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  1. curvbridger

    Demolition puzzle - removed rivet feature

    So, a 3/4" pin or so driven against the torched surface under the head flattened it smooth?
  2. curvbridger

    Demolition puzzle - removed rivet feature

    Curious - What is the explanation for the flat area on the removal side of what I believe is a standard bridge rivet? What removal methods would have been used? I can see the torch mark, but how was the head removed? Did the head removal method leave the flat area?
  3. curvbridger

    Historical practice for specifying A7-39 Steel

    Yes, the structure was "mission critical" for WWII. Still puzzled why the designer straightforwardly published stresses up to 19.8ksi, rather than what I believe was the published allowable of 18ksi...
  4. curvbridger

    Historical practice for specifying A7-39 Steel

    I am looking at a steel structure built in 1942 by American Bridge Company of Gary, IN. The steel specification has not been recorded in the available documents. The design drawings list design stresses as high as 19.8ksi in tension. The shop drawings list AASHO as the construction...
  5. curvbridger

    Welding A588 to A572

    The thickness of the flanges of the A588 is 1 3/4". The A588 material is Grade B. The A572 material is a similar thickness. The structure is statically loaded and will be exposed to temperatures from +100degF to 0degF. Weld are typically large fillets, but include full penetration groove...
  6. curvbridger

    Welding A588 to A572

    The yield point for both materials is 50 ksi. The A588 is a rolled beam, the A572 is structural plate. Does that help?
  7. curvbridger

    Welding A588 to A572

    I have a structure in which weathering steel performance is not an issue, but I have some available A588, and some available A572. What problems could arise from welding these materials together? What electrode should be used?
  8. curvbridger

    Kicker Beam Design

    I don't believe you will find any canned answers to this situation. I would start with trying several load distribution methods. Lever-rule will probably be the thing to use. I would use one distribution factor for moment, and another for shear, and apply them throughout. Take the layout at...
  9. curvbridger

    Estimate of lateral deflection of curved girder span.

    I am curious if any of you know a simplified method for estimating the lateral deflection of a cirved steel I-girder. I will eventually be doing fe, but I need to know a rough number for preliminaries. The cross-section in the end span contains straight and curved sections, based on a "ramp"...
  10. curvbridger

    Bridge collapse near Pittsburg, PA

    Critical components for this collapse, from what I have gleaned from news: 1. It was non-composite. No alternate load path for the failed beam. 2. The deck drainage was infiltrating the beams through the asphalt wearing course. Voids in the box contained water! 3. Low vertical clearance...
  11. curvbridger

    Passive Pressure Curves - Barker

    Thanks for weighing in. I believe after doing some additional searching that the author is R. Barker of Va Tech University.
  12. curvbridger

    Passive Pressure Curves - Barker

    Our local bridge owner has included in its design manual a set of curves describing the passive/active earth pressure coefficients for various sands based on movement at the top of wall. I would like to find the equations that these curves are based on. The chart is credited Barker (1997)...
  13. curvbridger

    Engineering Union

    Engineering, when practised in the public sector (as opposed to industrial - as stated previously) would have additional conflicts of interest if they operated within a union context. Union members have a responsibility to protect the jobs, reputation, etc. of their fellow union members...
  14. curvbridger

    Drainage for Tabgent Caisson Wall

    Thanks to all for your input. At this point, I intend to design for hydrostatic pressure, while tying to drain it away anyway. I will be using closely spaced rather than truly tangent shafts, although controlling this with temporary casing feels iffy. All things considered, horizontal drains...
  15. curvbridger

    Drainage for Tabgent Caisson Wall

    Has any one seen an effective way to establish positive drainage behind a tangent caisson wall in a cut situation with an exposed height of about 30 feet? Could vertical holes be drilled behind the shafts and filled with a free draining material and then outlet at the base of wall somehow...
  16. curvbridger

    Driveway Bridge Engineering Review

    Jhpf, I think that the primary area in which we disagree is in the area of consequences of failure. I agree that railings fail alot, but the life and economical damages are relatively minor, compared to highway structure failures. Even if the railing is struck and fails, the vehicle will...
  17. curvbridger

    Driveway Bridge Engineering Review

    I have always been interested in driveway crossings, and hope to one day build a few as a "retirement" job. Due to the possibility of fire engines, concrete mixers, fuel oil delivery trucks, etc., I have always held that H15 or H20 should be used, as a minimum. As for traffic...
  18. curvbridger

    Anchor Bolt Design

    Sign structures subject to gusting winds (especially from traffic loading) have experienced fairly frequent fatigue failures. For best installation practice refer to Michigan DOT website at http://www.mdot.state.mi.us/specbook/ Refer to Section 810.03N In my opinion, supporting sign bases on...
  19. curvbridger

    AASHTO Design Vehicles

    It is NOT an HS-20. It is the sum of an HS-20 (or an alternate tandem) with a lane load placed in regions of contributing effect. Curvbridger
  20. curvbridger

    Where is the deck longitudinal joint come from?

    I do not know what you mean about the origin of the longitudinal deck joint. The idea here seems to be to limits effects in the transverse direction. Think about it: If you had a bridge LENGTH of 100 feet, would you not expect significant movement at the ends? Limiting the width serves to...

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