Design Summary

Review ULS, SLS, and fire check results across all load combinations in the collapsible Design Summary panel. Covers accordion layout, Category Rollup badges, View All Combinations matrix, and material quantity calculations.

Overview

The Summary tab collects every design check result into a single scrollable panel. After running a batch analysis across multiple load combinations, the panel identifies the governing combination and utilisation ratio for each check type without requiring you to step through combinations manually.

Accordion layout

Results are organised into collapsible accordion groups, one per check category:

Group	Checks covered
ULS — Flexure	Uniaxial / biaxial moment capacity, ductility
ULS — Shear	Concrete + steel shear contribution, maximum shear
ULS — Torsion	Torsion capacity and combined shear-torsion
ULS — Longitudinal force	Chord tension / compression at the flexure-shear interface
SLS — Stress	Concrete compressive and steel tensile stress limits
SLS — Crack width	Characteristic crack width per code method
SLS — Effective stiffness	Effective moment of inertia, long-term factors — an indicator, not a check
Fire	Reduced capacity at elevated temperature for the specified FRL

:::caution[Effective stiffness is not a deflection check] The Effective Stiffness (Ief/Ig) row reports the cracked-to-gross stiffness fraction of the more-cracked axis. It is an indicator, not a verdict: the tool has no span, so it performs no deflection check — there is no span/depth, L/250 or other serviceability limit comparison anywhere in it. The row carries no ratio and no pass/fail, and never contributes to a group verdict. Use the reported Ief with standard beam formulae to compute a deflection yourself. :::

All groups open collapsed by default. The first thing visible is the Category Rollup badge on each header row.

Category Rollup badges

Each accordion header shows a Category Rollup badge — the worst utilisation ratio across all load combinations in that group, followed by the group’s verdict:

OK (green): every gating check in the group ran and passed
OK (amber): the group passes, but an advisory applies — see the warning triangle described under View All Combinations. An advisory is never a code failure
FAIL (red): at least one check in the group fails
N/A (grey): the group produced no verdict — either no combination generated real demand on any check in it, or no check converged. This is not a pass: an unevaluated group is reported as unevaluated rather than shown green

The verdict is not read off the ratio alone. A check that carries no utilisation ratio — minimum reinforcement, ductility, the prestressed $(M_{uo})_{min}$ gate, a refused torsion check — can fail the group while the displayed worst ratio is still below 1.00. In that case the ratio renders neutral rather than green, so it is never mistaken for the verdict.

Scan the full design status at a glance without expanding any accordion. Open a group only when you need the per-combination breakdown. The same verdict drives the colour of the corresponding results tab (ULS, SLS, Fire), so you can see which limit state needs attention before opening the panel at all.

Design Summary panel with accordion groups collapsed. Category Rollup badges show the worst utilisation per group; red badges indicate at least one failing combination.

Per-combination breakdown

Expand an accordion group to see each load combination in that category:

Column	Description
Combination	Load combination name or label
Utilisation	η = demand / capacity
Status	Pass (η ≤ 1.00) or Fail (η > 1.00)
Governing action	The critical action (M, V, N*, etc.) for that combination

The governing combination — the one with the highest utilisation — is highlighted at the top of the expanded list.

View All Combinations

The View All Combinations section at the bottom of the panel expands to a full matrix: every load combination on one axis, every check type on the other. This is the fastest way to:

Find combinations that govern multiple check types simultaneously
Compare how a particular combination performs across the full design suite
Identify check categories where all combinations pass comfortably

Click View All Combinations to expand the matrix; click again to collapse it.

Matrix cells use the same colour scale as the accordion badges: green ≤ 0.85, amber 0.85 – 1.00, red > 1.00. The amber band is a proximity warning, not a failure — only a ratio above 1.00 is a code failure. An em dash (—) indicates that a check is not applicable for a particular combination — for example, a combination with zero shear produces no shear utilisation entry.

An amber warning triangle may appear beside a passing ratio. In the matrix this is the arc-face restraint advisory — the restraint of a bar on a curved face could not be confirmed. An advisory is never a code failure, and is only ever shown on a check that passes. The same triangle is used on the accordion check rows, where it can also mean the minimum-reinforcement scope advisory.

View All Combinations matrix showing utilisation ratios for every combination against every check type.

Member type classification advisory

The declared Member Type (the General tab dropdown) is always what selects which member-type-scoped checks run — flexural ductility, the Cl 8.1.5 conditional-use gate, seismic hinge ductility, and the D ≥ 750 mm deep-member transverse reinforcement check. It never depends on the load level any individual combination happens to reach.

