VIMSAC

Verification of Interaction, Member, Serviceability and Connection Specifications

Pre-release technical preview for evaluation partners. Commercial cloud subscriptions and site licenses launch Q4 2026.

1 Single-Click Project-Wide Verification: Powered by vectorized parallel execution that evaluates millions of checks in seconds—verifying and optimizing every member, connection, diaphragm, and anchor across an entire project in a single click ($\text{DCR} \le 1.0$).

2 Auto-Generated Approval PDF Reports: Automatically compiles comprehensive, glass-box PDF calculation dossiers for the entire project—complete with code citations, symbolic equations, and step-by-step substitutions—ready for direct submission to approval bodies.

3 Complete Member, Joint & Anchorage Coverage: Unifies AISC 360 (Chapters B–L, Appendices 2, 3, 4, 8), AISC 341/358-22, SDI DDM04, ACI 318-19 (Anchorage), ASME BTH-1 (Lifting Lugs), and AISC Design Guides 1, 2, 3, 4, 7, 9, 11, 13, 16, 24, 29, 31, 33, 38, and 39.

4 FEA Floor Vibration & Foundation Dynamics: Evaluates structural habitability, pedestrian footfalls, and rotating machinery foundations per AISC Design Guide 11 (full Bathe subspace iteration FEA with Sturm sequence checks), Sétra Footbridges 2006, and ACI 351.3R.

Structural Compliance & FEA System

Whole-Project Verification and Approval Submittals in a Single Click

Traditional structural workflows fragment member sizing, connection detailing, concrete anchorage, floor vibration FEA, and equipment foundations across disconnected spreadsheets. VIMSAC unifies vectorized parallel code checking, multi-objective cost optimization, and instant regulatory PDF generation inside a single execution loop.

Vectorized Single-Click Solve

Evaluate millions of member, connection, and anchorage permutations in seconds. VIMSAC processes every framing element and joint across all governing LRFD and ASD load combinations simultaneously, eliminating manual element-by-element post-processing.

Approval-Ready PDF Dossiers

Generate complete, project-wide PDF calculation packages with one click. Every limit state is documented with exact code clauses, symbolic formulas, numerical substitutions, and constructability checks formatted for building department and peer-review sign-off.

Zero-Retention Ephemeral Security

Project-wide compliance audits, Bathe FEA vibration runs, and connection cost optimizations execute within isolated, transient environments with zero persistent disk storage; structural models and reports are purged immediately upon delivery.

Structural Verification Specifications

Select a structural compliance domain to inspect its mathematical formulations, governing design standards, and automated sizing routines.

Member Capacity, Stability & Torsion Checks

Mathematical & Numerical Formulations

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Slenderness & Column Buckling: Evaluates compact, noncompact, and slender element reductions alongside flexural, torsional, and flexural-torsional buckling across rolled wide-flange, channel, angle, tee, and HSS profiles.
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Lateral-Torsional & Web Shear Buckling: Resolves plastic yielding, inelastic LTB, and elastic LTB regimes with moment gradient modifiers, slender-web bend-buckling reductions, and post-buckling tension field action.
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Saint-Venant & Warping Torsion: Solves fourth-order differential torsion equations to extract twist angles, pure Saint-Venant shear, warping shear, and warping normal stresses under concentrated and distributed torques.
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Filled Composite Bilinear Interaction: Formulates axial compressive strength and non-linear axial-flexural interaction curves for concrete-filled composite columns with local tube slenderness reductions.

Governing Codes & Regulatory Compliance

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AISC 360 Chapters B through H & Appendix 8: Enforces compactness limits (Table B4.1), Direct Analysis Method stability ($P\text{-}\Delta / P\text{-}\delta$ amplifiers and geometric stiffness $[K_G]$), tension, compression, flexure, shear, and biaxial interaction (Equations H1-1a/b) under LRFD and ASD.
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AISC 360 Chapter I & Appendix 2 Composite Members: Verifies encased and filled composite columns, composite beams with headed stud anchors, and high-strength steel/concrete composite interaction (up to 100 ksi steel and 15 ksi concrete).
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AISC Design Guide 9 Torsional Analysis: Audits open wide-flange, channel, and tee shapes alongside closed HSS sections under pinned, fixed, and free warping boundary conditions.

