Building geometry 10

[hoshang]

Hi all,
Please find the attached image.
Do you think the proposed geometry acceptable regarding center of mass and center of rigidity considerations? FYI the red circle is the center of mass.

 

[HTURKAK]

The attached sketch is basement plan of a bldg. I could not see the subject red circle . Provide more info. ( other storey plans , sections A-A and B-B to get better responds.

Use it up, wear it out;
Make it do, or do without.

NEW ENGLAND MAXIM

 

[hoshang]

I could not see the subject red circle .

Sorry, please find the attached image.

 

[BAretired]

The geometry does not appear to be a structural problem, but it is a terrible parking arrangement.

 

[hoshang]

Provide more info. ( other storey plans , sections A-A and B-B to get better responds.

Please find the attached file.

but it is a terrible parking arrangement.

How would you arrange the parking?

 

[hoshang]

Hi,
The attachments

 

[dik]

One of the worst I've seen... How essential is it to have parking; is it possible to have it on site, somewhere or off-site. Those parking stalls will cost over $50,000 per stall... likely closer to $75,000 each.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[hoshang]

How essential is it to have parking; is it possible to have it on site, somewhere or off-site.

It should be on site (as indicated on the attached drawings).

Those parking stalls will cost over $50,000 per stall... likely closer to $75,000 each.

I'm not aware what do you mean.

 

[dik]

The added cost to the structure for having parking within will likely cost this much per vehicle space.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[BAretired]

How would you arrange the parking?

Hard to say without knowing the constraints. The floor area is too small to have an efficient parking arrangement, but it might be improved by utilizing some of the wasted space.

 

[hoshang]

Those parking stalls will cost over $50,000 per stall... likely closer to $75,000 each.

For this building being residential apartment, the parking apartment within the building is a requirement.

The floor area is too small to have an efficient parking arrangement, but it might be improved by utilizing some of the wasted space.

Can you give an insight on how to utilize some of the wasted space?

 

[HTURKAK]

Eng.hoshang ,

The center of mass ( red circle is the basement plan ) could not be the correct location. I have no idea for , how did you find the location. The structure has plan irregularity. I do not have any idea for seismicity and applicable codes in your region.

Some general points ;

- The cantilever beam length around 3.0 m in general is not allowed for high seismic zones ,
- Consider adding some shear walls to reduce the eccentricity and improve the seismic resistance,
- Ask the services or consultancy of an experienced structural engineer.

Say my opinion .




Use it up, wear it out;
Make it do, or do without.

NEW ENGLAND MAXIM

 

[hoshang]

The center of mass ( red circle is the basement plan ) could not be the correct location. I have no idea for , how did you find the location.

I used AutoCad tools to find the center of mass.

I do not have any idea for seismicity and applicable codes in your region.

Per soil report:
According to available information regarding seismic activity and referring to the earthquake map shown in appendix C, it is clear that the site is located within the zone VII of medium activity according to Mercalli scale, which is equivalent to earthquake of (5) in Richter scale. Such earthquakes when occur can cause slight damages such as some cracking of ordinary masonry walls, fall of plaster, small slides along sand or gravel banks, and damage in drainage systems table 1 of appendix C. It is necessary to consider these facts in design by construction well-built structures with high quality. A coefficient of horizontal acceleration Kh= 0.2 can be used for seismic analysis.
According to UBC code requirements the site is located in zone (2B), soil profile type (SD) can be used in the analysis. According to ASCE 7-16
Ss=0.6, S1=0.2.

The cantilever beam length around 3.0 m in general is not allowed for high seismic zones ,

Now you have idea for seismicity, then would you consider the location as high seismic zone?

Consider adding some shear walls to reduce the eccentricity and improve the seismic resistance,

I'm planning on using shear walls at stair locations (in addition to the elevator core). Do you think this reasonable?

 

[BAretired]

Can you give an insight on how to utilize some of the wasted space?

Not without considerably more information about the site and upper floor plans.

 

[hoshang]

Not without considerably more information about the site and upper floor plans.

Please find the attached file.

 

[BAretired]

I can't open that file, but in any case, I do not wish to engage in an architectural/structural engineering design review.

 

[hoshang]

but in any case, I do not wish to engage in an architectural/structural engineering design review.

I'm planning on using shear walls at stair locations (in addition to the elevator core). Do you think this reasonable?
Do you think the proposed geometry reasonable regarding eccentricity between center of mass and center of rigidity considerations?

 

[driftLimiter]

...regarding eccentricity between center of mass and center of rigidity considerations?

What considerations are you concerned with?

Building codes may prohibit buildings with excessive torsional irregularity in very high seismic zones. This needs to be determined based on the specifics of the building and the code requirements.

Given your Ss = 0.6 and S1 = 0.2, it seems unlikely you would fall into a category that strictly prohibits it. But nonetheless you must address the torsional irregularity as part of the lateral design.

 

[BAretired]

quote (BAretired)
but in any case, I do not wish to engage in an architectural/structural engineering design review.

I'm planning on using shear walls at stair locations (in addition to the elevator core). Do you think this reasonable?
Do you think the proposed geometry reasonable regarding eccentricity between center of mass and center of rigidity considerations?

My comment was in regard to the parking arrangement. I think it is terrible as drawn with two cars blocking two others from moving out. The space appears to be too small to significantly improve parking, but the architect may have some ideas. It is impossible to address the question based on the basement plan alone. One must understand other constraints imposed by the site plan and the upper floor plans.

With regard to your question regarding eccentricity between center of mass and center of rigidity, the notion that there could be a structural issue would not have occurred to me. Based on the information I have seen so far, it appears to be a complete non-issue.

I cannot see how you have arrived at the red circle to determine the center of mass. I believe it should be approximately where I have drawn a blue circle, but perhaps you have a huge mass in the south west corner.

 

[hoshang]

What considerations are you concerned with?

I meant how one can decrease the eccentricity between center of mass and center of rigidity in my case.

It is impossible to address the question based on the basement plan alone. One must understand other constraints imposed by the site plan and the upper floor plans.

The plans are attached in my post on 27 Dec 23 21:26. What does the cross lines mean in your post?