Testing.

we're sorry the video wouldn't upload in time,

but you can view our video on st public.

Design Brief

Design a trussed bridge that can support a load of 4.0kg when its placed on the bottom of the trusss.


The best design will be the one with best specific strength (strength to weight ratio) at this load.

Construction

We used paddle pop sticks and PVA glue to help it glue together in the process of building, we also used sand paper to smoothe out the edges of the paddle pop sticks. We used pliers to cut the sticks so it would mend to help build the bridge. We changed our deck becuase it kep falling apart and it wasnt the wright length. Madi and I found it a bit hard but some of it was quite easy.

Preliminary Idea

After we drew our Preliminary Idea we had to do a PMI which is

a plus, minus and an interesting thing. for example the interesting thing could be

the design of the bridge.

Research and Investigation:Pratt Truss

Pratt Truss

A truss bridge is a bridge composed of connected elements (typically straight) which may be stressed from tension, compression, or sometimes both in response to dynamic loads. Truss bridges are one of the oldest types of modern bridges. The basic types of truss bridges shown in this article have simple designs which could be easily analyzed by nineteenth and early twentieth century engineers. A truss bridge is economical to construct owing to its efficient use of materials.

Research and Investigation.

K Truss.

 In the K Truss, the length of the members that undergo compression is reduced. The design of this bridge is complicated and is considered to be one of the hardest bridges to build.

Research and Investigation

Warren Bridge

The Warren bridge consists of longitudinal members joined only by cross angled members.
The load on this bridge causes compression and tension in the center of the bridge.

Research and Investigation:truss type

Howe Truss

From 1840 to about 1870 the standard railroad bridge was the Howe truss, a rectangular trussed frame of wooden diagonals and vertical iron tie rods. This bridge was invented by William Howe, a farmer turned inventor.

Research and Investigation

Research and Investigation

Shear

Ahear is a force that causes parts of a waterial to slide past one another in opposite directions.

Research and Investigation

Torsion.
Torsian is a action that twist a material.

Research and Investigation

Compression

Compression is a force that squeezes material together. When a material
is in compression, it tends to become shorter.

Research and investigation

Tension
Tension is a forse that strechers a material apart. When a material is in tension, it tends to become longer.

Suspension Bridge.



The suspension bridge can span 2,000 to 7,000 feet, way farther than any other type of bridge! Most suspension bridges have a truss system beneath the roadway to resist bending and twisting.

Research and Investigation

The truss bridge...


consists of an assembly of triangles. Truss bridges are commonly made from a series of straight, steel bars. The Firth of Forth Bridge in Scotland is a cantilever bridge, a complex version of the truss bridge. Rigid arms extend from both sides of two piers. Diagonal steel tubes, projecting from the top and bottom of each pier, hold the arms in place. The arms that project toward the middle are only supported on one side, like really strong diving boards. These "diving boards," called cantilever arms, support a third, central span.

Research and Investigation

Research and Investigation

The beam bridge...

consists of a horizontal beam supported at each end by piers. The weight of the beam pushes straight down on the piers. The farther apart its piers, the weaker the beam becomes. This is why beam bridges rarely span more than 250 feet.

Research and Investigation

Arch bridge
It has great natural strength. Thousands of years ago, Romans built arches out of stone. Today, most arch bridges are made of steel or concrete, and they can span up to 800 feet.

Design Situation

Desing a trussed bridge that can support a load of 4.0kg when it is placed on the bottom truss.

The best design will be the one with best specific (strength to weight ratio) at this load.

Engineers are not always interested in designing the strogest bridge. They are more interested in designing the best bridge to do the job.

A second challenge requires the bridge to be tested to destuction in order to determine its overall specific strength.

Restrictions

- The bridge is to be made from 3 mm x 3 mm paddle pop sticks.
-The total mass