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Recent content by Mark_J

  1. Mark_J

    Structural 3d Modeling- Theory help needed (AWC/ NDS- Deck)

    I have, it feels soft. The guys putting up 20 decks a year, almost exclusively with composite decking, getting the home owner calls, won't go past 12" o.c. joist spacing. They do NOT use conventional lumber for decking any more, it rots and cracks and no home owner stains their deck every 3 years.
  2. Mark_J

    Structural 3d Modeling- Theory help needed (AWC/ NDS- Deck)

    It was first relayed to me by a contractor who builds mostly decks. Roof top and regular. I have 2 investment properties with trex decking, one was built at 24 oc, 1 at 16. Forget about 24, you can see the banana, the 16 feels very soft. Not like a conventionally framed deck with 1x planks, much...
  3. Mark_J

    Precast Double T-Beam Cracking Question

    It looks like a fairly large failure at the support. Shear, support, bearing plates. 1/2" steel and connectors seem like the path forward
  4. Mark_J

    Structural 3d Modeling- Theory help needed (AWC/ NDS- Deck)

    I signed up for skyciv about 6 months ago. It's actually very nice. $100 a month and does a ton of designs. Latest is full steel detail connection designs with illustrations. For the price, I don't think anything compares on the market. Fixed, or not fixed, on wood joists though, you'll get a...
  5. Mark_J

    Structural 3d Modeling- Theory help needed (AWC/ NDS- Deck)

    12" o.c. is a must when using trex decking. It's on every single job I do and 16" o.c. is a diving board after 2 years. Bounce, L/18 (or less) on the joists and oversize the beams.
  6. Mark_J

    Underpinning

    Shore up the point load if you can to get the shored load away from the underpinning. Doing just that in a few weeks.
  7. Mark_J

    Precast Double T-Beam Cracking Question

    It looks like the steel bearing plate is heavily corroded.
  8. Mark_J

    Residential Girder Detailing

    Brick is a sponge for water.
  9. Mark_J

    new concrete retaining wall / abutting existing rubble wall

    I would think the building department would make the owner(s) backfill the pit. They don't like open pits next to sidewalks for extended periods of time.
  10. Mark_J

    new concrete retaining wall / abutting existing rubble wall

    This looks like Philadelphia. The rubble wall is clearly at the same bottom of elevation as it's no longer neighbors. Do you mean the front porch area? You can undermine walls within reason, similar to an underpinning operation. You can even underpin the location of house that is about to fall...
  11. Mark_J

    Slab monolithic with grade beam or raised?

    I'm assuming those are helical piles. It is not uncommon for them to be 4" or so off centerline. I've come to the conclusion you need a portion of the slab to resist the torsion from this eccentricity. Forget about the grade, many times the foundation is basement, well below grade. I'd thicken...
  12. Mark_J

    Soil Supporting Garage Slab

    Should be fine. What do they have specified, 2 grade beams going into the assumed over excavated garage/basement location (18' wide)? I put a 2x4 key and thickened slab in anticipation of the builder not compacting the soil properly.
  13. Mark_J

    Table R602.3(5) IRC (size/height/spacing of wood studs)

    Just curious. Can you post wind pressure, LF loads, and height? I'd like to put into my calculator and see how much deflection fails.
  14. Mark_J

    Engineering Design 'Stack'

    Bookmarking PDF-XChange for future research. I need a good pdf tool to work with pdf letters, forms and plans.
  15. Mark_J

    Concrete wall spalling - causes?

    My guess is the elevation is facing South and in an area of freeze/thaw commonly occurring during the winter (i.e. 20^ at night, 40^ day) during winter months. Water is collecting directly under the lintel and it is popping out the concrete to the rebar.

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