Sensitivity Analysis & Structural Sizing

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Single-Click Catalog & Pareto Sizing: Evaluates the complete AISC shapes database in parallel to select minimum-weight sections and extract Pareto trade-offs between unit steel weight, section depth, and governing $\text{DCR}$.
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Architectural Envelope & Bracing Optimization: Enforces ceiling plenum depth and flange width constraints while evaluating capacity sensitivity to lateral unbraced intervals.
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Project-Wide Attrition Diagnostics: Quantifies candidate rejection rates across slenderness, lateral-torsional buckling, biaxial interaction, and deflection limits across the entire member schedule.

Web Openings, Curved & Crane Girder Checks

Mathematical & Numerical Formulations

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Isolated & Expanded Web-Opening Vierendeel Mechanics: Computes plastic neutral axis shifts, cut-tee flexural-torsional buckling, web-post horizontal shear buckling, and cubic moment-shear interaction across single penetrations and castellated/cellular beams.
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Curved Member 3D Vector Mapping & Warping: Transforms straight-chord frame forces into curved-axis tangential, radial, and binormal vectors, solving arch snap-through, in-plane/out-of-plane buckling, HSS ovalization, and lateral flange bending.
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Crane Girders & Stepped Mill Columns: Computes transformed section properties for wide-flange girders with cap channels, moving wheel-load influence envelopes, and exact transcendental effective length factors for stepped columns.
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Rainflow Cycle Counting & Miner Fatigue: Extracts closed full cycles and half-cycle residues from variable-amplitude stress histories to compute Palmgren-Miner cumulative damage and root-mean-cube effective stress ranges.

Governing Codes & Regulatory Compliance

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AISC Design Guides 2 & 31 Web Penetrations & Expanded Beams: Verifies reinforced and unreinforced rectangular/circular openings alongside non-composite and composite castellated and cellular beams.
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AISC Design Guide 33 Curved Steel Design: Enforces vertically curved arch and horizontally curved girder interaction equations using Isolated Flange and elastic normal stress methods with second-order amplification.
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AISC Design Guide 7, CMAA 70 & AISC 360 Section J10 Cranes: Evaluates cab/pendant impact, lateral side thrust, longitudinal tractive forces, CMAA Class A–F deflections, and web local yielding, crippling, and sidesway buckling under wheel loads.
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AISC 360 Appendix 3 & ASTM E1049-85 Fatigue: Verifies allowable stress ranges across Stress Categories A through G—including transverse PJP and fillet weld root reductions—for crane girders, stiffener toes, and rail clips.

Sensitivity Analysis & Structural Sizing

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Automated Opening Stiffener & Infill Plate Sizing: Sizes horizontal reinforcing bars at web penetrations and full- or partial-depth infill plates at high-shear castellated and cellular beam supports.
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Curvature Bracing & Cap-Channel Optimization: Tunes radial bracing intervals for curved girders and optimizes composite wide-flange plus top-channel crane runway sections.
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Fatigue Detail Category Upgrading: Evaluates cumulative damage sensitivity across weld categories to guide transitions from intermittent fillet welds or bolted clips to continuous CJP details.

Moment, Bracing & HSS Connection Checks

Mathematical & Numerical Formulations

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End-Plate Yield-Line & Non-Linear Bolt Prying: Evaluates unstiffened and rib-stiffened extended end-plate yield-line mechanisms alongside thin-plate bolt prying forces and AISC Table J3.1 bolt pretension bridges.
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Non-Orthogonal Uniform Force Method (UFM) & Gusset Buckling: Resolves 2D non-orthogonal gusset equilibrium for sloped beams and inclined braces, projecting 30-degree Whitmore sections onto plate boundaries to switch between compact ($K = 0.50$) and cantilevered ($K = 1.20$) buckling.
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Column Panel Zone & Concentrated Force Limit States: Evaluates column flange local bending, web local yielding, web crippling, compression web buckling, and panel zone shear deformation at moment joints.
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HSS Chord Plastification & Punching Shear: Computes chord wall plastification, punching shear rupture, and sidewall local yielding/crippling across T-, Y-, K-, and X-connections in round and rectangular HSS.

Governing Codes & Regulatory Compliance

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AISC 360 Chapters J & K and Design Guide 24: Verifies ASTM F3125 high-strength bolts (Grades A325/Group A, A490/Group B, Group C, and A307), directional fillet welds, block shear rupture, bolt bearing/tearout, and HSS branch connections.
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AISC Design Guides 4, 13, 16 & 39 Moment Connections: Audits flush and extended (4E, 4ES, 8ES) moment end-plate connections, Manual Part 9 prying equations, and wide-flange column continuity plate and web doubler stiffening rules.
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AISC Design Guide 29 & Wrench Clearance Screening: Verifies vertical bracing gusset interfaces and enforces Section J3.3 minimum bolt pitch, Table J3.4 edge distances, and Manual Part 7 pneumatic impact wrench socket clearances before stress evaluation.

