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Recent content by GraemeL

  1. GraemeL

    Damping Ratio for Secondary System

    That looks like a good paper to back up the Regulatory Guide. It is interesting that there appears to be no mention of how damping is affected by the stiffness of the secondary item - i.e. its fundamental period or by its level of ductility. Haven't read it cover to cover, so may have missed...
  2. GraemeL

    Cold climate steels and fabrication practices

    We are involved in specifying the changes required to enable a skid mounted plant designed for Australian conditions to be fabricated and installed in Canada in temperatures down to minus50 celsius. We were thinking of specifying ASTM A148 plate, hot rolled and SHS/RHS steels instead of the...
  3. GraemeL

    displacement, velocity and acceleration domains

    Thanks for that, after reading your reply I also found a description of this in Chopra's "Dynamics of Structures" p222ff that I borrrowed off a colleague.
  4. GraemeL

    displacement, velocity and acceleration domains

    I would appreciate if someone would provide definitions for the displacement, velocity and acceleration domains wrt a response spectrum. I understand that the period is increasing as one shifts from the displacement to the velocity to the acceleration domain in a response spectrum, but I have...
  5. GraemeL

    FEMA 450 and allowable stress design factor for seismic forces

    FEMA 450, in its section on the design of Architectural, Mechanical and Electrical Components, Chapter 6, has a method of converting the calculated seismic forces to those that can be used in codes that still use working stress methods for their acceptance criteria. Section 6.2.6.1 "Allowable...
  6. GraemeL

    B31.3 & FEMA 450 - seismic design of process piping

    FEMA 450 Section 6.2.6.1 "Allowable Stress Design" gives an expression for converting the strength design seismic forces that are calculated using Eqn 6.2-1 to those that can be used in acceptance criteria that are in terms of allowable stresses: "The earthquake loads determined in accordance...
  7. GraemeL

    Padeye

    It is common practice to specify materials for lifting points and the plates or members to which the lifting point is attached that have guaranteed through-thickness properties. However, the Shell Guidelines for Lifting Points and Heavy Lift Criteria, doc EM/039 allows otherwise if the design...
  8. GraemeL

    Draft AS/NZS 1170.4 - Draft Number DR PPCD 8 - Floor height coeff.

    It is available from: http://spex.standards.co.nz/upload/100256/std%20030127%2008.pdf Commentary from: http://spex.standards.co.nz/upload/100256/Com%20030127%20final.pdf
  9. GraemeL

    Draft AS/NZS 1170.4 - Draft Number DR PPCD 8 - Floor height coeff.

    I have been using the calibration test version of the draft earthquake loading code for NZ and Aust, AS/NZS 1170.4 PPCD 8, Januay 2003. Re Equations 8.3(1) through to 8.3(3): It is not clear to me whether the value for the Floor Height Coefficient CHi determined from Eqn 8.3(1) applies when...
  10. GraemeL

    Steel Moment Frames with Large Dia Pipe..any details?

    Hi there, Offshore platforms have jacket structures made from tubulars. They are most often concentrically braced structures but the smaller ones (usually unmanned platforms) sometimes are moment resisting frames. As the platforms have to resist horizontal environmental loads and maybe...
  11. GraemeL

    Difference between MCE and PGA

    The MCE is the largest credible earthquake that appears to be possible along a recognised fault or within a geographically defined tectonic province under the presently known or presumed tectonic framework. Thus no matter how long a return period you consider, the MCE represents the best guess...
  12. GraemeL

    Copy of DR 1170.4 PPCD 6

    I will answer my own posting: Links to a later version plus commentary, DR 1170.4/PPC8 exist on: http://www.sesoc.org.nz/
  13. GraemeL

    Determining The Load (Capacity) Rating for a Proposed Structure Design

    Is this warehouse on an offshore platform? If not, you are in the wrong forum my friend. A structural engineering forum would seem more appropriate, e.g. "structural engineering other topics" and you may get more sensible answers for your situation. [dazed]
  14. GraemeL

    seismic dead load

    You need to include all the building's weight in the determination of the seismic forces on a building. Excluding walls just because they are parallel to some theoretical earthquake direction seems like courting disaster to me.
  15. GraemeL

    How to reinforce long shear walls?

    I would be tempted to look at your problem another way. I am writing this in an 8 storey building whose lateral load resisting system comprises of a central core that houses two lift shafts and two stair wells. The rectangular box gives four shear walls with one side punctured at each floor...
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