A flat roof is subject to the following uniformly distributed loads: a dead load of 29 psf (pounds per square foot of roof surface), a roof live load of 12 psf, a snow load of 13.5 psf, and a wind load of 22 psf upward. (Although the wind itself is in a horizontal direction, the force that it exerts on this roof is upward. It will be upward regardless of wind direction. The dead, live, and snow loads are gravity loads and act downward.) a. If load and resistance factor design is used, compute the factored load (required strength) in pounds per square foot. Which AISC load combination controls? (Express your answer to three significant figures.) R₁ psf -Select- b. If allowable strength design is used, compute the required load capacity (required strength) in pounds per square foot. Which AISC load combination controls? (Express your answer to three significant figures.) Ra = psf -Select-

2. Roof joists are spaced at 2m and span 6m between supporting girders, and joist depth of 600mm. The allowable deflection limits for OWSJ are L/360 under snow load. The OWSJS are subjected to a dead load of 2.96kPa which includes the estimate joist weight of 0.15kPa, an occupancy load of 2.4kPa, and the following: SULS 1.99kPa SSLS = 1.25kPa Select a suitable OWSJ which satisfies the limit states design.

Wind can produce very high drag loads on high-rise bulidings. Since calculating the áow around a buildingis quite diffcult, you decide to perform an experiment to find the drag on the nearly completed Mirabellabuilding at Univesity Drive and Myrtle Avenue in Tempe. The building is 250 ft tall and approximately 210ft wide (at its widest part)   A) determine the drag on the Mirabella building for a sustained wind speed of 40 mph. Supposethat the temperature remains the same both inside and outside of the wind tunnel test section. If theatmospheric pressure is 100 kPa, what would the pressure have to be inside the tunnel test section tomaintain dynamic similarity between the model and the full-scale building? (You may assume that thetunnel is operating at maximum speed.

True or false, the load on a column for my particular floor depends on the tributary area of the column on the floor?