These browser-based calculators run entirely in your browser — no download, no license, no Excel required. They share the same algorithms and design-code references as our spreadsheet tools and are freely available to all visitors.
Generates the axial force–moment interaction diagram for circular reinforced concrete columns using strain compatibility. Computes nominal and factored capacity envelopes per AASHTO LRFD 10th Edition and plots user-supplied load cases against the diagram.
Calculates shear resistance of the eccentrically loaded bolt group using the elastic and instantaneous center of rotation methods per AISC LRFD. Supports standard and irregular bolt layouts with a live graphical display.
Computes moment and shear influence lines at any section of a continuous beam with up to 8 spans and variable EI. Slides a user-defined truck (default HS20) in both directions and combines with lane load to generate moment and shear force envelopes along the full beam length.
Performs biaxial analysis of general-shaped base plates under combined axial load, biaxial moment, shear, and torsion. Supports rectangular, circular, polygon, and custom plate shapes with openings.
Computes the moment–curvature response of circular reinforced concrete columns. Implements Mander confined and unconfined concrete stress–strain models and steel model with strain hardening. Features interactive curvature slider with real-time cross-section state.
Computes natural frequencies, mode shapes, and modal participation factors for continuous beams. Supports variable stiffness, distributed and concentrated masses. Displays animated mode shapes with interactive deflection readout.
