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Mr. Christian Thomas Parker, P.E., M.ASCE

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Mr. Christian Parker, P.E., M.ASCE


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1 to 20 of 40 total
Posted By Christian Parker 02-01-2023 12:07 PM
Found In Egroup: Integrated Buildings & Structures
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Right, the issue is that there's no distinction in any one load combination between beneficial dead load which you'd want to underestimate, and simultaneous detrimental dead load which you'd want to overestimate.  It's akin to designing for an expected service load with a phi factor of 1.0 and a load ...
Posted By Christian Parker 02-01-2023 11:20 AM
Found In Egroup: Integrated Buildings & Structures
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Sarah, Thanks for the response.  These are all good points, and for new construction we would always consider alternative load paths and detail for all plausible demands, even if there's ambiguity as to how to determine those demands.  It was a presentation about a new stadium that first got me thinking ...
Posted By Christian Parker 01-31-2023 01:34 PM
Found In Egroup: Peer-to-Peer Standards Exchange
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Dwayne, My interpretation is that when an overhang is present, the overhang pressure need only be applied to the overhang itself; not the entire roof.  In MWFRS roof loads, there is no penalty to the roof for having an overhang; only the additional pressure acting on the overhang itself per 27.3.3 (ASCE ...
Posted By Christian Parker 01-31-2023 10:31 AM
Found In Egroup: Integrated Buildings & Structures
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In foundations, we design for overturning by balancing the acting moment and the resisting moment to a minimum factor of safety.  However, there are also cases in superstructure where we rely on bearing to transfer force and need to prevent net tension, using structural weight as ballast.  I'm working ...
Posted By Christian Parker 01-30-2023 02:32 PM
Found In Egroup: Integrated Buildings & Structures
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Lots of great responses on this.  One aspect that I haven't heard opinions on yet is the qualifications for other disciplines within Civil Engineering.  If we consider flood damage a hydrologic failure, then hydrology is responsible for more loss of property and life than all structural hazards combined.  ...
Posted By Christian Parker 01-30-2023 01:49 PM
Found In Egroup: Integrated Buildings & Structures
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Erik, Thanks for sharing your perspective.  I've worked on small and large buildings in many different sectors and personally, I find residential work quite challenging.  New commercial buildings go up with the understanding that there will be structure and it will impose certain constraints on program ...
Posted By Christian Parker 01-30-2023 11:16 AM
Found In Egroup: Professional and Career Topics
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Fascinating question, Mitch. I grew up in a college town, attending public schools that were totally college-oriented. Most of my classmates have ended up with graduate degrees, typically in humanities or basic sciences. I always felt that college was overemphasized in an economy where most services ...
Posted By Christian Parker 01-30-2023 11:15 AM
Found In Egroup: Professional and Career Topics
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Thanks, Venessa. These are great points, but I've always had reservations about CE salary concerns. I got curious about this a little while ago, since it's such a hot topic in my field of Structural Engineering, the lowest-paid Civil discipline. Here's what I concluded: - STEM salaries are nearly twice ...
Posted By Christian Parker 01-26-2023 04:59 PM
Found In Egroup: Integrated Buildings & Structures
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NCEES offers PE licensure in many practice areas, including Civil Structural.  But among PE disciplines, Structural Engineering is the only one I'm aware of that has a separate, more specialized, exam option.  The Licensure Committee at NCSEA reports that ten US states now have some form of practice ...
Posted By Christian Parker 01-19-2023 12:29 PM
Found In Egroup: Integrated Buildings & Structures
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Hello Ammar, Have you considered heat straightening?  Depending on the level of distortion, this may be feasible to perform in the field.  This article from 2010 provides a good introduction: https://www.aisc.org/globalassets/modern-steel/steelwise/082010_aug10_steelwise_web.pdf For smaller members, ...
Posted By Christian Parker 01-04-2023 01:52 PM
Found In Community: Peer-to-Peer Standards Exchange
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Hello Justin, I always consider a moving load to be live, but to James's point I would be hesitant to take advantage of a reduction for a live load that will be present concurrently with a full design floor or roof load.  For the 0.75 reduction, are you referring to ASD load combination 4 in ASCE 7, ...
Posted By Christian Parker 11-20-2022 10:22 AM
Found In Egroup: Peer-to-Peer Standards Exchange
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Ah, I see.  I tend to think of the ASCE 7 as a balancing act between ease of implementation and economy of design, but you make a great point about the importance of transparency.  I would argue that the current live loads are very easy for engineers to use (aside from those pesky load combinations), ...
Posted By Christian Parker 11-14-2022 03:26 PM
Found In Egroup: Peer-to-Peer Standards Exchange
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Ron, I appreciate the thorough explanation, and I'm sorry for not responding sooner.  In fact, I wish this timeline was part of my undergrad curriculum.  Only after entering practice did I realize how little I knew about ASD, and how much my understanding of design loads and limit states suffered for ...
Posted By Christian Parker 11-11-2022 05:52 PM
Found In Egroup: Peer-to-Peer Standards Exchange
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James, Thanks for the response.  You make a good point, but for environmental hazards, the safety factor lives in the return period to establish uniform risk.  For example, I'm told that snow loads in ASCE 7-16 and earlier resulted in dramatically different probabilities of failure across different ...
Posted By Christian Parker 11-11-2022 05:51 PM
Found In Egroup: Peer-to-Peer Standards Exchange
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Chad, Thanks for the thoughtful response.  It's certainly true that we wrap a lot of big questions into our floor loads, and it may be true that the public cares more about minimizing risk from human-imposed loads than minimizing risk due to external hazards like earthquakes.  That's hard to quantify, ...
Posted By Christian Parker 11-11-2022 02:20 PM
Found In Egroup: Peer-to-Peer Standards Exchange
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Thank you, Ron.  I'll look out for that announcement. Does anyone have an opinion either way about the IBC vs ASCE 7 approach to service wind?  Using a fixed factor is simpler, but ASCE's MRI method ties the drift check to more tangible performace objectives. ------------------------------ Christian ...
Posted By Christian Parker 11-11-2022 10:57 AM
Found In Community: Peer-to-Peer Standards Exchange
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Hello Alex, I can't speak to the Indian codes, but I wonder if part of the reason you're not able to "fully utilize" the section is that stability limit states and flexure-torsion interaction govern the design.  In AISC 360 (US code for steel), single angle flexural members must be checked for yielding, ...
Posted By Christian Parker 11-09-2022 08:05 AM
Found In Egroup: Peer-to-Peer Standards Exchange
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No worries; I'm glad you found the correct reference.  That's what ASCE Collaborate is for! Best of luck, ------------------------------ Christian Parker P.E., M.ASCE Structural Project Engineer Washington DC ------------------------------
Posted By Christian Parker 11-08-2022 08:49 AM
Found In Egroup: Peer-to-Peer Standards Exchange
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Hi Daniel, Great question.  I'm not a bridge engineer, but composite design (steel beam/girder engaging a concrete slab in compression) typically assumes general yielding of most or all of the steel section rather than triggering failure at initial yield of the extreme compression or tension fiber.  ...
Posted By Christian Parker 11-07-2022 04:18 PM
Found In Community: Peer-to-Peer Standards Exchange
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I second Mr. William's comments.  As I see it, it's similar to the code equations including GCpi for MWFRS: for most buildings this will zero out between windward and leeward surfaces, but the onus is on the engineer to convince herself that the diaphragm(s) can be relied upon to balance internal pressures.  ...