The truss ABC shown in the figure supports a vertical load W at joint B. Each member is a slender circular steel pipe (E = 30,000 ksi) with outside diameter 4 in. And wall thickness 0.25 in. The distance between supports is 23 ft. Joint B is restrained against displacement perpendicular to the plane of the truss.
Determine the critical value Wcr of the load.
![1795_6db86d81-2fc3-4078-906e-17c14dd9ef41.png](https://secure.tutorsglobe.com/CMSImages/1795_6db86d81-2fc3-4078-906e-17c14dd9ef41.png)