The development of the current computer-oriented methods of structural analysis can be attributed to, among others, J. Argyris, R. Clough, S. Livesley, H. Martin, M. Turner, E. Wilson, and O. Structural engineering is the science and art of planning, designing, and constructing safe and economical structures that will serve their intended purposes.
Structural analysis is an integral part of any structural engineering project, its function being the prediction of the performance of the proposed structure. As this diagram indicates, the process is an iterative one, and it generally consists of the following steps:. Planning Phase — The planning phase usually involves the establishment of the functional requirements of the proposed structure, the general layout and dimensions of the structure, consideration of the possible types of structures e.
This phase may also involve consideration of non-structural factors, such as aesthetics, environmental impact of the structure, and so on. The outcome of this phase is usually a structural system that meets the functional requirements and is expected to be the most economical. This phase is perhaps the most crucial one of the entire project and requires experience and knowledge of construction practices in addition to a thorough understanding of the behaviour of structures.
Preliminary Structural Design — In the preliminary structural design phase, the sizes of the various members of the structural system selected in the planning phase are estimated based on approximate analysis, past experience, and code requirements.
The member sizes thus selected are used in the next phase to estimate the weight of the structure. Estimation of Loads — Estimation of loads involves determination of all the loads that can be expected to act on the structure.
Structural Analysis — In structural analysis, the values of the loads are used to carry out an analysis of the structure in order to determine the stresses or stress resultants in the members and the deflections at various points of the structure.
Safety and Serviceability — Checks The results of the analysis are used to determine whether or not the structure satisfies the safety and serviceability requirements of the design codes. If these requirements are satisfied, then the design drawings and the construction specifications are prepared, and the construction phase begins.
Revised Structural — Design If the code requirements are not satisfied, then the member sizes are revised, and phases 3 through 5 are repeated until all the safety and serviceability requirements are satisfied. Commonly used structures can be classified into five basic categories, depending on the type of primary stresses that may develop in their members under major design loads. The members of tension structures are subjected to pure tension under the action of external loads.
Because the tensile stress is distributed uniformly over the cross-sectional areas of members, the material of such a structure is utilized in the most efficient manner. Tension structures composed of flexible steel cables are frequently employed to support bridges and long-span roofs. Because of their flexibility, cables have negligible bending stiffness and can develop only tension.
Thus, under external loads, a cable adopts a shape that enables it to support the load by tensile forces alone. In other words, the shape of a cable changes as the loads acting on it change. In a suspension bridge, the roadway is suspended from two main cables by means of vertical hangers. The main cables pass over a pair of towers and are anchored into solid rock or a concrete foundation at their ends.
Because suspension bridges and other cable structures lack stiffness in lateral directions, they are susceptible to wind-induced oscillations. Bracing or stiffening systems are therefore provided to reduce such oscillations. Besides cable structures, other examples of tension structures include vertical rods used as hangers for example, to support balconies or tanks and membrane structures such as tents. Compression structures develop mainly compressive stresses under the action of external loads.
Two common examples of such structures are columns and arches. Columns are straight members subjected to axially compressive loads. An arch is a curved structure, with a shape similar to that of an inverted cable. Such structures are frequently used to support bridges and long-span roofs.
Arches develop mainly compressive stresses when subjected to loads and are usually designed so that they will develop only compression under a major design loading. However, because arches are rigid and cannot change their shapes as can cables, other loading conditions usually produce secondary bending and shear stresses in these structures, which, if significant, should be considered in their designs.
Because compression structures are susceptible to buckling or instability, the possibility of such a failure should be considered in their designs; if necessary, adequate bracing must be provided to avoid such failures. Trusses are composed of straight members connected at their ends by hinged connections to form a stable configuration.
When the loads are applied to a truss only at the joints, its members either elongate or shorten. Thus, the members of an ideal truss are always either in uniform tension or in uniform compression. Real trusses are usually constructed by connecting members to gusset plates by bolted or welded connections.
Although the rigid joints thus formed cause some bending in the members of a truss when it is loaded, in most cases such secondary bending stresses are small, and the assumption of hinged joints yields satisfactory designs. Trusses, because of their light weight and high strength, are among the most commonly used types of structures. Such structures are used in a variety of applications, ranging from supporting roofs of buildings to serving as support structures in space stations.
Shear structures, such as reinforced concrete shear walls, are used in multi-storey buildings to reduce lateral movements due to wind loads and earthquake excitations. Shear structures develop mainly in plane shear, with relatively small bending stresses under the action of external loads. Top 25 Strength of Materials Books Collection. Building Science and Materials by John Elliott. Highway Engineering By S. Khanna and Justo. Signal processing and linear systems by B.
Electronic Instrumentation and Measurement. Collins — Work on Your Grammar: Advanced. Collins — Work on your Phrasal Verbs. Engineering Physics McGraw Hill. Handbook on the Physics and Chemistry of Rare Earths. Particle Physics and Inflationary Cosmology — Linde. Inorganic Chemistry Catherine 4th Edition.
Physical Inorganic Chemistry. Organic Chemistry McGraw Hill. Organic Chemistry. Starr, R. Cook and J. Home Blog.
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