When the active design code is AS 3600-2018 and the declared type disagrees with the load level reached across the ULS envelope, the ULS group shows an advisory note beneath its check rows — for example, a section declared Beam whose worst-case combination reaches column-level axial compression ( $N^* \geq 0.10 f'_c A_g$ , AS 3600 Cl. 10.3.2) prompts a note suggesting the section should also be checked as a column, and a declared Column whose combinations never reach that axial level prompts the equivalent beam-side note. This advisory is not shown for EN 1992-1-1 or ACI 318-19 designs — the equivalent concept exists under those standards but the note is gated by the active design code. The note is advisory disclosure only — it never adds or withholds a check on its own; see Section analysis § Ductility applicability for what the declared type actually gates.

The same note appears in the flexure panel’s Member Type block (General tab) and in the generated PDF report’s assumptions section; all three surfaces are gated by the active design code and stay consistent.

Minimum reinforcement scope advisory

When the active design code is AS 3600-2018 and the declared Member Type is Slab, the ULS group shows an advisory note beneath its check rows, and the Min Reinforcement row’s verdict renders as the amber advisory triangle instead of a green tick.

$A_{st,min}$ is computed from the Cl. 8.1.6.1(2) beam expression, with $\alpha_b = 0.20$ . For a two-way slab, Cl. 9.1.1 substitutes a different deemed-to-satisfy minimum — $A_{st}/bd \geq 0.24 (D/d)^2 f'_{ct.f} / f_{sy}$ for a slab supported by columns at its corners, or $0.19 (D/d)^2 f'_{ct.f} / f_{sy}$ for a slab supported by beams or walls on four sides — required in each direction.

ACS does not apply Cl. 9.1.1. Neither one-way versus two-way action nor the support condition can be determined from a cross-section: both are member-level facts, and the tool has no input for either. Rather than substitute a coefficient it cannot justify, ACS applies the beam expression and states that it has done so.

The practical consequence is that for a two-way slab supported on corner columns, the $A_{st,min}$ shown is 17 % below the Cl. 9.1.1(a) requirement ( $0.20 / 0.24$ ), and only one direction is checked. Verify $A_{st,min}$ against Cl. 9.1.1 in each direction for any two-way slab. For a one-way slab the Cl. 8.1.6.1(2) expression is the governing requirement and the value shown is correct.

The advisory is disclosure only — it does not change the number, and it does not change the ULS group verdict. The same text appears in the Warnings section of the generated PDF report. It is not shown for EN 1992-1-1 or ACI 318-19 designs: Cl. 9.1.1 is an AS 3600 provision.

Minimum reinforcement basis above 500 MPa

$f_{sy}$ sits in the denominator of the minimum-tension-reinforcement expression under all three codes, so a higher-strength grade lowers the code minimum. At 600 MPa the AS 3600 Cl. 8.1.6.1(2) minimum falls by 16.7 %. That is the correct arithmetic and it is part of what the grade buys — but a required area dropping by a sixth with nothing beside it reads like a defect, so it is stated.

Whenever the section’s reinforcement is above 500 MPa, the Min Reinforcement row carries a basis note giving the clause, the $A_{st,\min}$ it produced, the $f_{sy}$ it was evaluated at, and what the same section would have required at 500 MPa. Below 500 MPa there is no note: the clause is applied at the grade you chose and nothing about it has changed.

Three things the note is careful about:

The comparison is measured, not asserted. ACS evaluates the clause twice — once at the section’s $f_{sy}$ and once at 500 MPa — and reports the difference it actually found. Under EN 1992-1-1 the $0.0013 b_t d$ floor can govern at both strengths, and the note then says the minimum is not lowered rather than quoting a reduction that did not happen.
It is a basis, not a warning. It renders muted, never red. The verdict it accompanies is sound.
A mixed-grade section is flagged as one. The $f_{sy}$ quoted is the mean over the section’s reinforcement, which need not be any single bar’s grade, and the clause takes no account of where the higher-strength bars sit. The note says so and asks you to check the tension-face steel against the clause directly.

The same string appears on the flexure panel’s $A_{st,\min}$ card and in the PDF report’s Design Summary, from one source — the panel and the report cannot say different things about why the minimum is the number it is.

Section-level assumptions

Above the governing check rows, an amber triangle appears whenever the run made any section-level assumption — something the engine had to assume about the section itself rather than about one combination. It sits above the checks because it qualifies every verdict below it: an assumption about the section is an assumption behind each of its results. The strip states how many apply and points at the PT tab, where each one is set out in full. It carries the count rather than the text because both cases are tendon facts with a paragraph of explanation and a named control behind them, and this strip is capped at a quarter of the panel height.

