Basic Runway length and Corrections
Basic Runway Length
Correction for Elevation, Temperature and Gradient
Correction for Elevation
Corrections in runway length
(i) correction for elevation:
[`L'= L.(7/100).(E/300)`]
L1 = L + Lc
E = elevation from MSL (m)
L = Basic runway length
Lc= Correction due to elevation
L1= Corrected length
Correction for Temperature
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| Correction for Temperature in runway |
- Standard temp = 15 – 0.0165 (E)
Correction for Gradient
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| Correction for Gradient in Runway |
Basic Runway length
Length of runway under following assumed conditions
(i) Airport at sea level
(ii) Temperature at airport is 15 'C (standard)
(iii) Runway is levelled in longitudinal direction.
(iv) No wind blowing on runway.
(v) Aircraft is loaded at its full capacity.
(vi) There is no wind blowing enroute to destination
(vii) Enroute temperature is standard.
Stress Strain Curve for Mild Steel
Stress Strain Curve for Mild Steel
OA is Proportionality limit
• OB is Elastic limit but OB is
Non linear
• The slippage of the carbon
atom within a molecular
mass leads to drop down of
stress marginally from C to C’
• C is upper yield point
• C’ is lower yield point (also
known as Yield Stress f y )
• For exp Fe-250 =>
f y =250N/mm 2
• C’D is constant stress region
called Yield Plateau
DE is Strain Hardening region,
material starts offering
resistance against deformation
• EF is Necking region where
drop down of stresses occur
upto Failure point
• Necking region exists only in
ductile material
• In mild steel, ABC are closer to
each other, therefore it is
known as Linear Elastic Metal,
and Yield stress and elastic
stress is taken as 250N/mm 2
• The Fracture or Failure in mild
steel depends upon
Percentage of carbon present
in a steel
The strain at yield stress is
about 0.00125 or 0.125%
• CD represents plastic
Yielding i.e. it is the strain
which occurs after the
yield point with no
increase in stress
• The strain at point D is
about 0.015 or 1.5%
• The strain in the range CD
lies between 10 to 15
times the strain at yield
point
Ultrasonic Pulse Velocity NDT on concrete
Ultrasonic Pulse Velocity Non Destructive Test
Non Destructive Tests
2. Ultrasonic Pulse velocity test
• This test deals with the measurement of
time of travel of electronically generated
mechanical pulse through the structure
to be tested that is further used to
analyse its quality.
• The mechanical pulse is generated with
the help of Electro Acoustic Transducers
and detected with the help of
Transmitter that is further used to
analyse the time of travel and the
velocity of pulse through the structure so
as to represent the quality of structure.
Slump and Compaction Factor Test
Slump and Compaction Factor Test
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| Slump and Compaction Factor Test |
1. Slump Test:
• Most common method
• Frustum having top diameter 10cm, bottom
dimension around 20 cm, height of 30 cm
• Concrete to be tested in filled in the mould
in four layers where each layer is
compacted 25 no of times with the help of
rod
• Mould is removed immediately by lifting it
in upward direction which causes the
concrete to subsidize and the subsidence of
the concrete is referred as slump which may
also defined as difference of the height of
the mould and the top level of the subsidize
concrete.
Higher the value of Slump, more is the
workability
• This test is not suitable for the concrete which
process either very high workability or very low
workability.
• It is not a suitable method for very wet or very
dry concrete
• If the concrete slumps evenly it is called true
slump.
• If one half of the cone slides down, it is called
shear slump.
• In case of a shear slump, the slump value is
measured as the difference in height between
the height of the mould and the average value
of the subsidence. Shear slump also indicates
that the concrete is non-cohesive and shows the
characteristic of segregation
2. Compaction Factor Test:
• It is more precise and sensitive than slump test
• This test is used for the concrete possessing
medium and low workability for which slump
test is not suitable.
