Literature Survey
Background:
The structural support in structural engineering refers to load-resisting system of a structure. The structural system transfers loads through interconnected structural components or members. Commonly used structures can be classified into five major categories, rods, beams ,columns, trusses, cable and arches .the structures are classified on the basis of how the forces i.e shear, compression, tension and bending are distributed in the members of the structures under major design loads. However any two or more of the basic structural types may be combined in a single structure, such as a building or a bridge in order to meet the structures functional requirements.
Types of support structures
Beam
A beam is a simple design of a support structure. The major characteristics of this type of structure is its ability to span over
…show more content…
The triangular members allow the distribution of loads along the span of the bridge. Manufacture of truss support structures is usually time consuming as each member has to be
Constructed individually. Trusses are small beams added together to support a large amount of load and span over large distances. Most times the assembling of trusses is simple. However once assembled they can take a great amount of space.
A cantilever is a support structure that is only externally supported from one side of the structure with a free end on the counter side. Cantilevers can experience almost all types of stresses like bending, shear, axial and torsional shear. This type of structure has been used by engineers throughout history which to deviate from using support pillars and external bracing (mostly architectural purposes). Cantilevers can come in different construction like slabs and trusses . The Chinese architectural tradition is known for using all types of cantilever forms.
Beam(Slab)
A connecting rod subjected to an axial load F may buckle with x-axis as neutral axis in the plane of motion of the connecting rod, {or} y-axis is a neutral axis. The connecting rod is considered like both ends hinged for buckling about x axis and both ends fixed for buckling about y-axis. A connecting rod should be equally strong in buckling about either axis [8].
The area of where the bridge was to cross the Ohio River was said to be one of the hardest places to build but came with some advantages. The section of the river had a solid rock base for the supporting pier to be built on. Since the engineers knew they could build a pier that would not settle they decided on a continuous bridge design. This design type distributes the weight so the steel trusses could be smaller and riveted together. This alone saved an estimates twenty percent of steel that was originally thought to be need to make the bridge cutting down the cost. The two continuous trusses span a collective 1,550 feet across the water. With addition of the north and south approach viaducts, for trains to go under the bridge, the superstructure’s total length is 3,463 feet. The bridge was made to hold two sets of tracks making the width 38 feet and 9 inches. The design called for 27,000 cubic yards of concrete and 13,200 tons of steel with some members being four foot square beams that span a distance of seventy feet. The design was the first step in a long process that would take several years to
Following the collapse of the I-35 Bridge, other bridges in the country, with similar construction designs, were scrutinized. According to federal statistics, more than 70,000 of the 607,363 or roughly 12 percent of the bridges in the United States are classified as “structurally deficient.”
According to Suspension bridges: Concepts and various innovative techniques of structural evaluation, “During the past 200 years, suspension bridges have been at the forefront in all aspects of structural engineering” (“Suspension”). This statement shows that suspension bridges have been used for over 200 years, and that people are still using them today because they are structurally better bridges. This paper shows four arguments on the advantages of suspension bridges, and why you should use one when building a bridge. When deciding on building a suspension bridge, it has many advantages such as; its lightness, ability to span over a long distance, easy construction, cost effective, easy to maintain, less risk
counterweight is hoisted up as high as possible it has lots and lots of potential
Golden Gate Bridge held the title as one of the longest bridges for a reason. It has a total length of 2,737 meters with a width of 27 meters. It also has a clearance of 67 meters for ships to pass by. Besides its incredible dimension, its architecture also plays a tremendous role for its beauty. The bridge employs art deco style, a chevron or beveled shape, used to add visual effect. The concrete structures at the ends of the bridge have chevron form as well as the concrete at the base of the towers. There are two shafts in each tower, 90 feet apart decreasing in width as they go up. The two shafts are connected by cross bracing and having four horizontal struts above. The bridge’s art deco design and towers were designed by architect Irving F. Morrow.
...ad to use cantilevers which were beams anchored at only one end. These beams carry the load to support where the force is concentrated by a moment and shear stress. Fallingwater indeed was a revolutionary structure due to the fact that it had many unique aspects. From how famous the house became, Fallingwater was featured on the cover of Time magazine, in 1938.
The architecture and engineering firm hired with the task of designing and constructing the tower, SOM, assigned Bruce Graham and Fazlur Khan to the project. They implemented a bundled tube design that was the first of its kind on such a large project that paved the way for the design and construction of future skyscrapers. This design allowed for 4.5 million square feet of office space, more customization of the floor layouts, up to 3 foot of sway within the building, and the stiffness needed to stay standing at the height in which it was built. The tubular design also allowed Sears to save about $10,000,000 on steel alone compared to previously used steel frame designs. Additionally, SOM managed to save 95% of the time usually spent welding by using prefabricated parts referred to as Christmas trees. This not only majorly sped up the process, but allowed Sear to save on labor costs. In addition to 3 trussed layers in the building, there were trusses and spandrel beams designed into every floor to help the load distribute more evenly.
These buildings were two and ten stories, respectively, and used steel moment frames as the lateral load resisting system in both directions.
Boomilevers are most commonly built as right triangles, in order for them to withstand the most force. Naturally, this creates a hypotenuse, and also helps to define the device. If the tension member is the hypotenuse, then the device is known as a “tension boomilever.” In contrast, if the compression member is the hypotenuse, then it is known as a “compression boomilever.” When the testing of the boomilever begins, a weight is placed on the side farthest away from the base, or the distal end.
Studs -- common wall framing member the member that goes from bottom to top plate in one continues length. Non Bearing Wall- Minimum 2x3 framing material. If floor space needs to be saved you can frame 2x4 the flat way only in...
integrity by using a flared foothold, or pier, and the terrain to anchor each end of the span. It was
The structural engineers use geometry in their design in order to calculate the spacing of their columns and beams for proper strength for the building.
Structural Engineering deals with the design and construction of all types of structures including buildings and bridges. Emphasis is placed on mechanics and the behaviour of materials.
Chua, Ian Y. H. Civil and Structural Engineering Resource Web. 29 Jan. 2000. 2 Mar.