Suspension Bridges: How are They Constructed

Poyab Bridge under construction, Freiburg, Switzerland
Poyab Bridge under construction, Fribourg, Switzerland. Photo: iStock

Suspension bridges are among the most impressive engineering feats, with their long spans and elegant designs. These bridges rely on the strength of cables and towers to support the cables which provide safe passage over rivers, gorges, and other obstacles.

In this article, we will explore how suspension bridges are constructed.

Bridge Suspension Cables

Cables on Royal George Bridge - Colorado
Suspension Cable on Royal George Bridge – Colorado. Each cable is made up of 2100 galvanized steel wires. Photo: ©SMS

Once the towers are in place, the cables can be installed. The cables are assembled on the ground and then lifted into place using cranes or other heavy machinery. The cables are anchored to the towers using large steel plates, which are bolted to the tower and embedded in the concrete foundation. The cables are also anchored to the ground using massive concrete blocks, which are buried deep below the surface of the earth to provide a secure anchor point.

Suspension cables are an essential part of the suspension bridge design, which hold up the load (bridge deck or road) and are braced by towers on each side of the bridge. Anchoring the cables to the towers, or sometimes to the ground on both sides, enables the load to stretch across the entire span of the bridge without any further bracing required (e.g. truss or arches holding it up).

The cables are typically made of high-strength steel wires woven together that act as one unit. These cables can weigh thousands of tons and must be anchored securely to the towers and the ground.

The tension in the main cables is transferred to the suspension cables, which then transfer the weight of the bridge deck to the towers and anchorages at the ends of the bridge.

The towers provide additional support to the bridge and help to distribute the weight of the bridge evenly.

In the photo above of the Royal Gorge Bridge in the Rocky Mountains, Colorado, each of the cables consists of 2100 galvanized steel wires.

Bridge Deck

With the cables in place, the next step is to construct the bridge deck. The deck is typically made of steel or reinforced concrete and is suspended from the cables using hangers. The hangers are attached to the cables using large steel pins and are spaced at regular intervals to provide support for the deck. The deck is often assembled on the ground and then lifted into place using cranes or other heavy machinery.

Once the deck is in place, the final touches can be added. This includes the installation of guardrails, lighting, and other safety features, as well as the application of the final coat of paint. The bridge is then inspected to ensure that it meets all safety standards and is ready for use.

Summary

In conclusion, suspension bridges are an incredible feat of engineering, requiring meticulous planning, precision construction, and rigorous safety testing. The construction process involves the careful placement of towers, the installation of massive cables, and the suspension of the bridge deck. Despite the challenges involved, suspension bridges have become an iconic symbol of human ingenuity and technological advancement, connecting people and places all over the world.

The Impact of Climate Change and What We Can Do About It

Illustration of the effects of climate change, showing grass and then barren ground
Photo: iStock

Climate Change Overview

Climate change is one of the most pressing issues facing our planet today, and its significance cannot be overstated. It is a global problem that affects every aspect of our lives, from the environment to the economy, and if left unchecked, it has the potential to cause devastating consequences

In this essay, we will explore why climate change is so important and why urgent action is necessary to mitigate its effects.

The Environment

Oil Rig
Photo: Wikipedia CC

First and foremost, climate change also referred to as ‘global warming’, poses a major threat to our ecosystem. The Earth’s climate is a complex entity, and any changes to it can have far-reaching consequences.

The continuous rise in greenhouse emissions such as pollutants from cars, planes and industrial complexes is what is causing temperatures to rise. 

For example, these rising temperatures and changing rainfall patterns can lead to more frequent natural disasters such as hurricanes, floods, and droughts. These weather events can destroy homes and infrastructure.

The temperature has risen about 1.8 degrees F (1 C) over the last century, but most of this rise has occurred within the last four decades.

If this small rise in temperature doesn’t sound significant, it is and has already caused numerous issues across the globe. 

The natural disasters that are occurring because of this can also lead to a significant economic burden, as governments and individuals would be forced to spend billions of dollars to rebuild damaged infrastructure and homes, as discussed later in this article.

Upsetting the Balance of Nature

Koi fish
Photo: Pexels

Wildlife will not be immune to this changing environment. As temperatures rise, it is becoming increasingly difficult for some animals to adapt.

Some species could become endangered or even go extinct, and even now, polar bears are struggling to find food as the Arctic ice melts, and coral reefs are dying due to rising ocean temperatures. 

The potential results can have problematic effects on our crops and argriculture. Crop failures will lead to increased food prices and potential famine in certain parts of the world. Disruption in supply chains can lead to food and water shortages.

A negative change in the climate will also cause sea levels to rise, which can lead to flooding and erosion of coastlines, further exacerbating the damage caused by natural disasters. 

The Human Effect

Amazed Woman
Photo by Sincerely Media on Unsplash

Climate change can have a significant impact on our health. As temperatures rise, so does the risk of heat-related illnesses such as heat stroke and dehydration.

Increased air pollution due to industrialization and deforestation can result in respiratory problems, heart disease, and even cancer. It can also lead to the spread of diseases such as malaria and dengue fever, as warmer temperatures create more favorable conditions for disease-carrying insects to proprogate and spread to new regions.

Poor air quality resulting from increased pollution can exacerbate the situation as well. Respiratory problems such as asthma may be more commonplace and can also increase the risk of heart disease and stroke.

These health issues will disproportionately affect vulnerable populations, such as children, the elderly, and people with a pre-existing medical conditions. In populated communities, such as large cities, they can increase exponentially.

The Economy

As extreme weather events become more frequent, there is an increasing risk of damage to infrastructure, such as buildings, roads, and bridges. In addition, its impact on prices for food will be detrimental across the world.  Building sea walls and other protective infrastructure, is likely to be more common and subsequently very costly.

