Draw a Frame, Get the Bending Moment Diagram — New Free Structural Analysis Tool

Most free structural analysis tools online will solve a simply supported beam for you and stop there. Real structures aren't simply supported beams — they're frames with rigid joints, beams with internal hinges, trusses with pinned connections, columns fixed into a foundation. We built a free tool that handles all of it: draw the actual structure, assign real support conditions, and get the bending moment and shear force diagrams a proper matrix analysis produces — not a lookup-table approximation.

What it actually does

Draw nodes and members on a grid, the same way you would in STAAD or any other analysis package. For each support, choose pin, roller, or fixed. For any member end, you can add an internal hinge — the release that turns a continuous beam into something like a Gerber beam, or models a genuinely pinned connection inside a frame. Add point loads or uniformly distributed loads wherever they actually act. Hit Solve, and the bending moment and shear force diagrams are drawn directly on the structure, with the value labelled at every support, every load point, and the true peak — not just at a handful of preset stations.

Why internal hinges specifically

Most free tools skip this entirely, because it's genuinely harder to get right. A hinge forces the bending moment to be exactly zero at that one point, regardless of what's happening on either side of it — which is also what makes a hinge useful in the first place: it's how a Gerber beam avoids the settlement problems a fully continuous beam would have over an uneven foundation, and it's how certain frame connections are deliberately detailed to not transmit moment. A calculator that can't model that isn't modelling the structure you actually have.

How it's solved

By the direct stiffness method — the same matrix approach full commercial packages use, not a set of textbook formulas swapped in based on which case your structure happens to match. Every support type, every hinge, every load combination goes through the same general solve. That generality is what lets the same tool handle a simple cantilever and a multi-storey frame without switching methods underneath.