Sensitivity Analysis & Structural Sizing

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Vectorized Multi-Topology Connection Optimization: Explores discrete catalogs of plate thicknesses, bolt diameters, grades, weld sizes, pitches, and gauges across all project joints and load combinations in a single click.
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Continuity Plate & Doubler Avoidance Cost Modeling: Minimizes net fabricated connection cost by trading marginal end-plate thickness or bolt gauge adjustments against expensive shop-welded column stiffeners and web doublers.
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UFM Centroid Setback & Prying Elimination Tuning: Adjusts gusset interface centroids to eliminate secondary moments and sizes end-plates to reach the thick-plate prying-free threshold.

Prequalified Seismic Connection Checks

Mathematical & Numerical Formulations

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Probable Maximum Plastic Hinge Mechanics: Computes strain-hardening overstrength factors, probable plastic hinge moments, gravity-plus-seismic hinge shears, and projected moments at the column face.
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RBS Dogbone, End-Plate & Flange-Plate Stability: Evaluates radius-cut RBS plastic moduli, Case 1 and Case 2 seismic end-plate yield-line envelopes with thick-plate prying-free bolt sizing, and Bolted Flange Plate (BFP) compression buckling.
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Strong-Column / Weak-Beam (SCWB) & Panel Zone Shear: Verifies column-to-beam plastic moment ratios reduced for axial load and evaluates post-yield panel zone shear resistance incorporating thick column flange contributions.

Governing Codes & Regulatory Compliance

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AISC 358-22 Chapters 5 through 8 Standard Typologies: Verifies Reduced Beam Section (RBS), Bolted Extended End-Plate (4E, 4ES, 8ES), Bolted Flange Plate (BFP), and Welded Unreinforced Flange-Welded Web (WUF-W) connections.
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AISC 358-22 Chapters 9 through 15 & Design Guide 38: Audits Kaiser Bolted Bracket (KBB), ConXtech ConXL, SidePlate, Simpson Yield-Link, Double-Tee, SlottedWeb, DuraFuse Frames, and SpeedCore Composite Connections (DG38).
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AISC 341-22 SMF & IMF Prequalification Rules: Enforces Special and Intermediate Moment Frame limits on member depth, weight, flange thickness, highly ductile compactness, continuity plates, protected zones, and demand-critical welds.

Sensitivity Analysis & Structural Sizing

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RBS Trim & End-Plate Rib Stiffener Optimization: Tunes dogbone flange cut depths (10% to 25% of flange width) and compares 4E unstiffened versus 4ES/8ES rib-stiffened end-plates to reduce column panel zone demand.
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Automated Web Doubler & Continuity Plate Sizing: Computes required column web doubler and transverse continuity plate thicknesses for one-sided and two-sided seismic framing.
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Prequalified Typology Cost Benchmarking: Evaluates all eligible AISC 358 connection families across the seismic frame schedule to select the lowest-cost prequalified joint.

Base Plate, Anchorage & Lifting Lug Checks

Mathematical & Numerical Formulations

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Base Plate Flexure & Non-Superposition Shear Envelope: Evaluates frustum-confined concrete bearing and plate bending across concentric and uplift regimes, enforcing the maximum independent shear mechanism (friction, shear lug, or anchor rods) without unconservative summation.
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Eight Concrete Anchorage & Shear Lug Limit States: Evaluates Steel Tension, Concrete Cone Breakout (including deep-embedment $h_{ef}^{5/3}$ scaling for cast-in studs), Pullout, Side-Face Blowout, Adhesive Bond, Steel Shear, Shear Breakout, Pryout, and welded shear lug bearing/breakout.
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Below-the-Hook Lifting Lug & Pad Eye Mechanics: Computes pin-to-hole clearance reduction factors, effective net width, static and rotating pin bearing, single-plane fracture, double-shear pin tearout, cheek doubler load sharing, and 3D biaxial base weld stresses.