Is There Light At the End of the Climate Tunnel?

Offshore Wind Turbines
Digital Illustration of an offshore Wind Turbine

The transition to a low-carbon economy can create economic opportunities, such as the development of renewable energy sources and the creation of green jobs. ant economic issue. The effects of climate change can disrupt agriculture, leading to lower crop yields and higher food prices. This can have a disproportionate impact on low-income countries, where agriculture is a significant part of the economy. 

Given the significant impacts of climate change on the environment, human health, and the economy, we must take action to address this problem. The good news is that there are many things that individuals, governments, and businesses can do to mitigate the effects of climate change.

 

 

 

 

 

 

The Nike Missile System

Introduction

Nike Missile Sandy Hook NJ
Nike Missile Museum, Sandy Hook, NJ. Photo: ©SMS

A fairly unknown army base lies in a little peninsula on the north shore of New Jersey. It is not in use now but once was a thriving anti-missile installation where soldiers would be on alert for enemy missiles and planes heading towards New York City.

The Cold Days

It was the Cold War and enemy nations, namely the Soviet Union were working tirelessly towards advancements in jet planes and ballistic missile production. Given this, the United States established anti-aircraft systems across the country. They were strategically deployed around the major cities to combat this potential threat.

Due to the accelerated research and development that was occurring, missile technology took a giant leap forward. Additionally, the fear of Russian Bear Bombers entering American airspace was becoming more imminent than the threat of German or Japanese aircraft entering the United States after Pearl Harbor.

The Nike Missile System

Nike Missile, American Air Power Museum, Farmingdale , NY
Nike Missile, American Air Power Museum, Farmingdale, NY. Photo: ©SMS

Beginning in 1954, Nike Missiles replaced the gun batteries located across the United States. These were supersonic (Marc 2.25) command guidance systems and solid rocket booster missiles. They were designed to intercept long-range Soviet bombers and destroy them while still over the ocean. 

Soldiers stationed at these sites were on 24-hour turnaround shifts and lived in ready-made barracks. Examples of Nike Missile battery sites were Fort Tilden and Fort Hancock, New York, which had a Missile Launch Area (the radar area), AKA, the Integrated Fire Control Area (IFC). 

The sites had two missile batteries, known as double battery sites, and subsequently, each battery had two underground storage rooms for a total of four magazines at each site.

A missile magazine is the hardened storage barrier where the missile lies when inactive. Rooms accompanied the magazines; each had an elevator unit that raised and lowered the missiles.

Enter Ajax and Hercules

The Ajax was the first Nike Missile deployed. It was designed to destroy aircraft from 30 miles away. By 1958, a new, more advanced rocket replaced the Ajax, called the Hercules, which had a range of over 96 miles and was designed to carry a nuclear warhead.

Unbeknownst to the general public, there were close to 250 Nike missile bases across the United States and more located in Europe. The New York City area contained one of the largest networks of anti-aircraft Nike batteries, with over 20 sites circling the city in New York State and New Jersey.

From Missile Defense to Missile Offense

Cold War

NORAD Command Center Cheyenne Mountain Colorado
NORAD Command Center Cheyenne Mountain Colorado. Photo: Wikimedia US Gov. Public Domain

Building anti-missile bases was just one aspect of the country’s overall defense. In 1958 the North American Air Defense Command –  NORAD, (now called the North American Aerospace Defense Command) was commissioned.

Its origins trace back to World War II when the US and Canada began cooperating in air defense against the Soviet bomber threat.

In 1956, the two countries proposed to form an air defense system, and two years later, the joint Canada-US Military Study Group recommended more radar networks.

General Earle E. Partridge, the commander in chief of the newly formed joint US Command, Continental AirDefense Command (CONAD), directed another study of North American defense, which eventually led to the establishment of a combined air defense organization (NORAD) under a single commander,

The Ending of the Cold War

Defense

The takedown of the Berlin Wall marked the beginning of the end of the Cold War and resulted in the United States becoming the only superpower left.

Nike missiles were part of the U.S. Army Air Defense Command (ARADCOM), and in agreement with the SALT treaty, all missiles were decommissioned and removed in 1974; however, a few remain. The Sandy Hook, New Jersey, (NY-56) site is one of those Nike missile batteries that are currently open to the public.

NORAD’s mission remains however, and it now provides aerospace warnings for North America, which includes the monitoring of man-made objects in space, and the detection, validation, and warning of attack against North America whether by aircraft, missiles, or space vehicles.

Offense

The removal of the Nike missiles was not the end of missile deployment. It was only the beginning. After they were removed, a new, much more powerful rocket – the Intercontinental Ballistic Missile or ICBM, was deployed on both sides of the Atlantic, and still exists today.

These missiles are not anti-aircraft designed for defense, but take on an offensive posture following the Cold War strategy – A good defense is a good offense, or as some call it, “Peace Through Strength”.

2023 Update

Given the recent events following the surveillance balloon from China and its intrusion into US airspace, NORAD has modified its sensory equipment to detect smaller objects such as balloons.

What the Future Holds

No one can say for sure where this world is heading, but given the war in Ukraine, China’s threat to take over Taiwan, and Iran’s passion to build a nuclear weapon, it is essential that NORAD remains in existence and possibly a reevaluation of this nations air defense might be prudent.

 

The Iconic Chrysler Building

Overview

Chrysler Building form 42nd Street
Photo: ©SMS

Still the tallest brick building in the world and currently, the 11th tallest building in NYC, the Chrysler Building has been noted as one of the most graceful art-deco buildings ever built, the 1,046-foot (319 meters) skyscraper adorns the New York skyline with its silver spire, eagles, and scary gargoyles. 

Constructed by Chrysler Car Corporation, the building was designed to reflect the automotive industry with a decorated granite lobby, a showroom for the latest Chrysler cars, and its hood ornaments enriching the building’s exterior which is designed to resemble radiator caps.

