What Is a Lattice Girder?
A lattice girder is a type of girder with a criss-crossed web design, such as in gardening lattices, between the two edges of the girder. The diagonal lines of steel give support in all directions, helping to prevent the girder, which is one of the main support elements in a bridge design, from bending. Often seen on older bridges or buildings, lattice girders are also widely used in mining tunnels for roof support during excavations and can be erected quickly. They are also used for reinforcement when applying shotcrete, a form of concrete or mortar pneumatically applied at high velocity from a hose to construction supports.
One of the most well-known examples of lattice girder design is France's Eiffel Tower, built in latticed iron in the 1800s. Lattice girders are not used so much in building or bridges anymore as they have been replaced by solid steel plate girders. Tunneling operations, however, make good use of them as they are lightweight and can be easily assembled on uneven floor and wall surfaces with few workers. A lattice girder can be used as is or covered in shotcrete for additional load strength. Modern lattice girders are most often used in the 3-bar or 4-bar configurations, and the diagonal stiffening delivers load along the entire length of the bars for resistance.
In tunneling operations, a lattice girder is often chosen over a steel plate girder as it can be completely embedded in a shotcrete lining that allows for the easier molding of walls within a tunnel. It can adjust well to differing ground levels and provide a covering with the shotcrete that keeps out water. Static load studies have shown that even when not encased, the lattice girder has high load-bearing capability; it can handle loads well even when the shotcrete is still curing and soft. The ability to easily deform the girders to match the walls and flooring of a tunnel without affecting the load-bearing is why lattice girders are so trusted in mining projects.
Lattice girders are also used as a component to provide structure load bearing support for floors that will handle heavy loads. They are used to create what are called lattice girder slabs for high capacities. In curving wall designs, their surfaces can be bonded with polystyrene void-formers to reduce wall weight loads. A lattice girder can be a component in accommodating large arched openings when using these void-formers, due to the reduced weight load.
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![The Eiffel Tower is a world famous example of latter girder design.]()
By: KristanThe Eiffel Tower is a world famous example of latter girder design.
Discussion Comments
I planted two Chinese wisteria plants that will grow very tall and be quite heavy when they reach maturity. When I was looking for support for these plants, I decided to use a lattice girder because of their sturdiness.
Many types of support for trailing or climbing plants are not designed for a lot of weight. It has taken a few years for my wisteria to get very big, but I can see that in a few years, I will be glad I went with support that will handle quite a bit of weight.
I can attest to the power of lattice girder design to hold up even when made of normally weak materials. In my three-dimensional art class in college, we had to build a tower from spaghetti. My partner and I chose the lattice design, because the tower had to withstand pressure.
We glued several strands of raw spaghetti together to make each beam. The process was tedious, because we built the tower seven feet high.
I believe it took us three weeks of class to complete it. Our design paid off in the end, as our building won the strength test.
I have a lattice girder in my garden. I had never noticed before reading this that the Eiffel Tower uses one. I can see how the design could provide massive amounts of support.
My lattice girder is made of stained wood. I use it to support my climbing roses. The vines get pretty thick, and the huge blooms might cause an ordinary support beam to topple over under their weight. The lattice girder never tilts under the pressure.
Lattice girders are the top choice to support all types of flowering vines. My neighbors use them for honeysuckle and starflower vines, which completely cover the girder when fully grown.
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