Governing Codes & Regulatory Compliance

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ACI 318-19 Chapter 17 & Section 17.10 Seismic Anchorage: Verifies ASTM F1554 (Grades 36, 55, 105) cast-in headed studs, hooked J/L-bolts, expansion, undercut, screw, and adhesive anchors with coupled $5/3$ elliptical interaction and SDC C–F 1.3x ductile steel yield protection.
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AISC Design Guide 1 (2nd Edition) Base Plates: Audits column base plate bearing, yield-line cantilever bending, unwelded washer penalties, and the 0.80 grout-pad anchor steel shear reduction per ACI 318 Section 17.7.1.2.1.
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ASME BTH-1-2020 & AISC Manual Part 15 Lifting Lugs: Enforces Design Category A ($N_d = 2.00$) and Category B ($N_d = 3.00$) safety factors across Service Classes 0 through 4 alongside lateral dishing stability and shackle pin clearance rules.

Sensitivity Analysis & Structural Sizing

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Anchor Group & Base Plate Footprint Optimization: Optimizes anchor count, diameter, embedment depth, and base plate plan dimensions to minimize steel volume and core-drilling cost while accounting for overlapping breakout cones near edges.
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Shear Lug vs. Anchor Rod Balancing: Sizes welded shear lugs per ACI 318 Section 17.11 to transfer heavy base shear into concrete without oversized anchor bolts or edge breakout.
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Multi-Angle Rigging Pad Eye Sizing: Sizes minimum lug thickness, outer radius, cheek doublers, and fillet welds across vertical, angled, and oblique sling load envelopes with out-of-plane side pull.

Steel Deck Diaphragm & Rigidity Checks

Mathematical & Numerical Formulations

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Support & Side-Lap Fastener Shear Mechanics: Computes nominal shear strengths and connection flexibilities for arc spot puddle welds, self-drilling TEK screws, Power-Actuated Fasteners (PAF), button-punched seams, and weld washers.
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Seven Governing Diaphragm Capacity Modes: Evaluates edge support shear, interior panel shear, side-lap seam slip, corner fastener resultants, corrugated flute out-of-plane buckling, bare sheet shear yield, and composite/insulating concrete fill shear.
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Warping Shear Stiffness ($G'$) & Coupled In-Plane Deflection: Synthesizes fastener slip and profile end-warping distortion into effective shear stiffness $G'$, combining chord flexural bending and web shear distortion to solve total lateral diaphragm deflection.

Governing Codes & Regulatory Compliance

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SDI Diaphragm Design Manual (DDM04) & AISI S310-16: Verifies 1.5-inch B-Deck, 3.0-inch N-Deck, 9/16-inch Form Deck, and Composite Decks across standard support patterns (36/9 through 24/3) under calibrated Wind, Seismic, and Gravity factors.
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AISI S100-16 Section J4 Fastener Connections: Audits self-drilling screw tilting, bearing, pull-over, and shear rupture limits alongside arc spot weld effective diameters.
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ASCE 7-22 Section 12.3.1 Rigidity Classification: Benchmarks mid-span in-plane diaphragm deflection against average story drift of vertical lateral frames to classify Rigid, Semi-Rigid, or Flexible diaphragms.

Sensitivity Analysis & Structural Sizing

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Project-Wide Deck Gauge & Stitch Schedule Optimization: Sweeps across deck gauges (22ga to 16ga), support patterns, and side-lap stitch counts to minimize total installed material and fastening labor cost.
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Shear Stiffness ($G'$) & Multi-Zone Bay Tapering: Tunes stitch spacing to satisfy lateral drift limits and transitions high-density perimeter collector fastening to economical interior bay schedules.
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Weld vs. Mechanical Fastener & Span Trade-Offs: Compares puddle welds against PAF pins and screws while evaluating deep-rib N-deck flute buckling sensitivity to purlin span length.

Serviceability, FEA Vibration, Footbridge & Fire Checks

Mathematical & Numerical Formulations

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Bathe Subspace Iteration FEA & Sturm Sequence Verification: Executes full 3D finite element modal extraction for floor framing and pedestrian bridges using the Bathe subspace iteration eigensolver with Sturm sequence (Sylvester's Law of Inertia) verification, guaranteeing zero missed eigenmodes.
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Orthotropic Composite Deck & Footstep Time-History FEA: Couples Mindlin-Reissner orthotropic composite slab and MITC4 shell elements with modal footstep impulse time-history summations across resonant and transient frequency regimes.
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Pedestrian Crowd Synchronization & Lateral Lock-In: Formulates equivalent synchronized crowd counts for sparse and dense pedestrian streams to compute steady-state resonant accelerations and critical lateral crowd lock-in headcounts.
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Deflection, Roof Ponding & High-Temperature Fire Buckling: Evaluates 20 vertical/lateral deflection cases, roof ponding flexibility indices, and elevated-temperature elliptical stress-strain curves, cooler-story column buckling reductions, and critical failure temperatures.

