Example for calculations of seismic loads through a basic box structure. Only the primary elements are computed here, assuming a wood-framed structure with flexible roof diaphragm.
I am an Aerospace Engineer working a unique Civl Engineering project with seismic assesment requirements and found your lecture very informative and straightforward to understand, thank you very muc for your contribution for us in the technical world!
excellent! I really enjoyed it, very clear presentation. @ 20.08 for wind loads, you had mentioned the wind loads be the same. But the wall length are different, can you comment on that? @ 4.52, would the weight be the same if it were wind loads, 1/2 of 2-walls plus roof weight? thanks
Thanks...glad it was helpful. The wind load *pressure* is assumed to be the same in all directions. The total wind *force*, however, depends on how long the wall is to accumulate that pressure. For the second question, the wall and roof dead loads are what generate the seismic forces in a building by virtue of their inertia. Wind loads in contrast act externally to the wall, so the wall weights are not part of load computation.
Excellent article, congratulation, Could you give a lecture of Example for calculation of seismic loads for a conventional valve., like Globe valve as it may be useful for valve enginers
Sorry, that's a question outside the scope of things here. I make these specifically for my students in architecture but post them here for general info. The process here also is using older code provisions that have been superseded. The basic principles would be the same for a storage tank, though, that seismic forces come from inertial mass of whatever is being stored in the tank. I suggest you look at other more technically-based structures links. Dr. Structure here on RU-vid might be a good place to start.
Hi professor Deb. Do you have an example for designing cast-in-drilled-hole (CIDH) steel reinforced concrete piers? I have software to design the pier itself, but not sure how to establish horizontal seismic force for each pier (lateral loads near slopes already provide by my Geotech). I was proposing that I could take the tributary total dead load and simply multiply it by the calculated base shear factor of approximately .14W here in California zone 4. This is for my own residential foundation repair design. Thanks so much ! Ted
Hi Ted...sorry no, that's really outside the scope of the type of videos I make for my students. For a real project on your own house subject to the seismic loads you really need to consult with a licensed structural engineer. So much depends on the soil type of your foundations as well as the dead load of the house. 14% of your dead load may or may not be high enough for your location. The resonant interaction between the natural periods of vibration of the building and soil are a critical concern. Designing for seismic resistance is NOT a do-it-yourself job! This is not to even mention the necessary anchors and straps required throughout the house to maintain a continuous load path from the roof to the foundation.
I am new to the structural analysis. Roof DL (North-South) should be calculated 15 psf * 1 ft (12" strip a.k.a tributary width) which indicates the linear load along 60' long section?
I'm not quite sure if that's a question or a statement. If it's a question, maybe you could rephrase it as I'm not quite sure what is being asked. The loads computed in the N-S direction are those that accumulate (plus the wall DL) along the 100' width of the building, That force is then in turn resisted the the exterior N-S walls on the east and west faces that carries it to the foundation,
Professor how do i find the earthquake load that we put in to load the combination equation is that the base shear value or the resultant value of all floor or each story? which value do I use to check the earthquake load combination? Thanks.
In multistory structures the base shear is the total due to the inertial forces accumulating from top to bottom of the structure. This base shear then gets distributed to each level of the structure as a percentage of the total. Codes have a formula for that that also consider the mass of each floor level and period of vibration, all of which is beyond the scope of what I cover here in this basic example.
This is based on an old code in the United States (the Uniform Building Code of 1998), which is quite simplified from current codes. The intent of this example is to explain the basic principle of how seismic loads are generated and move through a structure without getting overly complex.
