Bentley Communities
Bentley Communities
  • Site
  • User
  • Site
  • Search
  • User
RAM | STAAD | ADINA
  • Product Communities
RAM | STAAD | ADINA
RAM | STAAD | ADINA Wiki Microstran Response Spectrum Analysis to AS 1170.4
    • Sign In
    • -RAM | STAAD | ADINA Wiki
      • +ADINA
      • +Integrated Structural Modeling
      • +Structural Analysis Support Solutions
      • +RAM Concept
      • +RAM Connection
      • +RAM Elements
      • +RAM SBeam
      • +RAM Structural System
      • +STAAD.Pro
      • +STAAD Foundation Advanced
      • +STAAD Advanced Concrete Design (RCDC)
      • +STAAD.building
      • +STAAD RCDC FE
      • +Scenario Services
      • +STAAD.offshore
      • +Limcon
      • -Microstran
        • FAQs: Microstran at Bentley
        • +License - Microstran
        • Microstran Awards and Certifications
        • Microstran Images
        • +Microstran Release Notes
        • -Microstran Support Solutions
          • Bentley's Tiered Offering of Microstran
          • +Help (?) not supported in Microstran
          • Microstran Adding Sections
          • Microstran Analysis of Tilt-Up Panels
          • Microstran Design of Fall Arrest Systems
          • Microstran ISM Interop
          • +Microstran Modeling Tips
          • -Microstran Non-Linear Analysis
            • Microstran Dynamic Analysis
            • Microstran Elastic Critical Load Analysis
            • Microstran Plastic Analysis of Frames
            • Microstran Response Spectrum Analysis to AS 1170.4
            • Microstran Response Spectrum Analysis to NZS 4203
          • +Microstran Restraints for Steel Design
          • +Microstran User Interface [FAQ]
          • +SELECT Licensing of Microstran
          • Symbol or Windings Fonts in Reports
          • Unable to use the Moving Load functionality
      • +MStower
      • +Structural Dashboard
      • +Structural WorkSuite
    • +RAM | STAAD Learning Resources

     
     Questions about this article, topic, or product? Click here. 

    Microstran Response Spectrum Analysis to AS 1170.4

       
      Applies To 
       
      Product(s): Microstran
      Version(s): V8i
      Environment:  N/A
      Area:  Analysis
      Original Author: Richard Collins
       

    An Excel spreadsheet, shown below, is available to assist in the use of Microstran Response Spectrum Analysis of structures to AS 1170.4. The procedure is described briefly in notes at the top of the spreadsheet. The spreadsheet calculates scale factors that have to be entered in Microstran dialog boxes during the response spectrum analysis. Values shown in the spreadsheet relate to this structure:

    Earthquake Example

    The spreadsheet is available at Microstran Excel Spreadhsheet Extensions.

    MICROSTRAN RESPONSE SPECTRUM ANALYSIS - AS1170.4        
             
    PROCEDURE:        
    1. Do dynamic analysis without RSA box checked.        
    2. File > List/Edit File command, then choose Dynamic Log.        
    3. Find fundamental period for direction of interest.        
    4. Enter the values shown in red. Do not change anything else.        
    5. Do static analysis with empty load case for RSA results.        
    6. Repeat dynamic analysis with…        
    a. RSA box checked.        
    b. Green value entered in Response Spectrum dialog.        
    7. Check dynamic log for 90% mass participation.        
    8. Analyse > Response Spectrum then:        
    In Dynamic Load Case Scale Factors dialog…        
    - transfer Reaction value to blue value below        
    - transfer magenta value below to Scale Factor.        
    9. Create Input/Analysis report and check base shear        
    for earthquake case.        
             
    Acceleration coefficient, a = 0.10   (Hobart=0.05 to Newcastle=0.11)  
             
    Height, hn = 12.0 m    
    Eq. 6.2.4(1):        
    Fundamental period = 0.26 sec.    
    Frequency (1) = 3.83 Hz.    
    C(1) = 0.306      
    Eq. 6.2.4(2):        
    Period for the orthogonal direction = 0.21 sec.    
    Frequency (2) = 4.83 Hz.    
    C(2) = 0.357      
    Minimum earthquake design coeff., C = 0.286      
             
    Structure period, T = 0.81   (Fundamental period from dynamic analysis)  
             
    Importance factor, I = 1   (1.00 or 1.25)  
    Eq. 6.2.3 = 0.144      
    Earthquake design coefficient, C = 0.286      
    Site factor, S = 0.67   (Rock=0.67 to Soft clay=2.0)  
    Structural response factor, Rf = 3.0   (Masonry=1.5 to MRF=8.0)  
    Gravity load, Gg = 5766 kN (9.81 x sum mass matrix diagonal - see dynamic log.)  
             
    Earthquake base shear force, V:        
    V, Eq. 6.2.2 = 368 kN    
    V, lower limit = 58 kN    
    V, upper limit = 481 kN    
    V = 368 kN    
             
    Microstran Response Spectrum dialog:        
    Scale factor = 0.327      
    Microstran Dynamic Load Case Scale Factors dialog:        
    Reaction = 165 kN (Value to be scaled according to Cl. 7.4.2.4)  
    Percentage of Section 6 horiz. base shear force = 90%   (Irregular=100%, Regular=90%)  
    Required base shear = 331 kN    
    Scale Factor = 2.004   (RSA values will be factored by this value)  

    • analysis
    • Microstran
    • Dynamic Analysis
    • AS 1170
    • Share
    • History
    • More
    • Cancel
    • Seth Guthrie Created by Bentley Colleague Seth Guthrie
    • When: Fri, Jan 30 2015 6:55 PM
    • Seth Guthrie Last revision by Bentley Colleague Seth Guthrie
    • When: Mon, Feb 2 2015 4:33 PM
    • Revisions: 3
    • Comments: 0
    Recommended
    Related
    Communities
    • Home
    • Getting Started
    • Community Central
    • Products
    • Support
    • Secure File Upload
    • Feedback
    Support and Services
    • Home
    • Product Support
    • Downloads
    • Subscription Services Portal
    Training and Learning
    • Home
    • About Bentley Institute
    • My Learning History
    • Reference Books
    Social Media
    •    LinkedIn
    •    Facebook
    •    Twitter
    •    YouTube
    •    RSS Feed
    •    Email

    © 2023 Bentley Systems, Incorporated  |  Contact Us  |  Privacy |  Terms of Use  |  Cookies