Governing Codes & Regulatory Compliance

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AISC Design Guide 11 (Chapters 4–7) & ISO 10137 Floor Vibrations: Audits floors via both simplified panel mechanics and Chapter 7 full Finite Element Analysis (FEA), benchmarking velocity spectra against Colin Gordon VC-A–VC-E microvibration curves and office/hospital comfort limits.
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AISC 360 Chapter L, Appendix 2 & Design Guide 3 Serviceability: Enforces deflection limits across floors, roofs, lintels, spandrels, and elevator sheaves alongside wind drift, shop camber rules, and roof ponding stability.
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Sétra 2006 / HiVoSS & EN 1990 Annex A2 Footbridges: Screens Traffic Classes I–IV against vertical (1.0–2.6 Hz) and lateral (0.3–1.3 Hz) risk ranges and classifies accelerations into Comfort Classes CL1 through CL4.
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AISC 360 Appendix 4 & EN 1993-1-2 Fire Design: Verifies structural steel and composite member survival up to 1200°C (2200°F) under ISO 834-1 and ASTM E119 fire exposures.

Sensitivity Analysis & Structural Sizing

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Fox-Kapoor Eigenvector & Den Hartog TMD Optimization: Guides modal frequency placement via analytical eigenvector derivatives and sizes optimal Tuned Mass Dampers (mass ratio, tuning frequency, and dashpot damping) to achieve CL1 comfort.
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Vibration-Governed Framing & Camber Scheduling: Upsizes floor beams when DG11 walking acceleration or VC microvibration velocity governs, and generates discrete quarter-inch shop camber schedules.
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Critical Failure Temperature Optimization: Evaluates demand-to-capacity ratio sensitivity under fire load combinations to maximize critical steel temperatures and reduce fireproofing thickness.

Machinery & Foundation Dynamics Checks

Mathematical & Numerical Formulations

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Rotating Centrifugal & Reciprocating Dual-Harmonic Forcing: Formulates centrifugal unbalance forces across rotor weight, speed (RPM), and balance grades alongside primary ($1\times$) and secondary ($2\times$) reciprocating slider-crank inertial harmonics.
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Gazetas 6-DOF Dynamic Soil Impedance: Computes surface and embedded elastic half-space soil springs and radiation damping dashpots across vertical, horizontal sliding, rocking, and torsional degrees of freedom.
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Coupled 6-DOF Frequency-Domain Inversion: Solves $[-\omega^2 \mathbf{M} + i\omega\mathbf{C} + \mathbf{K}]\mathbf{U} = \mathbf{F}$ directly in the frequency domain, capturing shaft elevation offsets and coupled horizontal-rocking modes.
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Force Transmissibility & Dynamic Soil Bearing: Evaluates dynamic force transmissibility, isolation efficiency, and combined static plus dynamic overturning bearing pressures against allowable dynamic soil capacity.

Governing Codes & Regulatory Compliance

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ACI 351.3R-18 Foundations for Dynamic Equipment: Verifies block, mat, and tabletop foundations across the $\pm 20\%$ anti-resonance separation mandate (Low-Tuned, Resonant Prohibited, and High-Tuned regimes) and foundation-to-equipment mass ratios.
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ISO 20816-1 & ISO 1940-1 Machinery Vibration: Audits broadband RMS vibration velocity across Machinery Classes I–IV into Zones A (Good), B (Satisfactory), C (Alert), and D (Trip) across rotor balance grades G0.4 to G16.0.
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Gazetas Aspect Ratio & Dynamic Bearing Rules: Enforces half-width plan orientation conventions and dynamic allowable soil bearing reductions under sustained harmonic excitation.

Sensitivity Analysis & Structural Sizing

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Minimum-Volume Block Sizing & Resonance Escape: Optimizes foundation length, width, and thickness to minimize concrete volume while shifting soil stiffness versus mass to escape the prohibited $\pm 20\%$ resonant band.
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Embedment Damping & Isolator Stiffness Tuning: Evaluates side-wall embedment depth to boost radiation damping and tunes spring/elastomeric isolators to achieve over 85% force isolation efficiency.
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Coupled Rocking & Eccentricity Minimization: Sizes foundation footprint extensions to align the combined machine-plus-block center of gravity with the soil centroid.

Direct Engineering Inquiries

Technical briefings, compliance benchmark suites, and structural validation dossiers.

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