Frame analysis

What it does today

• Linear, second-order (P-Δ, P-δ and flexural-torsional), linear buckling and modal analysis of 3D frames with Timoshenko beam elements
• Second-order, geometrically nonlinear and pushover analyses on equivalent imperfections or on a buckling mode, and geometrically nonlinear analysis in large displacements and rotations through load stages, under load, displacement, mean displacement or arc-length control, with its critical points, a switch to the buckled branch and the states where tension-only parts and gaps change
• Plastic members, either with plastic hinges on the yield surfaces of EN 1993-1-1 or with fibre sections, listing the hinges in the order they form; at first order the path ends at the collapse load factor
• Pushover analysis to EN 1998-1 4.3.3.4.2 with the target displacement of Annex B: up to 16 pushovers per building over directions, senses, eccentricities and load distributions, each with its capacity curve, equivalent single-degree-of-freedom system, drifts and damage checks at the target, mechanism and α_u/α_1
• Member checks of a plastic global analysis to EN 1993-1-1: each combination followed to λ = 1 at first order or in large rotations, and at every hinge or plastic zone the section class, the web stiffeners, the restraint within h/2 with its forces, and the stable segments of 6.3.5 and Annex BB
• Response spectrum analysis to EN 1998-1 with accidental torsion, and the storey checks of 4.4.2.2 and 4.4.3.2: drifts, the sensitivity coefficient θ and damage limitation; each run keeps the spectrum it used, which a chart shows beside a pushover's capacity curve
• Seismic isolation: isolators with restoring, yielding, friction and viscous parts, isolated bridges to EN 1998-2 section 7 with upper and lower bounds, and isolated buildings to EN 1998-1 section 10
• Load combinations to EN 1990 over its whole design basis: every kind of action and variable category, arrangements of load cases, seismic actions expanded by the 30 % rule of EN 1998-1, the ten verifications, and load factors given as ranges, checked at the extremes of their effects; with the recommended values or the Finnish decree 3/16 and K_FI
• Steel member checks to EN 1993-1-1 6.2 at every point where the forces can peak, between the stations too, and 6.3 over every combination of the verifications of resistance (STR, EQU with resistance, set C, accidental and seismic), by any of the three stability methods of 5.2.2(3) or on the unique imperfection of 5.3.2(11), with the beam-column method and section readings chosen, and with the 5.3 imperfections generated for every sway direction
• Members of rolled angles and channels (UPE and UPN) on their principal axes, class 4 ones included, checked in tension, compression, bending, shear and torsion and in flexural, torsional-flexural and lateral-torsional buckling
• Links between nodes for bearings, hinges and floor diaphragms, gaps that close, tension-only members, bearings that lift off, and point, partial, trapezoidal, temperature and distributed moment loads, changes of temperature over a stretch, and bimoments at nodes
• A model file, in the document container or as one JSON document, that is a valid model whenever it opens, edited through operations that say what a removal takes with it, with members divided into parts that form member lines, renumbered, given the combinations EN 1990 generates, kept open in sessions with undo, redo and recovery copies of unsaved work, and holding the runs of its analyses with the envelopes defined over them, whose results are stored in parts, so that a page of rows of one case or state reads that part alone
• A desktop program on Windows and Linux with the file commands, undo and redo, a command palette, a Model tree of every record and a Properties panel that edits the selected records, with numbers and units in the user's language, and deletes that name what depends on a record first

How it is verified

Closed-form results: a simply supported beam, a second-order cantilever and the critical moment of a beam on forks against Timoshenko and Gere, the Euler load of a pinned column, the natural frequency of a simple beam, the collapse load of a fixed portal against the combined mechanism by virtual work, a cantilever rolled into a circle and the elastica of an Euler column against the elliptic integral, and by hand the EN 1998-1 spectra, storey checks and isolated buildings and the EN 1998-2 isolated bridges.

Performance

Next

The desktop program's tables of every record kind, its loads and combinations panels and its 3D view, then time-history analysis, linear and nonlinear, which the underlying fem library now runs.