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Tutorial T01-2 - MasterFrame Simple Frame Design

Posted on September 17th, 2019 in Getting Started

Summary

The sources describe a step-by-step tutorial for creating, loading, analysing, and designing a simple goalpost frame using structural analysis software (likely "Masterframe"). The design process focuses on satisfying British Euro code requirements.

Frame Creation and Geometry

The frame, named "goal post one," was created using the snap grid tool.

Initial Geometry and Section:

The frame has a span of 7 1/2 by 3.9.
The column height is 3.955.
The initial member chosen for the columns was a UB 25414631.
The columns are defined starting at 0 and moving up. The beam spans between points that are 7.855 away from each other.

Haunched Member Definition: The top beam member was changed from a uniform section to a double hunched member.

The length of the haunch (X distance from the centre line out) was set to 0.5 metres on both sides.
The overall depth was set to 2.25 on both sides. This 2.25 depth at the centre line is approximately two times the serial depth at the support interface.

Supports: The base supports for the frame were defined as pinned bases.

Loading Application

The tutorial applied both member loading (UDLs and point loads) and nodal loading (wind load).

Load Type	Description	Value (kN)	Location/Grouping
Dead Load (UDL)	Uniformly Distributed Load	12.5	Applied to the first member.
Live Load (UDL)	Uniformly Distributed Load	7.5 (or 7.6)	Applied to the first member.
Point Load (Dead)	Concentrated Load	12.5 (initially 12)	Applied at 2.5 metres along the member (modified from 2 metres).
Wind Load (Nodal)	Point Load in the X-axis	12.5 (initially 12)	Applied as a nodal load, placed in the wind group (W-1 load).

Analysis and Loading Cases

The initial analysis of the frame as a plane frame showed the traditional bending moment diagram but did not include horizontal loads (only dead plus live).

Loading Case Generation: The analysis was set to the British Euro code. Loading cases were automatically created, resulting in 9 loading cases which included Sway stabilities and service cases.

Ultimate cases (Dead and Live) used 610 factors, excluding A and B variations.
Equivalent horizontal forces were incorporated at 0 and 180 degrees.
Service cases included live load only.
Cases involving wind (Dead + Live + Wind, Dead + Wind) also had the horizontal forces added.

Re-Analysis Results: After re-analysis with horizontal loads applied, the graphical results showed that the bending moment diagram was affected significantly: going to the dead plus live plus horizontal case resulted in a reduction on one side and an increase on the other, which addresses sway stability.

The deflected shape analysis showed 27 millimetres of horizontal movement in the X-axis for the current (unsized) members.

Steel Member Design

The design check used the "axial with moment" integration, which is the more generic check.

Beam (Upper Member) Design: Initially, the beam was failing, with unity checks reaching 1.9 and 2.1 for deflection.

Restraint: An assumption was made that the member had a restraint at 2 metres (1L was used for overall restraint).
Deflection Limits: The default limit of 1/360 was modified. The design subsequently referenced Table 2 (used for edge beams) for deflection limits. Custom criteria were set, accepting 1/200 for some cases and 1/100 for cantilevers. Type 2 criteria were applied to the beam.
Section Sizing: Stepping up the section size, the 305, 46 was found to be the lightest and shallowest section that worked, satisfying both deflection and lateral torsional buckling requirements under the new criteria.

Column Design: The design check applied to the columns also used "integrated axis equals moment" .

Effective Length: The $L_{cr}$ value was set to 1.5L .
Deflection Limits: Criteria 3 (for cantilevers) was applied for the deflection limit, and the software had to be told explicitly that the member was a cantilever .
Section Sizing: The initial column failed . The section was stepped up until the 305, 165, 54 worked . The other column required a larger section (40676) .
Switch to UC: To achieve uniformity and better performance, the columns were changed from UB to UC sections . The final chosen section was 203 by 60 UC for both columns, as the 52 UC worked on one side but not the other .

Iteration and Stability Check

Re-analysis with Revised Stiffness: After initial member design, the structure was re-analysed using the revised stiffness . This re-analysis caused the beam portion to fail again .

The beam section was subsequently increased to the 305/54 .
A final check confirmed the three chosen sections all worked .

P-Delta Analysis: A critical check was performed for the elastic critical load factor (alpha crit) . Since the alpha crit was found to be below 10 (specifically in the second loading case), a P-delta analysis (second order) was required for stability.

P-Delta was enabled using the Newton-Raphson method, which is preferred for rigid frames .
This second-order analysis was applied to all ultimate cases .
After the final P-Delta analysis and re-analysis, a scan confirmed that all three members worked, concluding the design tutorial .

