I'm currently designing a partially buried reinforced fixed-base concrete tank. When determining the seismic loads I am using ACI 350.3-06 with the modifications per §15.7.7.3 of ASCE 7-16. That section of ASCE 7 requires you to replace the impulsive response modification factor of ACI 350.3...
I've got a special reinforced concrete shear wall building with a discontinuous shear wall supported by columns at either end (vertical irregularity type 4). I'm designing the columns using the overstrength factor per ASCE 7-16 §12.3.3. but I'm not sure if I should be following the requirements...
For seismic design, the IBC and ASCE 7 define a story as the 'portion of a building included between the upper surface of a floor and the upper surface of the floor or roof next above". So basically the story height would be the floor-to-floor dimension. However there is no definition of what...
I'm reviewing an existing concrete and masonry structure that was designed in 1989. I can't find any information on the design code used but I would guess the ACI 318-83 that was revised in 1986. In the general notes section for the rebar lap splices I see this statement:
"UNLESS CALLED OUT...
Hi, question has popped up in the office regarding anchor reinforcement and the overstrength factor. When designing anchor reinforcement to restrain concrete breakout for seismic load combinations do you include the overstrength factor or just use the regular load combinations using rho? My...
I’m reviewing a structure built in 1980 that utilizes an NKX 20-20 floor deck. Looking around I’ve found a few pages of the ICBO report #1388 for Robertson Steel Floor and Steel Roof Deck with load tables. Does anyone have a full copy of the report? I’ve tried searching the web and sent lff a...
Hi, I’m in the process of moving on to a new company and am trying to clean/purge my soon-to-be old office. I have a number of old codes (ASCE 7-05, ACI 318-02/05/08 etc etc) and reference books for old codes (books on masonry design per the 2009 IBC, seismic design per 2012 IBC etc). I hate to...
Hi, I've got a general question. Typically I push some items that require design onto the Contractor (guardrails, metal stairs, pipe supports etc). They usually have an in-house Engineer design/stamp the items or they sub out to another engineering firm. My question is how in-depth of a review...
Hi, I posted this in the ACI(concrete) forum but thought I'd put it here as well. I have a project where an elevated concrete slab for a new cmu electrical building is under construction. The slab is elevated a few feet above grade due to the flood level and is supported by a concrete stem wall...
Hi, I have a project where an elevated concrete slab for a new cmu electrical building is under construction. The slab is elevated a few feet above grade due to the flood level and is supported by a concrete stem wall with strip footings around the perimeter. Both the slab and the stem wall are...
Hi, I'm working on a project under construction rehabbing an existing externally wrapped post-tensioned concrete tank that was built in the '60's. The Contractor has submitted a pipe support design that's basically a cantilever steel beam support off the existing 10" thick concrete core wall...
I'm designing a new concrete tank at a wastewater treatment plant in California. The client would like to have a stair going from the top of an adjacent building to the top of the tank (my vote was a spiral stair but I was vetoed). There isn't a problem with doing this however the vertical...
What is typically done with a roof ledger and a control joint in a cmu building? Are the ledgers discontinued at the joint or span across them? My initial thought is to just span across it but I am concerned it’ll cause some weird cracking to occur.
Hi all. I'm currently pre-designing a 1.8MG reinforced concrete tank (not prestressed). The tank is a thermophilic digester meaning the normal operating temperature for the sludge will be on the order of 135 deg F. Because this is a pre-design I decided to run some preliminary calcs using the...
Hey everyone,
I threw together a real quick and simple excel sheet to design a concrete beam using either ACI 318-14 or ACI 350-06 and was wondering if I could take advantage of the wealth of knowledge in this forum and have someone look at the template and see if I missed anything? You're more...
Hello! I'm brushing up on my hand analysis of a rigid diaphragm and have a couple quick questions. I found a really useful paper that goes step-by-step through the analysis of a rigid diaphragm and how to calculate the inherent torsion however I'm not sure a couple equations given in the paper...
This might seem a silly question but when calculating an interaction diagram for a concrete bearing wall for out-of-plane forces what is the Pn,max? The ACI code points you to the columns section which says that your Pn,max is a portion of your Po. The reduction is based on whether you have ties...
Generally when I do a structural design with MEP equipment, I require the Contractor to design the anchorage and provide the calculations for review. I usually have a note that stipulates the equipment pad sizes need to be coordinated with the anchorage calcs regarding thickness and edge...
Generally when I do a structural design with MEP equipment, I require the Contractor to design the anchorage and provide the calculations for review. I usually have a note that stipulates the equipment pad sizes need to be coordinated with the anchorage calcs regarding thickness and edge...
Hi, I'm designing a small electricial building in a high seismic area. I'm going with a special reinforced cmu shear wall with a flexible metal deck diaphragm. I have a couple openings in the diaphragm that will need additional framing (other than the steel beams supporting the roof) to transfer...
