Can any one give me the best roofing method to span a 175 foot by 160 foot building with out using columns and still be strong enough to withstand hurricanes.  I know of red iron I beams anything else?

Thanks fellow ICF nuts.
Clarence

We may be ICF nuts on this forum, but I don't think any one of is nuts enough to answer that question. Structural engineering by internet??? I don't think so!!!!!

You damn well better have an engineer's stamp on whatever plans you go by for this one.

Engineers are probably working on the project already since all plans have to be approved, but I thought most engineers new that. I'm just interested  in what alternatives are available.

I take it you meant to say "...knew that." So I ask, "knew what?" How to do that kind of a roof? If that's what you meant you give us too much credit, or you know too many engineers with expertise in BS!!!

If there's some structural engineers on this forum maybe they will offer some ideas of roof designs. Undoubtedly you will see some sort of truss design. Trusses offer the greatest strength for the amount of material required.

What sort of hurricane wind do you have to design to? When I was at the SPR our A-E firm designed several buildings with 120 mph wind as the criteria. The approach was to design a wall and roof covered in sheet metal in such a fashion that in a 120 mph wind the sheet metal would rip loose and fly away. It was cheaper to let the sheet metal go than try to keep a whole building on the ground. Columns and roof girders were I-beams but the largest building was only about 60' wide.

Chillmiester,

dmaceld is right. You need a structual engineer to engineer your wide bridge span. Most people here are not engineers nor are they commercial contractors, for your building is over 28,000 sq feet, although some do frequent this site. With the scant amout of information provided I would have to say it can be done and my favorite way would be an air filled dome like the Metrodome in Minneapolis Mn.

ICF Contractor

Clarence,.....I used to be an engineer for a truss company. All we manufactured though was wood. Longest clear span we ever did was 120', and that was one hell of a truss (and we don't worry about hurricanes or earthquakes in michigan). We built it in 3 pieces and spliced in the field. Truss was designed for 47psf and it was spaced at 48" O.C.  You talk about bracing,....there was almost as much lumber in splice material and bracing as there was in the actual truss! 175' truss as in you case is a whole different scenario,........kinda like comparing residential bldg to skyscrapers.

Bunt

I wonder if a reinforced shotcreted barrel vault would cover this wide span and still be strong enough to withstand uplift once the building is breached by wind?

A dome supposedly is the structure geometry most resistant to hurricane force winds. A barrel structure would probably withstand winds perpendicular to it. Parallel wind would probably blow out the ends. We had a warehouse at the SPR where Rita blew out the windward side and the opposite side. Rest of the building was hardly damaged. A good building design might be the Mormon Tabernacle roof resting on the ground!

Magnesium Phosphate cement 12,000 psi with basalt fiber as well as basalt rebar.

Google Luigi Nervi if you think it has not been done before.

Thanks every one. Now this is the response I was hoping for. The project is in the Caribbeean and will use about 12000 block. I've done hotel convention center, but wanted to see what everyone here had experience with large roofs.