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  1. bojoka4052

    Solving a system of equations; is there a way to make sure all values end up positive?

    I get b_w as a negative value, is it possible to force this to come out as positive value?
  2. bojoka4052

    Not sure how to address forces from one beam to another

    Could you please elaborate on this? This is similar to how my cross section looks; there are 5 different logitudinal beams on which I have applied all the loads. The transverse or what I earlier called "dummy elements" are connecting them, they have no self weight. My computer model includes...
  3. bojoka4052

    Not sure how to address forces from one beam to another

    These are the notes my colleague made for me; does it make any more sense? The dummy beams are there to distribute the loads inbetween the "real beams". What I am trying to do is Grillage Analysis of Bridge Decks, which is why I have this setup with dummy elements.
  4. bojoka4052

    Not sure how to address forces from one beam to another

    I have beam 1) for which I have checked the loads. Ive been told I need to control for the moment and shear from beam 2) onto beam 1) aswell. I dont understand how this works, how does the shear and moment from beam 2) affect beam 1)? This is how the beams 1 and 3 look, they're supposed to...
  5. bojoka4052

    What are some examples of shear compression and shear tension?

    I know what shear is, I know what tension and compression is, but I dont understand what shear compression and shear tension means? Is this simply when shear causes either compression or tension in the member? Example of shear tension? Example of shear compression?
  6. bojoka4052

    What is the more conservative load placement?

    In this case for a beam element model; would it be most conservative to put all the vehicle loads on the purple or green path? I am thinking it must be the purple one as its in the middle and the green one has supports directly underneath its path.
  7. bojoka4052

    What is the more conservative load placement?

    What if the stiffness is still higher on the right, and the same side sticks out longer than the left? Would it then be conservative to put all the load on the stiff side instead of the less stiff side?
  8. bojoka4052

    What is the more conservative load placement?

    I have a symmetric bridge deck about the red line, except that one side has slightly higher stiffness at the end. If I were to place loads on only one side, where would it be more conservative to place, the side with higher or lower stiffness? Supports are along the yellow dotted line.
  9. bojoka4052

    Need to reduce amount of load combinations

    This is a bridge with five different lanes (Sidewalk, Driving lane, Driving lane, Bike lane and sidewalk). This is how my beam element model looks, each beam in the longitudinal direction (x-direction) represents a lane. Supports are all roller supports. The loads I have that can be on or...
  10. bojoka4052

    How can I check if my model makes sense?

    I have made the structure below with beam elements; the transverse beams (In the Y-direction) does not have all the properties defined and is only supposed to carry loads between the longitudinal beams (In the X-direction). The structure is supported by rollers, and I want to find out if the...
  11. bojoka4052

    Special cross section

    I dont need all the properties defined for the beam element, only the three Ive been given (Iy, It, Az): This is from documentation: Ax= cross sectional area Ix= torsional moment of inertia Iy= Bending moment of inertia around local Y axis , usually the greater moment of inertia Iz= Bending...
  12. bojoka4052

    Special cross section

    I have three section properties given per meter length as seen below which I need to define a beam element with: Transverse bending stiffness [m^4/m] Torsion stiffness [m^4/m] Transverse shear stiffness [m^2/m] I can multiply with a certain length to remove the per meter, but after that, where...
  13. bojoka4052

    Internal lever arm

    I am reading a text about bridge cross section and lever arm. The lever arm is mentioned in relation to calculation of section properties of the bridge. I was wondering if having a big lever arm in the cross-section (generally speaking) is good or bad? Is it conservative to assume a small lever arm?
  14. bojoka4052

    Could someone help me understand why I get error message at the end? [Mathcad 15]

    I asked because it seems to be okay for t.bf and t.tf even though there is no subscript, but not for b.w. Does not seem to be any obvious solution, any suggestions on what I could do?
  15. bojoka4052

    Could someone help me understand why I get error message at the end? [Mathcad 15]

    I dont understand why it says the variable at the end (b.w) is not defined?
  16. bojoka4052

    Trying to understand what is happening in this bridge report

    So for the picture you posted, I would have 2 longitudinal J-beams and one longitudinal I-beam in my FEA model, which will be connected by the transverse members? And if I use say hundreds of transverse elements so I get a very fine grillage I might not have to create a shell model? Sounds like...
  17. bojoka4052

    Trying to understand what is happening in this bridge report

    Thank you IDS, I have one more section that has been confusing me if you would have the time: They say "One of the challenges is to divide the cross-section into individual beams. The subdivision chosen meets the criteria that the longitudinal beams have their "individual principal bending axes...
  18. bojoka4052

    Trying to understand what is happening in this bridge report

    I think you got it, another thing I was wondering about in the report if I may ask; They have the grillage model under the section "Analysis models for longitudinal design of superstructure". A seperate section "Analysis model for transverse design of superstructure" says "Transverse design will...
  19. bojoka4052

    Trying to understand what is happening in this bridge report

    I am reading a report about a multicellular deck bridge and they talk about points of contraflexure, and they say members should be spaced closer than 1/4 of the points of contraflexure which I dont understand? The bridge has 3 spans as seen below (L1, L2, L3), the middle one has a length of...
  20. bojoka4052

    How to use the date I have, delete it, and replace it with next set of data? [Excel]

    Thanks for taking the time Skip, I think its hard to explain without having a meeting, I was hoping to automate a task I believe I now should just do manually. There is no point in spending more time at this.

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