Masonry Design Methodology​

Advanced Yield Line Analysis (AYLA) Method

The Advanced Yield Line Analysis (AYLA) is the key advanced analysis feature of the MasterSeries Masonry module, setting it apart from traditional design approaches. It provides a comprehensive analysis of wall behaviour, including the effects of openings, wind posts, piers, and reinforcement.

How to Switch on AYLA

To use the Advanced Yield Line Analysis:

1. Click the Use AYLA icon to activate the method.

2. Using the down arrow next to the Analyse button, select the node density (Coarse, Medium, Fine, or Super Fine).

   • Medium density is recommended for initial analysis.

   • Use a finer density if the utilisation ratio is close to 1.0 (e.g., above 0.95).

3. Click Analyse to perform the wall analysis.

4. You can enable Auto-Solve to automatically reanalyse the wall after every input change, or leave it off and press Analyse manually once all edits are complete.

Methodology

1. AYLA is a plastic analysis method that determines the ultimate lateral load capacity of the wall by simulating its failure mechanism. It identifies the critical yield line pattern that will form at collapse.

2. Vertical loads are automatically taken down through the wall.

3. Localised additional compressive stresses are included where lintels, concentrated loads, or point loads occur above openings.

4. The yield line pattern shows the likely wall failure mechanism under lateral loading.

   • Heavier lines indicate earlier yield formation.

   • Blue lines represent yielding in one direction, and green lines represent yielding in the opposite direction (e.g., near supports).

5. The analysis fully considers the stiffness of wall leaves, piers, wind posts, and edge restraints when determining the wall’s overall capacity.

Permissibility

1. The use of yield line analysis is explicitly permitted by both British Standards and Eurocodes as a recognised method of obtaining bending moments in flat plates.

Traditional/Panel Method

When a wall has openings (doors, windows, service penetrations), the wall is conceptually split into a set of smaller sub-panels—typically piers beside openings and spandrel panels above and below them. Each sub-panel is treated as its own panel with its own support conditions, effective height and length, and bending moment distribution under lateral load. The global wall capacity is then judged from the performance of the governing sub-panel, along with overall stability checks.

This approach follows the traditional code methods that use bending-moment coefficients for panels supported on three or four sides. The British Standard provides guidance to treat the regions around openings as individual wall panels—an approach analogous to Hillerborg’s strip method in slab design. Eurocode 6 permits the use of recognised methods (for example, yield line or finite element) for determining bending moments in plates; for walls with large or complex openings it points designers toward yield-line analysis rather than prescribing a sub-panel recipe.

The Traditional/Panel Method (also referred to as the older panel method) remains available for simpler wall configurations or when a straightforward, code-based analysis is sufficient. This method follows the flexural strength approach found in masonry design standards.

How to Use the Panel Method

• When Use AYLA is not highlighted, the program operates in Panel Method mode.

• Vertical loads (including self-weight) are automatically taken down through the wall.

• Openings are handled by dividing the overall panel into sub-panels for both vertical and lateral (wind) loading.

• The Panel Method can handle up to two isolated openings.

Analysis Methods

You can choose whether to use the Advanced Yield Line Method or the older Panel Method.

Panel Method

In the panel method (Use AYLA not highlighted) the vertical loads are taken down through the wall along with the self-weight. Openings are dealt with by splitting the overall panel into sub-panels for both vertical and lateral (wind) loads. Note that the Panel Method can only handle 2 isolated openings.

Permissibility

1. The use of yield line analysis is explicitly permitted by both British Standards and Eurocodes as a recognised method of obtaining bending moments in flat plates.