• Principle of this test is based upon finding the
degree of compaction achieved by the standard
amount of work done by the concrete when
allowed to fall from known height
• This degree of compaction is represented in
terms of compaction factor that represents the
density ratio : Density of concrete obtained
during test to the Density of fully compacted
concrete
Compacting Factor=
Weight of partially compacted concrete/
Weight of fully compacted concrete
Failure of Plates: Riveted Joint
Failure of Plates: Riveted Joint
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| Failure of Plates: riveted Joint |
Non-Newtonian Fluid Examples - Dilatent, Bingham Plastic, Pseudoplastic, Thixotropic, Rheopectic
Non-Newtonian Fluid Examples - Dilatent, Bingham Plastic, Pseudoplastic, Thixotropic, Rheopectic
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| Non-Newtonian Fluid |
The Great Wall of China: A Monumental Feat of Ancient Engineering
Here's another captivating fact about civil engineering:
"The Great Wall of China: A Monumental Feat of Ancient Engineering"
Stretching over 13,000 miles (21,000 kilometers) across rugged terrain, the Great Wall of China stands as one of the most impressive architectural achievements in human history. Built over centuries by successive dynasties, this colossal structure is a testament to the ingenuity, determination, and craftsmanship of ancient Chinese civil engineers.
Constructed primarily as a defensive fortification to protect against invasions from nomadic tribes to the north, such as the Mongols and Xiongnu, the Great Wall comprises a series of walls, fortifications, and watchtowers, strategically positioned along China's northern border.
The construction of the Great Wall began as early as the 7th century BCE, during the Warring States period, and continued for over two millennia, with various dynasties adding to and reinforcing its structure. The most famous sections of the wall were built during the Ming Dynasty (1368-1644 CE), using bricks and stone blocks bonded together with a mixture of lime and sticky rice paste, known as "Chinese concrete."
One of the most remarkable aspects of the Great Wall's construction is the sheer scale and complexity of the project. Built across diverse geographical features, including mountains, deserts, and plains, the wall required innovative engineering solutions to overcome formidable challenges.
Engineers employed a variety of construction techniques tailored to the specific terrain they encountered. In mountainous regions, where the terrain was rugged and uneven, workers carved stone blocks from quarries and used them to build retaining walls and steps, creating a series of terraces that followed the natural contours of the land. In flat plains, where materials were abundant, rammed earth and tamped soil techniques were utilized to build long stretches of wall quickly and efficiently.
Despite its impressive size, the Great Wall was not just a physical barrier; it also served as a sophisticated communication network, with signal towers and beacon fires used to relay messages and warnings across vast distances. Additionally, the wall facilitated trade and transportation along the Silk Road, further enhancing its strategic importance in Chinese history.
Today, the Great Wall of China stands as a symbol of China's rich cultural heritage and a testament to the enduring legacy of ancient engineering marvels. Its awe-inspiring presence continues to attract millions of visitors from around the world, inspiring wonder and admiration for the ingenuity of the engineers and laborers who built it brick by brick over millennia.
let's dive into some fascinating structural details of the Great Wall of China:
1. Mortarless Construction:
In many sections of the Great Wall, particularly those built during the Qin Dynasty (221-206 BCE), the stones were stacked together without mortar. Instead, the builders relied on precise craftsmanship and interlocking techniques to create a sturdy and resilient structure. This technique, known as "dry stone masonry," allowed the wall to flex and adapt to changes in temperature and seismic activity without compromising its integrity.
2. Winding Design:
Contrary to popular belief, the Great Wall is not a straight line but rather a series of interconnected walls with various twists and turns. This winding design served multiple purposes: it followed the natural contours of the terrain, making construction easier and reducing the need for extensive earthmoving; it allowed defenders to take advantage of natural defensive features such as cliffs and valleys; and it provided better visibility for sentries stationed along the wall, allowing them to spot potential threats from a distance.
3. Optimized Defensive Features:
The Great Wall was more than just a physical barrier; it was a highly sophisticated defensive system designed to deter invaders and facilitate rapid communication and mobilization. Along its length, engineers incorporated a range of defensive features, including battlements, parapets, and watchtowers. The battlements provided cover for archers and allowed defenders to rain down arrows on approaching enemies, while the watchtowers served as lookout posts and signal stations, enabling rapid communication across vast distances using smoke signals or beacon fires.
4. Strategic Passes and Gates:
Throughout the Great Wall, strategically located passes and gates served as key chokepoints where defensive forces could concentrate their efforts and repel enemy attacks. These passes were fortified with additional walls, watchtowers, and defensive structures, making them formidable obstacles for would-be invaders. Famous passes such as Jiayu Pass and Shanhaiguan Pass were meticulously engineered to control access to vital trade routes and protect China's heartland from incursions.
5. Integration with Natural Features:
One of the most remarkable aspects of the Great Wall's design is its seamless integration with the surrounding landscape. Rather than imposing itself upon the environment, the wall harmonizes with the natural topography, blending into mountains, cliffs, and ridges. In some sections, the wall follows the contours of the land so precisely that it appears to be an extension of the natural rock formations, enhancing its camouflage and defensive capabilities.
