Four sided concrete roof

[boricuastructural]

Im an entry level engineer and have never designed a four sided roof (i think thats the term in english). I was wandering i you knew where to find information in regards on how to specify the reinforcement.

 

[UcfSE]

Speaking for myself, I am not familiar with the term "four sided roof". Would you mind describing it?

 

[jike]

Is this a concrete slab spanning two directions, to four perimeter walls?

 

[boricuastructural]

Its a roof that slopes in four directions. They are very effective for wind pressures. It like a gabled roof but in two directions.

 

[ctcray]

That's called a Hip Roof.

 

[boricuastructural]

Thanks.

 

[boricuastructural]

I have consulted and researched this and found different ways to specify the steel. I have seen one that I can not understand. It has steel in both directions with standards hooks at the end and also the temp reinforcement. It is the same as placing the regular reinforcement with dowels?

 

[csd72]

boricuastructural,

Are you sure that this is meant to be done in concrete? It is usual to do this type of roof in timber trusses.

csd

 

[boricuastructural]

csd72,

Yes. It is done in Puerto Rico where I live.

 

[csd72]

Watch out for the bowstring effect at the crank in the top of the roof.

csd

 

[csd72]

Si Buena,

Watch out for the bowstring effect at the crank at the top. The bottom reinforcement should continue up to lap with the top reinforcement frm either side (i.e. a kind of a splice).

Otherwise if you just had a bent piece of bar it would want to straighten and would therefore break out of the cover concrete (like a bowstring).

csd