Design Strength of Tension Members | Design of Steel Structures
DESIGN OFTENSION MEMBER
* The section should be compact and in order to minimize stress concentration, it should be so
arranged that as large portion of it as possible is connected to the gusset plate.
* Design strength is the lowest of the following:
1. Design strength due to yielding of gross section Tdg
. 
2. Rupture strength at critical section Tdn
3. The block shear Tdh
1. Design strength due to yielding of gross area:
Tdg =
2. Design strength due to rupture of critical section
Tdn =
where An =
For threaded rods and bolts, An =
3. Design strength due to block shear
Tdb =
or Tdb =
where Avg and Avn = Minimum gross and net area in shear
and Atg and Atn = minimum gross and net area in tension
* Design procedure:
1. Find Ag = where Tu = factored tensile force
2. Take A = 25 to 40 % more than Ag
.
3. Select the section, design the connection and find the strength.
4. Redesign, if strength is less or too much higher compared to the load.
5. Check for slenderness ratio which should be within the limits specified in Table 3 of IS 800–
2007.
Tension member splices
* Strength of splice plate and joint should be at least equal to the design load.
* If packing thickness in connection exceeds 6 mm, the design shear capacity of bolts in shear should
be reduced by a factor
bpk = 1 – 0.0125 tpk
.
Lug Angles
* Length of end connection of a heavily loaded tension member may be reduced by using lug angles.
* Use of lug angle may reduce the size of gusset plate, but it adds to the cost of connection.
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