These extraordinary structural details highlight the ingenuity and foresight of the engineers and laborers who built the Great Wall of China, transforming it into an enduring symbol of human achievement and resilience.
These extraordinary structural details highlight the ingenuity and foresight of the engineers and laborers who built the Great Wall of China, transforming it into an enduring symbol of human achievement and resilience.
Lost Cities Beneath Our Feet: The Hidden World of Subterranean Civilizations
Another captivating tale from the world of civil engineering:
Lost Cities Beneath Our Feet: The Hidden World of Subterranean Civilizations
Beneath the bustling streets and modern skyscrapers of some of the world's oldest cities lie hidden treasures of ancient civilizations, waiting to be unearthed by intrepid archaeologists and engineers.
In cities like Rome, Istanbul, and Cairo, layers upon layers of history have accumulated over millennia, with each generation building atop the ruins of its predecessors. But beneath this urban landscape lies a secret world of forgotten cities, tunnels, and infrastructure dating back centuries, if not millennia.
Take Istanbul, for example. Formerly known as Constantinople and Byzantium, this historic city has been inhabited for over 3,000 years. Beneath its streets lie a labyrinth of ancient cisterns, tunnels, and even entire underground cities, such as the vast network of passages beneath the district of Sultanahmet. These underground marvels served various purposes throughout history, from providing water storage and transportation routes to serving as shelters during times of war.
Similarly, in Rome, the ancient city of Aqueducts lies hidden beneath the modern metropolis. These monumental structures, built by the ancient Romans to transport water from distant sources to the city, showcase the ingenuity and engineering prowess of ancient civilizations.
Even more astounding are the subterranean cities of Cappadocia in Turkey. Carved into the soft volcanic rock, these underground complexes housed entire communities, complete with living quarters, churches, and storage facilities. Some of these underground cities could accommodate thousands of people and were used as refuge during invasions and raids.
The exploration and preservation of these underground marvels pose unique challenges for archaeologists and engineers. Excavating and studying these ancient sites require meticulous planning and cutting-edge technology to ensure their preservation while unraveling the mysteries of the past.
The hidden world beneath our feet serves as a reminder of the resilience and innovation of past civilizations and offers a glimpse into the rich tapestry of human history waiting to be discovered beneath the surface of our modern cities.
The Chilling Secret Behind the Hoover Dam: How Engineers Beat the Desert Heat to Build an Icon
A fascinating fact about civil engineering that might capture your interest:
Did you know that the construction of the Hoover Dam in the United States required an ingenious engineering feat to control the temperature of the concrete during its curing process?
The Hoover Dam, completed in 1936, is an iconic example of civil engineering prowess. Spanning the Colorado River between Arizona and Nevada, this massive concrete arch-gravity dam stands 726 feet tall and was built to provide water storage, flood control, and hydroelectric power generation.
One of the biggest challenges faced during the construction of the Hoover Dam was the scorching desert heat of the Mojave Desert, where temperatures often soared well above 100°F (38°C). Such extreme temperatures posed a significant risk to the integrity of the concrete used in the dam's construction. Rapid drying of concrete in high temperatures can lead to cracking and weakening of the structure, jeopardizing its stability and longevity.
To address this challenge, engineers employed a groundbreaking technique known as "cooling pipes" or "cooling galleries." These were an intricate network of steel pipes embedded within the concrete blocks as they were poured. These pipes carried chilled water from the nearby Colorado River, circulating it throughout the concrete structure, effectively dissipating the heat generated by the curing process.
Here's where it gets truly fascinating: the engineers strategically placed over 582 miles (937 kilometers) of cooling pipes within the dam's concrete structure. These pipes were laid in a precise grid pattern, ensuring uniform cooling throughout the entire mass of concrete. The chilled water circulated continuously through these pipes, maintaining the temperature of the concrete within an optimal range and preventing excessive heat buildup.
This innovative cooling system allowed the Hoover Dam to be constructed efficiently and safely, despite the blistering desert conditions. Without it, the concrete would have been prone to thermal cracking, compromising the structural integrity of the dam and delaying its completion.
The success of the cooling pipe system used in the construction of the Hoover Dam not only revolutionized concrete construction techniques but also set a precedent for the development of similar strategies in subsequent large-scale infrastructure projects around the world. It stands as a testament to the ingenuity and resourcefulness of civil engineers in overcoming formidable challenges to create enduring marvels of engineering.
