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Why are bolts used in bridges?

Why are bolts used in bridges?

Nearly all bridge bolts are designed for dynamic loading. They are designed to resist either tension forces and/or shear forces. Fatigue concerns govern bolts designed for cyclic tension forces. The FHWA recommendations were developed in order to assure the ability of bolts to achieve this preload.

What supports the girder?

A girder is simply a type of support beam. It is the main horizontal support of a structure or the large beam that supports smaller beams. Like beams, girders typically have I-shaped cross sections composed of two load-bearing flanges and a web for stabilization.

What is the purpose of anchor bolts?

Anchor bolts are used to connect structural and non-structural elements to concrete. The connection can be made by a variety of different components: anchor bolts (also named fasteners), steel plates, or stiffeners. Anchor bolts transfer different types of load: tension forces and shear forces.

How are bridges connected?

A typical connection is a splice in the main longitudinal beams of a bridge. These should normally be located where a change in the section size is appropriate. In medium span bridges this is often near the points of contra flexure where the bending moments are lower.

What is bolt value?

the minimum strength of the bolt in shear or in bearing is known as bolt value.

What are slip critical bolts?

Slip-critical joint, from structural engineering, is a type of bolted structural steel connection which relies on friction between the two connected elements rather than bolt shear or bolt bearing to join two structural elements.

How long does an anchor bolt need to be?

J-bolt anchoring bolts come in many different lengths, the most common are 6, 8, and 12 inches long. These bolts are threaded at the top, for about two inches, and the rest of the bolt is smooth.

What are the 3 main types of bridges?

Bridges can be found in a variety of shapes, but 3 basic designs rule the day; beam, arch, and suspension.

What is the most common type of bridge?

beam bridge
The beam bridge is the most common bridge form. A beam carries vertical loads by bending. As the beam bridge bends, it undergoes horizontal compression on the top.

What are the different types of girders called?

The horizontal narrower plates are called flanges and the deeper vertical plates are called web. Such girders are called Plate Girders. Girders can be of different types depending on what they support. When used in Crane gantries the girder is called Gantry Girder.

What kind of steel is a gantry girder made of?

It is made up from separate structural steel plates, which are welded or, in older bridges, bolted or riveted together. They form the vertical web and horizontal flanges of the girder. The gantry girder is a long steel beam that can carry heavy loads, especially moving loads. They are used at construction sites.

How are sills used to support a girder?

Post—A vertical support member that often helps to carry the girder. Sill plate—Fastened to the foundation by anchor bolts, sills provide a wood surface to nail to. Generally a pressure-treated 2 6. Sill sealer—A thin layer of insulation fitting between the sill plate and the top of the foundation wall.

How is a load attached to a plate girder?

Plate girders may be loaded in many ways. They may be loaded through floor slabs, floor beams which frame into the girder. They may be loaded through columns supported by them. Loads may also be suspended from a plate girder through hangers. Fig. 10.6 shows some examples of load application to plate girders.

What do the girders on a deck stand for?

Also called beams, deck girders provide the backbone of support for the joists, deck boards, post and railings that make up the middle and upper structure of the deck.

How are plate girders used in modern construction?

This type of girders has become obsolete in modern times. In rigid frame constructions and continuous beams large moments occurs at the supports. The girders may be haunched near the support to provide greater flexural strength. Present day plate girders are made of plate elements only.

What kind of bolts are used in construction?

Bolts that are fully or partially threaded with six-sided heads. Broad range of use such as construction and repair of bridges, docks, highway elements and buildings. Structural applications such as fastening walls to concrete.

Where to place a girder on a roof?

Place the girder as indicated on the plans — between steel supports called hold-downs on a sill plate on a roof deck or on a post-beam cap atop your support posts for a backyard deck.