Architect William Van Alen designed this masterpiece. 

Location

New York City donated the land between 42nd and 43rd streets and Lexington Ave to The Cooper Union school in 1902 before the Chrysler Corporation took it over in the 1920s. 

Located just west was the Grand Hyatt Building, now being demolished to make way for the supertall 175 Park Avenue, which wasn’t without controversy since many feel it will block the skyline view of the Chrysler from the west side. 

The Design

Close up collage of the Chrysler Building
Radiator caps on the Chrysler Building’ Photo: ©SMS

The Chrysler Building is laminated with Nirosta stainless steel, which is a metallic alloy of 18% chromium and 8% nickel, but contrary to popular opinion, the structure does not have scary gargoyles.

Starting on the 31st floor, we see radiator caps, relative to the year the building was constructed, and embellished, and then, moving up to the 61st floor, we find silver eagles, representing the official bird of the United States.

The eagles that some do call gargoyles are made of stainless steel and are approximately 20 feet tall, including the pedestal they stand on. They were designed to be both decorative and functional, serving as lightning rods to protect the building from strikes.

There are a total of 50 ornaments in all that adorn the Chrysler Building. The skyscraper contains 3,826,000 bricks a total of 3,862 windows.

Engineering

The Chrysler Building does not have gargoyles. Instead, it features eagle head sculptures called “Eagle Gargoyles” or “Eagle Finials” on the corners of the 61st floor. These sculptures were designed by American sculptor William Van Alen, who also designed the rest of the building’s decorative elements.

The eagle gargoyles are made of stainless steel and measure approximately 20 feet tall, including the pedestal they stand on. They were designed to be both decorative and functional, serving as lightning rods to protect the building from strikes.

The building has a solid core that stabilizes the structure and setbacks that help deviate wind forces.

Spire War

Top of Chrysler Building Includig Spire
Top of Chrysler Building Including Spire. Image by Pexels from Pixabay

During its construction, the building was in the midst of a battle with Lower Manhattan’s Bank of Manhattan at 40 Wall Street (now owned by Donald Trump) regarding who would have the tallest building in the world. 

The Chrysler Building was rising four floors a day and in 1929, both buildings reached 925 feet, but 40 Wall’s architect H. Craig Severance added two more feet to the top of his building, laying claim that it is now the world’s tallest building.

This distinction lasted briefly as William Van Alen secretly built a seven-story, twenty-seven-ton spire inside the Chrysler Building. Just a few weeks after the Bank of Manhattan claimed its fame, Van Allen lifted the spire through the roof of the Chrysler Building, and within 1½ hours, it became the world’s tallest, soaring 77 stories and 1,046 feet high (319 meters), beating the Bank of Manhattan by 119 feet. 

It wasn’t long before the Chrysler Building would lose its status though, as the Empire State Building topped it out only one year later in 1931. 

The Observatory

Back in the day, there was a speakeasy on the 66th, 67th, and 68th floors called the Cloud Club and there was an observatory, but for over 60 years, this has not been the case. That will all change soon. In 2020, the Landmarks Preservation Commission approved rebuilding a new observatory on the 61st floor, right alongside the eagle ornaments. 

Construction has not started yet but you can sign up for it and be notified when the observatory becomes a reality.

Chrysler’s Beauty Endures

No matter what skyscrapers might encircle it, nothing will keep the building’s brilliant art-deco stainless steel design and its majestic spire from decorating the City of New York skyline. Many consider the Chrysler Building to be the most beautiful in the city.

 

Potential Life-Sustaining Planets are Closer and Closer

SMACS 0723A galaxy cluster
Infrared light shows the deepest view of distant galaxies ever photographed. JWST Photo: NASA Public Domain

Overview 

The question of extraterrestrial life on other worlds has baffled even the foremost scientists for millennia. With the Hubble telescope and now, the James Webb telescope floating in the cosmos a million miles from Earth, we are finding more and more life-sustaining planets on a frequent virtual basis.

This is different from space observatories being able to determine the existence of exoplanets by spectrum analysis, calculating their gravitational pull from their sun, or by use of the transit methodan observational process whereby a star changes in brightness when a planet is seen orbiting around it. The JWST advanced technology surpassed those methods by actually taking pictures of these exoplanets. This is the first time this has ever been done! 

Exoplanets with Life? Maybe!

In 2013, a team of astronomers led by Dr. Duncan Wright from the University of New South Wales discovered the Wolf 1061 System, using the HARPS spectrograph, part of the European Southern Observatory’s telescope in La Salla in Chile. 

This solar system contains an inactive red dwarf star, orbited by possibly seven planets including three super-Earths. These planets may be capable of supporting life as we know it, as they have a low enough mass to be potentially rocky with a solid surface. 

The most interesting of the three planets is Wolf 1061c. At four times the size of the Earth, it is the closest habitable planet outside our solar system. It also sits in the Goldilocks Zone, close enough to its sun to contain liquid water and support life with its mild temperatures. 

Artist's impression of the planetary system around Wolf 1061
Artist’s impression of the planetary system around Wolf 1061. Photo: Wikipedia Public Domain

Even though rocky planets similar to our own and multi-planet systems are known to be abundant in our galaxy, most of the ones discovered are hundreds, if not thousands of light years away. They are too far for us to get to using current technology.

Still, with the hope of Wolf 1061c sitting right next door, scientists are now hopeful that they can test the planet’s atmosphere in more detail once it passes across the face of its star, making the not-so-lone Wolf planet easier to study and determine if it has the potential to sustain life.

Life is Out There

Illustration of an extraterrestrial
Photo: iStock

Here we list a sampling of just a few exoplanets that could sustain life. 

