Introduction to Dynamic Analysis

All real physical structures, when subjected to loads or displacements, behave dynamically. The additional inertia forces, from Newton’s second law, are equal to the mass times the acceleration. If the loads or displacements are applied very slowly then the inertia forces can be neglected and a static load analysis can be justified. Hence, dynamic analysis is a simple extension of static analysis. 

In addition, all real structures potentially have an infinite number of displacements.  Therefore, the most critical phase of a structural analysis is to create a computer model, with a finite number of massless members and a finite number of node (joint) displacements, that will simulate the behavior of the real structure. The mass of a structural system, which can be accurately estimated, is lumped at the nodes. Also, for linear elastic structures the stiffness properties of the members, with the aid of experimental data, can be approximated with a high degree of confidence. However, the dynamic loading, energy dissipation properties and boundary (foundation) conditions for many structures are difficult to estimate. This is always true for the cases of seismic input or wind loads.

To reduce the errors that may be caused by the approximations summarized in the previous paragraph, it is necessary to conduct many different dynamic analyses using different computer models, loading and boundary conditions. It is not unrealistic to conduct 20 or more computer runs to design a new structure or to investigate retrofit options for an existing structure.

Sectional Properties for various cross sections

Continuous beams are statically indeterminate structures, Bending moment of these beam elements are function of sectional properties, spans, loading, modulus of elasticity and moment of inertia. The figures given below depict the following properties for different sections.

Introduction to Aluminium Structures

We include aluminum with steel and reinforced concrete as a metal-based material of construction. While our basis for this grouping may not be immediately obvious, it becomes more apparent when considered in an historical context.

Prior to the development of commercially viable methods of producing iron, almost all construction consisted of gravity structures. From the pyramids of the pharoahs to the neoclassical architecture of Napoleonic Europe, builders stacked stones in such a way that the dead load of the stone pile maintained a compressive state of force on each component of the structure. The development of methods to mass-produce iron, in addition to spawning the Industrial Revolution in the nineteenth century, resulted in iron becoming commercially available as a material of construction. Architecture was then freed from the limitations of the stone pile by structural components that could be utilized in tension as well as compression. American architect Frank Lloyd Wright observed that with the availability of iron as a construction material, ‘‘the architect is no longer hampered by the stone beam of the Greeks or the stone arch of the Romans.’’ Early applications of this new design freedom were the great iron and glass railway stations of the Victorian era. Builders have been pursuing improvements to the iron beam ever since.

An inherent drawback to building with iron as compared to the old stone pile is the propensity of iron to deteriorate by oxidation. Much of the effort to improve the iron beam has focused on this problem. One response hasbeen to cover iron structures with a protective coating. The term coating may be taken as a reference to paint, but it is really much broader than that. What is reinforced concrete, for example, but steel with a very thick and brittle coating? Because concrete is brittle, it tends to crack and expose the steel
reinforcing bars to corrosion. One of the functions served by prestressing or posttensioning is to apply a compressive force to the concrete in order to keep these cracks from opening.

History of Concrete

Concrete science is a science about concrete, its types, structure and properties, environmental impact on it. Concrete science develops in process of development of construction technology, improving of experimental methods of research.

Concrete application in civil engineering can be divided conventionally into some stages:
1. The antique
2. Application of a hydraulic lime and Roman cement.
3. Portland cement technology formation and plain concrete application.
4. Mass application of concrete for manufacturing of reinforced concrete
    constructions.
5. Application of concrete for manufacturing of prestressed and precast
    reinforced concrete constructions
6. Wide use of concrete of the various types modified by admixtures.

The Antique Concrete

Pantheon in Rome.

Concrete domical building 43 m high (115-125 A.D.)

Golden Age of Concrete

Empire State Building, New-York,

USA (1931) 381 m high

Highway Functions Systems and Classifications

The classification of highways into different operational systems, functional classes, or geometric types is necessary for communication among engineers, administrators, and the general public. Different classification schemes have been applied for different purposes in different rural and urban regions. Classification of highways by design types based on the major geometric features (e.g., freeways and conventional streets and highways) is the most helpful one for highway location and design procedures. 

Classification by route numbering (e.g., U.S., State, County) is the most helpful for traffic operations. Administrative classification (e.g., National Highway System or Non-National Highway System) is used to denote the levels of government responsible for, and the method of financing, highway facilities. Functional classification, the grouping of highways by the character of service they provide, was developed for transportation planning purposes. Comprehensive transportation planning, an integral part of total economic and social development, uses functional classification as an important planning tool. The emergence of functional classification as the predominant method of grouping highways is consistent with the policies contained in this publication.

Types of Rocks

The term rock is used for those materials of many kinds which form the greater part of the relatively thin  outer shell, or crust, of the Earth; some are comparatively soft and easily deformed and others are hard and rigid. They are accessible for observation at the surface and in mines and borings. Three broad rock groups are distinguished, on the basis of their origins rather than their composition or strength:

Igneous Rocks

Igneous rocks, derived from hot material that originated below the Earth's surface and solidified at or near
the surface (e.g. basalt, granite, and their derivatives).

Sedimentary Rocks

Sedimentary rocks, mainly formed from the breakdown products of older rocks, the fragments having been

sorted by water or wind and built up into deposits of sediment (e.g. sandstone, shale); some rocks in this group have been formed by chemical deposition (e.g. some limestones). The remains of organisms such as marine shells or parts of plants that once lived in the waters and on the land where sediment accumulated, can be found as fossils.

Metamorphic Rocks

Metamorphic rocks, derived from earlier igneous or sedimentary rocks, but transformed from their original

state by heat or pressure, so as to acquire conspicuous new characteristics (e.g. slate, schist, gneiss).

An Introduction to Geology

The science of Geology is concerned with the Earth and the rocks of which it is composed, the processes by  hich they were formed during geological time, and the modelling of the Earth's surface in the past and at the present day. The Earth is not a static body but is constantly subject to changes both at its surface and at deeper levels. Surface changes can be observed by engineers and geologists alike; among them erosion is a dominant process which in time destroys coastal cliffs, reduces the height of continents, and transports the material so removed either to the sea or to inland basins of deposition. Changes that originate below the surface are not so easily observed and their nature can only be postulated. Some are the cause of the slow movements of continents across the surface of the globe; others cause the more rapid changes associated
with volcanic eruptions and earthquakes.