Direct Stiffness · Rigid Diaphragm · Timoshenko Cantilever Walls · Flanged (C) Sections · NZS 1170.5 ES + NZS 3101 Shear Limits
EI modifier reduces flexural stiffness of every wall element (default 0.25 for cracked reinforced concrete). Shear deformation always uses the web area only (Av = Lw·tw, As = Av/1.2) — flanges add flexural stiffness only. φow may be overridden per wall segment.
Plastic region class is derived automatically from μ: μ ≤ 1.25 → nominally ductile; 1.25 < μ ≤ 3 → limited ductile (αq = 3); μ > 3 → ductile (αq = 6). φ follows the demand basis: φ = 1.0 where the shear is derived from flexural overstrength (capacity design), φ = 0.75 where it is capped by the nominally ductile demand (μ = 1.25, Sp = 0.9). Self-weight uses the concrete density above × cross-sectional area × the storey heights each wall spans.
Walls that stop above ground (i.e. land on a transfer level) are modelled with their base rotation restrained by default — the transfer beam is taken as rigid, so the wall's overturning moment is delivered into the transfer structure and reported in the Transfer Level Actions table. Selecting Pinned releases that moment (the old behaviour) and gives a lower-bound stiffness for the wall above; run both and envelope the wall shears if the real transfer beam is flexible.
Define each floor level (Level 1 = lowest). Heights are the inter-storey height (from the floor below to the floor above).
| Storey Level | Storey Height (m) | Storey Weight (kN) | Action |
|---|
One row per wall segment, spanning Bottom Level → Top Level (inclusive) with constant properties. For a C-section, the web is the in-plane length Lw and the flanges sit at each end of the web (flange 1 at the low-coordinate end, flange 2 at the high-coordinate end). Enter a negative flange width to place that flange on the negative side of the web (one +ve and one −ve gives a Z-section; leave one at 0 for an L/T-section). Blank flange thickness defaults to the web thickness.
| Wall ID | Bot Lvl | Top Lvl | Section | Web | Flange 1 (start end) | Flange 2 (far end) | Xc (m) | Yc (m) | Orient | E (MPa) | G (MPa) | φow | Action | |||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Lw (m) | tw (m) | bf1 (m) | tf1 (m) | bf2 (m) | tf2 (m) | |||||||||||
Initialising…
At every level and for every load case: Σ(parallel wall shears) must equal the imposed storey shear ΣF above that level; Σ(perpendicular wall shears) must be ≈ 0 (torsional couple only); and Σ(V·lever arm) must equal the applied torque ΣF·e about the centre of mass. Wall moments are not checked here — where a wall lands on a transfer level its base moment is delivered into the transfer structure (see the Transfer Level Actions table in the results panel), not to the foundation.
Run the analysis to populate the checks.
Run the analysis to populate the results table.