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  1. Luceid

    ETABS: Display>show tables filtering problem

    I think ETABS doesn't let you filter from that location - you have to go into the format-filter-sort bar at the top. I think SAP and SAFE let you filter directly in the table, not ETABS (Fun, right?)
  2. Luceid

    Reaction Values Displayed Despite No Restraints ETABS

    What does the advanced meshing dialog box look like. Could the edge restraint be turned on in there? that's what this looks like
  3. Luceid

    Categorising this type of RC Beam

    Are the "web" bars stirrups? or are you talking about skin reinforcement - horizontal bars around the faces of the beam?
  4. Luceid

    Breakout Splitting Factor per ACI 318-19 17.6.2.6

    camin < cac -> ψ ≠ 1.0 per EQ.17.6.2.6.1a For Eq.b, I think the 1.5hef/cac is meant as a minimum. So if camin/cac is less than 1.5hef/cac, you can use 1.5hef/cac as your ψ. So I believe ψ = 0.99 in your case, assuming the other calculations are correct.
  5. Luceid

    Bending Moments in Slab after introducing the secondary beam

    Alright - well you can see a change in the typical midspan moment, it's no longer a nice parabolic shape. The beam is contributing some stiffness and crimping the moment diagram. I would test increasing the secondary and primary beam depths independently to study if one or both of these elements...
  6. Luceid

    Bending Moments in Slab after introducing the secondary beam

    Are there beams in the left-right direction? Many of these secondary beams are unsupported if not
  7. Luceid

    Bending Moments in Slab after introducing the secondary beam

    An image of the layout would help. If your slab is sagging at the beams - then the beams likely aren't stiff enough to support the slab. More depth does not mean more stiffness. EI/L Imagine a 300ft long beam with a perpendicular slab spanning 10'. The slab is probably going to "support"...
  8. Luceid

    cracked stiffness?

    What code are you designing for? For ACI - you can either use the approximate factors (0.25Ig for the slab - as you noted) or actually analyze the degree of cracking using nonlinear modeling or by calculating the degree of cracking yourself and applying a modifier that way (likely with...
  9. Luceid

    Frames appear shorter than they actually are

    Are you viewing releases in the display settings - or do you have object shrink turned on?
  10. Luceid

    Stirrups as punching shear reinforcement over columns

    Congestion really is the primary difference. There is a really minor calculation difference in a shear capacity - see ACI for this, but it's really not enough of a difference to worry about. Stud rails were originally invented to combat congestion from what I have been told
  11. Luceid

    Trouble to understand Rotational Stiffness knM/rad to kN/m in etabs?

    Can always test it using a simple stick model - use a super stiff frame element with a pin + rotational spring at one end and apply a point load at the tip. Calculate how much rotation you would expect based on a kN-m/rad unit assumption and see how it works out. Not sure why the units are so...
  12. Luceid

    Draw columns in ETABS

    Hm - weird. Yes - gird line intersections work like nodes
  13. Luceid

    Draw columns in ETABS

    Do you have nodes drawn already? Usually you need nodes to connect your frames to. Also - check veiw settings to make sure something weird isn't happening like frames being turned off
  14. Luceid

    SAP2000 Interactive Database Bug

    I am currently running into a problem where using the interactive database editor will overwrite some frame section properties and turn them into circles with a radius of 1-meter, even when we are not changing any section properties during the database edit. Has anyone else run into this issue...
  15. Luceid

    area load confusion greenhouse

    It depends what you want from your analysis Uniform loads will only be delivered at the nodes of the areas I believe. Therefore you won't get any load distribution along the supporting frame's length, except at eh discrete mesh locations. Uniform to frame loads area based on the local axes of...
  16. Luceid

    Non-Seismic Column Ties: 135 vs 90 Hooks

    Right - that's more what I was trying to figure out - does everyone just specify 135's or are there parts of the country/world where this would be more of a surprise in the field. Appreciate the follow up here - good discussions
  17. Luceid

    Seismic design of moment-resisting concrete frames with embedded pedestals

    I think the fundamental thing here is if you want the flexural failure to occur in the frame as you want - everything else needs to survive until them. You back out the Ve based on Mpr to protect your frame against shear. If the other elements supporting the frame will fail before Mpr or Ve [of...
  18. Luceid

    Maximum point load on un reinforced concrete wall?

    When making an interaction diagram - the upper bound for pure axial load, once you account for phi, 0.8 and 0.85 factors comes out to around 0.44*f'c. But typically you need to account for minimum eccentricity which causes some moment - and the length of wall you think you can distribute this...
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