DDSS - Tension Members

Design of Tension Members:

For this we need IS 800 - 2007

Tension members are linear member in which axial forces act to cause elongation. Such member can sustain load upto the ultimate load, which stage they may fail by rupture at a critical section. 

The factored design tension (T) in members shall satisfy:

T < Td

where, Td is Design strength of member.

#Td is classified under as for Bolted Connection:

1. Tdg

2. Tdn

3. Tdb

Consider Td value whichever is less.

1) Due To Yeild Strength (Tdg):

Cl 6.2 Page 32 

Tdg = Ag.fy/rmo

where,

Ag=Gross Area of Cross Section

fy=Yeild Stress of Material

2) Due To Rupture of Critical Section (Tdn):

Cl 6.3 Page 32

Tdn = 0.9.An.fu/rml

where,

An=(b-n.dh)t   For Chain Bolting

fu=Ultimate Stress of Material

Cl 6.3.3

If there is Single Angle Section then,

Tdn =(.9Anc.fu/rml) + (beta.Ago.fy/rmo)

where,

beta=1.4-0.076(w/t)(fy/fu)(bs/Lc) < (fu.rmo/fy.rml)

                                                                           >0.7

w=outstanding width

t=Thickness of Leg

bs=shear lag width

Lc=Length of end connection

An=Net area of Total Cross-section, as told above

Anc=Net Area of Connection Leg

Ago=Gross Area of the Outstanding Leg

3) Due to Block Shear (Tdb):

Cl 6.4

Tdn1 = (Avg.fy/ rmo.root3) + (0.9.Atn.fu/rml)

Tdn2 = (0.9.Avn.fu/rml.root3) + (Atg.fy/rmo)

where,

Avg = Lv.t

Avn= (Lv-n.dh).t

Atg = Lt.t

Atn = (Lt-ndh).t

#Td for Welded Connection:

The Block Shear Strength Should be checked for welded end connection for member which can shear off as block.

For this Avg = Avn = Lv.t

and Atg = Atn = Lt.t

where,

Lv is Longitudinal Length

Lt  is Transverse Length