📺How to design masonry walls with openings and wind posts? [WEBINAR RECORDING]

Posted on January 28th, 2022 in Webinars

Summary

This webinar, presented by Tommy White from MasterSeries Software, offers a comprehensive guide to designing masonry walls, particularly those with openings and wind posts, using their specialised software. The session covers various aspects of masonry design, including analysing walls under different loads, such as wind, gravity, and concentrated point loads, and evaluating their structural integrity against British and Eurocodes. Crucially, the webinar demonstrates how to address common design challenges like inadequate strength or excessive deflection through solutions like adjusting wall thickness, material strength, adding bed reinforcement, or incorporating wind posts and piers, highlighting the software's ability to implicitly check their performance. Finally, it outlines the licensing options for MasterSeries Software and provides contact details for further support and enquiries.

Key Topics

• Masonry Design Software
• Wall Design Parameters
• Structural Analysis Methods
• Licensing Options
• Technical Support

Description

This webinar, presented by Tommy White from MasterSeries, focuses on masonry panel design using MasterSeries software, with colleague Andreas joining to assist with questions. The session was recorded and will be available on the MasterSeries website.

MasterSeries Product Overview MasterSeries offers a comprehensive range of structural design products, including the Building Design Suite, PowerPad, and MasterPort. These integrate modules for frame analysis, portals, and simple beams, alongside advanced add-ons like wind analysis, BIM integration (with Tekla, IFC, Revit), and specialized finite element analysis for dynamic and seismic design. The masonry design software is available as a standalone program, though the Pile Cap module now integrates with other programs for efficiency.

Licensing Options Users have two licensing options:

• Perpetual licenses: A traditional purchase with an annual fee for updates.

• Annual or quarterly subscription: A lower upfront cost, but the software ceases to function if payments stop, similar to other industry packages. The software uses a cloud-based license check, allowing multi-user licenses to be shared across multiple PCs or locations globally with internet access.

Key Features of MasterSeries Masonry Design The software supports designing masonry panels with various complexities, including:

• Stiffened and unstiffened walls.

• Load-bearing peers.

• In-plane and out-of-plane analysis.

• Bed reinforcement.

• Design according to British and Eurocodes, including full National Annex implementation for various European countries. Users can also edit and create custom National Annexes. Historical Irish codes are also supported.

PowerPad Version Limitations The PowerPad version of the masonry module is a smaller version with limitations, such as:

• Support for up to two openings only.

• No wind posts or bed reinforcement design.

• Utilises simple codified formulas for panels with fixed and pinned supports, lacking advanced yield line analysis.

Demonstrated Design Scenarios and Solutions:

1. Laterally Loaded Walls:

    ◦ Fixity Conditions: The base of a wall can be set as fixed or pinned, depending on construction (e.g., continuous bedding on floors or supported on a shelf angle).

    ◦ Analysis Mesh: The software uses yield line analysis to find the weakest failure mechanism. Users can choose mesh densities (coarse, medium, fine, super fine), with finer meshes offering greater accuracy but longer calculation times. For results close to unity (e.g., 0.9 or higher), a more detailed mesh is recommended.

    ◦ Failure Solutions: If a wall fails lateral loading checks, solutions include: changing fixity conditions to more rigid (e.g., from pinned to fixed), increasing block thickness, or using stronger blocks. While stronger blocks (e.g., 17.5 N/mm²) significantly improve compressive strength, their impact on flexural strength under lateral loads may be limited beyond a certain threshold.

    ◦ Lateral Loads: Typical wind loads are around 1 kN/m², but can be as high as 3.5 kN/m² in exposed locations.

2. Walls with Vertical Loads (Line and Point Loads):

    ◦ Load Types: The software handles concentric and eccentric linear loads from roofs and floors, and point loads.

    ◦ Pre-compression: Vertical loads improve the flexural strength of the wall due to pre-compression.

    ◦ Bearing Stress: Point loads can cause failures due to high bearing stress. This can be addressed by:

        ▪ Defining the bearing width of the member (BW).

        ▪ Adding a pad stone (e.g., an engineering brick) beneath the point load to distribute the stress. This also accounts for additional buckling effects.

3. Freestanding Walls:

    ◦ These walls often fail due to stringent code load factors.

    ◦ Solutions include: reducing the spacing of supporting piers, increasing pier size, or thickening the wall.

4. Columns:

    ◦ The software handles eccentric point loads on columns.

    ◦ For compression problems, using stronger blocks (e.g., 17 Newton blocks) is an effective solution.

    ◦ Users can input custom values for axial and flexural strength, and bond values.

5. Walls with Openings:

    ◦ For complex walls with multiple openings, Yield Line analysis is used instead of sub-panel methods.

    ◦ Solutions for strengthening walls with openings:

        ▪ Bed Reinforcement: Internal bed reinforcement (e.g., Bekaert Murfor at every other brick course) can improve strength, and external reinforcement can be even more effective but might require less cover if rendered. The "Place parallel with gap" option allows for specifying two strips of reinforcement with a gap between them.

        ▪ Piers: Adding masonry piers can stiffen the wall, but significant stiffening often requires large piers. Piers can only be set at equal, symmetrical spacing; individual placement is not currently possible.

        ▪ Wind Posts: A highly effective method to stiffen walls with openings. A steel section (e.g., rectangular hollow section) is added. The wind post is implicitly checked as part of the overall masonry yield line analysis; its stiffness and strength are absorbed into the masonry, and it's assumed to be fully restrained. The software visually shows if the yield line passes through the post (meaning it acts as a stiffer part of the wall) or along it (meaning it acts as a support). While the post itself isn't explicitly designed, its top and bottom connections for shear must still be calculated by the engineer. Wind posts can be placed within the cavity (lying on minor axis) or in line with the wall.

6. Horizontal Point Loads:

    ◦ These can be applied by defining a line load over a very short length (e.g., 100mm) and increasing its intensity to represent a point load.

7. Freestanding Walls with Surge Loads:

    ◦ The software can analyse walls, such as those in car parks, with fixed supports (e.g., into columns and base) and subject to surge loads (e.g., 5 kN/m). Adding a wind post can effectively break up large spans and allow a thinner wall to work.

Additional Discussion Points:

• DPC (Damp Proof Course) Fixity: Most DPCs offer sufficient shear resistance for the base to be considered simply supported. Engineering bricks can provide a higher degree of strength continuity.

• Normalized Mean Strengths: Eurocode requires overriding the block strength with the normalized value, whereas British Standards offer options for hollow/solid blocks.

• Negative Loads (Uplift): Negative vertical loads can be input to represent wind uplift, causing tensile stresses. While possible, they are less common than other load cases.

• Load Combinations: The software considers load combinations, allowing users to specify leading or accompanying loads.

• Code Updates: MasterSeries software is updated several times a year to reflect changes and amendments in relevant codes, with critical updates being notified promptly.

• User-defined Properties: Engineers can add proprietary wind posts or custom blocks by defining their yield and moment capacity.

• Return Walls as Restraint: The code of practice provides rules for how return walls provide support and continuity, which can be modelled as fixed or continuous edges.

Support and Contact: MasterSeries provides sales and technical support, with contact details provided at the end of the webinar. Rental options for the masonry module are available for as little as £110 for a three-month recurring rental.