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  1. crossframe

    Bolt heads up or down?

    I've always thought it was as much (or more) for aesthetics than any other reason. In the states 'round these parts, bolt heads are on bottom for both top and bottom flanges and on outside of exterior girders. Presents a cleaner look that way.
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    Bridge Inspection

    Beware pink concrete. https://www.concreteconstruction.net/_view-object?id=00000153-8b78-dbf3-a177-9f79c7da0000
  3. crossframe

    Abutment wing wall

    We typically use straight-extension, flared, or U-back, and the names remain the same even for skewed bridges. I like U-back wingwalls because I think it looks cleaner, but it's usually based on owner (DOT) preferences. My state DOT prefers flared wingwalls because they are almost always the...
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    AASHTO eta factors & deformation

    Note that the eta factors are usually equal to 1.00 for all but the Strength limit states (AASHTO 1.3.2 - 1.3.5), so I would suggest it depends on the limit states you're using for the joints and bearings. Those are often designed for Service limits states.
  5. crossframe

    What expansion joint type to use for long bridge with transverse seismic movement?

    When considering the cost of a modular joint compared to a finger joint on a 980-ft bridge, will there really be that much of a difference to the overall construction cost? I'm all for stretching the money as much as possible, but you might want to consider the overall impact. Sometimes it...
  6. crossframe

    Elastomeric Expansion Bearings

    There is (or at least was) a lateral restraint check in AASHTO for elastomeric bearings to see if they needed a positive connection to the beam seat, typically based on friction as noted by BridgeSmith. As shown, the bearing can't go anywhere unless the vulcanization to the masonry plate fails.
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    Whats the most unique engineering unit you've encountered?

    Figanewtons and Boxafiganewtons, from my Holtz and Kovacs Geotechnical Engineering textbook (see attached file). Never encountered it the real world, but it must exist because it's in a textbook. And I once had a young engineer give me a quantity in "Gallons of Bridge Rail."...
  8. crossframe

    Hard hat history

    I generally don't wear a chinstrap, but I have one tucked up inside my hard hat so I have it with me (between the suspension and the shell, but down near the ratchet so it isn't really above my head). I have had to use it occasionally because of wind. I think the chinstrap photos outside the...
  9. crossframe

    AASHTO LRFD shear analysis of slabs and footings

    Yes. Transverse reinforcing in regards to slabs and footings refers to shear reinforcing, typically in the form of vertical stirrups.
  10. crossframe

    Steel-Reinforced Elastomeric Bearings Stiffnesses and Damping

    Seismic Design of Bridges, Publication Nos. FHWA-SA-97-006 through FHWA-SA-97-012, is a seven-volume set of design examples of different bridge types. Each example is incomplete, in that they are intended to demonstrate different aspects of the full design. Things omitted in one example are...
  11. crossframe

    Career Advice - Class I Railroad vs. Design Consultant, Entry Level

    I spent the first four years of my career for a certain large western U.S. state DOT. At the time, I too wanted to get out of field work and do some "real" design. I got my wish, and have had only sporadic stints in the field in the last 20 years. Often, I still miss it. Barring unusual...
  12. crossframe

    Exclude lane loading?

    A six-axle, 180k drill rig on a 75-ft single span bridge should be analyzed as a permit load. You can certainly specify no other vehicles on the bridge if that's what it takes to avoid overstressing the girders. A six-axle vehicle will probably occupy a decent amount of the span length by...
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    PE Exam Question

    Many moons ago, California required only 2 years of engineering experience. The board will discount experience that is not deemed "engineering experience," but a lot of that will be how you describe it. A lot of us do drafting as part of our engineering work, but it is only a part. After...
  14. crossframe

    Civil/Structures Masters programs at California state schools.

    Why trade Pismo Beach for Mission Beach? Water temperature, for one...
  15. crossframe

    Civil/Structures Masters programs at California state schools.

    If you went to Cal Poly, why would you consider SDSU or SJSU? I would think your BS would already be worth than their MS. I seem to recall a common destination after Cal Poly was U.C. Davis. The U.C. schools were always more geared toward research, but you probably already knew that. Other...
  16. crossframe

    Transverse Deck Slab Stiffness...

    Line-girder analyses like Merlin-Dash, and probably Bar7, (never used LARS) use the "S-over" live load distribution factors as you've noted. As you've also noted, grid and finite-element analyses, such as MDX, DESCUS, etc., are considered by AASHTO to be a "refined analysis" and they may...
  17. crossframe

    Skewed Bridges

    There can be uplift (not necessarily net uplift) at the acute corners.
  18. crossframe

    Career Advice

    Look into field work on bridge construction sites. I started doing that with Caltrans, and it was some of the most valuable experience I've gained. You'll need to be careful that it will be qualifying experience for the P.E. exam. Look for private firms that do bridge design work for Caltrans...
  19. crossframe

    wheel punching through cantilever slab ?

    The AASHTO Standard Specifications (3.24.4) stated that slabs dsigned for flexure in accordance with the specifications shall be considered satifactory in shear. The closest I can find to this in the AASHTO LRFD Bridge Design Specifications is C4.6.2.1.6, where the intent is not to check shear...
  20. crossframe

    Joint Seals (compression seals): replacements & retrofits

    A new compression seal in an old bridge never seems to last as long as the original. This particular seal was between two steel girder spans. I'm sure both side of the joint moving didn't help. Since it the only one to fail out of of four or five, it probably had more to do with the initial...

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