• Accidental torsión, respond spectrum

    The Venezuelan standard calls, when seismic forces are analyse the engineer have to take in account the accidental torsión with an excentricity of 6% of the story, we use the Venezuelan respond spectrum, does any command do this, I saw a video using IBC…
  • RE: Response Spectrum Analysis and Base Shear

    First one comment. As part of the mass definition for the response spectrum load case 3, you should add the udl in the X direction as well as shown below. This is to ensure that vibration of masses in all possible directions are considered for the eigensolution…
  • RE: How to change direction of seismic load in STAAD Pro?

    The response spectrum loading represents seismic acceleration applied at the base of the structure and this dynamic loading would vibrate the structure in both directions. The nature of RSA is such that the responses are all absolute maximum responses…
  • RE: Seismic analysis

    The structure is very stiff in Vertical direction ( Y dir.) . Generally, we consider the effect of vertical motion of the structure if there are cantilever and vertical projections. Thus, we don’t need to consider the modes with Y direction mass participation…
  • RE: Response Spectrum Analysis & Equivalent Lateral Force

    You need to also consider the fact that you are using a R value and an I value which are factored in the equivalent static analysis but the response spectrum base shear does not account for these. If you include these factors ( by multiplying the direction…
  • RE: Design as per Response spectrum results.

    Take a look at any of the program help sections related to response spectrum analysis, for example, Section - 5.32.10.1.8 Response Spectrum Specification per IBC 2012, which says: Dominant mode method. All results will have the same sign as mode number…
  • Design as per Response spectrum results.

    In an article on “Use of Signed response quantities in Response Spectrum Analysis – A Case Study “ by Mr. Sanjib Das Product Specialist, Bentley Systems it was stated that Instead of using the usual process, designers can use the Signed Response Spectrum…
  • RE: RAM Frame Response Spectrum Base Shears

    It's all correct what you said. Use the base shear at the end of the report only when the base is the ground. You also have the right idea regarding I/R and scale factors. I don't usually bother with a separate case for drift unless I get to a point where…
  • Response Spectrum Analysis as per Asce 7-10

    hi, i am doing the Response Spectrum Analysis in Staad as per Asce requirements, i have a doubt that as per 12.9.2 the modal response force to be divided by R/i, this is done by Staad internally or i have to input in direction factor?
  • RE: Rhythmic Excitation of Monumental Stairs in RAM Elements

    The response spectrum (acceleration and time data) is irrelevant if you only want the natural frequencies, but in Ram Elements something must be entered for the dynamic analysis to run. Depending on what you enter for the rsp, the scale factor and the…
  • Artificial time history matching a response spectrum

    Hello all, My question on creating time history (TH) from a response spectrum (RS). STAADPro provides the TH for a given RS in the output file but there is no option to get this TH in the text format. I save the output file as a text file. The output…
  • RE: Rotate Axes Behavior in RAM Frame

    You have the right idea about the rotate axes behavior on dynamic response spectrum loads in Ram Frame. When we calculate summations of things we do tend to do this along the global axis however, so the reported building story shear is along X and Y.…
  • RE: Response spectra

    That information should be sufficient to define the response spectrum per IBC 2012. Ram Structural System is another program Bentley offers, one that I happen to be most familiar with, but STAAD.pro is fine for your task. Here's our FAQ on response…
  • RE: Response spectra

    As your image indicates, it takes more than one coefficient to define a response spectrum curve. Building codes may differ, but for codes that use ASCE 7, you'll have to know To, Ts, TL and Sa for example. With some programs, like Ram Structural System…
  • response spectrum analysis question

    hi, i am doing an response spectrum analysis in staad pro, this is the first time i am doing the analysis after going thru your training session in the website. i have question regarding the base shear calculation, i have done the response spectrum…