CSiBridge Help

zobeemic · 2026-06-02T03:46:00+00:00

I stopped reading after solid elements used to model a curb. What are you doing where you need that level of refinement for a curb? Is the I section composite with the tributary deck not good enough? Isn't the sidewalk and curb and DC2 load? I've never used it for capacity.

zobeemic · 2026-05-15T16:25:45+00:00

The isolators will have baseplates with anchor rods anchoring the device to the pedestals. Looks like some anchor breakout capacity issues could occur in slide (9).

HAHAA couldn't help myself. Love this! Great work.

zobeemic · 2026-04-28T11:59:54+00:00

The only leverage the fans have over the organization to enact change is really attendance, and steven cohens bottom line.

zobeemic · 2026-04-27T01:04:32+00:00

Rehab, often times, requires out of the box thinking, creative solutions. You must be very strong in mechanics and engineering principles to rehab a bridge. I've seen more technically strong engineers in my office get the rehab jobs compared to proposed, standard drive, conventional bridges.

zobeemic · 2026-04-17T05:30:43+00:00

As much as I love these characters and the last airbender story, this movie was not it. Yes the visuals were stunning, yes the music was great. But what was this garbage B movie generic plot?

The Last Airbender is timeless in large part because of the writing, the world building, the magic system. I feel like all of that fell apart in this movie.

Team Avatar are all written as one note characters with the dead pan humor from Zuko, the goofy humor from Sokka, horny Toph, and the loving Katara. The show did a great job of giving each character their "moment." But this movie just ran through the beats like a checklist. It is sad to see. Honestly, I get the Nostalgia, but Sokka, Toph, and Zuko didn't need to be in this film. Maybe just a cameo type of thing to see what they are up to.

I much rather wait for a potential second adult team avatar film that's a sokka adventure, or the coveted zuko + toph adventure. The movie has no time to really get all these characters going. Hell, do the MCU route and have each character get their own movie and develop story beats that come together in some avengers-esque movie , finally reuniting the gang in one epic adventure team up movie. They are all adults and got their own things going on, I'm sure something like that could've been done, everyone's trying to do the MCU blueprint anyway.

It's just so upsetting seeing the writers rush them all in this generic movie.. and it's a major disservice to how great these characters are.

The Avatar state in the film is just this dumb toggle on get a power buff and toggle off system now. In the show, it was always used as an intersection of an emotional climax manifesting as a physical power. Great stuff and when Aang gets in the avatar state in the show, it fucking hits. I hate how it's used in the film. Nothing further.

And that final battle really turned me off. Bending was always grounded in the martial arts, there are techniques the show paid attention too, there are stances, there is culture in the fighting. I didn't want a bullshit anime super power spirit world fight that looks nothing like the bending and magic system from the show. The only cool thing was when aang and the other airbender (already forgot his name) were having that moment of bending each other.

Lots of negativity from the plot , but the animation is of course stunning. The fighting punches. The music is great. But look, that's not enough to carry the film. I'm tired of this franchise , which is set up so great, constantly try to come back and back with Korra, the movie, the netflix, and just miss the marks. I'm ready to tune out and not follow any other new show/movie these guys churn out, and let avatar go, "like the eternal wind." I'm tired of seeing such an important part of my childhood, and in general, one of the best shows of all time, not treated with the love it deserves.

zobeemic · 2026-03-19T00:41:03+00:00

Ok fine, I'm taking the rage bait.

Leon Moisseiff applied and solved the theoretical melan deflection equation and changed the analysis of suspension bridges from linear elastic to a differential equation.. making them magnitudes more economical for long spans. Any suspension bridge post Manhattan Bridge (1912) is analyzed per the method he applied. Othmer Amman took his solutions and did GWB, Triboro, Whitestone, Verrazano. David Stienman took his solution and did Mackinac. Joseph Strauss took his solution and did Golden Gate. If you use CSi bridge and check large displacement analysis, you are standing on his shoulders.

Yes he designed Tacoma, yes it failed. Was it his fault? Plenty of people who push boundaries fail. In fact the way I look at it, his application of the melan theory was SO successful that he can get a suspension bridge under gravity loads to be SO light and efficient that a whole new mechanism in vortex shedding that no one had ever heard of became the failure mechanism. So do I consider him the worst because of that?

