A truss bridge is a bridge whose load-bearing superstructure is composed of a truss, a structure of connected elements forming triangular units. The connected elements may be stressed from tension, compression, or sometimes both in response to dynamic loads; the basic types of truss bridges shown in this article have simple designs which could be analyzed by 19th and early 20th-century engineers. A truss bridge is economical to construct; the nature of a truss allows the analysis of its structure using a few assumptions and the application of Newton's laws of motion according to the branch of physics known as statics. For purposes of analysis, trusses are assumed to be pin jointed; this assumption means that members of the truss will act only in compression. A more complex analysis is required where rigid joints impose significant bending loads upon the elements, as in a Vierendeel truss. In the bridge illustrated in the infobox at the top, vertical members are in tension, lower horizontal members in tension and bending, outer diagonal and top members are in compression, while the inner diagonals are in tension.
The central vertical member stabilizes the upper compression member. If the top member is sufficiently stiff this vertical element may be eliminated. If the lower chord is sufficiently resistant to bending and shear, the outer vertical elements may be eliminated, but with additional strength added to other members in compensation; the ability to distribute the forces in various ways has led to a large variety of truss bridge types. Some types may be more advantageous when wood is employed for compression elements while other types may be easier to erect in particular site conditions, or when the balance between labor and material costs have certain favorable proportions; the inclusion of the elements shown is an engineering decision based upon economics, being a balance between the costs of raw materials, off-site fabrication, component transportation, on-site erection, the availability of machinery and the cost of labor. In other cases the appearance of the structure may take on greater importance and so influence the design decisions beyond mere matters of economics.
Modern materials such as prestressed concrete and fabrication methods, such as automated welding, the changing price of steel relative to that of labor have influenced the design of modern bridges. A pure truss can be represented as a pin-jointed structure, one where the only forces on the truss members are tension or compression, not bending; this is used by the building of model bridges from spaghetti. Spaghetti is brittle and although it can carry a modest tension force, it breaks if bent. A model spaghetti bridge thus demonstrates the use of a truss structure to produce a usefully strong complete structure from individually weak elements; because wood was in abundance, early truss bridges would use fitted timbers for members taking compression and iron rods for tension members constructed as a covered bridge to protect the structure. In 1820 a simple form of truss, Town's lattice truss, was patented, had the advantage of requiring neither high labor skills nor much metal. Few iron truss bridges were built in the United States before 1850.
Truss bridges became a common type of bridge built from the 1870s through the 1930s. Examples of these bridges still remain across the US, but their numbers are dropping as they are demolished and replaced with new structures; as metal started to replace timber, wrought iron bridges in the US started being built on a large scale in the 1870s. Bowstring truss bridges were a common truss design during this time, with their arched top chords. Companies like the Massillon Bridge Company of Massillon and the King Bridge Company of Cleveland, Ohio became well-known, as they marketed their designs to cities and townships; the bowstring truss design fell out of favor due to a lack of durability, gave way to the Pratt truss design, stronger. Again, the bridge companies marketed their designs, with the Wrought Iron Bridge Company in the lead; as the 1880s and 1890s progressed, steel began to replace wrought iron as the preferred material. Other truss designs were used during this time, including the camel-back.
By the 1910s, many states developed standard plan truss bridges, including steel Warren pony truss bridges. As the 1920s and 1930s progressed, some states, such as Pennsylvania, continued to build steel truss bridges, including massive steel through-truss bridges for long spans. Other states, such as Michigan, used standard plan concrete girder and beam bridges, only a limited number of truss bridges were built; the truss may carry its roadbed in the middle, or at the bottom of the truss. Bridges with the roadbed at the top or the bottom are the most common as this allows both the top and bottom to be stiffened, forming a box truss; when the roadbed is atop the truss it is called a deck truss. When the truss members are both above and below the roadbed it is called a through truss, where the sides extend above the roadbed but are not connected, a pony truss or half-through truss. Sometimes both the upper and lower chords support roadbeds; this can be used to separate rail from road traffic or to separate the two directions of road traffic.
Since through truss bridges have supports located over the bridge deck, they are susceptible to being hit by
The Kawasaki Ninja 650R called ER-6f or EХ-6, is a motorcycle in the Ninja series from the Japanese manufacturer Kawasaki sold since 2006. The 2012 model drops the R suffix from its name, it is a parallel-twin engined motorcycle, designed for normal use on paved roads. They features, with low-seating ergonomics and a low center of gravity; the engine has a 180° crankshaft, resulting in an uneven firing interval of 0° and 540°. The 650R and its naked sibling, the ER-6n, were introduced in 2006; the naked ER-6n was not sold in North America until the 2009 model year. The motorcycle fits above the Ninja 250R and Ninja 500R models, which existed in Kawasaki's sportbike lineup, which includes the Ninja ZX models. For 2009, Kawasaki released an updated Ninja 650R which includes new bodywork, gauges, a new tune on the same 649 cc engine. Along with chassis and minor tweaks, an all-new bodywork design was introduced to the 2012 Ninja 650 and ER-6n along with a new 2-piece seat assembly, 20mm wider handlebars, a new tachometer above an LCD display that shows speed, trip meters, fuel consumption and etc.