WASP-39 b

In 2022, the James Webb Telescope discovered a planet, called WASP-39 b in the Virgo constellation. Known as ‘Bocaprins’, the planet orbits a star about 700 light-years from Earth. Scientists were surprised to see that this planet’s atomic structure resembles water and carbon – two of the essential ingredients of universal life.

Kepler-186f

But that’s not all. Planets such as Kepler-186f are one of the planets that astronomers say have a very good chance of potential life, relative to the hundreds of other planets discovered outside of our solar system. Kepler-186f is the first exoplanet found to be in the habitable zone. Slightly larger than Earth, it is 490 light-years away. That’s not too far comparatively speaking.

Kepler-22b

Another close neighbor in the habitable zone is Kepler-22b. This body is about 150 light-years further away than Kepler-186 but has the promise of life just the same. It is about 15% closer to its sun than our Earth is to our sun, but its sun is smaller than ours, so there is a compensation effect where these two factors cancel each other out. 

Subsequently, it still provides the opportunity for the planet to remain in the habitable zone. Kepler-22b has a surface temperature of 72℉. This sounds like a good vacation spot when we get to that point of space travel. For Star Trek fans, you can envision the beautiful planets the crew visited when on shore leave. Well, not so fast.

Kepler-22b might be more on its axis than Earth, meaning half of the planet may have all sunlight 24×7 and the other half may be in complete darkness for every (of that) planet’s six months. Further study has revealed that the planet may be 90% ocean or more; thereby compensating for the seasonal issues. 

Additionally, Kepler-22b has been calculated to have a much stronger gravitational pull than our planet, so walking on this planet may be as hard as trying to walk briskly through water at the same speed that you would be walking on land. 

But if there are creatures on this planet, intelligent or not, natural evolution may cause these beings to look much different from us. Due to the planet’s strong gravitational pull, the aliens may have budging feet full of muscles that would make the strongest man in the world look like a stick figure. They may have more than just two or four legs. Additionally, their internal organs would have to be naturally engineered to handle the physical stresses of the planet’s strong gravity; such as an overly large heart.

The Day the Earth May Stand Still 

If Kepler-22b is life sustainable, it would take astronauts 635 years to get there. So since that is out of the question for us, but if there is intelligent life there or on other planets, their technology might provide a quicker way to come here and visit us. But is that what we would want?  

The Freedom Tower – From Construction to Completion

Overview

One World Trade Center - Freedom Tower photographed from Broadway
One World Trade Center – Freedom Tower looking south from Broadway. Photo: SMS Photos of a Lifetime ©

From tragedy to triumph, a tower soars 104 stories, 1,776 feet high, representing the year the Declaration of Independence was signed.

One World Trade Center (AKA The Freedom Tower) opened to businesses on November 3, 2014, and the three-story observatory, which opened on May 29, 2015, invites visitors to a spectacular view of the New York skyline.

Skidmore, Owings & Merrill, famous for designing some of the most notable modern tall buildings in the world, were the primary architects, under the supervision of designer David Childs. The firm, also known as SOM, was the architect of the Burj Khalifa and Chicago’s Willis Tower (formerly the Sears Tower).

The Preliminaries

Soon after the destruction of the original World Trade Center, the Lower Manhattan Development Corporation initiated proposals for the reconstruction of a new tower, as well as a plan to memorialize the victims of the September 11 attacks. 

When the public rejected the first round of designs, a second, more open competition took place in December 2002, in which a blueprint by Daniel Libeskind was selected as the winner. This design went through many revisions, mainly because of disagreements with developer Larry Silverstein, who held the lease to the World Trade Center at that time.

Construction began on April 27, 2006, but not after continuous delays and ongoing bureaucracy, including disputes between the Port Authority of New York and New Jersey and the developer Tishman Realty & Construction. The Tishman construction firm was famous for its participation in building some of the tallest buildings in New York City, including the original World Trade Center complex and the John Hancock Center in Chicago. John Tishman died on February 6, 2016.

Security Preparations

Bird's eye view of "ground zero" after the 9/11 attacks and before construction of the Freedom Tower
Bird’s eye view of “ground zero” after the 9/11 attacks and before the construction of the Freedom Tower. Photo: SMS – Photos of a Lifetime ©

No doubt that security was a prominent concern in the design and construction of this tower, and terrorism was indeed a major consideration. 

No one was more concerned than the NYPD, and after many debates and delays, the final proposal for the Freedom Tower 11-Year was approved and shown to the public on June 28, 2005, with a 187-foot base of concrete added.

Additionally, the building had installed stainless steel panels and blast-resistant glass. The Freedom Tower is designed to withstand earthquakes and has an elaborate security facility integrated within it.

In addition to 24×7 monitoring, there is a high-tech security system that includes video analysis in which computers would alert security personnel to abnormal situations automatically.

There are additional security apparatuses that have been installed, but their actual function has not been made public. What is known is that there are radiation detectors abound in lower Manhattan and the NYPD Hercules Team is ready at a moment’s notice.

Building the Skyscraper

Foundation of One World Trade Center
Construction of the foundation of One World Trade Center. Photo:  SMS – Photos of a Lifetime ©

On November 18, 2006, 400 cubic yards of concrete were poured onto the building’s foundation.

On December 17, 2006, a ceremony was held in Battery Park City, with the public invited to sign a 30-foot (9.1 m) steel beam. The beam was welded onto the building’s base on December 19, 2006. Construction was slow but continuous. 

In 2012, workers installed the steel framework at the top of the tower to support the 408-foot spire. The spire was fabricated as 16 separate sections at a factory near Montreal, Quebec, and was transported by barge to New York City in mid-November of that year. 

On May 10, 2013, the final component of the skyscraper’s spire was installed, making the building, including its spire, reach a total height of 1,776 feet, representing the date of the Declaration of Independence.

