Underground bunker - entrance from ground level above
Underground bunker - entrance from ground level above
(OP)
I work as a design technician for a Civil Engineering Consulting Firm. Predominantly we work in land development (ie, subdivisions, street, utilities) but sometimes we get other unique projects. A client we have has a home on a the side of a butte. The existing home's graded pad was done by the home builder at the the time and they only graded enough to fit the house and the driveway. Approximately 5' out fron the front of the house the hill has a 2:1 slope down. See image for existing conditions.
The client came to us to have a large retaining wall designed to create grassy/recreational space in front of the house. They are adding approximately 3500-4000 sf of flat area to the front of their lawn. The retaining wall reaches a max height of 20'. See image for reference.
That is not all, the client is also taking advantage of this hillside fill project to bury a root cellar/bunker in the back fill area. They have already purchase the cellar, it is an 8' diameter culvert with sealed ends and a door on one side. It spans 36' long. We have finished the engineering for the retaining wall and backfill grading but we need to figure out some way to gain entrance from the top of the fill area down in to the bunker.
That is where I hope this community can help. Has anyone else done a project like this, what have you done for an entrance to an underground structure? Large precast vault? Manhole with ladder rungs? Concrete stair case cut into the ground?
Originally we designed the retaining wall around the end of the bunker so the door was accessible from the outside, but the owner said that would cause the cellar to become too cold during the winter. The point is to have it self regulate by being buried.
The client came to us to have a large retaining wall designed to create grassy/recreational space in front of the house. They are adding approximately 3500-4000 sf of flat area to the front of their lawn. The retaining wall reaches a max height of 20'. See image for reference.
That is not all, the client is also taking advantage of this hillside fill project to bury a root cellar/bunker in the back fill area. They have already purchase the cellar, it is an 8' diameter culvert with sealed ends and a door on one side. It spans 36' long. We have finished the engineering for the retaining wall and backfill grading but we need to figure out some way to gain entrance from the top of the fill area down in to the bunker.
That is where I hope this community can help. Has anyone else done a project like this, what have you done for an entrance to an underground structure? Large precast vault? Manhole with ladder rungs? Concrete stair case cut into the ground?
Originally we designed the retaining wall around the end of the bunker so the door was accessible from the outside, but the owner said that would cause the cellar to become too cold during the winter. The point is to have it self regulate by being buried.
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RE: Underground bunker - entrance from ground level above