Austin Norberg's Activities

Complex Reinforcing Steel in Shells

Austin Norberg — Thu, 07 Oct 2021 14:00:39 GMT

I am building an Elements model to analyze and existing structure, specifically a concrete dome. Based on the existing drawings (which are from 1940), there is some intricate reinforcing detailed within the structure. There are reinforcing hoops which arc around the dome, almost like flower petals. Is there a way to asign specific and/or specialized reinforcing to shells so that I can check the stresses in the shell? Or will it only tell me the area of reinforcing required in each axis?

RAM Elements Manual

Austin Norberg — Tue, 10 Aug 2021 22:33:28 GMT

My firm has several RAM Elements licenses and we have for years. Somewhere along the line, it seems that we lost the user manual, either the hard copy or the PDF, whichever we had, no one can find it. Now I can't find the manual anywhere online, other than websites which seem... sketchy. Is there a place on the Bently website where I can download the RAM Elements manual?

Thank you,

Columns in Walls

Austin Norberg — Wed, 25 Nov 2020 18:45:11 GMT

I have modelled a building with "other" type walls (masonry) and due to some of the framing requirements, I have to put columns inside the walls for large point loads.

I notice that when I run the column design module, the module gives me a maximum D+L axial load of 221 kips. When I run a lateral analysis in RAM Frame and check the D+L load case, the output tells me that I have an axial load of about 91 kips, significantly less. I notice at the same time that the adjacent walls have disproportionately high axial loads in them for the framing that they should be carrying.

My question is, does RAM Frame distribute load out of the column into the walls? Is there a way to determine what proportion of the load might be distributed from the column to the walls? Or is maybe due to the concrete walls above intersecting with the walls below?

I've included some clips of the framing and output below.

Thank you,

Distribution of Gravity Loads to Walls In RAM Frame

Austin Norberg — Tue, 24 Nov 2020 14:15:04 GMT

How does RAM Frame distribute gravity loads to shear walls? I had some questions after working in a larger model and so I created a test file as described below:

I used RAM Structures to model a small cube-shaped building that is 10' wide, by 10' long, by 10' high. The roof structure is a one-way deck supported on perpendicularly oriented steel joist spaced at 2.5' O.C. with a roof dead load of 20 psf (all-inclusive). I modeled 4 "other" type walls with a self-weight of 75 psf to support the roof on each side. I specified that each of the walls should be "lateral" in their properties.

I then went to RAM Frame and ran an analysis and have checked the loading on the walls in the results, both under load cases and load combinations. The output that RAM gave me did not make sense in regards to the load distribution. The the sum of the gravity loads of the structure was correct, but the distribution was off. Based on tributary areas, the walls which support the roof joist should have a total gravity load on them of 8,250 lbs each and the walls not supporting roof joist should have a total gravity load of 7,750 lbs each, with a total combined load (4 walls total, 2 of each kind) of 32,000 lbs.

RAM in its analysis says that the walls supporting the roof joist have a total gravity load of 8,070 lbs each, and the walls not supporting the roof joist have a total gravity load of 7,930 lbs each, with a total combined load of 32,000 lbs. The combined total is correct and makes sense. What does not make sense to me is the load applied to each wall. It appears that RAM Frame is treating the diaphragm as a semi-two-way deck and distributing load not primarily based on tributary area or is perhaps ignoring the gravity framing.

I have tried running the analysis with the diaphragm being rigid, semi-rigid, and flexible, with P-delta effects turned off and it does not change the final result.

How is RAM distributing the forces from the diaphragm/deck to the walls? Am I missing something here? I've included the RAM file in case it was needed.

Thank you,

communities.bentley.com/.../Wall-Loads-RAM-Test.rss

Separate Exterior and interior Structures

Austin Norberg — Tue, 13 Nov 2018 23:24:39 GMT

I am designing a steel-framed structure with an interior mezzanine that is a separate structure from the main building. Is there a process for defining the interior mezzanine such that it does not receive wind loading and all wind loads are applied to the exterior framing? I can see from the modeling that mezzanine is deflecting under load cases/combinations with wind and am concerned that portions of wind load may be being applied to the interior framing that should be assigned to the exterior. Also, I don't want to design my interior framing for wind loads, only gravity and seismic.

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Tue, 13 Nov 2018 05:46:33 GMT

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