Steel design using MasterFrame pro - 2017

Posted on December 14th, 2017 in Webinars

Summary

The following is a summary of the steel design process and features discussed in the Master Frame Pro webinar, drawing exclusively from the provided source material.

Overview and Setup

The webinar focuses on steel design using the power of Master Frame Pro. The session is divided into two parts: reviewing how Master Frame is used for steel design, including design checks, and highlighting the advantages of using the tools available in Master Frame Pro.

Software Versions and Prerequisites: Master Frame Pro facilities are available for Master Frame 500, 1500, or unlimited versions. The PowerPad version and the simple 50-member version do not include these Pro facilities.

Before beginning design, the presenter performed housekeeping within the software utilities. This included checking the default database is using 275, 355 (as the default), and 460 steel. The software was configured to include all sections for UBs and UCs. The presenter customized the available sections, choosing to stick with UK sections (including standard circuit hollow sections, squares, rectangles, UK ANG, and PFC channels) while deliberately removing European sections and bearing piles from the drop lists. Additionally, the presenter ensured the design utilized the Euro code as the default, coupled with the UK National Annex.

Standard Steel Design Checks

The presenter first used a simple frame (a multi-story braced construction with a portal on top) to demonstrate the design checks.

Loading and Analysis: Analysis requires setting up appropriate loading cases. The system initially generated 32 loading cases, including ultimates, equivalent horizontal forces, and sway stabilities. The speaker refined this list, noting that sway stabilities are not part of the Euro code, bringing the total down to 29 cases.

Types of Member Design Checks:

1. Integrated Design / Beam and Beam Portion or Axial with Moment: This check is applied to individual members. When applying this, key member information and critical forces/deflections (e.g., from case 13 and case 15) are displayed.

2. Fully Restrained Members: If a member is designated as fully restrained, the lateral torsional buckling check is omitted, resulting in better load factors.

3. Deflection Limits: Deflection limits can be set as a 1/value (e.g., 360, 250). Alternatively, entering a value between 1 and 20 draws from a table of predefined limits. For instance, "table 1" can be used to set 1/360 for live load and a less onerous 1/250 for dead load.

4. Section Management: Sections can be listed either by serial size (depth) or by weight. Users can also filter sections by applying member limits, such as setting a minimum width (e.g., 130) or minimum thickness for the web and flange.

5. Intermediate Restraints: For primary members (e.g., floor beams) that are not fully restrained over their entire length but are restrained by incoming members or purlins, lateral restraints are created. When restrained at intermediate intervals (e.g., 1-meter centers), the design should use 1L for the distance between restraints.

6. Appendix G: This check, typically used for rafters, works out the design to the point of counterfletcher, potentially avoiding the need for lateral torsional buckling checks.

7. Columns in Simple Construction: This check applies to columns receiving pinned end members with bracing elsewhere in the structure. In Eurocode, this is internally applied as an axial moment check.

8. Discontinuous Strut and Tie: This check is applied to bracing members (e.g., hollow sections or X braces). It is crucial when applying this check to consider the reduced capacity due to bolt holes, as placing two 22mm holes could result in a 40% loss of cross-sectional area.

9. Elastic Critical Load Factor (P-delta): This final check identifies if the frame is unstable and requires P-delta (second order) analysis. The presenter advises performing P-delta analysis only once proper section sizes have been determined, as using flimsy sections initially can generate exaggerated, non-existent additional forces.

Master Frame Pro Advanced Features

The Pro version offers additional tools that greatly streamline the design process, particularly for larger frames.

Steel Member Design Groups: The most important additional tool is the ability to create design groups. A member can only belong to one design group . Users can create groups for specific member types (e.g., corner columns, primary edge beams, roof ties) and set consistent parameters (e.g., simple construction, deflection limits, and minimum section depths) for the entire group. Once parameters are set, the Auto Design feature can be run, which sizes all members in that group simultaneously.

Scanning and Output Rationalization:

• Scanning for Failures: After analysis and auto-design, the frame can be scanned to identify any failing members.

• Unity Values Display: The software can display the unity values (member utilization factors) directly on the frame. This visualization helps identify which specific members are governing the design (e.g., showing 0.95 utilization) and whether they should be separated into a distinct design group for re-sizing.

• Rationalized Output: Master Frame Pro allows the user to filter output reports extensively. The system can be configured to only output the critical portion from each member and only the most critical check for each section size used in the frame. This significantly reduces the volume of output (e.g., reducing 318 design checks to 21 individual section size design checks).

• Report Generator: The Report Generator allows users to configure and pre-configure standard output formats, including graphics, load diagrams, internal forces, and filtered steel design outputs, making reporting easier without repeated manual selection.

Steel Connection Design Groups: Connection design groups allow multiple common connections (such as base plates, eaves, or column splices) to be designed as a single unit. This integration ensures that the connected sections are correctly configured for connection design. Specific connection types, such as beam-to-column or beam-to-beam fin plates, can be checked, highlighting potential overstressing or detailing practice problems.

Summary with Timestamps

This summary of the Master Frame Pro webinar on steel design is presented in a table format with timestamps, drawing exclusively from the provided source material.