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PYRAMID Blocks : Laborers used 2.3 million blocks of limestone and granite to build the Great Pyramid of Khufu, which stands 146 meters high, has a 230-meter-square base and weighs about 6.5 million tons. interesting……
The Ancient Pyramid technology
The ancient pyramids are among the most astonishing structures in the world. Built in ancient times by workers who didn’t have the benefit of modern tools and machinery, they are a constant source of fascination. Most of us think of ancient when pyramids come to mind, but they exist in many parts of the world. Why did the ancients build pyramids? What was their purpose? Is there any special meaning behind the pyramid shape? How were they built without earth-moving or heavy-lift machinery? In this article, we’ll examine pyramids around the world, how they were constructed and who used them.
What is a pyramid?
A pyramid is a geometrical solid with a square base and four equilateral triangular sides, the most structurally stable shape for projects involving large amounts of stone or masonry. Pyramids of various types, sizes and complexities were built in many parts of the ancient world (like Central America, Greece, China and Egypt). In the history of Egypt and China, they were primarily tombs and monuments to kings and leaders. The pyramids of the Mayans and Aztecs of Central America were mainly religious temples, though some of them housed burial chambers.
The Central American pyramids were smaller and sometimes wider than their Egyptian counterparts. These pyramids also took longer to finish — they were often built and modified over hundreds of years, while Egyptian pyramids took a couple of decades to construct. Pyramids in Central America were integrated into Aztec and Mayan cities, whereas Egyptian pyramids were located away from the major cities.
The ancestors of these great structures are the burial tombs found throughout North America and Europe — simple mounds of earth that covered burial chambers. The first tombs of the Egyptian pharaohs were flat, box-shaped buildings called mastabas (Arabic for “bench”). Pharaohs later built grander tombs by adding levels on top of the box to form stepped pyramids. Stepped pyramids are prevalent in Central America. In Mesopotamia, they were called ziggurats.
The Egyptians took pyramid design to new heights, culminating in the construction of the pyramids of Giza in the 26th century B.C. Laborers used 2.3 million blocks of limestone and granite to build the Great Pyramid of Khufu, which stands 146 meters high, has a 230-meter-square base and weighs about 6.5 million tons. A number of pyramids, including the Great Pyramid of Khufu, have survived thousands of years of exposure to the elements, a tribute to the ancient architects, engineers and workers who built them.
Mathematics is essential in our modern society. From economic models used at Wall Street to Google’s search algorithms and so many things more, mathematics is all around us and stands at the forefront of our scientific knowledge. Ancient mathematics started far before civilization, even before language itself. Most even claim the construction of all the ancient structures across the world could not have been created without the use of some form of advanced mathematical technology.
The origins of mathematics probably lie in the abstract concepts of numbers and values. Modern studies of animal cognition have shown that these concepts are not unique to humans but can also be found in certain animals such as apes. Mathematical ideas would have been part of everyday life in ancient hunter-gatherer societies, from probable simple comparisons of objects to defining what time of year it was. The idea of the “number” evolving over time is supported by the appearance of certain languages that have preserved the distinction between “one”, “two”, and “many”, but not specifically numbers larger than two.
The oldest known supposed mathematical object is the Lebombo bone that was discovered in the Lebombo mountains of Swaziland, Africa and was dated back to approximately 35,000 BC. It consists of 29 distinct notches cut into a baboon’s fibula. Other prehistoric artifacts were discovered in Africa and France, dated between 35,000 and 20,000 years old, suggesting early attempts to quantify time.
The Ishango bone that was found near the Nile river (northeastern Congo), may be as much as 20,000 years old and consists of a series of tally marks carved in three columns running the length of the bone. Many scholars think the Ishango bone shows either the earliest known demonstration of sequences of prime numbers or a six month lunar calendar.
In the book “How Mathematics Happened: The First 50,000 Years”, by Peter Rudman, he argues that the development of the concept of prime numbers could only have been created after the concept of division, which he dates to after 10,000 BC, with prime numbers probably not being understood until about 500 BC. Peter Rudman also writes that “no attempt has been made to explain why a tally of something should exhibit multiples of two, prime numbers between 10 and 20, and some numbers that are almost multiples of 10.”
The Ishango bone, according to scholar Alexander Marshack, may have influenced the later development of mathematics in Egypt as, like some entries on the Ishango bone, Egyptian arithmetic also made use of multiplication by 2, however, this is disputed.
