Week 2 Challenge

Design of Tension Member

1. Net Area for tension member calculation problem

Calculate the net section area for the tension member as shown in Figure below. The plate size is 260 x 20 thick and Bolt size is 20 mm.

Plate – Drilled Hole

Answer

Aim- To Calculate net section area of tension member of given figures.

Given data-

Plate width b= 260mm, thickness of plate t= 20mm, Bolt Size =20mm

Bolt hole dia d_h =20+2 = 22 mm

As per IS-800.2007 Clause-6.3

Net area of cross section A_n = (b-n d_h) t = (260 – 4 X 22) X 20 = 3440 mm²

Plate – Zigzag bolting

Angle (200 x 100 x 12 with M20 bolt)

2. Sag rod design problem

Design a sag rod as shown in Figure below. Purlins are supported at 1/3^rd points by sag rods.

Assume centre to centre distance of Rafter spaced at 8 m , spacing of purlin = 1.2 m, Self weight of roofing (including thermal insulation)= 60 kg/m² , Wind pressure intensity = 150 kg/m²,Slope of rafter = 15 degrees, Live Load =75 kg/m². Assume self weight of purlin as 100 kg/m.

Answer-

Aim - To Design of Sag Rod

Procedure-

• Calculate Total Dead Load and Live Load
• Load calculation at sag rod
• Calculate required net area and size of rod

Calculation of following Attachment.

3. Determine section size for given tensile load

Design a single angle member of length 5m to carry axial tensile force of 500 kN. Yield strength fy of the material to be considered is 350 N/mm².

Answer-

Aim- Design a tension member of single angle as per Indian Standard and Checking section

Procedure -

• Calculate required area of cross section from given factored load
• Choose an angle section from required area calculated
• Calculate design strength of the member due to yield
• Calculate design strength of member by reputure of net section
• For a given member assume welding with welding length and calculate block shear capacity

Calculation as per following attachment-