Summary with Timestamps

The following table summarizes the tutorial steps, actions, and key results drawn from the sources, organized by timestamp:

Timestamp Range	Section/Action	Key Details and Results
00:00:02,960 – 00:00:47,040	Frame Setup & Geometry	The video introduces the creation of a simple goalpost frame with a span of 7 1/2 by 3.9. A new frame called "goal post one" is created using the snap grid tool. The column height is 3.955. The initial columns were chosen as a UB 25414631. The beam spans between points 7.855 away from each other.
00:02:01,120 – 00:03:04,960	Defining Haunched Member	The top member was changed from a uniform section to a double hunched member. The X distance (haunch length from the centre line) was set to 0.5 metres on both sides. The overall depth was set to 2.25 on both sides. This depth is roughly 2 times the serial depth at the support interface.
00:03:06,640 – 00:03:52,320	Applying Member Loading	Member loading (UDLs and a point load) was applied to the first member. A dead load UDL of 12.5 kilonewtons was applied. A live load UDL of about 7.5 (or 7.6) was applied. A dead point load of 12.5 kilonewtons was applied at 2.5 metres along the member .
00:03:52,560 – 00:04:31,040	Applying Nodal Loading (Wind)	The wind loading was simulated as a nodal load instead of a point load on the end of the member . A load of 12.5 kilonewtons was applied in the X-axis . This was placed in the wind group as a W-1 load .
00:04:32,960 – 00:04:44,880	Defining Supports	The static supports at the base were defined as pinned bases .
00:04:46,840 – 00:05:11,360	Initial Analysis	A quick analysis of the frame as a plane frame showed the traditional bending moment diagram, but it only included loading from the dead plus live and did not include any horizontal loads .
00:05:12,800 – 00:05:34,640	Setting Code	The analysis was confirmed to be working to the British Euro code .
00:05:38,520 – 00:06:25,320	Loading Case Generation	Automatic case creation resulted in 9 loading cases . Ultimate cases (Dead and Live) used 610 factors . Equivalent horizontal forces were included at 0 and 180 degrees . The cases generated included Sway stabilities and service cases (e.g., live load only) .
00:06:35,040 – 00:07:20,720	Re-Analysis and Sway	After re-analysis with horizontal loads applied, the bending moment diagram showed a reduction on one side and an increase on the other when switching to the Dead + Live + Horizontal case, which is relevant for sway stability . The deflected shape analysis showed 27 millimetres of horizontal movement in the X-axis for the current unsized members .
00:07:50,240 – 00:08:11,120	Starting Design Check	The design check chosen was the "integrated axial with moment" , which is the more generic option .
00:08:12,000 – 00:09:03,600	Beam (Upper Member) Initial Failure	The upper member was failing . Restraint was assumed at 2 metres along the member . Unity checks reached 1.9 and 2.1 for deflection . Both deflection criteria and member size needed improvement .
00:09:04,560 – 00:11:15,040	Beam Deflection & Sizing	The default deflection limit of 1/360 was considered too onerous . Deflection limits were modified, referencing Table 2 (used for edge beams) . Custom criteria were set, including accepting 1/200 and 1/100 for cantilevers . Type 2 criteria was applied to the beam . The section size was stepped up until the 305, 46 was found to be the lightest and shallowest section that worked .
00:11:41,360 – 00:12:54,640	Column Design (Initial)	The "integrated axis equals moment" check was applied to the column . The effective length ($L_{cr}$) was set to 1.5L . Criteria 3 for cantilevers was applied for deflection limits . The software had to be explicitly told the member was a cantilever . The initial column failed . The section was stepped up to the 305, 165, 54 .
00:13:02,000 – 00:14:27,180	Column Sizing (UC Standardisation)	The second column, when checked with the 54 section, failed (within 1%) and required a larger section (40676) . A decision was made to change the columns from UB to UC sections to ensure uniformity . Both columns were eventually standardized to the 203 by 60 UC .
00:14:27,740 – 00:15:00,380	Re-analysis with Revised Stiffness	After member sizing, the structure was re-analysed using the revised stiffness . This caused the beam portion to fail again . The beam section was subsequently increased to the 305/54 . A final check confirmed all three chosen sections worked .
00:15:29,060 – 00:15:48,460	Stability Check (Alpha Crit)	The elastic critical load factor ($\alpha_{crit}$) was checked and found to be below 10 (particularly in the second loading case) . This required a P-delta analysis (second order) for stability .
00:15:53,420 – 00:16:20,860	P-Delta Implementation	P-Delta (second order analysis) was turned on . The Newton-Raphson method was used, as it is preferred for rigid frames . P-Delta was applied to all ultimate cases .
00:16:32,620 – 00:16:49,180	Final Confirmation	After the final P-Delta analysis, a scan confirmed that all three members work, concluding the design .