A steel cable used in a suspended roof system has an allowable tensile strength of 150 ksi. It must safely carry a load of 1,060 kips. Determine its required diameter.

The maximum permissible load on a steel bar of 20 mm dia when the factor of safety is 1.8 and the ultimate stress is 495 MPa is (a) 863.9 kN (c) 8.639 KN (b) 86.39 kN (d) 0.86 kN

Wood planks are used on each working level. The deck width/bearer span is 5 ft.. The bearers and posts are standard pipe and the pipe material is A36 steel with a yield stress of 36,000 psi and modulus of elasticity of 29,000,000 psi. Bearers are to be located at a vertical spacing of 10 ft (largest, lowest post height). Posts are to be 7 ft oc (plank length) parallel to the building wall and 5 ft apart (bearer length) perpendicular to the building wall. There are four working levels and the anticipated scaffold loading will be med duty. A. Assuming the ultimate bending strength of the planks is 3,800 psi (apply a 4:1 F.O.S.), determine the required minimum plank thickness to the nearest 100th.  B. Based on the bearer material provided, what is the minimum pipe size that can be safely used? See Appendix 2 in your textbook for steel pipe properties.  C. Based on the post material provided, can a 2” standard pipe be used safely? Be sure it satisfies buckling stress conditions only.

Assuming k= 3000 lb/in?, and considering only the bending stress: What rail type would you recommend if only a single force of P = 30,000 lb is applied to it?