9 Fink Truss Bridge Advantages and Disadvantages | Uses of Fink Truss Bridge | Fink Roof Truss Span

What is Fink Truss Bridge? | Fink Truss Bridge Advantages and Disadvantages | Fink Truss Bridge Design Details | Uses of Fink Truss Bridge |Fink Roof Truss Span

What is Fink Truss Bridge?

The Fink truss is a type of truss that is commonly used in residential houses and bridge engineering. Although it started as a bridge truss, its present application in bridges is uncommon.

Albert Fink patented the Fink Truss Bridge in 1854. Albert Fink created truss bridges for a number of American railways, most notably the Baltimore and Ohio and the Louisville and Nashville.

The Louisville and Nashville Company Company’s 1865 Annual Report of the President and Directors includes 29 Fink Truss bridges out of a total of 66 bridges on the railroad.

The Baltimore and Ohio Railroad erected the first Fink Truss bridge in 1852 to over the Monongahela River at Fairmont, Virginia (now West Virginia).

It was made up of three 205-foot-long spans. At the time, it was the longest iron railroad bridge in the United States.

Because the web members of Fink trusses are fragmented to produce shorter members, they are employed for longer spans with high pitch roofs. It is one of the most popular type of home building truss.

It is made up of many boards or steel bars that connect to form an intersection at the roof’s top angle.

These trusses support the rafters and offer rigidity to the roof.

Fink Truss Bridge Design Details

The presence of many diagonal members extending down from the top of the end posts at various angles differentiates Fink Truss.

These diagonal members extend to the bottom of the truss’s vertical members, with the longest diagonal extending to the center vertical member.

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Many Fink trusses lack a lower chord (the lowest horizontal member). When viewed from the side or below, the bridge has an unfinished saw-toothed appearance, making the design very easy to identify.

If the bridge deck is held along the bottom of the truss (called a through truss) or if a lightweight lower chord is provided, the many diagonal members emanating from the end post tops are used to identify the structure.

An Inverted Fink Truss do not have a top chord and includes a bottom chord.

Fink Roof Truss Benefits

A fink roof truss is the most common type of truss, providing a simple, versatile, and cost-effective roofing solution.

The “fink” is a simple webbed truss design that offers the most cost-effective roof solution.

The web elements create a ‘W’ to offer a strong structure with good load carrying capacity. The roof weight is totally transmitted to the wall plates for support.

By increasing or tripling the number of plies, the fink truss can also be utilized as a support for other trusses, as in a “hip” roof.

Fink Roof Truss Span

The fink truss is the most commonly used truss in roof design due to its design versatility. The finks truss provides a cost-effective and versatile roof solution with spans up to 14 meters and pitch ranges from 10° to 60°.

Uses of Fink Truss Bridge

Today, Fink design trusses are used for pedestrian bridges and as roof trusses in building construction in an inverted (upside down) form where the lower chord is present and a central upward projecting vertical element and linked diagonals provide the roofing bases.

Fink Truss Bridge Advantages and Disadvantages

Fink Truss Bridge Advantages

1. A Fink truss is the ideal choice for various architectural styles, allowing for a variety of roof lines while providing the necessary strength and stability.
2. Use for longer spans with high pitch roofs because many web members are fragmented to make shorter members.
3. Prices of building homes with Fink trusses is lower than that of homes with traditional trusses, however, it needs more time to build and cut materials.
4. It is easy to assemble a Fink truss due to the smaller size of the members and there are fewer joints for them to fail while supporting a high roof as compared to other types of trusses
5. It is better for the structural integrity when compared to Pratt trusses, especially in areas with high wind speeds.
6. The Fink Truss is a simplified webbed truss design that offers the most cost-effective roof option for roof structures. Roof loads can be transferred to the wall plate thanks to the fink design.

Fink Truss Bridge Disadvantages

1. Because it is made of smaller members, it is more delicate than steel or wrought iron trusses and cannot support roof loads for very long. This makes them a risky choice for long-span roofs.
2. It relies on strong connections between the web members and cripples the ability to absorb forces as well as traditional trusses do.
3. It is not a well-known type of truss in the United States, and it cannot use traditional methods of engineering.
4. It is not as strong as traditional trusses, and it needs to be handled with care when building and erecting bridges.

Fink Truss Bridge FAQS

What is a fink truss?

A fink truss is the most common type of truss used, especially on homes and pedestrian buildings.

The truss features an interior web design fashioned like a W to provide the best strength-to-weight ratio for spans ranging from about 5m to around 14m, which covers the vast majority of household dwellings being built today.

What is a fink truss used for?

Today, Fink design trusses are used for pedestrian bridges and as roof trusses in building construction in an inverted (upside down) form where the lower chord is present and a central upward projecting vertical element and linked diagonals provide the roofing bases.

What are the advantages and disadvantages of fink trusses?

Fink design trusses are primarily used for short spans, such as homes, and they perform excellently; there are numerous examples of them standing the test of time.

They can be built off-site and lifted into position, supported at each end by load-bearing walls. They can also be made on-site, which is perhaps less common nowadays.

However, every now and then, someone constructs an intermediate wall, resulting in a new intermediate support that fundamentally changes the way the truss functions.

Except for the roof, the truss is typically intended to support minimum loads. It is not often intended to handle loft floors, which may necessitate the use of additional joists.

The drawback in this scenario is that people may expect it to perform more than it was planned for or capable of.

The fink truss is a structure that for any changes to its support and loads must be tested.

In practice, people may think it is appropriate to change supports and add loads, but this could jeopardize the integrity of the roof, and possibly the entire structure.

How does a Fink truss work?

Fink trusses are composed of a succession of triangles, so only short sections of the truss are supported or joined to other elements of the truss.

Loading on most parts is distributed throughout various parts of the truss, decreasing direct loading on any one area, giving them significant strength when compared to other truss types.

Can span large areas utilizing relatively narrow and thin timber for the load put on them since they are often positioned closer together and spread that load uniformly without adding undue weight to the supporting walls.

The disadvantage is that they provide just a small amount of attic storage space.