Bridge Builder

Drag between two grid dots to place a piece. Join the two banks with a road, then brace the shape. Tap a piece to remove it, or use Undo. On a keyboard, use arrows to move, Enter to start and finish a piece, Escape to cancel, and Delete to remove.

Red means tension: the piece is being pulled. Blue means compression: it is being squashed. Grey carries very little axial force, the force along a piece. Amber marks bending demand in the deck beneath the truck. Inspect a piece for its peak capacity used, and move the truck-position slider to compare different moments.

A shape can move even when its pieces are strong. A square can become a diamond; a triangle keeps its shape. Look for an unbraced shape or a joint that can drop, then change the geometry and test again.

You view the bridge in 3D, while the structural simulation uses a simplified 2D model for exploring shapes and load paths. Bamboo uses the simulator’s beam properties, rather than measured bamboo strength. Real joints, glue, sideways bracing, material variation and self-weight all matter. Build and test a physical model before drawing conclusions about real strength.

Challenges 6–10 add paper tubes, rope, aluminium, steel tubes and laminated timber, with different model stiffness, tension, compression and bending limits. You will work with shorter stock, a low ceiling, wider gaps and heavier trucks. These values let you compare designs; they are not measured engineering data.

No account is needed. You can put access to the simulator after a lesson checkpoint as a reward, then ask students to explain one improvement. This public version keeps work in this browser on this device. Download the project before moving computers or clearing browser data.

Inside a StudioLoom lesson, builds save with the student’s work and a chosen test can become evidence.