Which of the following should be minimized in the design of a tension member?
Deduction for rivet and bolt holes
The tensile capacity of a steel member depends on the net sectional area (gross area minus deductions for holes). To maximise the tensile strength:
- The deduction for rivet/bolt holes should be minimised
- Larger holes → larger deductions → smaller net area → lower strength
- Holes should be staggered (if possible) to reduce the net area deduction using the s²/4g formula
The gross sectional area and allowable tensile stress are design parameters that depend on the member size and material grade — they are not minimized. The net sectional area is what must be maximized (by minimizing hole deductions).
Important Questions from Tension Member
A single angle in tension is connected by one leg only. If the areas of connecting and outstanding legs are respectively a and b, then what is the net effective area of the angle?
A) \(a-\frac{b}{1+0.35\times\frac{b}{a}}\)
B) \(a+\frac{b}{1+0.35\times\frac{b}{a}}\)
C) \(a-\frac{b}{1+0.20\times\frac{b}{a}}\)
D) \(a+\frac{b}{1+0.20\times\frac{b}{a}}\)
The net area of round bars to resist the tension, is the area of the cross-section at
A steel plate is 300 mm wide and 10 mm thick. It has one rivet of nominal diameter 18 mm. The net sectional area of the plate is
The best tension member section will be as:
For preliminary sizing, the rupture strength of net section may be approximately taken by using the below equation as per IS ∶ 800-2007,
Tdn = αAnfu/γml
What is the "α" value for one or two bolts along the length in the end connection or equivalent weld length.
