(Solved): Structual Design A concrete floor system (shown below) is to be supported by four wide- flange steel ...

A concrete floor system (shown below) is to be supported by four wide- flange steel beams spaced 12 feet apart that rest on masonry walls along the 44 foot length. The floor carries a live load of $70\mathrm{lb}/{\mathrm{ft}}^2$ and the slab depth is $6"$ ". Assume that light weight reinforced concrete weighs $110\mathrm{lb}/{\mathrm{ft}}^3$ and the beams are simply supported on the above mentioned masonry walls. Design the lightest weight steel beams required to support this structure for moment capacity only assuming: (Disregard any torsional loading conditions and don't forget the weight of the beams!) a. The beam is unbraced b. The beams are braced at the mid-span only c. The beams are brace at the third points of the span