Critique this arch-support layout

[dbhansen]

Do you see any problems with this proposed arch-support layout? The 2 bricks to the right of the landing, specifically. The red line in pic #2 is where I would cut the brick to make room for the soldiers. Any thoughts? I'm quite unsure about building the arch....

The gap is an expansion joint, by the way (not just sloppy cutting!).

[christo]

Do you have a sketch of how you plan to construct the arch?

My arch was constructed in such a way as to really push against the side walls and I had to beef up wall support to keep the opening from failing. Unfortunately I learned this after I pulled the forms out (perhaps too early) and it failed a few hours later... second time w/butressing was the charm.

There is also plenty of talk/examples on this forum about casting from refractory cement a solid top for the entry (both flat and arched). In most cases, that seems to remove any need for butressing or concerns for outward forces on the entry walls.

I think the expansion gaps are a good idea but due to different densities of firebrick I cannot hazzard a reliable guess as to how wide to make them. They will fill with ash so I'm not sure if you get into much trouble if they are too wide.

Christo