Negotiating the Wind Forces

Optimizing One  World Trade Center for high winds was unique as the tower’s design included a geometrical shape that helps reduce exposure to wind loads.

Additionally, the core has reinforced concrete which provides the main support against resistance to the wind forces and other forces of nature.

The Observatory

View from Freedom Tower Observatory
View from Freedom Tower Observatory of downtown Manhattan taken on opening day. Photo:  SMS – Photos of a Lifetime ©

The One World Trade Center observatory opened on May 29, 2015, and is currently the highest of the four observatories in the city at  1,268 feet.

There are three floors, including exhibits and a restaurant.

The most convenient way to purchase tickets would be to purchase them online.

 

Surrounding Area

World Trade Cener North Tower Reflecting Pool
World Trade Center North Tower Reflecting Pool. Photo: Wikimedia Public Domain

Visitors who come to the Freedom Tower should also visit the 911 Memorial, which is a tribute to the 3,000 people who were lost, including the first responders.

The memorial contains the footprints of the former Twin Towers. It has continuous running water over two one-acre pools, one for each of the towers, called “Reflecting Absence“, signifying the physical void left by those who were lost. 

Skyscraper Wind Forces and How to Overwide Them

NYC Midtown Skyline Western View
NYC Skyline Looking West from Long Island City. Photo: Photos of a Lifetime ©

Overview

Skyscrapers are defined as being at least 330 feet (100 meters) high with supertalls classified as 984 feet (300 meters) and mega tall at 1,968 feet (600 meters) or higher.

From the Burj Khalifa in Dubai to the Shanghai Tower in China and the Empire State Building in New York, there is no doubt that these structures are a marvel of modern engineering and they stand as a testament to human ingenuity and perseverance. For architects and engineers, the challenge to design them is complex.

From the foundation to the roof, they are carefully planned and executed by scivi engineers, which might take years to complete before even one brick is laid down. Considerations towards building codes, structural stability, aesthetics, and of course economics are primary factors to be studied.

Exploring the making of skyscrapers is an exciting journey for anyone interested in how tall buildings are constructed. This article is a credit to the dedication to the architects and engineers who build them.

Enter the Forces of Nature

Burj Khalifa
Burj Khalifa, Dubai, UAE – Tallest Building in the World. Photo by Wael Hneini on Unsplash

Wind loads (wind forces) that hit the buildings can cause them to sway. The higher the building is, the more wind it will be subject to.

Skyscrapers will sway and can easily move several feet in either direction.

To reinforce the structure to withstand these winds, there are several options that engineers will use.

 

Empire State Building – A Prime Example of Mitigating Wind Forces

Empire State Building
Photo by Ben Dumond on Unsplash

Before we delve into the engineering specifics, let’s get familiar with the general idea of how buildings suppress wind forces and what better example to use than the famous Empire State Building?

Most tall buildings use multiple methods to mitigate strong winds, so let’s take a look at what engineers have done with this 1,472-foot-high iconic structure.

  1. Streamlined shape: The building has a tapered shape that reduces wind resistance and helps to distribute wind forces evenly across the building. More commonly known as setbacks.
  2. Wind bracing: The building has a series of steel braces that run diagonally between the exterior columns, which helps to provide additional support and stability against wind forces.
  3. Corner columns: The building’s corner columns are larger and stronger than the interior columns, which helps to distribute wind forces more evenly throughout the building.
  4. Tuned mass damper: The building has a large pendulum-like device called a tuned mass damper located on the 58th floor. The damper helps to counteract wind-induced building oscillations by moving in the opposite direction of the building’s sway, effectively damping out the oscillations.

Now let’s take a look at the process from start to finish.

Designing the Structure 

3D rendering of a modern building with construction using CAD software
3D rendering with construction specifications using CAD software. Photo: iStock

Economics always comes into play, so whatever the planned design is, it must be within the developer’s budget. Architects use computer-aided design (CAD) software to create 3D models of a building.

Usually created on networked desktop computers, CAD is used primarily for analyzing and optimizing a building’s design.

Of course with skyscrapers, there may be hundreds of CAD diagrams that would be needed. The software includes the building codes that they must follow.

Building the Foundation 

Foundation of One World Trade Center
Foundation of One World Trade Center 4/6/2008. Photo: Photos of a Lifetime ©

It should go without saying that structural stability is of the utmost importance and the foundation is the first step in helping to buttress the building from the forces of nature to which these buildings may be subject. 

Beginning with the foundation, engineers must determine if the soil below the building is strong enough to support the structure. A good example is in New York City where there is solid bedrock that makes it perfect for the construction of skyscrapers. 

Rebar at construction site on Long Island
Rebar ready for pouring of concrete at a construction site. Photo SMS ©

Steel and concrete are the most commonly used materials for foundations. Concrete is strong under compression, but not as strong under tension, and in its pure form, it is unsuitable to withstand the stresses of the wind forces and vibrations,

To compensate for this lack of tensile strength, workers pour a liquid concrete mixture into a wire mesh steel frame, called rebar or reinforcing bar, which strengthens the tension component of the concrete. Together, the product is known as reinforced concrete and forms a strong solid foundation to support any tall building. 

Strong Internal Cores

One of the most popular methods for mitigating wind forces is the ability to build strong cores in the center of the building. Usually constructed around the elevators are solid steel and/or concrete trusses, braced by steel beams.

Most of the tall buildings of the 20th century use this method and it is still going strong into the 21st century, but usually, there are more obstacles to the wind added, especially if the building is of the super or mega tall variety.

Corner Softening

Taipei 101 in Tiawan China
Taipei 101 in Taiwan China uses corner softening to dampen the winds

This is a style that softens the edges of tall buildings to reduce the vortices (strong winds) that these structures are subject to.

The 1,667-foot Taipei 101 in Taiwan uses this method which is very effective in controlling high winds.

