📺Concrete Design to EuroCode 2

Posted on January 9th, 2018 in Webinars

Summary

The sources provide a detailed overview of the MasterSeries software's capabilities for concrete design, primarily focusing on its use in structural analysis, beam design, frame design, and Finite Element Analysis (FEA) for slabs, all aligned with Eurocode 2.

MasterSeries Product Overview and Concrete Capabilities

The MasterSeries platform consists of three main product ranges: the Building Design Suite (the "big" suite), the Lighter Power Path Suite, and a custom suite where users can select only the required components. All three ranges are capable of handling concrete design.

• Building Design Suite: This core suite includes the Analysis Center and BIM integration, with concrete design available as an add-on.

• Power Pad Suite: This option is capable of handling 100 member frames and concrete design.

• FEA Add-on: The Finite Element add-on (available for the Building Design Suite or Power Pad) allows for the design of flat slabs, transfer slabs, shear walls, and rafts.

• Standalone Modules: Separate modules are available for retaining walls and pile caps, although these were explicitly noted as not being covered in the presentation.

• Software Components: Whether using the Building Design Suite or Power Pad, users interact with MasterFrame, which serves as the analysis component of these programs.

Concrete Beam Design

Concrete beam design can be accomplished using the commercial version of the Concrete Beam Designer (which handles up to 16 continuous spans) or via the MasterFrame integration.

• Free Version: A free version of the Single Concrete Beam Designer is available from the website for simple, single-span beams.

• Design Process: The concrete beam designer supports simple, isolated, simply supported, continuous, and cantilever beams. Users can define the number of spans (e.g., inserting a span to go from two to three spans), set section sizes, apply loading (dead load and live load per metre squared), and specify slab spacing to automatically magnify loads.

• Eurocode Considerations: The design process specifically accounts for the difference between the legacy BS code (bending moment diagrams) and the Eurocode method, which uses a distorted force diagram incorporating "shear drag". The shear drag is limited and never gets bigger than the support maximum moment.

• Reinforcement: The software suggests reinforcement (e.g., sidebars for beams deeper than 750 deep). Users can easily adjust the suggested reinforcement (e.g., 3x16s, 4x20s) by left and right-clicking with the mouse to increase, decrease, or remove bars.

• Frame Interaction: The beam designer can simulate the effect of upper and lower columns (and their heights) which will affect the resulting moments in the beam.

Frame Analysis and Optimization

For frames, the MasterSeries uses MasterFrame for analysis.

• Loading Patterns: For concrete (or rigid steel) structures, it is essential to handle additional loading patterning. Loads are designated into groups (e.g., D1/L1, D2/L2) which facilitates the simple creation of alternate load patterns (maximum, minimum, maximum). The software assumes permanent dead loads are not patterned, adhering to a "sensible approach" taken in the Eurocode.

• Load Application: Users can apply uniform loads, point loads (e.g., representing a thick wall), and more complex loads like thermal expansion, shortening, or off-centre torsion for edge beams.

• Redistribution: The software provides a "very, very powerful" method for redistributing moments . Instead of applying a fixed percentage arbitrarily, the user can determine how much redistribution is necessary, viewing the impact via a gray line on the moment diagram. Redistribution up to 30% was demonstrated to help the reinforcement work .

• Column Design: Column design checks are rigorous, analyzing axial capacity alongside moments in both the X and Y directions, checking uniaxial moments, and biaxial moments (dominant X or Y). The program classifies columns as slender or otherwise, using the $K_1$ and $K_2$ factors recommended in the UK's National Annex, as the Eurocode itself lacks specific guidance on effective length and classification.

• Pad Foundations: Pad foundation design requires setting parameters like concrete class (e.g., C32/40), surcharge, and safe working pressure. Checks include beam shear (straight across the face, checked at $D$ from the column face) and column head punching shear (checked at 1D and 2D perimeters). The design accounts for issues arising from asymmetrical column placement, which creates pressure problems and affects punching shear.

Finite Element Analysis (FEA) for Slabs

When designing large structures, such as 3D frames with transfer slabs or flat slabs, the FEA capability is used.

• Pattern Loading in FEA: For FE surfaces, users define load patterns by selecting panels that belong to different load sets (D1L1, D2L2, etc.), which allows the system to pattern the loading automatically. Patterning is run either East-West or North-South, but never both simultaneously, to avoid doubling the load.

• Attached Beams: When modeling drop beams attached to a slab, the section size defined should only be the depth projecting below the slab, not the full depth, and they should be defined as rectangular beams.

• Meshing: The program automatically meshes surfaces (default resolution is 1 meter). Users can review graphical error results and apply local mesh intensities (e.g., down to 0.25 meters radius) around critical nodes or high-stress areas to reduce errors.

• Design Moments: Results can be displayed using $M_x$ and $M_y$ moments, but the more applicable results for concrete slab design are the Wood and Armer moments (MRX and MRY). Peak smoothing can be applied to handle high local moments near supports.

• Strip Averaging (Banding): To achieve a more pragmatic reinforcement design for slabs, users can employ strip averaging (banding). This averages the moments over a defined width (e.g., 1 or 2 metres, based on column strip dimensions). This technique reduces the moment required for design compared to using the unique peak values.

• Punching Shear in FEA: Currently, the software allows inspection of stresses around columns, but users would need to perform a manual check on punching shear using external tools (like spreadsheets from the Concrete Society) by taking the column reaction and floor loading area.

• Deflections: To obtain a realistic deflection assessment for serviceability checks, users can modify the material factor (Young's modulus) to account for cracked sections (with or without short-term or long-term creep), which is a very onerous check.

Customization and Defaults

MasterSeries allows extensive customization of design rules and parameters (over 100 parameters).

• Saving Defaults: Users can save specific settings (like covers, assumptions for column bracing/restraint, and methods of detailing) as a default file (e.g., "multi-story"). These settings are then automatically used in subsequent new files.

• Load Manipulation: The MasterFrame environment allows for easy manipulation of loads, such as deleting a load by setting its value to zero or using the "Kill" function, or copying loads to multiple members in copy mode. Global editing is available for changing the load values on multiple members simultaneously.

Summary with Timestamps

The following table summarizes the key topics and features of the MasterSeries concrete design software discussed in the sources, organized chronologically with timestamps.