Introduction

This report presents a paper beam designed to span a 270mm gap between two wooden columns. The beam had to be made of 3 pieces of A4 paper and could only be held together with sticky tape and glue.

Experimental Sketches

paper-bridge

experimental-design

Experimental Procedures

Rig: The rig that was used to test the strength of the beam had a gap of 270mm and was elevated 230mm of the ground. The rig was made of wood.

experimental-rig

The weight on the beam was delivered on a block of wood which was approx. 60mm x 120mm x 20mm. This block was placed on the beam at any location then loaded. The beam was tested until collapse.

experimental-testing

Results & Discussion

Weight Result
1.0kg No real bending of the beam.
1.5kg Can see slight bending
2.5kg Easily noticeable bending, with tiny creases starting to appear
3.5kg Nearly collapsing, very visible crease lines
3.84kg Collapses in the centre of the beam.

 

The beam held up well until the 3kg mark where the beam started showing signs of creasing and failure.

The UTS (Ultimate tensile strength) was 37.534 newtons, this was calculated by getting the maximum weight the bridge held and multiplying the weight in kilograms by 9.8 to get the Newtons. The factor of safety for the beam is 7.66 meaning that it can hold 7.66 times the minimum amount of weight it is supposed to hold which is 500g. The structural efficiency which is determined by dividing the maximum load by the weight of the beam was approximately 214.

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