But that’s not all Taipei 101 uses against wind vortices as we will see below.

 

Setbacks

New York Telephone Building NYC 1926
Lower Manhattan’s NY Telephone Building was one of the first to employ the setback method. Photo: ©Joseph H. Sachs 1926

In 1916, due to the shadow effect that tall buildings would leave on the sidewalks of New York, specifically, the 555-foot tall Equitable Building that was completed a year before, a new zoning law was enacted that would force developers to apply setbacks to all tall buildings.

New York City’s Empire State Building and Chrysler Building are excellent examples of setback design, as well as examples of the esthetic beauty of the art deco structures of that time.

Not only were setbacks desirable but, from an engineering point of view, they helped to diminish the harsh winds that tall buildings were subjected to.

Twisting

Shangai Tower
Shanghai Tower (right). Photo by qi xna on Unsplash

Spiraling skyscrapers are becoming more popular. Not just for their aesthetic appeal, but also because of their ability to reduce wind vortexes by up to 24%.

For the Shangai Tower, this resulted in a reduction of $58 million that the developers did not have to add to buttress the building.

Even more, aesthetically pleasing is the 1,417-foot tall Diamond Tower in Jeddah, Saudi Arabia. If that’s not intriguing enough, there is the 1,273-foot Dubai Tower that not only twists but also rotates 360 degrees. Built by Italian/Israeli architect David Fisher of Dynamic Architecture, the building gives spectators and residents alike an ever-changing view of the Dubai skyline.

Tubular System

Willis Tower Chicago
Willis Tower in Chicago uses a tubular system to mitigate the wind. Photo: ©SMS

The Willis Tower in Chicago is an excellent example of a building that employs the tubular method for addressing wind forces.

This super tall consists of a collection of nine tubes supporting each other, subsequently buttressing the building to fight off the winds more than if it was just one straight up-and-down structure.

Additionally, since they level off at different heights, the wind forces are inherently disrupted.

 

Cutout

A less used method but efficient nonetheless. The wind is allowed to pass through specific areas of a building. which reduces the wind loads on the building. Below is an animation demonstrating how the building negotiates the wind forces using cutouts on various floors.

When employing the cutout wind method, other methods of wind optimization are used along with it.  New York’s 432 Park Ave makes use of this system. Additionally, the building uses the tuned mass damper system as described in the next section.

Tuned Mass Damper (TMD) (AKA harmonic absorber)

Damper illustration for Taipei 101
Tuned Mass Damper illustration for Taipei 101

Large, heavy dampers, usually near the top of the building compensate for building vibrations, such as high winds. Similar to a pendulum that sways back and forth, these dampers will move against the wind thereby stabilizing the building.

In technical terms, the mass damper is designed to work in harmony with the oscillation frequency of the building from the wind, thereby reducing the overall sway of the structure. 

Combination of the Above

Many times, a multiple of these strategies are used to tackle the vortices, and in so doing, they can be very effective in taming the wind. 

Constructing the Superstructure 

The superstructure is the actual building, more specifically, it is the framework that connects the foundation to the roof, and this is where the CAD model is pertinent. The CAD model will help to identify the best location for the support columns, known as the centroid

Engineers will select the most economical material and size of steel for these columns. They must also ensure that the columns are spaced far enough to resist both wind and potential seismic forces. Consideration will go into the type of concrete material and the size of the floor slabs, based on how much weight the slabs must support.

They must also consider the thickness of the slabs based on the amount of deflection allowed by the building codes, but we’ll leave the details of these considerations to another article that provides the specifics of these components.

Structural Engineering in a Nutshell

Watch this video which lays out the concepts of the engineering techniques required to build a tall building.

Summary

The engineering behind the making of skyscrapers is a complex and lengthy journey. When engineers design a supertall, they must consider many different aspects of the project. They must select materials that can withstand the forces of nature such as high winds, heavy precipitation, and even earthquakes.

They must also ensure that the building is structurally sound. In today’s skyscrapers, you can rest assured that the hard work and dedication that was put into each of these buildings by the architects, engineers, and construction workers make these buildings sound and secure. 

 

An In-depth Look at How Steam Engines Work and Their Impact on History

A steam powered locomotivec
Photo: iStock

‍Overview

The power of steam has had a significant impact on the history of humankind and the concept of how they work is fascinating. From the Industrial Revolution to the modern day, steam engines have been used to power the world in a variety of ways. 

In this article, we’ll take an in-depth look at how steam engines work and the impact they’ve had on history. We’ll explore the science behind how steam is generated and how its energy is used to power machines. 

We’ll also discuss the various applications, from powering locomotives to generating electricity. By the end of this article, you’ll have a comprehensive understanding of the science, history, and impact of steam engines.

History 

SS Savannah Hybrid Steamboat
SS Savannah. Half steamboat, half sailboat.

The first steam engines were used in the mid-17th century to pump water out of gold and silver mines. The first steam-powered ship, the SS Savannah was launched in 1819. However, it wasn’t until the mid-19th century that steam engines were widely used for industrial production. 

While the first steam-powered locomotive was built in 1829, it wasn’t until the 1850s that railroads began to widely use them. 

The Industrial Revolution was a time of incredible innovation and growth in the mid-19th century. The invention of the steam engine during this period greatly contributed to its growth. 

Many of the machines and products we use every day were first developed during this period. Engines powered by steam were used to power textile mills and other industries. They drove a variety of machines, from looms to cranes. They were used to power the bellows (furnaces) for forges. Forges were used to make swords, knives, agricultural tools, and many other metal products.

How Steam is Generated

Before we can discuss how steam engines work, we first need to understand how the energy source for these engines is produced. 

