In Structural Analysis, we analyze the structures with different methods based on its structures type. Two types of structures are determinate structures and indeterminate structures. Generally, it is actually not possible to perform an exact analyze of a structure. Hence, approximations for structure geometry, material limit and boundary, loading type and magnitude must be made. Determinate structure simply means that all the forces in the structure can be determined from the equilibrium equation. If there are more unknowns than the equation, the structure is indeterminate.
Determinancy=Reactions-Equilibrium
Statically determinate beam can be solved by the equilibrium equation consist of summation of horizontal force ∑fx=0, summation of vertical force ∑fy=0 and summation of moment ∑M at a point =0. One of the advantages of statically determinate beam is that it is easier to be analyzed. As one of the common statically simply supported beam with a pin support and a roller support, which results in three reactions- equilibrium = 0 hence determinate. Even though one of the supports has settled, there will be no stress caused due to the less of fit or settlement, this is because roller support allows rotation and hence it will be in equilibrium state. Besides, determinate structure that allows rotation at such will not be affected by the temperature reaction. For example, expansion due to hot weather and constraint due to cold weather will not influence the structure equilibrium. Besides, bending moment or shear at any point is independent and not relying on the material property. This is because the structure itself allows rotation from roller support and hence it will not cause any unnecessary stress to the material of beam i...
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...ave of water, wind loading and settlement of support. However, those situations stated will cause stress due to the ability of the beam to compact and redistribute the load among the beam. To overcome the disadvantage, the most suitable material, cross section and second moment area is required to be used to design the highest efficiency structure in real life application.
In conclusion, statically indeterminate beam’s most significant advantage is safety. All fundamental of structure is to withstand load and function to serve its designated purpose. Hence, real life structures are mostly indeterminate to brace the unknown external load or internal defect and yet still able to achieve stability.
References
Carpinteri, Alberto. Structural Mechanics: A Unified Approach. Taylor & Francis, 1997.
Wearne, Phillip. Collapse - Why Buildings Fall Down. TV Books , 2000.
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
Gunel, M. Halis. Ilgin H. Emre. "A proposal for the classification of structural systems of tall buildings" Building
Today, engineers rely on damping systems to counteract nature's forces. There are many types of damping systems that engineers can now use for structures, automobiles, and even tennis rackets! This site focuses on damping systems in structures, mainly architectural variations of the tuned mass damper.
"The arch enables wide spaces to be crossed by the use of the minimum of materials, thus relieving weight which would otherwise put an intolerable burden on the structure" (Kamm, n.d., para 6).
The transfer will govern the design, with decompression in service. It was found that eliminating small detachment of the tendons by using reinforcement in the top of the beam, resulted in savings. Another approach using strands near the top, but low enough that decompression requirement is achieved with a transfer, would limit the top stress
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.
The first is for control of buckling in the main girders during construction. The wet concrete imposes significant bending of the bare steel girders and the compression flange needs to be restrained against buckling. The second function is that bracing can be used to distribute the vertical bending effects between the main girders, and to ensure that lateral effects such as wind loading and collision loading are shared between all the girders. The third function is dimensional control, as a result of unequal loading, the horizontal distance between the flanges of adjacent girders will vary if not constrained. Bracing was placed at every transverse stiffener location for both girder sizes. 4 x 4 x ½ inch angles were used for bracing elements (Figure
The final designs of the Tacoma Narrows Bridge, once finalized, were a sharp and drastic contrast from the design by Leon Moisseiff. Instead of a thin plate girder, an open-air stiffening truss with a depth of 33 feet (10 m) would form the new road deck. Newer, larger towers that rose 58 feet (18 m) higher and 21 feet (6.4 m) wider than Gertie's towers, would support the bridge's main cables, now 20 1⁄4 inches (510 mm) in diameter versus Gertie's 17 1⁄2 inches (440 mm). Newer, larger anchor blocks would support a load that weighed 1.6 times as much as the original bridge. However, some elements of Galloping Gertie were incorporated into the 1950 span. The tower pedestals were enlarged and raised 17 feet (5.2 m). On the west end stood a 450-foot (140 m) long approach viaduct with the same 8-foot (2.4 m) deep girders Gertie's main deck had. This approach viaduct used three support towers, two with thin support beams and one with the structural complexity and design of one of Gertie's main towers - each spaced 150 feet (46 m) apart. The viaduct, after a structural examination, was kept and utilized as part of the 1950 bridge's design, with an additional box strut brace added to the tower closest the shoreline (officially known as Tower #3 in the design plans), and widening of the upper box strut for the new bridge's
This design employs an enhanced low-impact design, with an estimated weight load of 220 lbs.
Figure 2 shows the meshed model of lower suspension arm with 2.4 mm of mesh size and 10node Tetrahedron element (TET10) were considered for the analysis.
I’d never really built a bridge that was supposed to be tested and I definitely lacked experience at building in general. Also, I thought that even though I had a really stable desing, m y execution might’ve not been able to make the bridge hold its own. So I eventually scrapped the idea of making an arch. The next best thing was the Warren Truss bridge. The Warren Truss bridge is a type of bridge design that consists of equilateral triangle trusses. Even though it was really simple, it would be very good for a centered load. The design commonly has a centered vertical piece that prevents the bridge from buckling. When weight is applied to the bridge, the vertical pieces are in tension (as well as the horizontal base piece and inner diagonals) and the diagonals are in compression. While reading about the Warren Truss, I found the Pratt Truss as well. The Pratt Truss mainly used right triangles and worked the same way except it would be better for longer spans. I decided to combine both designs to create my
A beam is a simple design of a support structure. The major characteristics of this type of structure is its ability to span over
The channel section (both C and I) have higher bending stiffness as compared to solid square bar with equal cross section area. Considering the bending stiffness of solid square section as 1, the relative bending stiffness of other sections are:
Objects in equilibrium state are defined as isolated objects with precise constant properties such as pressure, temperature and volume. In addition to that the total net force a nd acceleration must be equal to zero (1). Achieving equilibrium state requires knowledge in all object’s properties and behavior. The following research paper will carry the outcomes of our research in the topic, starting with a simple description of the types of the equilibrium state, followed by engineering and mathematical explanations to the topic. After that it will show examples from mechanical engineering classwork and world applications of the topic. The paper will close with the problems faced while completing the research.
Optimization is a chronic and natural process usually witnessed in our daily life events. In various disciplines such as engineering designs, manufacturing systems, agricultural sciences, physical sciences, economics, pattern recognition etc. optimization is observed. Optimization is, thus a process of making best, effective and functional solution out of possible choices no way differs from the structural optimization which is being conceived in the present work. Structural optimization is a decisive and tricky step, where the designers are able to generate better designs saving time and money. Conventional optimization approaches like mathematical programming method, optimality criteria method etc. fails miserably in structural design problems which are highly complex and time consuming in nature. Optimization problems are mathematical models formulated to solve complex designs that may be of multi-objective nature in certain cases. Structural design procedure involves conceptual design and design realization leading to several probable results since higher degree of ambiguity is experienced in every steps. Conceptual design phase is more dependent on decision variables than in advance optimization phase. Optimization is one of the major tool for decision making at the conceptual or realization phase of modern design techniques. In design realization stage optimization is achieved by mathematical and numerical search methods.