Week 9 Challenge

1. Design of dual slope (pitched) roof frame

Design a 3 hinged pitched roof frame of a steel building. Assume no wind load acting on the walls and roof. Analyse the frame structure and draw bending moment, shear force and axial force diagrams of the frame. The slope of the roof is 1 in 10 and the roof is accessible for maintenance purpose (assume 75 kg/m²) only. Dead load on the roof are given below. Assume bay spacing as 5 m and frame width is 20 m. (Design code as per AISC:ASD. No seismic load consideration required)

Weight of roofing sheet = 5kg/m²

Weight of purlins + tertiary members = 25 kg/m²

^{Answer -}

^{Open the Staad.}

^{Create the model structure of file and opeen it.}

^{Define and assign the nodes and beams as per given data of structure.}

^{Assign properties of structure such as tappered section and beta angles for columns.}

^{Create and design the support to columns and internal hinge.}

^{Add loading such as load case details as per given for dead load and live load.}

^{Add load combination such as DL+LL.}

^{In loading we assign self weight, member load as per given data.}

^{Go to analysis and perform analysis.}

^{After that go to design use AISC:ASD code in options.}

^{Add design parameters and apply on the structure.}

^{In commands use steel take off and check codes apply on structure.}

^{Ckeck utility ratio is less than 1 or not.}

^{Do some try error based proprties after we get proper section which utility ratio is less than 1.}

^{Seen the bending moment diagram, Shear force diagram, Axial force diagram.}

^{Also seen the maximum bending moment, maximum shear force, maximum axial force.}

^{Check our section is pass or fail in design.}

2. Draw Bending Moment diagram for following Frame using STAAD.Pro

Figure 1)

Given

Supports are fixed and pinned.

Angle of slopes - 5.71 degrees

Width of frame - 20 m

Height of end column - 10 m

Height of mid column - 10 tan 5.71 - 1m

Height of mid column - 10 + 1 =11 m

Loading udl = 20 kn/m

Point load - 10kn

Process

Create frame model on staad.

Assign properties as to beams and columns.

Assign to loading to section of member.

Run the analysis.

Check bending moment diagram.

Figure 2)

Given

Supports are pinned.

Angle of slopes = 20 degrees

Width of frame = 10 m

Height of end column = 20 m

Height of mid column = 10 tan 20 = 3.64 m

Height of mid column = 20 - 3.64 =16.36 m

Loading udl = 10 kn/m

Point load = 30kn

Process

Create frame model on staad.

Assign properties as to beams and columns.

Assign to loading to section of member.

Run the analysis.

Check bending moment diagram.

Figure 3)

Given

Supports are Hinged.

Width of frame = 8 m

Height of end column = 10 m

Loading udl = 20 kn/m

Point load = 10kn

Process

Create frame model on staad.

Assign properties as to beams and columns.

Assign to loading to section of member.

Run the analysis.

Check bending moment diagram.