Some Topics in PA
Hi, I have my PA coming in a week. There are some topics I am not very clear about and hope someone can help me with them.
1. Geotechnical Report.
I have read Site planning and Design chapter 7 thoroughly but when it comes to the real geotechnical report I am still confused about when to use shallow/deep foundations.
The answer to this question based on the picture is individual footings.
Piles are wrong because 'piles are a type of deep footing that are required when upper layers of soil are unstable and the building must be built on bedrock. Because the boring logs show loamy soils within 6'-10' of the surface, pile foundations are not the best choice.'
Doesn't loamy soil have low bearing capacity? How do I know if sand with fragment of clay is suitable for shallow foundation?
2. Occupant Load
- 6 conference rooms, 900 sf each,
- 15 supervisor offices, 440 sf each,
- 2 electrical closets, 300 sf each,
- 4 pantries with some chairs and a bar, 250 sf each.
When calculating occupant load on this floor with the program above, why are pantries counted as accessory to occupancy B and use 150, instead of 300 as accessory storage area?
3. Passive Cooling in Hot Arid climate
Why is stacked ventilation also considered? I am assuming it would only work during night time since during the day we would want to avoid hot dusty wind.
This is a question from Ballast and all of them are correct ...
In many desert areas of the country, the climate during the summer is hot and dry during the day, but cooler and quite comfortable at night. In such an area, which of the following building conditions would be desirable?
- Exterior shading devices
- Dark color on the south facade - this can't be right .... right???
- Light-colored roofing
- Insulation on the exterior of masonry walls
- Vented openings facing the prevailing wind
Thank you so much for answering my questions : )
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Hi Yue,
Individual or isolated footings would be good for this because they can bear on the sandy lean clay. Sand is not good for shallow foundations because it has high permeability and the water affect this foundation. I believe the best foundation for sand is a pile foundation.
For the pantry occupancy, I could not find it on code but I think it has something to do with tables and a bar being in that space. Also, you can have an accessory space without separation if the space is less than 10% of the main occupancy.
The stack effect can exhaust by natural convection, where hot air rises and cold air stays at lower level. I think that in order for the stack effect to work in this environment the outdoor air has to be cooler than the inside air. For this hot arid climate, exterior shading is good, dark color is bad, light colors is good, and vented openings may be good for the wind to cool down building.
I am also studying for PA, hope this helps.
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