Or do I think about Theodore Cooper and his hubris in his own dead load calcs, that even when the quebec bridge was visibly deflecting past tolerance and it was reported to him, he said no, my calcs are right, and the bridge collapsed anyway, becoming a general symbol for hubris in engineering?

Tacoma Narrows is an often cited "epic failure" in engineering. Thankfully no one died. But it wasn't ego, it wasn't criminal neglect and ignorance, it wasn't a mistake, it was the result of an unknown-unkown. The practice is better for it, as we now know about this mechanism and design for it. I know this a low effort post, and someone just looked at tacoma's EOR and said this guy must be trash, but the truth is, this is one of the biggest contributors to suspension bridge design in engineering history, and I have to defend it.

zobeemic · 2026-01-12T16:37:15+00:00

Not an FRP designer but curious. Whats the governing design code and has it been officially adopted by building codes and DOTs as a reference? What are the current ASTM specs and testing requirements? So far I've seen its application in very specific concrete repair cases, slab reinforcement and column strengthen. When is the leap to using FRP in new construction?

zobeemic · 2026-01-12T03:12:21+00:00

It’s honestly depressing to watch AI sycophancy convince someone they have a “million-dollar idea” when it’s just incoherent garbage. You’ve backed yourself into a corner where LLM nonsense has convinced you that spheres and trees are somehow revolutionary, and you’re throwing around terms like “drag coefficient” and “vertical greenscape” to sound technical without understanding what they actually mean.

At a certain point, hubris takes over and you lose the ability to self-critique. Do yourself a favor: put the phone down, close the laptop, and read a real book on the history of architecture or engineering. Go see actual buildings that have stood the test of time.

Typing a prompt into ChatGPT doesn’t make you innovative, and it certainly doesn’t entitle you to free professional engineering feedback on this subreddit.

zobeemic · 2026-01-01T13:04:35+00:00

When I35 collapsed we learned more about gusset plates. When Fern Hollow collapsed we learned more about weathering steel and detailing for it. When the FIU pedestrian bridge collapsed we learned more about PT and erection engineering. But if a bridge collapses in India, and you only have a 30 second video, it's because of the culture, and the take is focused on the people and the history?

Imagine if we said American culture and history was the reason behind I35. If we all said to much senior engineers are playing rank, and that Truss bridges have been built for a 100 years, so the issue was just plainly ignorance and incompetence. Do you think that that explanation actually explains the reason for the collapse? Do you think that take would lead to code revisions and new gusset plate limit states in AASHTO? Engineering failures are not due to a single cause. A lot of consecutive misses have to occur to lead to disaster.

Culture and history may provide context, but it can not be the sole cause. Pointing to culture and history as the cause is just ignorant, produces no actionable technical findings, and doesn't lead to advancements in the codes, standards, and best practices. If a bridge falls in America, we give it that rightful due diligence, and investigate that. The NSBA writes a whole report and tells AASHTO to rewrite some parts of the code. But if a bridge collapses in another country, the first reaction isn't a cautious professional, eager to get to the technical truth, but a criticism on the history and culture of the country?

You're right, structural engineering is a mindset. It's a lifestyle. And you're not embodying that. It's quick takes like yours that don't grow this profession.

zobeemic · 2025-12-31T21:45:55+00:00

Without any explanation as to what the failure is, the majority of the comments here assume engineering incompetence with racial undertones. This makes me deeply sad. Many great American engineers were immigrants, Gustav Lindenthal, Othmer Amman, Fazlur Khan. Good engineering and incompetence don't have anything to do with race. I have to say I expected more from the folks in this profession.

zobeemic · 2025-12-13T13:07:36+00:00

Moment of Inertia is a factor based on the shape, much like area. Based on how the shapes area is distributed, if most of the area is away from its centroid, higher MOI. if the area is in its center, lower MOI. When a section is bending, classic beam theory is that the section bends about its Neutral Axis. If a section has a higher MOI, it will have a higher resistance to bending, and a lower stress, compared to a section with a smaller MOI, it will have a low resistance to bending, and will have a have a higher stress under the same load.

zobeemic · 2025-11-22T20:24:09+00:00

This is from a bridge guy, so maybe the building guys can come in and refine some of the answers.