The new Ninja 650 comes equipped with an Economical Riding Indicator which activates when the bike is consuming low amounts of fuel. For 2017 Kawasaki has updated the Ninja 650 with a new frame trellis style adding to the new lighter weight and better handling. With new sharper styling it has done away with the distinctive side mount rear shock for a more conventional one, it has added a slipper clutch. In Europe the Ninja 650R is sold as the ER-6f, the "naked" roadster version is sold as the ER-6n. In 2009, Kawasaki introduced the ER-6n in the USA; the ER-6f differs from the Ninja 650R, as it features the passenger handlebars as standard. In addition, the option of ABS brakes was made available for both the ER-6f. There is a derivative of the ER-6 called the Versys which utilizes many of the same components. In many European countries the 6n naked version has proven more popular than the ER-6f. Production has stopped for the ER-6n model since 2018, it has been replaced by the Z650 series. Kawasaki Ninja series ER-6n at Kawasaki Europe ER-6f at Kawasaki Europe Motorcycle Daily review of 2006 model MotorcycleUSA.com comparison test of the 2006 model and the Suzuki SV650
Peter Benenson was a British lawyer, human rights activist and the founder of human rights group Amnesty International. Benenson refused all honours but in his 80s to please his family, he accepted the Pride of Britain Award for Lifetime Achievement in 2001, he was born in London as Peter James Henry Solomon, to a large Jewish family, the only son of British-born Harold Solomon and Russian-born Flora Benenson. His army officer father died from a long-term injury when Benenson was aged nine, he was tutored by W. H. Auden before going to Eton. At the age of sixteen, he helped to establish a relief fund with other schoolboys for children orphaned by the Spanish Civil War, he took his mother's maiden name of Benenson as a tribute to his grandfather, the Russian gold tycoon Grigori Benenson, following his grandfather's death. He enrolled for study at Balliol Oxford but World War II interrupted his education, he served in the Intelligence Corps at the Ministry of Information where he met his first wife, Margaret Anderson.
He worked at Bletchley Park during World War II in the Testery. He is listed as RSM Benenson in room 41 as a cryptographer. After demobilisation in 1946, Benenson began practising as a barrister before joining the Labour Party and standing unsuccessfully for election at Streatham in 1950 and for North Herts constituency till 1959, he was one of a group of British lawyers who, in 1957, founded JUSTICE, the UK-based human rights and law reform organisation. In 1958, he moved to Italy to convalesce. In the same year, he converted to the Roman Catholic Church. Benenson claimed to have been shocked and angered by a newspaper report of two Portuguese students from Coimbra sentenced to seven years in prison for raising their glasses in a toast to freedom during the regime of António de Oliveira Salazar, though this story has been shown to be a myth.. At this time, Portugal was ruled by the authoritarian Estado Novo regime, anti-regime conspiracies were vigorously repressed by the Portuguese state police and deemed anti-Portuguese.
He wrote to editor of The Observer. On 28 May 1961, Benenson's article, entitled "The Forgotten Prisoners", was published; the letter asked readers to write letters showing support for all those imprisoned for their political or religious beliefs. To co-ordinate such letter-writing campaigns, Amnesty International was founded in London in July 1961 at a meeting of Benenson and six other men, who included a Conservative, a Liberal and a Labour MP; the response was so overwhelming that within a year various groups of letter-writers had formed in more than a dozen countries. Appointed general secretary of AI, Benenson stood down in 1964 owing to ill health. By 1966, Amnesty International faced an internal crisis; the advisory position of president of the International Executive was created for him. In 1966, after a report of British use of torture in Yemen, he began to make allegations that the British government had infiltrated the governance of AI. An inquiry was set up which reported at Elsinore in Denmark in 1967.
The allegations were rejected and Benenson resigned from AI. While never again active in the organisation, Benenson was personally reconciled with other executives, including Seán MacBride. Marriage to his first wife Margaret Anderson ended in divorce in 1972, he married Susan Booth in 1973. They had two children and were married until his death in 2005, he died of pneumonia on 25 February 2005 at the John Radcliffe Hospital, aged 83, having been a resident of the nearby village of Nuneham Courtenay where he was buried. Pincock, S.: Peter James Henry Solomon Benenson. Lancet, 2 April 2005. Obituary, BBC News "The forgotten Prisoners" 1961 article