Ladder Bridge

Equipment

• 1 x 5m spar
• 4 x 4m spars
• 18 x 1.2m spars
• 2 x 1.8m spars
• 4 pickets
• 4 guy ropes
• 2 x 4m light lines for hand ropes
• 1 x 8m rope
• 1 large log approx 2m long
• 4 tent pegs
• log for counterweight
• Sand bags

Method

Prepare a ladder, which will form the actual bridge, using 2 x 4m spars and 12 x 1.2m spars. Ensure that the first 1.2m spar is 1m up from the butts of the 4m spars.

Use the last 6 x 1.2m spars to form the uprights for the handrails.

Using 2 x 4m spars (13ft), 1 x 1.2m spar and 2 x 1.8m spars as below

Attach guy ropes to the top of the frame at points A and B.

Lay the frame on one side so that spar AB is vertical.

Lash the 5m spar to the centre of AB but do not use frapping turns – this spar must be able to pivot. The lashing should be approx. 1.5m from one end. Tie the counterweight log onto the ‘short’ end and tie the centre of the 8m rope firmly to the other end of this spar.

Raise the frame so that the butts of the 2 x 4m spars are on the ground. The frame should be close to and parallel to the ravine which the bridge is to cross. Guy it securely.

Place the 2m log behind the frame (on the opposite side to the ravine). Knock in 4 large pegs to keep it in place. This log is the pivot for the ladder.

Tie the ends of the 8m rope to the end of the ladder which be pushed across the ravine. Carefully place the ladder across the ravine with the butt ends between the uprights of the frame and resting on the log.

If the counterweight is not sufficiently heavy to ensure that the 5m spar will pivot easily to raise the far end of the ladder, add sandbags until it is comfortably balanced.

Note: Since the design of the project the principles of Health and Safety have changed dramatically.
Caution should be exercised to assess the risks associated with this build and especially regarding possible falls from height, so handrails or belays and harnesses may be required.

To download the complete plan and design document please click here.