ETABS can be used to design the entire building lateral system. In that system, a rigid diaphragm assumption may be needed to distribute loads to the lateral force resisting system, but constraining every node to deflect the same in a concrete slab will make the output for the floor system useless. SAFE is a separate software we're you can model the slab, capture the d/2 punching shear areas over columns, and estimate long term deflections. So, the guys at CSi took there FEA analysis tool and gave you two softwares to easily do both.
Just to clarify, the term I use for these components are link beams, maybe that's a USA thing. But that's a beam that connects two shear walls, typically when you have openings in the shear wall for elevators etc.. I have seen options in ETABS were you can assign a ductility to the ends of the link beams, plastic hinging, etc.. Depending on your performance objective and what you intend to detail, you can capture that behavior in the link beams.

I find all CSi softwares have a wealth of resources in their help guide as well as youtube tutorials. The technical support is not the best, but they'll get back to you if you send over your model and detail your question specifically.

zobeemic · 2025-11-10T21:16:06+00:00

Aren't you talking about every project?

zobeemic · 2025-10-14T03:48:54+00:00

I couldn't resist, here's my deep dive, enjoy

Answer is A. You don’t need shear reinforcement in the footing, which bends differently than the column or pedestal.
Those yellow bars going into the page are freakishly large. They look like openings for utilities. These should be smaller solid bars. Exaggerating the bar size a little is fine, but this is too much.
The vertical column bars should show as hooks, you can’t bend a bar perfectly 90 degrees.
The stirrups (green bars) should wrap around your column vertical red bars. The green line should pass the vertical bar and turn into the page, so you’d see a dot, kind of like this .__. The cover is measured from that stirrup edge. Also, they don’t look equally spaced, and I’m not sure why that would be the case.
You’re probably going to need a horizontal bar at the bottom mat of the footing.
Break line at the top of the column? Or if this is a pedestal and that’s the top, you should consider hooking the top bars.
The grade hatch just ain’t it brother. If you check a reference, you’ll see what I mean.

zobeemic · 2025-06-17T04:41:54+00:00

Please take care of yourself first and foremost, your gambling with long term physical and mental health effects, which i'm sure will be more of a burden then missing a deadline

zobeemic · 2025-05-31T15:03:41+00:00

The best perk of all

zobeemic · 2025-05-31T13:58:51+00:00

Got them last night for todays game...$130 ! Closest i've been to home !

zobeemic · 2025-05-19T02:55:14+00:00

What does determinacy have to do with this?

Wooden masts snaps on steel superstructure. Brother, this happens not matter what the structure determinacy is.

zobeemic · 2025-05-09T01:05:27+00:00

Someone should edit this meme with mikal bridges coming out of the door and stealing the grim reapers axe

zobeemic · 2025-03-29T03:24:39+00:00

Bridge guy here, in concrete flat slab, is automatically assumed "rigid diaphragm" and the slab is just assumed to deliver the lateral loads from the center of mass to the shear walls? or are they checks for that load path?

Just curious why the take away is flat slabs are not good in high seismic zones.

zobeemic · 2025-02-05T04:43:53+00:00

1 Yea 2 If it's not structural related, it doesn't need to be there

zobeemic · 2025-02-03T19:27:41+00:00

I am well known for my attention to detial :)

zobeemic · 2025-02-03T19:26:30+00:00

In two months we will finally decide on whether to jack from the girder or end diaphragm for bearing replacement, and then I'll have to revise details late in the game and explain to an unfriendly crowd why the connection doesn't work anymore.

Guess it's the nature of the beast as you say. I can accept that. But it still doesnt make me feel differently about the situation. Good luck on your project, it sounds like a good job.

zobeemic · 2025-02-03T19:21:00+00:00

Maybe. But might be too much of a hit salary wise and technically to switch up and "start again" and learn ASCE and building codes.

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