Tutorial T01-1 - MasterFrame Simple Steel Beam Design

Posted on October 1st, 2019 in Getting Started

Summary

This is a comprehensive summary of the tutorial detailing the steps involved in designing a simple steel beam using Master Frame and the Steel Design module, initially referencing Eurocode 3.

Setting Up the Project and Initial Beam Configuration

The process begins by opening the Master Series software and starting Master Frame. A new file, tutor 1-01, is created within the Demo directory. The user selects the simple beam option in the pre-processor.

Initial Section and Geometry:

• A trial section is chosen: 457 152 52 steel section with a strength of 275.
• The initial member length is modified from 9 meters to 6 meters by shifting the coordinate by minus 3 meters.

Defining Loads and Load Cases

Member loading is applied directly onto the beam:

• Dead Load (D1): A Uniformly Distributed Load (UDL) of minus 15 kilonewtons (vertically down, Y-axis).
• Live Load (L): A UDL of 20 kilonewtons down.
• Live Point Load (L): A point load of 40 kilonewtons applied at 3 meters, placed in the middle of the beam.
• Self-Weight: Self-weight is automatically included, applied in the D1 group, with a loading of 77.01.

The supports are automatically set to be pinned. The first support is pinned, while the second support has a vertical support (although a Z-axis restraint could be added, it won't matter as the analysis is done as a plain frame).

Analysis Under Eurocode

The design code is set to Eurocode using the UK National Annex. The default 610 loading type is selected.

The software initially generates two loading cases: Dead Live Ultimate and Live Load Only. A third case, Dead Live Service, is temporarily added but then deleted to match the tutorial.

The analysis is performed using static analysis, plain frame. Notional horizontal loads are automatically applied, though they have no effect because all supports are pinned.

Analysis Results (Graphical and Tabular):

• Graphical Results: The bending moment diagram can be viewed and scaled (e.g., to 200).
• Deflections: The live load only case shows 11 millimeters of deflection, while the dead plus live case shows 25 millimeters of deflection.
• Support Reactions (Serviceability): The support reactions are 160, 80, and 80 either side.
• Ultimate Member Forces: Maximum shearing is 184, and the maximum moment is 319-320 kilonewtons. The 25 mm deflection occurs at the 3-meter length.

Steel Design and Optimization (Eurocode)

Entering the steel design module, the initial design check results in a failure (indicated by a blue screen).

Applying Lateral Restraints:

• Lateral restraints are introduced for stability.
• Portion one is set from zero to two meters. This action automatically divides the 6m member into three portions.
• The middle portion is still overstressed, partly because it exceeds the local capacity of the initial section.

Section Sizing: To remedy the failure, the section size is increased. By sorting available sections by weight order, the software determines that the 457 152 by 60 is the lightest section that satisfies the Eurocode requirements.

Design Output: The default deflection limit is 1/360 for live load only serviceability. The design output can be printed as a summary and a detailed design check for the critical portion, showing the unity values for the three member portions.

Redesign to British Standard (BS 5950)

The tutorial then demonstrates switching the design code to the British Standard (BS).

1. Changing the code updates the loading cases to use the 1.4 and 1.6 factors typical of the BS.
2. After re-analysis under the new, heavier BS loading, the previously acceptable Eurocode section (457 152 by 60) results in a failure of approximately 10% due to lateral torsional buckling under BS 5950.
3. To satisfy the British Standard, a heavier section is required. The software identifies the lightest options that work as the 66 (in the 533 range) or the 67 on a 406.

Summary with Timestamps

The steps for designing a simple steel beam using Master Frame and the Steel Design module, referencing Eurocode 3 and subsequently the British Standard, are summarised below in a tabular format, including the relevant timestamps: