Question

a) Explain with an illustration why only external pressures are considered when determining the primary (i.e. global) structural action due to wind loads.

b) What range of Cpi would you consider for a residential apartment building?

c) Which exposure classification would apply for the following situations:

a. Wind coming from Lake Ontario for a building located on the waterfront in Toronto.

b. A tourism center located in a national park in Northern Ontario.

c. A structure located on the edge of an urban area with a few homes between it and farmland.

d. A storage unit for a construction company located in a rural community without many trees.

d) What conditions must be satisfied for the equivalent lateral force procedure to apply?

Answer all of this, if not please answer some of it. Thanks

Answer 1

Ans(a) : As the wind load applied to the structure is an external force and all the internal forces would cancel each other by equilibrium condition assuming that if wind is not there nothing will happen to structure. So the internal pressure doesn't come into role and only external pressure are considered while taking any action for the wind load being applied to structure.

Ans(b) : Cpi stands for cost performance index. It is a measure of financial effectiveness and efficiency of project. The Cpi range is around 155-160.

Ans(c) : Below the exposure class are mentioned as mild or severe as per their conditions to environment and structure.

1. Very severe. Like sea breeze.
2. Mild. Due to no coastal area.
3. Mild. Same case as above.
4. Severe. As trees are less it would have severe exposure to the environment.

Ans(d) : Equivalent lateral force method is used for distributing stress on the floors which are able to transfer lateral loads. The condition is that the structure should not have discontinuity in mass and stiffness should not be there along the height. Then only this method will be applicable.