Tension Member Hole Allowance Deduction
When designing tension members, the net effective area is used to determine the member's capacity. This is calculated by deducting the area of holes made for fasteners (like bolts) from the gross sectional area.
Calculating Holes for Angles and Web Plate
For a tension member constructed using four angles connected to a web plate, specific rules apply for deducting bolt holes:
- Angles: Allowance is made for one hole per angle leg connected to the web plate. Since there are four angles, this accounts for the primary connection points.
- Web Plate: The web plate itself requires fastener holes to connect with the angles. In this configuration, allowance is typically made for two holes in the web plate. This accounts for the fastener holes along the width of the web plate where it connects to the angles.
Therefore, the standard allowance considered is one hole for each angle and two holes for the web plate.
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.