Boiling Point

Steam is the result of water being heated past its boiling point. When water is heated past 212° F (100°C), it turns into a gas, which is steam. The result is that the volume of steam (the amount of space that a substance or object occupies) is always greater than that of water; therefore, it will want to push its way out of the container if the container is not large enough to hold it.

This is why it is recommended not to place aerosol spray cans near heating sources. The spray is in liquid form but if it is near a heating source and the liquid starts to boil and turns into steam, there is a chance that the can will explode since the steam needs to expand. 

The mechanism for Boiling the Water

Boilers are what are used to boil the water into steam. There are several types of boilers, but they all have one thing in common: they are enclosed vessels that contain water.

Steam boilers are used to power a variety of machines. The most well-known application was to power locomotives. As we mentioned above, when water is converted into steam, the steam will push its way out and if this force of pressure is harnessed in a way that it can be regulated, it becomes a source of energy that can become very useful. 

In the steam engine, there are openings in the boiler to let the steam out, and when this steam comes out, it becomes a force pressure on which anything it touches will have an effect; in other words, if there is a wheel barrel next to where the steam is thrust out, it will propel the wheel barrel quite a distance.

Enter the Piston

Diagram of a piston
Steam enters the cylinder (red pipe) and pushes the piston down. Steam stops and the piston moves back up. This cycle repeats itself until the process is stopped. Animation: Wikimedia Public Domain.

If the steam is connected to a piston, which is a cylindrical body inside a container (noted in green), usually metal that slides down when a force hits it (in this case steam), it will move, and if another object is connected to the piston, (where the white hole is at the bottom) such as a wheel, the piston will then move the wheel. 

Now picture a row of pistons set up to move when the power of the steam hits on it, it can then move any number of wheels. 

Pistons have an additional feature and that is their ability to move back up to the top of their cylinder once the force of the steam stops, and if this process is regulated so that the steam comes out at regular intervals, the wheels that the pistons are connected to will keep on rolling.

This is how steam locomotives work, not to mention steamboats and machinery in factories as you will read further on.

Steam engines are also used to generate electricity in power plants. When it is generated in a boiler and then forced through a turbine, it spins a wheel, which is connected to a generator. This generates electrical energy via electromagnetism (the creation of electric current by spinning magnets).

Applications of Steam Engines 

Locomotives

Steam Locomotive
Photo by 44833 on Pixabay

Locomotives were all the rage in the 19th and early 20th centuries and it was the most common application of steam engines during the Industrial Revolution.

They were used to pull freight and passenger trains and were especially useful for transporting goods over long distances since they were much more efficient than horse-drawn wagons.

Additionally, these trains were able to climb steep hills. 

Ships

Many people think that steam engines came into widespread use on land, but they were also used to power ships. Ships were initially powered by wind and muscle power, but when the power of steam came along, they were used to power commercial ships in the early 1800s.

Steam engines were used in larger ships, such as steamships, which sailed between Europe and the United States. A perfect example is the Titanic. Although it came to a tragic end it was a giant and beautiful steamship that traveled across the Atlantic and powered everything from the kitchen cooking appliances to the giant pistons that moved the ship.

Automotive 

Steam engines are used to power automobiles in two ways. Some steam cars use a steam engine to power the wheels. Others use steam to generate electricity that can be used to power an electric motor. Steam cars have a long history dating back to the early 1900s. They were used throughout the 20th century until they were largely replaced by internal combustion engines.

Factories

Another common use was to power factories. They were used to mass-produce goods, and the engines were used to power the machinery that was used to produce goods, such as lathes, looms, and other industrial machinery.

Modern-Day Uses of Steam Engines

As we progress into the 21st century, the employment of steam is still being used for various purposes. They are often used in remote areas, such as deserts and mountains, where electrical grids are not available. In these areas, steam engines generate electricity.

Power Generation

Electrical power plants are no exception and there are still power grids in the US and around the world that use steam to generate electricity. The steam used in a power plant is usually generated by burning coal or natural gas, which then drives the pumps that transport water uphill. 

Conclusion

The impact of steam engines on history can’t be overstated. It is estimated that steam engines powered about 90% of the world’s industrial production around the start of the 20th century, which greatly contributed to the growth of many industries.

The textile industry, for instance, could not have grown to its current size without the use of steam. They were used to power the looms that were necessary for producing textiles on a large scale. Steam engines also helped transform the iron and steel industry. Before the invention of steam engines, the iron was produced in small forges. Once steam engines were used in forges, iron production could be carried out at larger scales. It also contributed to the growth of agriculture by powering irrigation systems.

 

 

 

Black Holes – Most Massive and Most Distant

Illustration of a black hole
Illustration of a Black Hole Photo: iStock. Elements of this image furnished by NASA.

Leave It Up to James Webb

In July 2023, astronomers discovered the most distant active supermassive black hole to date. This gravitational phenomenon is located in galaxy CEERS 1019, which is seen as it was when the universe was just 570 million years old. This is only 100 million years after the Big Bang, making it the earliest active supermassive black hole ever observed.

The Most Distant One – CEERS 1019

The black hole is also one of the least massive seen in the early universe, measuring the equivalent of about 9 million suns. This is much smaller than the supermassive black holes that are typically found in the centers of galaxies, which can weigh billions or even trillions of suns.

The discovery of this early black hole is baffling astronomers since it has been concluded that supermassive black holes form from the gravitational collapse of massive stars, but in this case, is not clear how a star could have formed so early in the universe and grown to be so massive in such a short time.

This raises questions about the evolution of galaxies. It is thought that supermassive black holes play a role in the formation and evolution of galaxies, but it is not clear how. The discovery of this black hole suggests that supermassive black holes may have been more common in the early universe than previously thought and that they may have played a more important role in the evolution of galaxies than we had realized.

Hopefully, it is a case where we have to back to the drawing board, but this black hole is definitely something where additional thought needs to be done where there may be other entities at work here that we just don’t know about – yet!

