Concrete – What type of beam should be used over a split arch doorway

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I am building a building in Indonesia. It's using RC-frame construction. My builders don't have much expertise, nor do I.

The basis for my building is three reinforced concrete pillars, 30cm * 30cm, 3.5 metres tall, with 4.75m between the pillars.

There is some seismic activity in the area.

What I want, basically is an arched doorway somewhat similar to this:

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but split into two by the central pillar, so that left and right of the pillar are mirror images.

I then want two windows of similar design (i.e. rectangular with an arch on top) further towards the corner of the building (so not bisected by the pillar).

So the shape of the beam could be a straight line above the top of the arcs, or it could follow the arcs, so it would then be basically – straight line, semi-circle, straight line, quadrant.

Which design for the beam makes more sense?

Best Answer

Beams rarely follow curves in cases like this. Put a standard beam at the height of the zenith and frame down to shape the arch, thereby creating the proper rough openings for the windows. Install the center post under the beam.