Thanks everyone for your replies. I had searched the 'net for a person or company to do such a structure (the suspension cables) but didn't have much success. I believe the pipe is now along a bridge that's being rebuilt over a creek, thus the temporary nature. We are a competitor to Bridge...
I've been asked to design a temporary bridge for a 2" waterline to span 145'. Rather than do such a large structure for such a small thing, I was thinking a suspension cable set might be more appropriate. Does anyone know who does that sort of thing? I've seen those types of structures done...
I once worked for an FRP manufacturer and designed structures with FRP shapes. It is customary to include shear effects in deflection calcs. In the steel joist business, I've seen people calculate the Ix of the chords, use that as an equivalent beam, and then add about 20% to the deflection to...
One other thought since you all brought up K-factors - We generally use a K factor of 2.0 for the truss vertical in the out of plane direction unless you have a good reason to use something less like 1.5. You can use a K=0.8 or 0.85 for the in plane K-factor for the truss verticals.
The code statement you referenced about framing into the bottom chord was placed there by yours truly (via appropriate correspondence with the AASHTO committees). The problem with framing the floorbeam into the bottom chord is that the chord will "ovalize", as shown in KOOTK's post and referred...
It sounds like a fun experimental project for an engineer to me. If it's for a paying customer I wouldn't touch it with a 10' pole. Unless you know where it's been done before successfully, then who knows what will happen, as many posters have speculated. Five feet is very shallow...
See the book "Guide to Stability Design Criteria" by T Galambos, particularly chapter 15. What you have is a top chord synonymous to a column buckling restrained by "elastic lateral restraints" - springs. The guide is intended for pony truss bridge design but you may find enough info there to...
Based on your own definitions, then you've answered your own question - non-uniform. Is your pipe "full" or an open channel type flow as in a drain pipe? It's been a long time since I've broached the subject but hydraulic jump comes to mind of your situation if it's open channel type flow.
There have been several continuing education seminars on the topic from AISC/NSBA. I haven't checked but you might find them on the AISC website. It has been a hot topic at the last few NASCC (North Am. Steel Const. Conferences) too. "Fracture Critical" is often confused with "non-redundant"...
The property is roughly 200' wide by 1500' long. It has a small creek in a very deep ditch down the long side. It's all along a RR track so it's more like a drainage ditch than a creek. The RR is several feet below and along the long edge of my property. I just thought it very odd that the...
Thanks for the reply. No construction contemplated, I was investigating using it as collateral for a loan and the bank insisted I get flood insurance, when it wasn't needed way back when I used a mortgage to buy it. I'd like to get it "corrected", if possible. It may affect future sale...
Excellent question. I'm fascinated by how many different approaches there are to the same problem. Not saying any are correct or incorrect, just different. It's enough to drive lawyers nuts. Here's mine, which I'll admit may have a math mistake, no time to check thoroughly. I'm somewhat...
There are so many assumptions in loading, soil capacity, material strengths, factors of safety, and the like that a slight difference in actual vs. theoretical should be fine. Sounds like the engineer in this case (and I’ve run across my share of Dr. dot the I and cross the T’s) might be “good”...
Anyone have experience with changing a FEMA flood zone? I own property that FEMA changed partially into a flood zone in 2011. The problem is they put the high end of the property (about 10 acres) in the flood zone while the end 7' lower is not in the flood zone. The property has never flooded...
While most states are very similar - either 15 pdh per year or 30 pdh every two years, about a dozen are oddballs with various ethics course requirements (no state I know of will allow carryover of ethics hours) and various renewal cycles. If you have NY then you probably won't have to do too...
I remember an almost identical load on a beam years ago and my father looked over my shoulder and did it in his head. I had just finished college and I spent about an hour doing a shear and moment diagram to verify it or prove him wrong. At that time my mechanical degree only made things more...
Many good comments here. You should spend some time in the field. Regarding the 1/8" difference mentioned, you'd be surprised at how much beating, bending, warping and who knows what else happens to steel by the time it gets put to bed.
If you galvanize the tube, then sealing it shouldn't be necessary since the inside is protected by zinc. If you don't galvanize and attempt to seal a tube, I've seen many instances where water will be sucked into the tube at a weld pinhole. So it better be sealed and inspected for absolutely...
Sometimes with pedestrian bridges you have to use some engineering judgement. The ped. bridge guidespec was generally written to cover truss bridges which were light and narrow, like an overhead sign structure, compared to regular highway bridges. Lateral loads and fatigue from wind could...
