Horse Stable with Masonry walls and metal roof beams 1

[Dara_1]

I have a project in a high seismic region which is a horse stable (40'*x117') with so many openings on the sides that doesn't let me use vertical bracings and design it like a normal warehouse.

The roof should be metal and I want to use z purlins that sit on w-shapes. I don't know if I have to put the beams on steel columns and run them all the way down to the foundation or if should I put them on the CMU walls.

 

[milkshakelake]

It's hard to say, because it's a very general question. It depends on your layout and requirements. It's not clear what you're trying to achieve. Maybe a sketch or plan would help.

Generally, if you can avoid steel columns, it'll be easier to construct. You can make reinforced CMU columns. Just check for slenderness, axial load, and eccentricity (if any). If you need them to be moment-resisting, you should use steel columns.

 

[KootK]

I'd bear your steel beams on the masonry assuming that your intent is for the masonry to be your building's lateral system.

 

[Eng_Struct]

I agree with KootK. You should take advantage of CMU and turn it into load bearing. Given the masonry thickness, you may be able to get away from having to provide CMU columns.

For gravity system, I would check the walls for combined bending and axial as well where bending is due to wind. For lateral system, I would consider series of cantilever wall sections in between the large openings to be providing lateral resistance. Note that openings, depending on the size, will effect stiffness of shear wall. You may find the centre of stiffness not aligning with centre of mass, thereby resulting in torsional shear that will need to be considered.

 

[1503-44]

What's high?



--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[GeorgeTheCivilEngineer]

General question for my own interest - if it's a horse stable can't you design it to a lower (what we'd call) consequence class? Or has the client insisted on seismic resistance?

 

[1503-44]

Some horses are worth way more than a Mercedes. There are a lot of people living in worse than CMU walls and metal roofs, and not designed for seismic conditions either. It sounds like they might be at least a little special to someone.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[phamENG]

Be careful with steel. Stables are prone to ammonium hydroxide condensing in the roof structure. Some woodworkers seek out old stable timbers because it does some neat stuff to the wood (and some even built little kilns to try to create the process in a semi controlled environment). But ammonium hydroxide is a corrosive base that will rust steel.

 

[Dara_1]

 

[Dara_1]

The city wants the roof to be metal and doesn't let wood structure because of fire hazards that exist in the area.
The pictures are the preliminary conceptual architectural drawings and we can change them.

I'm more inclined to go with the system in the image below now that I did a little bit of research. I found this system in an article from NCMA (National concrete masonry association. I just don't know why they didn't put the steel beams on the CMU walls directly.

 

[Dara_1]

 

[1503-44]

It would seem that, if you are already planning to use steel beams for the roof, adding steel columns is probably cost effective. It also adds continuity to the system design. Steel IMO has better inherent properties for seismic design. Plus steel frame work combined with no load cmu infill walls is a proven, conventional and effective construction practice. Why bother with constructing all those reinforced CMU columns. Shop fab steel columns are easy and erection time is minimal.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[phamENG]

What you're proposing is called a Metal Building System (MBS), or some still refer to it as a 'pre-engineered metal building'..

These systems do have some benefits, but also several draw backs. Be sure you understand the implications for masonry detailing, foundation design, and building preforms specifications. Read up on the Metal Building Manufacturers' Association guide specs, AISC's design guides (particularly the one on serviceability), and Newman's book on foundation design for these things.