Two cases apply today, and both are declarations a tendon did not make:

An undeclared bond state. A PT tendon saved before the Bond control existed carries no declaration and is analysed as bonded (grouted), which selects the tendon-stress law, the transformed-section duct deduction, the crack-control tendon set and the Cl. 8.2.1.5 duct factor $k_d$ — so it reaches the flexure, shear, crack-width and section-property results alike. See Prestressing § Bond type on saved sections.
An undeclared strand position, where the strand is modelled on the duct centreline. That overstates the effective depth $d_p$ at a sagging section. Set Strand position in duct on each tendon — see Prestressing § Strand position within the duct.

Like every advisory in this panel, these are disclosure only: they never change a number and never change a group verdict. The same text appears in the Warnings section of the generated PDF report, and on the sectionWarnings field of every by-id derived read in the API.

Checks that could not be computed

A section-level check can fail to run at all — the calculation throws rather than returning a verdict. The row for such a check shows a circle-slash mark and the verdict column reads as not computed; hovering the row shows the failure message. This is a fourth row state, distinct from the three verdict states:

Mark	Meaning
Green tick	The check ran and the section satisfies it
Red cross	The check ran and the section fails it
Amber triangle	The check passes, with an advisory that qualifies the verdict
Amber circle-slash	The check did not run — nothing was measured, so there is no verdict either way

The row sits under the group that owns the check: ULS and SLS checks appear among their own rows, while a prestress-loss or time-dependent failure gets its own PT or TDE group, which is present only when that analysis failed. Open the named results tab for the detail — each panel renders its own error with a retry.

A group containing a did-not-compute row never reads a green OK. Its heading reads N/A and the panel border and footer go neutral: the ratio-bearing checks that did run are still reported truthfully, but an unverified check must not sit under a pass. A genuine failure still takes precedence — a group with both a failed check and an uncomputed one reads FAIL.

Before September 2026 (#5778) a check that threw had its row omitted entirely, which was indistinguishable from a check that does not apply to the section — a slab’s deep-member transverse-reinforcement row, say, is absent because the clause does not govern. The two are now distinct: absent means not applicable, and the circle-slash means not computed.

Staleness and cover-incomplete disclosure

The panel reads the batch design check by design-option ID (GET .../design-options/{id}/batch-design-check, #5038) rather than resubmitting the section as a payload, so a save in flight is a window in which the last-fetched result is not yet current. While a save is pending or the panel is otherwise waiting on the persisted section, a staleness badge appears beside the panel title and every pass/fail mark, ratio and category verdict in the body is replaced with a pending placeholder (”…”) rather than shown desaturated — colour alone is never the disclosure, and the same withholding is what a screen reader hears (the body carries aria-busy while recalculating). Row and column labels — the check name, the governing combination — stay visible; only the verdict itself withholds.

If Cover is set to Code-Based with no Exposure Class selected, the section has no cover to compute against and the panel shows “Design Summary unavailable” instead of any check results — select an Exposure Class, or switch Cover back to Manual, to restore the panel.

A section with no load combinations saved yet reads No load combinations instead: the design checks run against the applied actions, so there is nothing to analyse until at least one combination exists. Add one in the Actions panel (see Load combinations) and the panel fills in as soon as the save lands. This is an empty state, not a failure — before the 2026-09 release (#5959) the panel asked the server anyway and rendered its refusal, so the ordinary gap between drawing a section and entering its loads was reported as an error.

Material quantities

Below the check results, the panel shows calculated material quantities:

Quantity	Description	Units
Concrete volume	Cross-sectional area × unit length	m³/m
Reinforcement mass	Total steel mass per unit length (longitudinal bars + stirrups)	kg/m

Quantities are computed for all section shapes, including curved and circular outlines. For circular columns the calculation accounts for the full circular area including arc segments.

Non-finite coordinate guard

Material quantities require all section vertices to have finite coordinates. If the section geometry contains a NaN or infinity coordinate — which can occur when parametric inputs produce a degenerate shape — ACS returns a structured error rather than propagating meaningless quantities.

The quantities panel shows an explanatory notice and the error code non_finite_coordinate in this case. To resolve it, review the section outline inputs and correct any degenerate dimension or parameter that produces a non-finite vertex position.

Section analysis — running ULS and SLS checks, shear and torsion design
Reinforcement — placing bars and stirrups
Getting started with ACS — first analysis walkthrough