The Physics of Bridges
The design of the bridge superstructure is based on a set of loading conditions
which the component or element must withstand. A bridge engineer must take into
account a wide variety of loads which may vary based on the duration of the load
(permanent or temporary), the direction of the load (vertical, longitudinal, etc.), and the
effect of the load (shear, bending, torsion, etc.).
In order to form a consistent basis for design, organizations like AASHTO, American
Association of State Highway and Transportation Officials, have developed a set of
standard loading conditions which are applied to the engineer's design model of the
structure. Other nations maintain their own set of design loads like the BS 5400 loads
utilized in the United Kingdom or the Ontario Highway Bridge Design Code, OHBDC,
loads utilized in the Canadian province of Ontario and elsewhere in that nation. (1)
Permanent loads, as the name would imply, are those loads, which always remain on a
bridge throughout its life. Although the term dead load is often used synonymously with
permanent loads, there are distinctions, which need to be made. Permanent loads are
divided into the following three major categories: dead load, superimposed dead load, and
pressures.
The dead load on a superstructure is the aggregate weight of all superstructure elements
(i.e. those elements above the bearings). This would include, but not be limited to, the
deck, wearing surface, stay-in-place forms, sidewalks and railings, parapets, primary
members, secondary members (including all bracing, connection plates, etc.), stiffeners,
signing, and utilities. One of the first steps in any design of a superstructure is to compile
a list of ...
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...HTO load distribution specification, when appropriate.
The AASHTO code places the distribution of loads for concrete slabs within the same
section as that which describes the general design criteria for this element. For load
distribution criteria pertaining to other less common flooring, such as timber flooring
(wood), you can be referred to the AASHTO specifications directly for information.
Bibliography:
References:
1. American Association of State Highway and Transportation Officials (AASHTO): Standard Specifications for Highway Bridges, Washington, D.C., 1977
2. Bakht, B. and Jaegar, L.G.: Bridge Analysis Simplified: 1985
3. Serway: Physics for Scientists and Engineers: Vol. 1, 4th ed. 1996
4. Hoelsher, R.P. and Springer, C.H. and Dobrovolny, J.S.: Graphics for Engineers: Visualization, Communication, and Design, New York, New York, 1968
Ballast (10) - heavy material that is placed low in vessels to improve stability. Ex: iron, gravel, and lead
Philip B. Meggs, Alston W. Purvis. Meggs’ History of Graphics Design. New Jersey: John Wiley & Sons, Inc, 2006.
The 1890 story “An Occurrence at Owl Creek Bridge” by Ambrose Bierce was composed with a structure that shows time fluidity. The story illustrated the perceived function of time as beyond reality as it slows down to the satisfaction of the delusions of protagonist, Peyton Farquhar, as he experiences a dying incident on the day of his execution. Farquhar was charged with the crime of an attempted act to destroy or sabotage the Owl Creek Bridge, and was thereafter sentenced to death by the Federal Army. Farquhar believes as he also leads the readers the same that he has escaped execution and has made his way back home. The dying protagonist’s experience was portrayed in a slow flow of time that seemed to exactly fit the many circumstances that occurred just in time for reality to come and take its place in time.
Meggs, Philip B., and Alston W. Purvis. Meggs' History of Graphic Design. Hoboken, NJ: J.
Since humans are mortal, the sensation of pain is integral to the human condition. On one hand, pain alerts the body of a danger that is threatening its overall well-being; however, pain can be used as a means of torture to break the psyche or willpower of someone. As Lancelot races to save his queen from the evil Méléagant, he encounters the Sword Bridge. This Bridge is notorious for its slender construction, making it impossible for one
van Wijk, J.J., "Views on Visualization," Visualization and Computer Graphics, IEEE Transactions on , vol.12, no.4, pp.421,432, July-Aug. 2006. Retrieved from http://ieeexplore.ieee.org.uproxy.library.dc.uoit.ca/stamp/stamp.jsp?tp=&arnumber=1634309&isnumber=34266
Benjamin, Walter. "The Work of Art in the Age of Mechanical Production." Illuminations. Ed. Harry Zohn. New York: Schocken, 1969. 217-252. Print.
Friendship can be shown through the words of anyone in any form, whether it is short or long, in a simple poem to a complicated novel, even in a simple common book such as, Bridge to Terabithia. The author, Paterson, uses many of reasonable literary elements in her book, such elements encompass: character, plot, setting, theme, style, point of view, and tone. These seven elements show us that friendship between the main characters, Jesse and Leslie, in Bridge to Terabithia, although interrupted by many everyday occurrences, can develop quickly, without one's realization. And that friendship, that was suddenly started, can be suddenly gone with the least suspected. In this instance, friendship is suddenly ended, there would be the realization of feelings that maybe there was something more then friendship; something not initially felt when the friendship actually once existed.
"Design, 1975–present". In Heilbrunn Timeline of Art History. New York: The Metropolitan Museum of Art, 2000–. http://www.metmuseum.org/toah/hd/dsgn4/hd_dsgn4.htm (October 2004)
“An Occurrence at Owl Creek Bridge” by Ambrose Bierce starts off with the protagonist, Peyton Farquhar, standing on a railroad bridge twenty feet above the water. Farquhar stands on a plank with his wrist tied behind his back, and neck tied with rope. The Northern army surrounds him, waiting for the sergeants signal to release Farquhar upon his death. At this moment, Farquhar stares at the river below his feet, watching pieces of driftwood flow downstream. He notices the river flowing slowly. To keep his mind off the current situation, Farquhar closes his eyes, thinking about his wife and children. While thinking, he hears a loud clanking noise, which he soon realizes it to be his watch ticking. Farquhar visions himself escaping by jumping
Based on the research conducted, the bridge being built will be a Pratt or Parker Bridge with a height of about 2.5 inches. Members will connect to one another through lap joints, and when a lap joint cannot be used, an end joint with two gussets securing it in place will be used. Gorilla Glue and Alteco ST50 Super Glue will be used to connect members at these joints. The glue will be applied to balsa members pinned to a workspace through a glue applicator to assist in applying a precise amount of
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Fluid motion over the objects surface is inducted by mechanical means. This is externally introduced by way of a pump or fan.