Which truss is the strongest

Two of the most used truss bridges are of the Pratt and Howe design. Through our experiment it was found that the bridge design that minimized the maximum compression force was the Howe Bridge. What is the strongest shape for a bridge? The overall shape of many bridges is in the shape of a catenary curve. The catenary curve is the strongest shape for an arch which supports only its own shape. Freely hanging cables naturally form a catenary curve.

The hexagon is the strongest shape known. Why are triangles used in bridges? Triangles are used in bridges because they evenly distribute weight without changing their proportions. When force is applied on a shape like a rectangle it would flatten out. This beam turns he square into two triangles that can each distribute weight evenly. What is placement of travel surface?

How much weight can a truss bridge hold? Truss bridge number one held 24 pounds. The second truss bridge held 23 pounds so the average weight held by the truss bridges was Why is a bridge important? Bridges are immensely important. Bridges allow safe passage where previously it was not possible or much more difficult.

To maximize the efficiency of the truss, the truss can be loaded at the joints of the bottom chord. Roof trusses can be loaded with a ceiling load for example. Another thing to note is that, depending on the geometry and loading, Pratt trusses can have more unloaded members than Howe trusses.

The Fink truss in its most basic form has web members that follow a V-pattern which can be repeated several times. As the top chords are sloping downward from the center, the V pattern becomes noticeably smaller.

As Fink trusses rely more on diagonal members, they can be very efficient at transmitting loads to the support. Derivatives of the Fink truss include the Double Fink and the Fan truss types.

Double Fink trusses are essentially Fink trusses that repeat the pattern twice on either side. If the most basic Fink truss can be characterized by a double-V, then a double fink would look like a double-W. In the exterior, a gambrel truss has two different slopes, where the slope gets steeper from the center. Due to outward-protruding shape, gambrel trusses can be effective to be fitted with a hollow center, which can be used as a storage area.

As such, the upper section of a barn is usually shaped in a gambrel. In the case of a barn, as the members are usually constructed with wood, the structure acts more like a frame than a truss.

Derivatives of the gambrel include the Mansard roof, which is also called a French roof, hence its popularity in France. SkyCiv offers two truss software; one Free Truss Calculator to model and analyze the internal forces of a truss structure.

Free to use, premium features for SkyCiv users. Try our Mobile App. How to Determine the Reactions at the Supports? How to Calculate an Indeterminate Beam? Truss Tutorials What is a Truss? Source: Warren Truss Calculator. Originally designed in by railway engineers Thomas and Caleb Pratt, the Pratt truss bridge is one of the most common bridge designs. Its diagonals are usually parallel and slope towards the centre of the bridge, as demonstrated in the illustration below.

This bridge design is more complex than the Warren truss variation, and is also more expensive due to the extra materials needed to build it. The Pratt truss is a hot favourite among engineers and those nerdy science folk because when you crunch a whole heap of numbers better them than me! The Howe truss, patented in by William Howe, a millwright from Massachusetts, is very similar to its friend the Pratt truss; except that its diagonals face the opposite direction away from the centre.

The small change simply means a change in direction of where the force is applied. Originally, because their larger parts were constructed from wood, it was a popular design because it was cheaper to build. However, in recent years the Pratt design tends to be more popular and is slightly better at distributing force.

If you want to get technical about it: in the Howe truss design, the longer diagonal members are in compression, while the shorter vertical members are in tension. This is in contrast to the Pratt truss design. The K truss bridge design was a variation on another Pratt truss style, called the Parker truss. The idea of the K truss is to break up the diagonal members into smaller lengths, in the hope of reducing their likelihood of buckling under pressure. Truss bridges, unlike other bridge designs, are able to carry roadway within their structure.

Neat, right?! Furthermore, the pony truss allows traffic to travel through the structure of the bridge, however the two sides of the bridge are not joined at the top or cross-braced.