Predynastic Egyptians of the 5th millennium BC pictorially represented geometric designs. It has been claimed that megalithic monuments in England and Scotland, dating from the 3rd millennium BC, incorporate geometric ideas such as circles,ellipses, and Pythagorean triples in their design.
The currently oldest undisputed mathematical usage is in Mesopotamian sources. Thus it took humans at least 45,000 years from the attainment of behavioral modernity and language to develop mathematics as such.
Still much is unknown about the history of mathematics, especially how ancient structures were built with such a high level of precision and detail and without the supposed use of highly advanced mathematics we know today.
Mesopotamian clay tablets dating back to the 4th millennium BC claim their advanced knowledge was given to them by advanced beings they refer to as the Anunnaki (meaning something as “those who Anu sent from heaven to earth”). Maybe new findings of ancient objects can shed more light on how ancient man obtained its advanced knowledge of mathematics.
At first glance, the cable-stayed bridge may look like just a variant of the suspension bridge, but don’t let their similar towers and hanging roadways fool you. Cable-stayed bridges differ from their suspension predecessors in that they don’t require anchorages, nor do they need two towers. Instead, the cables run from the roadway up to a single tower that alone bears the weight.
The tower of a cable-stayed bridge is responsible for absorbing and dealing with compression forces. The cables attach to the roadway in various ways. For example, in a radial pattern, cables extend from several points on the road to a single point at the tower, like numerous fishing lines attached to a single pole. In a parallel pattern, the cables attach to both the roadway and the tower at several separate points.
Engineers constructed the first cable-stayed bridges in Europe following the close of World War II, but the basic design dates back to the 16th century and Croatian inventor Faust Vrancic. A contemporary of astronomers Tycho Brache and Johannes Kepler, Vrancic produced the first known sketch of a cable-stayed bridge in his book “Machinae Novae.”
Today, cable-stayed bridges are a popular choice as they offer all the advantages of a suspension bridge but at a lesser cost for spans of 500 to 2,800 feet (152 to 853 meters). They require less steel cable, are faster to build and incorporate more precast concrete sections.
Not all bridges require great hunks of steel and concrete though. Sometimes a tree root or two will do the trick.
Good quality concrete starts with the quality of materials, cost effective designs is actually a by-product of selecting the best quality material and good construction practices. Following are 10 Things to remember during Concrete Mix Design and Concrete Trials.
1. ACI and other standards only serves as a guide, initial designs must be confirmed by laboratory trial and plant trial, adjustments on the design shall be done during trial mixes. Initial design “on paper” is never the final design.
2. Always carry out trial mixes using the materials for actual use.
3. Carry out 2 or 3 design variations for every design target.
4. Consider always the factor of safety, (1.125, 1.2, 1.25, 1.3 X target strength)
5. Before proceeding to plant trials, always confirm the source of materials to be the same as the one used in the laboratory trials.
6. Check calibration of batching plant.
7. Carry out full tests of fresh concrete at the batching plant, specially the air content and yield which is very important in commercial batching plants.
8. Correct quality control procedures at the plant will prevent future concrete problems.
9. Follow admixture recommendations from your supplier
10. Check and verify strength development, most critical stage is the 3 and 7 days strength.
Important note: Technical knowledge is an advantage for batching plant staff, even if you have good concrete design but uncommon or wrong procedures are practiced it will eventually result to failures.
The multiple-stage method of diversion over the tops of alternate low construction blocks or through diversion conduits in a concrete dam requires shifting of the cofferdam from one side of the river to the other during construction. During the first stage, the flow is restricted to one portion of the stream channel while the dam is constructed to a safe elevation in the remainder of the channel.
In the second stage, the cofferdam is shifted and the stream is carried over low blocks or through diversion conduits in the constructed section of the dam while work proceeds on the un-constructed portion. The dam is then carried to its ultimate height, with diversion finally being made through the spillway, penstock, or permanent outlets.
A cofferdam can be defined as “A watertight construction designed to facilitate construction projects in areas which are normally submerged”, such as bridges and piers.
A cofferdam is installed in the execution area and the water is pumped out in order to facilitate work for workers and enable them to work in dry conditions and can construct structural supports, enact repairs, or perform other types of work in a dry environment. In some regions of the world, a cofferdam is better known as a caisson. Working inside a cofferdam can be hazardous if it is installed improperly or not safely pressurized, but advances in engineering have led to increased safety for workers using this unique work environment.
