Someone help me Please. Question are many but solve systematically 1. Calculate

Question

Someone help me Please. Question are many but solve systematically

1. Calculate the distributed wind loads (#/ft) exerted on each edge of the 2nd floor and roof diaphragms (N?S and E?W directions).

2. Calculate the distributed seismic loads (#/ft) exerted on each edge of the 2nd floor and roof diaphragms (N?S and E?W directions).

3. Compare the wind and seismic forces transferred to each shear wall or braced frame. The greater of the two is considered the critical load condition for that element. It is important to note that the critical load (wind or seismic) CAN be different in the two directions.

4. Calculate the overturning moments on each masonry shear wall from the critical load condition (see above). Assume the stabilizing moment is from weight of shear wall ONLY (not floors, etc. connected to it. Calculate and compare these moments with the stabilizing moment – calculate the stability factor for wind and seismic loads.

5. If there are 41 anchors (approximately every 2’) connecting each masonry shear wall to the foundation along the base of the wall (assuming critical loading condition), what is the required shear capacity of each anchor (in lbs force). Assume that each anchor handles the same amount of sheer as the others.

6. Calculate the hold down forces anchoring each braced frame to the ground, assuming anchors at each end of the frame. Assume the critical loading condition.

7. If round cross?bracing rods are used in the braced frame and are made of steel with an allowed tensile stress of 22 ksi, what is the required diameter of rods required (may be different in top and bottom frame). Assume that the rods are available in 1/8” increments of diameter. Assume the critical loading condition.

8. Calculate the loads on each side of the braced FRAME (the rigid elements to which the rods are attached – see inset). Assume the critical loading condition. Draw a diagram of the frame and label each member with its load.

9. Calculate the chord forces (T and C in lbs) associated with the critical load condition at each edge of roof.

10 .If there are 41 anchors (approx.. every 2’) connecting the roof diaphragm to each sheer wall, AND if we assumed that these bolts must handle both shear AND chord forces from the roof, what is the required sheer capacity of each bolt (in lbs).

***example of another problem just one fourth of it.

Explanation / Answer

Solution:

Wind pressure = ( 0.0256 V2*(Cc)*(Cq)*(I))

Cc for 20 ft height = 0.67

for 40 ft height = 0.84

Importance factor for police station = 1

Cq value for the building upto 40 ft tall = 1.3

Pressure upto second floor level = 0.0256*(802)*0.67*1.3*1

Pressure upto second floor level = 14.270 psf.

Pressure upto terrace floor level = 0.0256*(802)*0.84*1.3*1

Pressurre upto terrace floor level = 17.89 psf.

North- south direction:

Wind speed for a height of 30ft considered for second floor

10 ft height is considered for roof portion

(W)30= 14.27*30 = 428.1 plf

(W)40= 17.89*10 = 178.9 plf

Width in north south direction = (100/2) = 50ft

(Wind load)upto second floor = 428.1*50 = 21.4 Kilo pounds

(Wind load)roof level = 178.9 *50 = 8.945 Kilo pounds.

East - West Direction:

Width in east-west direction = 40 ft

(Wind load)upto second floor = 428.1*40 = 17.1 Kilo pounds.

(Wind load)roof level = 178.9 *40 = 7.156 Kilo pounds.

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