Hello -
A client has a piece of equipment that is going to be stored on site for about 1 year before installation. They would like it to be temporarily anchored until then. We are exploring using concrete blocks (deadman block, eco block, etc) with weights around 3-4kips per block. The...
Hello All -
I am interested to see how other folks approach nonstructural component support design when the support system is more analogous to a structural system than a component.
Consider a 500lb sheet metal box transformer (ap = 1.0; Rp = 2.5), and the following two cases:
A sheet...
Hello,
I'm working on some equipment support/anchorage designs that are supported by steel platforms. We calculated the Fp forces based on ASCE7 Ch13 to determine the anchorage forces between the equipment and platform and then used Chapter 15 to analyze the platform structure itself (OCBF...
Hello,
A client is relocating a PEMB canopy about 100 yards from its current location. No change in seismic/wind conditions (SDC D). After reading Ch14 of the 2022 CEBC, our understanding is that since we are not modifying the structure at all (e.g. not adding seismic mass, not removing any...
Hello All -
I have a question about the limitations of composite action. The general understanding is that when your stud anchor capacity (∑Qn) < 0.85*f'c*beff (Cs,max), your section is partially composite because you can't transfer the full load into the concrete.
[ol 1]
What happens if...
Hello,
I have a question about rooftop unit nonstructural component forces and how they relate to building diaphragm forces.
Say I have an RTU that weighs 1000lb. It is spring isolated, resulting in an Fp ~= 2500lbs. I design the connections to the roof utilizing the Fp force (ASCE7 Ch...
Hello All,
I am working on replacing rooftop equipment on an existing single-story building.
The new RTUs are located along the column line in the middle of the building with supports on either side of the column, attached to the glulam member, increasing the negative moment. In 2010, a...
I am curious why there is no 'quick calc' or any checklist item that relates to the capacity of the diaphragm. I am currently looking at type C2/C2a checklist. They do have checks for openings and irregularities, but not capacity checks.
If the irregularity checks are compliant, you could...
Hi Everyone,
I am a little confused by the language in ASCE41 (surprise surprise) regarding the checking of an existing concrete moment frame and what actions are considered to be deformation or force-controlled.
Per Section 10.3.2.1:
"Deformation-controlled actions are defined by the...
Hello All,
I have a question regarding ASCE41-13 7.2.8.1. I am checking overturning on pre-cast panels of a steel frame building. The panels are not positively attached to the columns for in-plane/overturning - only out-of-plane. All in-plane and overturning forces are resisted at the...
Hello,
I have been scratching my head on this for a bit, so thought I would ask.
I've calculated my chord force (CF) in a flexible diaphragm. The metal deck is attached to a perimeter steel beam with puddle welds @12". What is the correct method to determine the force on the puddle welds?
In...
Hello,
I have a question on how to check/verify typical foundation requirements (overturning, bearing pressure, etc.) when I have a steel column mounted on a pilaster part of a continuous wall.
I guess I am not sure how you would figure out what your 'footing' dimensions are to determine...
Hello Everyone,
I am trying to determine proof loads for some post-installed epoxy anchors using Hilti HIT-RE 500 V3 epoxy. Previously I had found this documentation from OSHPD from 2008 (which seems to be an interpretation of the CBC):
Test loads should be greater of 2x maximum allowable...
Hi Everyone,
I have a few questions about flexible diaphragms and the hand calculations vs. modeling results (using SAP2000).
By hand calculation, a flexible diaphragm would equally distribute forces to lateral systems based solely on tributary width regardless of stiffness. I have built a...
Hello All,
I am looking for any information on the type of anchor shown in the attached image. The building was constructed in the 1960's and has concrete tilt-up panels. These anchors are used for pretty much all of the connections from steel members into the concrete (diaphragm to wall...