A cofferdam is a temporary dam or barrier used to divert a stream or to enclose an area during construction. The design of an adequate cofferdam involves the problem of construction economics. When the construction is timed so that the foundation work can be executed during the low-water season, the use of cofferdams can be held to a minimum. However, where the stream flow characteristics are such that this is not practical, the cofferdam must be so designed that it is not only safe, but also of the optimum height.
Height Limitations for Cofferdam
The height to which a cofferdam should be constructed may involve an economic study of cofferdam height versus diversion works capacity. This may include routing studies of the diversion design flood, especially when the outlet works requirements are small. If outlet works requirements dictate a relatively large outlet conduit or tunnel, diversion flows ordinarily may be accommodated without a high cofferdam. It should be remembered that the floodwater accumulated behind the cofferdam must be evacuated in time to accommodate another storm.
The maximum height to which it is feasible to construct the cofferdam without encroaching upon the area to be occupied by the dam must also be considered. Furthermore, the design of the cofferdam must take into consideration the effect that excavation and de-watering of the foundation of the dam will have on its stability, and it must anticipate removal, salvage, and other factors.
Generally, cofferdams are constructed of materials available at the site. The two types normally used in the construction of dams are
- Earthfill cofferdams and
- Rockfill cofferdams
Whose design considerations closely follow those for permanent dams of the same type. Other less common cofferdam types are concrete cribs filled with earth or rock, and cellular-steel cofferdams filled with earth or rock. In this case, the major portion of the cofferdam consists of an earth and rock embankment, and steel sheet piling was used to affect final closure in swift water. Cellular steel cofferdams and steel sheet piling are adaptable to confined areas where currents are swift.
If the cofferdam can be designed so that it is permanent and adds to the structural stability of the dam, it will have a decided economic advantage. In some embankment dams the cofferdam can even be incorporated into the main embankment. In such instances, the saving is twofold-the amount saved by reducing the embankment material required and the amount saved by not having to remove the cofferdam when it is no longer needed.
Innovators: Gregory Deierlein, Stanford University; Jerome F. Hajjar, Northeastern University
“Elastic high-strength steel cables run down the center of the system’s frame. The cables control the rocking of the building and, when the earthquake is over, pull it back into proper alignment.”
“A steel frame situated around a building’s core or along exterior walls offers structural support. The frame’s columns, however, are free to rock up and down within steel shoes secured at the base.”
Last fall, the engineers successfully tested a 26-foot-tall, three-story, steel-frame building outfitted with the new system, built atop the E-Defense shake table—the world’s largest earthquake simulator—in Miki City, Japan. Steel “fuses,” not structural elements, absorbed the shock of an earthquake greater than magnitude 7, and cables pulled the building back into plumb once the shaking stopped. After an earthquake of that scale, the deformed fuses could be replaced in about four days—while the building remained occupied. Jim Malley of the San Francisco firm Degenkolb Engineers calls the system the next step in the evolution of green building. “As structural engineers,” he says, “our sustainable design is the ability not to have to tear buildings down after earthquakes, but to use them for hundreds of years.”
Engineering is a term applied to the profession in which knowledge of the mathematical and natural sciences, gained by study, experience, and practice, is applied to the efficient use of the materials and forces of nature. Engineers are the ones who have received professional training in pure and applied science.Before the middle of the 18th century, large-scale construction work was usually placed in the hands of military engineers. Military engineering involved such work as the preparation of topographical maps, the location, design, and construction of roads and bridges; and the building of forts and docks; see Military Engineering below. In the 18th century, however, the term civil engineering came into use to describe engineering work that was performed by civilians for nonmilitary purposes.
Civil engineering is the broadest of the engineering fields. Civil engineering focuses on the infrastructure of the world which include Water works, Sewers, Dams, Power Plants, Transmission Towers/Lines, Railroads, Highways, Bridges, Tunnels, Irrigation Canals, River Navigation, Shipping Canals, Traffic Control, Mass Transit, Airport Runways, Terminals, Industrial Plant Buildings, Skyscrapers, etc. Among the important subdivisions of the field are construction engineering, irrigation engineering, transportation engineering, soils and foundation engineering, geodetic engineering, hydraulic engineering, and coastal and ocean engineering.
Civil engineers build the world’s infrastructure. In doing so, they quietly shape the history of nations around the world. Most people can not imagine life without the many contributions of civil engineers to the public’s health, safety and standard of living. Only by exploring civil engineering’s influence in shaping the world we know today, can we creatively envision the progress of our tomorrows.