Bridge Builder Game

A physics bridge building game. Join beams between the red anchors to span the gap, stay under budget, then press Test and watch a car or truck try to cross. Every beam stretches under load, and the colors show which ones are close to snapping.

How to play Bridge Builder Game

• Each level is a gap between two banks. Red dots are fixed anchors on the banks and piers; everything else you build hangs from them.
• Pick a material and drag from any anchor or joint to a nearby grid point to add a beam. The end becomes a new joint you can build from. Beams can span up to three grid squares.
• Road is the only material the vehicle can drive on, so you need a continuous road from bank to bank. Wood is cheap and light. Steel costs more but stretches much less.
• Press Test. Gravity and the vehicle's weight load the bridge; beams turn from green to yellow to red as they strain, and a beam that is pulled or squeezed too far breaks.
• Triangles are the secret: a beam that is part of a triangle cannot bend out of shape, so trusses of triangles under or over the road hold far more than a flat road.
• Get the vehicle to the far bank to clear the level. Spend 75% of the budget or less for three stars, or up to 90% for two. You cannot test a bridge that is over budget.

Controls

• Mouse or touch: drag from a joint to a grid point to add a beam. Or tap a joint to select it, then tap grid points to keep building from it.
• Choose Erase and tap a beam to remove it. Undo takes back your last change.
• Keyboard: 1 Road, 2 Wood, 3 Steel, 4 Erase, Z to undo, Space or Enter to start and stop a test.

Tips

• Start with a road from bank to bank, then add a zigzag of wood beneath it so every road segment sits on a triangle.
• Tie your truss into the lower anchors on the bank faces; it spreads the load into the ground.
• Watch which beams turn red during a test and strengthen only those, for example by swapping them for steel.
• A deeper truss is stronger than a shallow one, but it costs more beams, so look for the balance that saves money.

FAQ

How do you build a bridge in this game?

Drag beams between anchors and joints to make a road from one bank to the other, add triangles of wood or steel to support it, then press Test to see if a car or truck can cross.

Why did my bridge break?

A beam stretched or squeezed past its limit. A flat road on its own sags and pulls apart, so support it with triangles underneath or above.

What is the difference between wood, steel and road?

Road is the driving surface. Wood is cheap and light, steel is stiffer but costs more, and all of them break if they are strained too far.

How are stars awarded?

Clearing a level earns at least one star. Spend 90% of the budget or less for two stars and 75% or less for three.

Is my bridge saved?

Yes. Your design on every level and your best stars are saved in this browser, so you can come back and improve a bridge later.