided by theircorresponding specified safety factors W.

9. Wu gives the envelope Ultimate Design Uniform Load, for six nominal resistances,(additionally an equivalent one for beam deflection is considered), multiplied by theircorresponding specified resistance factors Ø Wu must be confronted with thedifferent load combinations of required uniform strength for factored loads (or requiredresistance). AISI96 recommendations, (Section A4), are based on ANSI/ ASCE 7Specifications.

10. Loads for Nominal Strengths or Resistances: Simple Curves and Tables.

W1 - Bending Only

W1- L Curve (or table) gives Load Carrying Capacity, for the Nominal Strength forBending, with lateral buckling restricted. Procedure I (Sec.3.1.1.), was chosen forMn=Se.Fy, with Se, (effective section modulus) calculated with the extreme fiber at Fy.

W2 - Bending for lateral Buckling

W2- L Curve (or Table) gives Load Carrying Capacity for the Nominal Strength forBending (Mnb), with lateral buckling. Mnb=Sc.Fc, with Sc, (Effective Section Modulus)calculated with the extreme compression fiber at Fc (elastic or inelastic CriticalStress)=Mc/Sf, with Sf (Full Section Modulus), (Sfx for all, except H sections withrotated axis), and Mc, Critical Moment for Lateral-torsional buckling.

a) Critical Stress Fc is calculated for open cross sections members, C-Channels, I-Beams and Z-Beams,(singly, doubly and point symmetric sections), with twisting andlateral displacement as an unity, for lateral-torsional buckling, following Sec.C3.1.2.1 ofthe 1999 AISI Supplement. (Procedure a).

b) Critical elastic Stress Fe in lieu of Fc, is calculated for closed box-type member

sections BR and BS (Square and rectangular boxes), following Sec.C3.1.2.2 of the1999 AISI Supplement.

c) Design Stress Fb2 in lieu of Fc, is calculated for member sections H (Hat orinverted hat), where compression flanges tend to buckle separately accompanied byout-of-plane bending of the web, following the simplified analysis, in Sec.2 of Part II, ofthe 1996 AISI Design Manual.

For 1999 AISI Supplement when the depth of holes do/h>=0.38, effective width shallbe determined by section B.3.1(a).

W3 - Shear Only for End Reaction

W3- L Curve (or Table) gives Load Carrying Capacity for the Nominal Strength forShear (Vn) only on end support (e), always without attached transverse web stiffenersprovided.1999 AISI Supplement gives reduction coefficient qs to multiply Vn.for C sections withholes.

W4 - Shear or Shear + Bending for Interior Reaction

W4- L Curve (or Table) gives Load Carrying Capacity for the Nominal Strength forShear (Vn) only or Combined Shear and Bending , on interior support, (i), alwayswithout attached transverse web stiffeners provided. Program chooses minor value for



W4, and indicates it and also which the governing cause is, on Tables. When laps areconsidered, as lap lengths are limited, Shear values for one web are dominating.

W5 - Web Crippling for End Reaction

W5- L Curve (or Table) gives Load Carrying Capacity for the Nominal Strength forWeb Crippling (Pn), only on end support (e), for EOF (End One Loading) according toSection C3.4.

For the end support of a Z-shape, if the flange is bolted, and both the support and thesection satisfied the requirements at 3.4, Pn value would be increased, multiplied by1.3.

W6 - Web Crippling or Web Crippling + Bending for Interior Reaction

W6- L Curve (or Table) gives Load Carrying Capacity for the Nominal Strength forWeb Crippling (Pn), only or Combined Web Crippling and Bending, on interiorsupport, (i) for IOF (Interior One Flange Loading) according to Section C3.4. Programchooses minor value for W6, and indicates it, and also which the governing cause is,on Tables.For the support point of two nested Z-shapes, if all required conditions at C.3.5.1 weresatisfied, Load Carrying Capacity would be increased.

For calculating W5 and W6, different equations are given on Table 3.4-1, by 1996 AISISpecifications, for single Unreinforced Webs, or for I (two C connected back to backaccording to D1.1) and similar sections.1999 AISI Supplement gives reduction coefficient Rc to multiply Pn for C sections withholes.Web Stiffeners built according to Art. B6-1, at each support (Se or/and Si) are optionaltools for eliminating Crippling problem.Program advices the economic lengths for the beam, in order to use the web stiffenersat each support.

W7 - Equivalent for Maximum Deflection

W7- L Curve (or Table) gives optionally the Equivalent Uniform Load CarryingCapacity for an imposed Maximum Deflection service condition, as a fraction of thespan Length (e.g. L/240).For LRFD Method Load Factor is assumed equal to 1.50, by default.

W8 - Equivalent to Construction Load

W8- L Curve (or Table) gives optionally the Equivalent Uniform Load for an imposedConcentrated Construction Load= 1KN or 0,22 kips applied at the worst situation, andas a service condition.For LRFD Method Load Factor is assumed equal to 1.40, by default.

Mnb= Nominal Flexural MomentMnb-L Curve gives optionally the Nominal Strength for Bending with lateral bucklingversus the span length, for any or none lateral restriction.For example, if User fixes Cb=1 with free flanges and no bracings, for C and Z shapes,with Fy=33ksi and Fy=50ksi steels, He obtains Chart II-1a to 2b from the AISI 96Design Manual.



Appendix

Appendix A According to AISI 2001 Specification, Chapter C3.1.3.

The reduction factor, R, shall be limited to roof and wall systems meeting the followingconditions:1) Member depth less than 11.5 in. (292 mm)

2) Member flanges shall have edge stiffeners3) 60 ≤ depth/thickness ≤ 1704) 2.8 ≤ depth/flange ≤ 4.55) 16 ≤ flat width/thickness of flange ≤ 436) For continuous span systems, the lap length at each interior support in each

direction (distance from center of support to end of lap) shall not be less than 1.5d.7) Member span length shall be no greater than 33 feet (10 m)8) For continuous span systems, the longest member span length shall not be more

than 20% greater than the shortest length.9) Both flanges shall be prevented from moving laterally at the supports.10) Roof or wall panels shall be steels sheets with 50 ksi (640 MPa or 3520 kg/cm2)

minimum yield point, and a minimum of 0.018 in. (0.46 mm) base metal thickness,

having a minimum rib depth of 1-1/4 in. (32 mm), spaced a maximum of 12 in. (305mm) on centers and attached in a manner to effectively inhibit relative movementbetween the panel and purlin flange.

11) Insulation shall be glass fiber blanket 0 to 6 in. (152 mm) thick compressedbetween the member and panel in a manner consistent with the fastener beingused.

12) Fastener type: minimum no. 12 self-drilling or self-tapping sheet metal screws of3/16 in. (4.76 mm) rivets, having washers ½ in. (12.7 mm) diameter.

13) Fasteners shall not be standoff type screws.14) Fasteners shall be spaced not greater than 12 in (305 mm) on centers and placed

near the center of the beam flange, and adjacent to panel high rib.15) The design yield point of the member shall not exceed 60 ksi (410 MPa or 4220

kg/cm2).

Appendix B According to AISI 2001 Specification, Chapter C3.5.1.

The following conditions shall be satisfied:1) The ends of each section shall be connected to the other section by a minimum of

two ½ in. (12.7 mm) diameter A307 bolts trough the web.2) The combined section shall be connected to the support by minimum of two ½ in.

(12.7 mm) diameter A307 bolts trough the flanges.3) The webs of two sections shall be in contact.4) The ratio of the thicker to the thinner part shall not exceed 1.3.

Cold-Formed Steel Beam Design_Manual

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