Mankind has always been fascinated by travel. The man on the move always adopted certain tools or means in order to simplify his journeys. When civilization came into being, and travel and exploration changed to commutation, more and more sophisticated aids, and tools of travel were adopted as a measure to reduce time. Bridging the gap between two points which were divided by impassable geography such as huge valleys, rivers, and even small streams were felt, which led to the development of the log bridge, the primitive ancestor of a common beam bridge. The beam bridge is often considered to be the most basic and simplest of all bridge types, by the virtue of its design and engineering. Indeed today though modern engineering and sciences have progressed substantially and have enabled superior structural constructions, beam bridges are not only used widely across the world but their design is also integrated into the design of several other modern bridges.
Engineers often insist that there is no hard and fast definition for a beam bridge, after all the bridge is constructed in accordance of the need of the situation and architects and engineers often liberally break the definition. A beam bridge is a bridge which is constructed with the help of one or multiple spans placed over abutments. Simply put, a beam bridge is a slab which is placed over at least two abutments, which are basically vertical pillar like supports which hold up the bridge. The total of all slabs, which forms the entire length of the bridge is known as the bridge deck. In case of beam bridges, two natural supports such as two banks of the stream or river can also be used as abutments. In modern times, multiple abutments that look like gigantic pillars are used. In this way, the length of the entire bridge can go on for several miles. All one needs to do is add in more abutments. The length between two abutments is known as a 'span'.
Today, there are several newer and hybrid constructions where a combination of beam bridge and other bridges is used. For example, a truss bridge has the abutments of the beam bridge. Or the really, really long bridges that run across seas or deltas, usually tend to have a small suspension bridge in the middle which enables ships and boats to pass from under them. The remaining portions are regular beam bridges. The basic principle, of the beam bridge is the bridge deck (which is the beam) which is supported by abutments, and is featured to be 'simply supported'. Further classification of beam bridges, based upon their features and construction is also possible.
The following is a quick list of famous beam bridges of the world. Now, though the following bridges are defined to be beam bridges, you will find that some of the really long ones typically have a suspension bridge in between them or have some other engineering design such as a truss bridge somewhere in between, as an engineering enhancement.
Manchac Swamp Bridge, United States
The Manchac swamp bridge is located in Louisiana is the 7th longest bridge in the world and 3rd longest in the United States, which carries Interstate 55 across the swamps. The engineering structure of this bridge is such that it's abutments are concrete trestles which are two pillared. The total length of the bridge is 22.80 miles (36.69 km) and it's piles or abutments were driven 250 feet (76 m) into the swamps. The cost of one single mile amounted to $7 million.
Tianjin Grand Bridge, People's Republic of China
The Tianjin Grand bridge is one of the youngest and also the second longest of all bridges and is a sea link. This bridge has small suspended portions with the remaining long portions being regular beam bridges. The Tianjin Grand bridge carries the Beijing-Shanghai high speed railway for 113.7 kms (70.649905 miles).
Lake Pontchartrain Causeway, United States
The Lake Pontchartrain causeway is a dual bridge which crosses the Lake Pontchartrain, Louisiana. This bridge is the 7th longest bridge in the world and also the longest bridge in the United States, running for 38.35 kms (23.82958 miles). This bridge has a Bascule in between which enables the passage for water navigation.
Donghai Bridge, People's Republic of China
Also known as the East Sea Grand Bridge, the Donghai Bridge is the longest sea crossing bridge and is of substantial economic importance for the People's Republic of China as it acts as the connection between mainland China and Yangshan, off-shore deep water port. The bridge runs for 32.5 kms (20.19456 miles). The bridge has some cable stayed portion for water navigation.
King Fahd Causeway, Bahrain and Saudi Arabia
The King Fahd causeway was a mammoth project which had a cost of USD 1.2 billion. The causeway bridge runs for 25 km (15.5343 miles) and remarkable long width of 23 m (75 ft) which is taken up by 4 lanes. The construction of the bridge lasted from 1981 to 1986.
Some of the other beam bridges include:
Vasco da Gama Bridge, Portugal
Confederation Bridge, Canada
Great Belt bridge, Denmark
Chapel Bridge, Switzerland
Chengyang Bridge, People's Republic of China
I-5 and I-90 Intersection Bridges, United States
On the whole, any bridge which has a bridge deck supported by abutments is a beam bridge. If you observe properly, a majority of bridges are beam bridges with some hybrid engineering being inducted in them.