Fu Ultimate stress of the material (Ksi)Fy Yield stress of the material (Ksi)e edge distance (in)s bolt spacing (in)Φ Load resistance Factor

d Nominal diameter of bolt (in)t thickness of the critical materialµ mean slip coefficeint

multiplier

hole factor

Number of Slip Planes

minimum bolt tension (kips)

number of bolts carrying the applied tension

tension force due to LRFD combinations (kips)

End Projectionl angle length

Ab Nominal area of bolt (in2)

Du

hsc

Ns

Tb

Nb

Tu

Ag Gross sectional area (in2)

Anv Net area subjected to shear (in2)

Ae Effective net area (in2)

An Net area (in2)

Ant Net area subjected to tension (in2)

t1

InputsUnits Length inch

force kipsstress ksi Inputs

Beam End reactions

Dead load (D)

live load (L) Criteriea

Wind load (W)

Snow Load (S)

Eq. Load (E) Calculate Bolt design

Nominal load due to initial rainwater or ice Strength (φRn)exclusive of the ponding contribution (R)

as per the load combination defined belowMinimum number of Bolts,

LRFD Load Combinations1.4D

Assume suitable Number of Bolts (n), edge (e), spacing (s) and gauge (g)

Bolt Type ASTM A325-NBolt Dia 3/4 inch= 0.75 inch Assume angle thickness (t)

Material Properties

Elements Designation SpecificationsBeam W36x231 ASTM A992 50 65Column W14x90 ASTM A992 50 65 Design CheckAngles 2L5x3 1/2 A36 36 58

Geometric Properties

Beam W36x231 0.76 Bolts

Column W14x90 0.71 limiting shear strength

Angles 2L5x3 1/2 Design not safe

CriteriasConnection type = Bearing Type connection Angle Bolt bearing on angle Shear yielding shear rupture block shear rupture

Force Type = Shear and torsionDesign is Safe

Beam Bolt bearing on

Bolt bearing on

Column

Design is Safe Design not safe

Design of Double angle connection is complete

Rd=

Rl=

Rw=

Rs=

Rlr= Roof live load (Lr)

Re=

Rr=

Ru=

n1=Ru / φRn

1.2D + 1.6L + 0.5(Lr or S or R)

1.2D + 1.6(Lr or S or R) + (0.5L or 0.8W)

1.2D + 1.3W + 0.5L + 0.5(Lr or S or R)1.2D ± 1E + 0.5 L + 0.2S0.9D ± (1.3W or 1E)

Fy (ksi) Fu (ksi)

tw =

tf =

nφRn ≥ Ru of bolt groups (nφRn)

(φRn) (φRn) (φRn) (φRn)

Beam Web (φRn)

φRn ≥ Ru

Beam Web (φRn)

Yes

No

Yes No

Angle length- Angle thickness -Minimum spacing in any direction- 2 2/3 (2.667) d (AISC J 3.3)Minimum edge distance- Sheared edge is the worst case (from table J 3.4)

for single row of bolt

for n number of bolts across the section

s=g= centre to centre spacing of bolts along perpendicular direction to the line of force

In lap joint it is the centre to centre distance between rows of fastener

Check Shear on net Area of Angles ref. Steel Buildings (Green Book) pg 210

(when tension is there strength strength is reduced to 30% of the minimum specified tensile strength)

Fu= Minimum specified tensile strength

the thickness required for shear= l= length of angle

Minimum angle length shoud be one half of the "T" dimension of the beam to be supportedMaximum is 5/8 inch

Anet= t (W-dh)

t(W-ndh)

Anet can never be lesser than 0.85Ag

centre to centre spacing of fastener in a row, also called fastner pitch

total shear strength of the section (Fv) = 0.3*FuAv

t=Ru/[Fv(l-ndh)n1]

Fv= Shear strength of one angle

dh= hole diameter

n1= number of angles

Pg 1481 LRFD Manual

(when tension is there strength strength is reduced to 30% of the minimum specified tensile strength)

8.5 inch

one half of the "T" dimension of the beam to be supported

t1, End Projection

t, Angle Thickness

l, Angle length

s, bolt spacing

Column

Leh

Lev

g

d

g, gauge distance

BeamBeam

BeamBeam

Double Angle Connections

Inputs Notations Definition unitsFy of Beam stressFu of Beam stressFy of Column stressFu of Column stress

horizontal edge distance lengthPu Axial force forceVu Shear Force forcet angle thickness lengthd bolt diameter = 7/8" lengthn number of bolts no unit

OutputsD/C ratio

1. Check strength of bolts and angles

φRn= φRn From Table1

1. Check strength of bolts and angles

2. Check the Beam Web for bolt bearing

D/C < 1 0 Review the designTRUE

o.k 3. Check Supporting Member Flange for bolt bearing

2. Check the Beam Web for bolt bearing

φRn= t* φRn From Table 2

D/C < 1 0 Review the designTRUE

o.k

3. Check Supporting Member Flange for bolt bearing

φRn= t* φRn From Table 3

D/C < 1 0 Review the designTRUE

o.k

3. Design strength of Beam

3a. Beam Web Bearing strength

already done

4. Design strength of Beam

4a. Column Web Bearing strength

already done

Leh

ΦRn= design strength of bolt will be selected from table( pg 1521-1533)

Ru= ( Pu2+Vu

2)1/2

D/C = Ru/(φRn)

ΦRn= Beam Web design strength will be selected from table( pg 1521-1533)

Ru= ( Pu2+Vu

2)1/2

D/C = Ru/(φRn)

ΦRn= Support design strengthwill be selected from table( pg 1521-1533)

Ru= ( Pu2+Vu

2)1/2

D/C = Ru/(φRn)

Table 1

number of rows angle thickness8 3\8

1\27 3\8

1\26 3\8

1\25 3\8

1\24 3\8

1\23 3\8

1\22 3\8

1\2

Table 2

number of rows8 1.5

1.757 1.5

1.756 1.5

1.755 1.5

1.754 1.5

1.753 1.5

1.752 1.5

1.75

Table 3 Number oF rows Support Design strength/t8 14627 12796 10965 914

For Fy=36 ksi & Fu=58 ksi

For Fy=36 ksi & Fu=58 ksi

Leh

4 7313 5482 365

Bolt and angle strength number of rows angle thickness303 8 3\8346 1\2264 7 3\8352 1\2225 6 3\8300 1\2186 5 3\8248 1\2147 4 3\8196 1\2108 3 3\8144 1\268.5 2 3\886.6 1\2

Beam Web Design strength/t number of rows731 8 1.5731 1.75639 7 1.5639 1.75548 6 1.5548 1.75457 5 1.5457 1.75365 4 1.5365 1.75274 3 1.5274 1.75183 2 1.5183 1.75

Number oF rows Support Design strength/t8 16387 14336 12295 1024

For Fy=50 ksi & Fu=65 ksi

For Fy=50 ksi & Fu=65 ksi

Leh

4 8193 6142 410

Bolt and angle strength34043329637925232520827116521612116176.886.6

Beam Web Design strength/t819819717717614614512512410410307307205205