The Big One

Although the James Webb telescope is bringing never-before-seen wonders to our eyes, the famous Hubble is not without merit.

300 million light-years away at the heart of the Coma Cluster lies one of the largest black holes ever discovered. The Coma Cluster is a large collection of over 1,000 galaxies, which is quite amazing in its own right.

Of these thousands of galaxies is the elliptical supergiant NGC 4889, discovered in 1785 by the British astronomer Frederick William Herschel. 

NGC 4889 shines as the largest and brightest galaxy and its supermassive black hole is breaking all kinds of records. In comparison, the mass of the black hole at the center of our Milky Way galaxy is about four million times that of our Sun. The mass of the black hole at the center of NGC 4889 is around twenty-one billion times the mass of our Sun.

Early in its life, astronomers would classify the black hole as a quasar. A quasar is a massive and remote celestial object, releasing large amounts of energy. It is believed that quasars themselves contain massive black holes and are just a stage in the evolution of some galaxies.

At this time as a quasar, NGC 4889’s black hole was devouring all the stars, gas, and galactic dust in its path. This massive meal only fueled the black hole into forming an accretion disc that orbits the black hole and accelerates the black hole’s gravitational pull. The galactic dinner is heated up to millions of degrees and expelled around the black hole up to a thousand times the energy output of our own Milky Way. 

Once the supermassive black hole’s appetite was filled and the lavish meal finished, the black hole fell into a deep and dormant state that it is currently in. The environment of the surrounding galaxy is so peaceful that stars are forming from the remaining gas that’s calmly orbiting the black hole.

Quasars and black holes continue to remain mysterious objects to astronomers and scientists. Luckily with new images thanks to various telescopes around the world astronomers can further their knowledge of these objects. Even though it is impossible to directly see a black hole since light can’t escape its gravitational pull, the mass of a black hole can still be determined. Astronomers in Hawaii at the W. M. Observatory and the Gemini North Telescope measured the velocity of stars moving around the center of NG 4889. These instruments determined the massive supermassive black hole. 

 

The Space Shuttle Program

Space Shuttle Columbia from its 16th flight landing at Kennedy Space Center
Space Shuttle Columbia from its 16th flight landing at Kennedy Space Center Photo: Wikimedia Public Domain

The End of a Successful Era in Space and the Beginning of a New One

In 1975, the Apollo space program came to an end, along with it a legacy of unparalleled achievements, but this was only the beginning.

NASA was already working on a new venture for a more efficient spacecraft that they could reuse instead of relying on the disposable rockets that cost them billions of dollars to build each time.

This idea of a reusable rocket that could launch astronauts into space, but dock and land like an airplane were well-accepted for future space travel.

Enter the Space Shuttle Program

Early space shuttle concept
Early space shuttle concept. Photo: Wikimedia Public Domain

In 1972, President Nixon announced that NASA would develop a reusable space transportation system (STS). They decided that the shuttle would consist of an orbiter attached to solid rocket boosters and an external fuel tank. This design was considered safer and more cost-effective. 

One of the first obstacles was to design a spacecraft that didn’t use ablative heat shields, which subsequently burned up each time the shuttle re-entered the Earth’s atmosphere.

For the shuttle to be reusable, a different strategy would have to be initiated. The designers came up with an idea to overlay the craft with insulating ceramic tiles that would absorb the heat of reentry, without causing any danger to the astronauts. 

The First Flights

The first of four test flights began in 1981, leading to operational flights starting in 1982. They were used on a total of 135 missions from 1981 to 2011. The launchpad used was the Kennedy Space Center in Florida. 

Like the previous Saturn V rocket, the Space Shuttle had different components of its own, which included the Orbiter Vehicle (OV), a pair of recoverable solid rocket boosters (SRBs), and the expendable external tank (ET), containing liquid hydrogen and liquid oxygen as fuel. 

The Shuttle was launched vertically, the same as any rocket in its category would launch, using the two SRBs to jettison it. The SRBs operated in a parallel fashion by utilizing the fuel from the ET. 

Once the mission had been completed, the shuttle would land similar to a jet aircraft on the runway of the Shuttle Landing Facility of KSC or Rogers Dry Lake in Edwards Air Force Base, California. After landing at the base, the orbiter was then flown back to the KSC on the Shuttle Carrier Aircraft, which was a specially modified Boeing 747.

Tragedy Hits

Although the accomplishments that the shuttle program has achieved are beyond expectations, there were two unfortunate events during its time.

Challenger January 28, 1986

Shortly after liftoff, the Space Shuttle Challenger exploded f the U.S. space shuttle orbiter Challenger, claiming the lives of seven astronauts.

Among those who were lost were teacher-in-space Christa McAuliffe, commander Francis (Dick) Scobee, pilot Michael Smith, mission specialists Ellison Onizuka, Judith Resnik, and Ronald McNair, and Hughes Aircraft engineer Gregory Jarvis.

Space Shuttle Crew
The crew of Space Shuttle mission STS-51-L poses for their official portrait on November 15, 1985. In the back row from left to right: are Ellison S. Onizuka, Sharon Christa McAuliffe, Greg Jarvis, and Judy Resnik. In the front row from left to right: Michael J. Smith, Dick Scobee, and Ron McNair. Photo: Wikimedia Public Domain

Columbia Feb 1, 2003

It was the final mission of Columbia. Seven crew members lost their lives when the shuttle burned up over the state of Texas during its reentry on Feb 1, 2003.

NASA Columbia Crew
The STS-107 crew included, from the left, Mission Specialist David Brown, Commander Rick Husband, Mission Specialists Laurel Clark, Kalpana Chawla, and Michael Anderson, Pilot William McCool, and Payload Specialist Ilan Ramon. (NASA photo. via Wikipedia)

 

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