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  1. maxwolf

    Allowable Bearing Stress to be confirmed

    For the design of a residential cellar extension using new CIP retaining walls down to 10ft below grade, the allowable bearing is tentatively assumed to be 1500 psf. There is no geotech report available. The cellar will be an extension of an existing rowhouse cellar. At a minimum, a test pit...
  2. maxwolf

    New load on existing CIP flat plate

    Am trying to determine a code compliant method to determine if a new, higher live load can be accomodated by an existing CIP plate. Plate: 8", 4ksi with only bottom bars (#4's @13" ea way) explicitly stated. Top bars indicated only with codes that refer to a lost drawing. Overall the building...
  3. maxwolf

    Packaged freezer unit - Breaker/Max Fuse Size

    Hi All, I need to buy a packaged freezer unit and have received a spec from Norlake with the following electrical data: 208-230V/60Hz/1P Total system refrigeration amps = 11.4A Total system defrost amps = 7.1A Min. circuit amps = 14.2A Max fuse size = 20A We told Norlake that we have a 15A...
  4. maxwolf

    lateral system alteration and code requiremets question

    Mike and Steel, Thanks for the comments. I've advised them not to do it. New York is a seismic zone, though rather mild. We just had a small quake a couple weeks ago that shocked a lot of people. I found the 10% limits in lateral capacity reduction in the newer IBC but not the 2003 version...
  5. maxwolf

    lateral system alteration and code requiremets question

    Hokie66, Sorry for the delayed response. It's two issues: the wall is right on the property line, and they have little money to work with.
  6. maxwolf

    lateral system alteration and code requiremets question

    Thanks JAE and Wannabe, The local code is New York City (2008 (current) vs 1968 (old code) vs 1938 (old, old code). The 10% change limit rings a bell. I'll look it up in the am.
  7. maxwolf

    lateral system alteration and code requiremets question

    There's an existing, unreinforced masonry building, 4 stories, that was built ca. 1900. The perimeter masonry walls are load bearing, the interior is framed in steel with heavy cinder fill on terra cotta arched floors (155 lb/sf DL). One of the exterior walls (5 wythe at 1st floor, 3 wythe at...
  8. maxwolf

    Low concrete strength, very high entrained air

    Thanks for all the responses. Sorry for my late feedback -I came down with the flu a few days ago. More details: The work I'm reviewing is the patching of an existing 12" slab, originally done in the 70's I think. The patching maintained the same slab depth and reinforcement as the...
  9. maxwolf

    Low concrete strength, very high entrained air

    We have a 12" slab on grade and some small amount of foundation work (say, 18 yd3), which had a low f'c (around 2800 psi). Corrected core tests from over 56 days came in at around 3550, which is more than the spec'd f'c = 3500. Petrographic tests/micrographs show the culprits to be very high...
  10. maxwolf

    Stainless bolts in AESS canopy

    Thanks, Ron. I'll check out asce 8, but if they don't list it in the aisc 360 spec, how can a bolt or screw be qualified?
  11. maxwolf

    Stainless bolts in AESS canopy

    I'm working on an HSS architecturally exposed structural steel canopy with some stainless, exposed screws, currently designed as countersunk (3/4" dia - 10). The aisc 360-05 spec does not list anything for stainless steel bolts or screws. A193, B8(M) could work based on calcs, but if they...
  12. maxwolf

    Wind loading debate

    The old New York City Building Code(1968) allows for use of 30 psf wind loads for up to around 100ft for buildings. This is for the MWFRS as well as cladding to my knowledge. I've seen it used for both. ASCE 7-02 and other versions of course require much higher wind loads for cladding...
  13. maxwolf

    2" Diameter Hole Stress Raiser Question

    I'm trying to determine how much yielding around a 2" diameter hole in the side of a 7" diameter pipe column is acceptable. The column is subject to bending and axial load. We've modeled the hole with FEM solid modeling and pretty well defined the areas of yielding - a shallow zone around...
  14. maxwolf

    AASHTO Question on Aluminum Castings for Streetlights/Signs

    Ron, True, though even then Fb=18.3 ksi. m
  15. maxwolf

    AASHTO Question on Aluminum Castings for Streetlights/Signs

    Hi All, In Table 6-9 ‘Allowable Stresses for Casting Alloys’ (Aluminum) in AASHTO's Standard Spec for Structural Supports for Hwy Signs, Luminaires..., Section 6, the allowable stresses for A444 and A356 are given for various tempers. The allowable tensile/compressive stress for bending for...
  16. maxwolf

    Need isolation plate material between aluminum and concrete

    Thanks for the comments. I did a little more reading. For the HD galv. steel bolts in contact with the aluminum base: "...Doyle and Wright [2]show that the rate of corrosion of aluminum does not increase from being in contact with galvanized steel. They conclude: "zinc is very compatible...
  17. maxwolf

    Need isolation plate material between aluminum and concrete

    A streetlight base made of aluminum (357-T6) is to be bolted to a reinforced concrete foundation. The 4 foundation bolts are hot dipped galvanized steel. The outside of the light base is subject to urine, deicing salts and sea air. I first considered some kind of plastic plate (ABS for...
  18. maxwolf

    Collar Joint Question

    The bricks are 3-5/8" wide. So the two inner wythes with a two inch collar joint between them net out 9-1/4." I suggested cmu before as you mentioned, Dick, but the archtiect said no. He wants a parapet of only clay brick. Thanks very much for the comments.
  19. maxwolf

    Collar Joint Question

    I'm working on a parapet that's 48" high. It's 3 wythes thick with the inner two wythes acting compositely. The outer wythe is a veneer separated by a cavity. ACI 530-02 and UBC say a 2" min collar joint for 5' height for the 2 grouted wythes. I don't think we can go much less than that...
  20. maxwolf

    Sleeve Connection Bearing Stress

    Thanks very much for the comments.

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