Bentley Communities
Bentley Communities
  • Site
  • User
  • Site
  • Search
  • User
RAM | STAAD | ADINA
  • Product Communities
RAM | STAAD | ADINA
RAM | STAAD | ADINA Wiki Member End Forces and Joint Equlibrium
    • Sign In
    • -RAM | STAAD | ADINA Wiki
      • +ADINA
      • +iTwin Analytical Synchronizer_
      • +Structural Analysis Support Solutions
      • +RAM Concept
      • +RAM Connection
      • +RAM Elements
      • +RAM SBeam
      • +RAM Structural System
      • -STAAD.Pro
        • +Revision History
        • -STAAD.Pro Support Solutions
          • STAAD.Pro Safety Related Features
          • +Analytical Modeling workflow
          • +Building Planner workflow
          • +Connection Design workflow
          • +Physical Modeling workflow
          • +Piping workflow
          • -Postprocessing workflow
            • Adding a Company Logo into STAAD.Pro Report
            • Annotations for Maximum Bending Moment or Shear Values not Visible
            • Are Applied Loads in Equilibrium with the Support Reactions
            • Are Story Drift of the Floors Within Allowable Limits
            • Beam Annotation - Change Font and Turn Off Unit Display
            • Changing Beta Angle of a Member
            • Changing Stress Output Units in the *.ANL File
            • Changing the date stamp in the printed Output file
            • Changing Units from inch to cm
            • Comparison of Bending Moment of a structure modeled with member and plate entities
            • Difference Between the Local and Global Deflection
            • Displaying Deflection Diagram
            • Displaying the Bending Moment Diagram
            • Displaying values of nodal displacements, bending moments etc. on the plots
            • Finding out Forces/Moments for reinforcement design of slabs modeled using solid elements
            • Finding out the max forces/displacements/support reactions/stresses for a group of entities
            • Graphically See Node Displacement
            • How to change the plate stress contour color to customize the view in the post processing tab?
            • How to create a video file for Mode shape Animation
            • How to find out axial forces ( tension and compression ) in members
            • How to reset the colors in diagrams?
            • Including pictures in STAAD.Pro Reports
            • Incorrect Shear Force and Bending Moment diagrams
            • Max Absolute stress in Plate Contour
            • Member End Forces and Joint Equlibrium
            • Member end forces are not matching with support reactions for the inclined member
            • Member End Forces Output
            • Mismatch in sign of beam end forces within different tables
            • Moment Values in kip-inch instead of pound-feet
            • Moment Vector Along the Local Positive Z Axis
            • Output items do not appear within Results Setup in STAAD.Pro
            • Plotting Bending Moment Diagram on a selected set of members
            • PRINT LOAD DATA command
            • Print Section Displacement and the Print Joint Displacement don't Match
            • Print Section forces in STAAD Output
            • PRINT STATICS LOAD (EXT and INT interpretation)
            • Print Truss w/ Output Forces
            • Printing Picture Full Page
            • Purpose of Beam - Graphs Page
            • Query Member End Forces for Selected Beams
            • Range too big error when copying data from STAAD.Pro table to Excel
            • Reporting member end forces in global axis system
            • Saving a 3-D Rendered View
            • Sign conventions for forces/moments in beams
            • STAAD Report with More Than 3 Decimal Places
            • Stability Checks for a mat foundation modeled in STAAD.Pro
            • Torsion Stress Report
            • Values of shear force and bending moment do not match between member query and postprocessing tables
            • Viewing different colors for different utilization ratio range
            • Viewing Plate Stress/Moment Envelope Plots
            • What does the note mean: TOTAL NO. OF JOINTS IS GREATER THAN 1000 NO OUTPUT FOR APPLIED JOINT EQUIVALENT LOADS
            • What Version of the Design Code is STAAD.Pro Using
            • When I try to copy/paste results from the Post Processing tables into an Excel spreadsheet I get a message saying “Range too big” or “Selection is too large”
          • +Steel AutoDrafter workflow
        • +STAAD.Pro OpenSTAAD
        • +(+) Archived Wikis
        • +STAAD.Pro - Known Issues
        • +STAAD.Pro Download/Installation/Performance/Security
        • +STAAD.Pro Licensing Solutions
        • +STAAD.Pro Webinars/Videos/Events
      • +STAAD Foundation Advanced
      • +STAAD Advanced Concrete Design (RCDC)
      • +STAAD.building
      • +STAAD RCDC FE
      • +Scenario Services
      • +STAAD.offshore
      • +Limcon
      • +Microstran
      • +MStower
      • +Structural Dashboard
      • +Structural WorkSuite
    • +RAM | STAAD Learning Resources
    • Simplifications to Bentley's Engineering Simulation Software Licenses

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

    Member End Forces and Joint Equlibrium

       
      Applies To 
       
      Product(s): STAAD.Pro
      Version(s): All
      Environment:  N/A
      Area:  Postprocessing workflow
      Subarea:  n/A
      Original Author: Surojit Ghosh
       

     Member End Forces

    Member end forces and moments in the member result from loads applied to the structure. These forces are in the local member coordinate system.

    The end forces (FX, FY and FZ) will be positive if the forces are in the positive local axis. The following figure shows the positive member end forces.

    The member end moments (MX, MY and MZ) follow the right hand rule. If the right hand thumb points the positive local axis, then the fingers point in the direction of the positive moment. The following figure shows the positive member end moments.

    Joint Equilibrium

    The joint equilibrium should be checked in three planes (XY, YZ and ZX plane). For each plane, the axis which is perpendicular to that plane is considered for the joint equilibrium check. The summation of forces along that axis and moments about that axis should be zero.

    Example:

    In this example, the following plane is considered - member 31501, 31518, 1139 and 1140 is on that plane and member 1032 is perpendicular to this plane. 

     

    Force Equilibrium:

    The following forces are considered —

    Positive FZ force at node 1015 for member 1139 : 0.02 kN

    Negative FZ force at node 1015 for member 31501 : -0.482 kN

    Positive FZ force at node 1015 for member 1140 : -0.675 kN

    Negative FZ force at node 1015 for member 31518 : 0.797 kN

    Negative FX force at node 1015 for member 1032 : 0.34 kN

    So the summation of force along the axis perpendicular to the plane is: 0.02+(-0.482)+(-0.675)+0.797+0.34 = 0

    Moment Equilibrium:

    The moments are acting at the member end. To check the joint equilibrium, the reactions at node 1015 is considered.

     MZ force at node 1015 for member 1139 : 4.668 kN-m

    MZ force at node 1015 for member 31501 : 45.66 kN-m

    MZ force at node 1015 for member 1140 : -116.441 kN-m

    MZ force at node 1015 for member 31518 : 66.11 kN-m

    MX force at node 1015 for member 1032 : 0.003 kN-m

    Summation of moment about the axis perpendicular to the plane is: 4.668+46.66+(-116.441)+66.11+0.003 = 0

    • Share
    • History
    • More
    • Cancel
    • Surojit Ghosh Created by Bentley Colleague Surojit Ghosh
    • When: Sun, Mar 23 2014 4:05 AM
    • Modestas Last revision by Bentley Colleague Modestas
    • When: Fri, Mar 24 2023 7:53 AM
    • Revisions: 4
    • 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