Bentley Communities
Bentley Communities
  • Site
  • User
  • Site
  • Search
  • User
  • Welcome
  • Products
  • Support
  • About
  • More
  • Cancel
RAM | STAAD | ADINA
  • Product Communities
  • More
RAM | STAAD | ADINA
RAM | STAAD | ADINA Wiki RAM Concept Shear Reinforcement [FAQ]
    • Sign in
    • Working Remotely with RAM or STAAD
    • -RAM | STAAD | ADINA Wiki
      • +Integrated Structural Modeling
      • +Limcon
      • +Microstran
      • +MStower
      • -RAM Concept
        • +Known Issues in Ram Concept
        • RAM Concept Case Studies
        • +RAM Concept Feature Articles
        • +RAM Concept Getting Started Guides
        • RAM Concept Images
        • RAM Concept Key Features
        • +RAM Concept Release Notes
        • -RAM Concept Support Solutions
          • +Installation - RAM Concept
          • +RAM Concept Capabilities [FAQ]
          • +RAM Concept Design Strips [TN]
          • +Ram Concept Design Topics
          • RAM Concept Files [FAQ]
          • +RAM Concept Load History Calc Options [TN]
          • RAM Concept Loading [FAQ]
          • +RAM Concept Modeling and Meshing [FAQ]
          • +RAM Concept Plans And Printing [FAQ]
          • +RAM Concept PT Optimization
          • -RAM Concept Reinforcement [FAQ]
            • RAM Concept - Reinforcing bar out of cross section
            • RAM Concept Shear Reinforcement [FAQ]
          • +RAM Concept Tendons [FAQ]
          • +RAM Concept-RAM Structural System Integration [TN]
          • STAAD.Pro CONNECT Edition - Ram Concept
        • RAM Concept Videos
      • +RAM Connection
      • +RAM Elements
      • +RAM SBeam
      • +RAM Structural System
      • +Scenario Services
      • +STAAD Advanced Concrete Design (RCDC)
      • +STAAD RCDC FE
      • +STAAD Foundation Advanced
      • +STAAD.building
      • +STAAD.offshore
      • +STAAD.Pro
      • +Structural Analysis Support Solutions
      • +Structural Dashboard
      • +Structural WorkSuite
      • Structural Synchronizer Links
    • +Webinars
    • +RAM | STAAD Learning Resources

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

    RAM Concept Shear Reinforcement [FAQ]

      Product(s): RAM Concept
      Version(s): Any
      Environment:  N/A
      Area:  Design
      Original Author: Bentley Technical Support Group
       

    Why does my flat slab (or flat plate) model have one-way shear reinforcement or fail the shear check?

    When some engineers design flat slabs by hand, they ignore the one-way shear checks. They decide that punching is all that is appropriate. (This is often decided without much consideration – it just “seems right”).

    Concept does not make this decision, as nowhere does the code advise to ignore one-way shear checks in a flat slab or flat plate. In fact, ACI 318-02 rule 11.12.1.1 specifically requires a one-way shear check in flat plates. Nonetheless - you should decide what the possible failure mechanism is and so what is appropriate. It may, or may not, be appropriate to ignore the one-way shear results.

    In Ram Concept, one-way shear checks are independent of the punching shear check. Transverse shear reinforcement is detailed by the program, if required for one-way shear capacity. Stud rail reinforcement is detailed, if required for punching shear capacity. Transverse steel reinforcement is not considered in the punching shear check. Stud rails are not considered in the one-way shear check.

    One of the biggest factors in thick slabs (especially in mats) is the fact that the program designs for shear at each cross section, while the design codes generally allow the designer to ignore shear some distance from the face of the support (typically "d"). In cases where shear reinforcement is only required in the last section at the face of the support it can be ignored.

    The results have a lot more shear reinforcement than expected.

    This is likely to be a shear core issue. Refer to “About shear core” on page 99 and “Shear core in slabs” on page 100 of Chapter 22, “Defining Design Strips” or the design strips technote. In summary, when the shear core is small relative to the total section area and demand, a lot of shear reinforcement may be required.

    For a post-tensioned beam, the reason could be that Concept is deducting a fraction of the (bonded) duct from the web width per the appropriate code rules.

    Concept calculates the number of duct by dividing the Strands per tendon by the Max strands per duct (as specified in the Materials) and rounding up to the next integer.

    Refer to the following sections for an explanation of Concept’s shear web calculation:

    • For AS 3600, “Section 8.2 Shear Design” on page 415
    • For BS 8110, “Section 3.4.5 Design shear resistance of beams” on page 432.
    • For IS 456, “Section 22.4 Design shear resistance of beams” on page 460.

    Note: There is no ACI 318 rule concerning deduction of ducts.

    What does this audit text mean: “Depth “d” is zero - replacing with “column” effective depth. Depth is still zero - giving up.”?

    The is likely a combination of two things:

    • there is net compression force and a small moment, and as such the bending designer does not provide any reinforcement, or
    • the minimum designer has been turned off. If this is the case, you should consider turning the minimum designer back on.

    A similar condition tends to occur near the inflection point of a span. In these locations the moment can be very small and a flexural capacity check can pass with very little top reinforcement, but if there is no tension reinforcement at the tension face, or of there is a lot more reinforcement on the compression face, this skews the calculated depth to the tension reinforcement (d) and drastically reduces the shear capacity.

    Can I model user shear reinforcement?

    Starting with Ram Concept V8i SELECTseries 9, release 5.2 user defined transverse reinforcing can be specified.

    A wiki on user defined shear reinforcement in RAM Concept is available at the following link:

    http://communities.bentley.com/products/structural/structural_analysis___design/w/structural_analysis_and_design__wiki/13771.user-defined-shear-reinforcing-in-ram-concept.aspx

    Prior to release 5.2, transverse reinforcement is always designed by the program and cannot be modeled as user reinforcement. Program designed transverse reinforcement also cannot be changed by the user. 

    Does the reinforcing weight in the Estimate Report include transverse reinforcement?

    Yes, transverse reinforcement is included in the reinforcement weight in the Estimate Report.

    • FAQs
    • SELECTservices
    • RAM Concept
    • transverse
    • Shear
    • Share
    • History
    • More
    • Cancel
    • Seth Guthrie Created by Bentley Colleague Seth Guthrie
    • When: Wed, Oct 1 2008 1:03 PM
    • Seth Guthrie Last revision by Bentley Colleague Seth Guthrie
    • When: Tue, Jun 23 2020 11:53 AM
    • Revisions: 21
    • 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

    © 2021 Bentley Systems, Incorporated  |  Contact Us  |  Privacy |  Terms of Use  |  Cookies