A howe truss refers to a type of truss bridge that is made of a lot of chords, and diagonals whose members that are vertical are in tension and diagonal members are in the state of compression. This type of truss known as Howe Truss was invented by a man named William Howe in the year 1840. There are various howe truss bridges that have been built in many different places all over the world and are famous for their design.
In this article, we are going to learn about and understand what is howe truss bridge, howe type truss bridge advantages and disadvantages, pratt and howe type truss bridge and famous howe truss bridge. We also try to understand the design of the Howe designed truss.
Let us begin with understanding what is howe truss bridge and the difference between a pratt truss bridge and a Howe truss bridge.
What Is Howe Truss Bridge?
A howe type truss bridge is a type of bridge that is used for heavy-duty carriage and is most likely used for railroad bridges. This type of truss bridge consists of upper and lower chords that are made of wooden and these chords are linked to each other with the help of sets of dual iron rods and wooden and counter braces.
Howe Truss Bridge Design
The design of the howe truss bridge is simultaneous to that of the pratt truss. However, there is a difference between them. In the howe truss bridge, the structural beams are sloping towards the center of the bridge. This structural approach is created in such a way that the diagonal members of the howe truss bridge are in compression and the vertical web members are in a state of tension.
Pratt And Howe Truss Bridge
Even though very similar, pratt and howe trusses have some differences. Let us take a look and try to understand the difference between pratt and howe type truss bridges.
Pratt Vs Howe Truss Bridge
Pratt truss – This type of truss has diagonal members that slant down towards the middle
Howe truss – This type of truss has diagonal members that begin to slant away from the middle
2. Material used
Pratt truss – To make pratt truss, lighter and thinner type of steel or iron is used for the making of the diagonal members of the truss
Howe truss – Steel is not very economical when it comes to howe trusses. It is not suitable for members handling the force that is in a state of compression.
3. Shape of the truss
Pratt truss – The beam that is downward is attached to a vertical beam in order to form a “z” that is sideways and in the middle of the structure, a structure shaped in “v” is done.
Howe truss – The beam that is downward is attached to the vertical beam and forms a sideways “z” and in the middle of the truss structure, a “v” that is upside down is formed.
Howe Truss Bridge Advantages And Disadvantages
The following are the advantages and disadvantages of the howe type truss bridge:
1. Extremely strong –
The load-bearing capacity of the truss bridge is huge due to the structure of interconnecting triangles. The structure has managed to capture a balance between the state of compression and tension. This indicates that no part of the bridge is bearing a disproportionate weight.
2. Material has been used effectively –
The material that has been used to make the truss bridge has been used effectively despite being made of a lot of linked parts to form the structure. Wood, iron, and steel, each material that has been used to make the howe type truss bridge has been used to their full potential. The building of a howe trusses is a very efficient decision when compared to other truss bridges.
3. It can withstand any extreme conditions –
Truss bridges are capable of withstanding the extreme weather conditions that other types of bridges may not be able to. They can span up to great lengths and can be used in untraversable locations like deep ravines between mountaintops. They are used throughout the mountainous areas to carry railway lines for traveling.
4. It can carry roadways on its structure –
The load of the road and traffic can be carried along with various areas of the truss bridge like the middle, that is through the truss, or the bottom truss, etc. Options like these make howe type truss bridges extremely versatile and cost-efficient.
1. They need a lot of space –
The design structure of a truss is large and the interconnecting triangular components ought to be large enough in order to be able to bear the loads and distribute them. In restricted places, this type of truss bridge may not be the best option.
2. Howe truss bridges are very heavy –
This truss bridges are large, use a lot of materials, and therefore, are very heavy. Some extent of reinforcement may be required to cope with the weight of the bridge. If the landscape is not able to support a howe designed truss bridge, then you may have to install bridges of some other types.
FAMOUS HOWE TRUSS BRIDGE
Now, we are going to take a look at some of the most famous howe truss bridges from all over the world that are famous for the design of howe type truss.
- Russeintobel bridge – Switzerland
- King Louis bridge – Germany
- Akkagawa bridge – Japan
- Columbia bridge – USA
- Mud river covered bridge – USA
- Monaghan bridge – Canada
- Boheimkirchen Footbridge – Germany
- Balclutha railway bridge – Australia
Some of these are still in use while some of them had been demolished long ago. However, you need to understand these bridges are extremely powerful and become an asset if they are built rightly and are used at the right place. They are complex to build and need to be made carefully with great supervision.
So, with this, I hope you understood what is a howe truss bridge, howe trusses bridge design, pratt and howe truss bridge, howe type trusses advantages and disadvantages, and some famous howe type truss bridges, etc.