Steel Frame or Not

[engstructural]

Steel Frame or Not

I have a project where the architect had proposed a steel frame the building has dimensions 20x11.5m, 7.0m to eaves - with not internal walls etc. The budget is tight and the architect wants to investigate the possibility of using an external walls of 100/100/215 with steel wind/restraint posts at approx. 2.5m centres built into the inner leaf. The top of the posts would have to be tied to the wall plate. He wants to use a traditional type cut timber slate roof (or timber trusses) and I would assume we would look at constructing the ceiling as a horizontal timber diaphragm carrying the windpost reactions back to the gable walls.

Looking at it in theory it would seem an acceptable solution however the height and area of the building is making me a little uncomfortable with this as a solution. Has anyone any experience of this or can anyone see any issue which I should be taking account of in the decision of structure type?

 

[Ron]

Sounds like a pre-engineered metal building application to me. What's the problem? Not familiar with your steel terminology.

 

[Ussuri]

Ron,

The building described above is not steel, he is querying whether it should be. The architect wants to use an external cavity wall 100mm outer, 100mm cavity and 215mm inner constructed from concrete blocks. To stiffen the wall panel they are proposing wind posts (steel angle sections designed to be cast into the concrete wall with ties into the mortar joints). The posts span vertically and need some sort of connection at the top of the wall to provide support.

The approach is perfectly acceptable and we have done it in the past (although not with a 7m high wall) and the trick is making the connection at the top work to transfer the load from the posts. Its been a long time since I did masonry design but the size of you masonry panels might also cause you a problem so you might consider bed joint reinforcement.

 

[Ussuri]

If i remember correct the US term is wythe. So 4 inch outer wythe, 4 inch gap and 8.5 inch inner wythe.

 

[msquared48]

Sounds complicated to me. How can this be budget effective?

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[hokie66]

Why not build the walls as reinforced masonry rather than introducing the complication of building in rolled steel sections? Why a 4" cavity? How is the 100 mm veneer tied to the structural wall across such a wide cavity?

 

[apsix]

Hokie, they probably require a 4" cavity to accommodate the European strength insulation.