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One of the biggest non-nuclear explosions in history, the Black Tom explosion, caused significant damages to the Statue of Liberty, but couldn’t topple it. The statue's strong iron frame is connected to the copper skin by these flat bars. Interestingly the flat bars are capable of flexing. What will happen in this design if a strong force acts on the copper skin? You can see the flat bars are bending. These flexible bars act like spring isolators and the force transferred to the statue is greatly reduced.
On that crucial day this is how the statue was saved from a topple.
The beauty of this statue obviously lies in the copper skin. The statue looks like a single solid piece but is in fact made up of many copper sheets, that too of just 2.3 mm thick. The copper sheets are riveted together to form this beautiful statue. The key here is the perfection at which they were able to achieve the details of the lady liberty on the copper sheets. How did they carve all these minute details on a gigantic scale around 140 years ago?
This man, Mr. Bartholdi, is the genius behind this beautiful statue. This is the first clay model he made: a Statue of Liberty with a height of 4 feet. He wanted to convert this 4-foot model into a 151-foot tall final model. The normal pantograph scaling technique would fail for such a massive scaling operation. Instead, Mr. Bartholdi used a genius method: the method of plump lines.
Check out this scaling operation in three stages. The original clay model was first surrounded by perfectly spaced plumb lines. The second model’s plumb structure was exactly two times larger than the original plumb structure. The second model was almost 8 feet tall, and the artists first had to build a wooden armature to support it. If you want to scale up her nose, mark a few key points on the nose. Let’s focus on this point. First they had to insert a plane and touch this point. One can easily measure the Z location of this point. Now we have two more coordinate measurements pending, X and Y. It is clear that the point on the nose lies between these two plumb lines. This allowed them to easily measure the X coordinate value. The same technique was used to measure the Y coordinate value. To reconstruct a nose, they had to mark and measure many such points. If you want to scale the nose up two times, simply multiply all these values by 2. At the other end, a wooden skeleton is waiting to be covered with plaster. The workers started to cover the nose with plaster, but they had to conform to the scaled up measurements of the points. When you complete the plaster work conforming to the data values, the nose is scaled accurately. Thousands of such data points were transferred to scale up the whole model. One can easily cross check the scaling operation with the help of double measurement.
It is believed that Bartholdi did two more scaling operations to reach the final full-sized model, each time adding more details to the statue. They were not able to contain the final Plaster model in their studio. Instead, they split the statue into many pieces.
Now comes the magic of the repoussé operation. From the final plaster model, the workers
fabricated a wooden skeleton. This wood skeleton conforms to the shape of one section of the garment. Thin copper plates were placed against the wooden skeleton and then hammered. This way, the copper plates achieved the exact same shape of the plaster model. Since the hammering was done from the inside, the other surface was smooth, free from hammer marks.
The French workmen made a total of 300 such copper plates. Now, the challenge was how to connect the different plates perfectly and strongly. For this, they used the riveting technique. Here is an interesting question for you. On the clothes of the Statue, you can easily see overlapping copper plates and tiny rivets. However, we don’t see any overlapping or rivets on the face. This is true even on the hands and feet. In these regions, all you can observe is a tiny line. How is this possible? As shown, the normal riveting method results in rivet heads on both the sides. To give the statue an elegant look, the engineers used countersunk rivets in these regions. Since the sheets were not overlapping, they had to add an extra copper strip, then do the riveting work. This technique prevents outer projections of the rivets. This amount of care was given by the engineers to give the statue a polished look.
The riveted copper plates were supported by iron armature strips. The next big question is how to erect these pieces vertically so that even a strong wind force will not collapse them. These plates need strong internal support. Bartholdi, who had no idea how to build a support skeleton for the Liberty lady’s skin, approached the most popular architect of that time Eugène Viollet-le-Duc. Eugène Viollet-le-Duc’s solution was a set of masonry walls which comprised many compartments.These compartments would be later filled with sand and the copper skin would cover the whole structure. This structure definitely is incredibly strong against the wind force. Batholdi thought his engineering problems were over. However, in 1879 passed away without leaving a detailed engineering plan of his structure.
This time Bartholdi approached none other than Mr. Gustave Eiffel, the man who would build the Eiffel tower years later. Eiffel’s structure was totally different from Eugène Viollet-le-Duc. It was slender and modern.
These four giant beams which taper towards the top are the main central pylons inside Eiffel’s structure. The structure was reinforced with horizontal and inclined bars. Look at the way he designed a supporting structure for the hand of the statue. The main columns of the central pylon were fitted with a set of girders. These girders were kept on the pedestal. Now, starts the long journey of tension bars. They get connected with a set of lower girders which are embedded with the pedestals. By tightening these huge nuts of tension bars, the entire iron structure of the statue will be bonded firmly with the pedestal. Eiffel made the iron structure super strong - what a genius! As we already learned, flexible flat bars connect the copper skin to the strong iron frame. This way, Mr. Eiffel ensured that his structure would sway slightly when it is windy outside.
In this miniature model of the Statue of liberty, I have used thick bars to connect between the central core and the skin of the statue. When I shoot a bullet on this, this statue is just topples. In the second model I have used thin and flexible bars. As you can see this statue survives a topple. The vibration of skin was able to absorb energy from the bullet. Please note, to make the bullet heavy, we added a steel ball in between.
However, here they faced another problem: an electrochemical reaction between the iron and copper. If they are directly connected, the metal will corrode in just a few years. Eiffel solved this problem by inserting shellac coated asbestos pieces between these metals.
On that crucial day this is how the statue was saved from a topple.
The beauty of this statue obviously lies in the copper skin. The statue looks like a single solid piece but is in fact made up of many copper sheets, that too of just 2.3 mm thick. The copper sheets are riveted together to form this beautiful statue. The key here is the perfection at which they were able to achieve the details of the lady liberty on the copper sheets. How did they carve all these minute details on a gigantic scale around 140 years ago?
This man, Mr. Bartholdi, is the genius behind this beautiful statue. This is the first clay model he made: a Statue of Liberty with a height of 4 feet. He wanted to convert this 4-foot model into a 151-foot tall final model. The normal pantograph scaling technique would fail for such a massive scaling operation. Instead, Mr. Bartholdi used a genius method: the method of plump lines.
Check out this scaling operation in three stages. The original clay model was first surrounded by perfectly spaced plumb lines. The second model’s plumb structure was exactly two times larger than the original plumb structure. The second model was almost 8 feet tall, and the artists first had to build a wooden armature to support it. If you want to scale up her nose, mark a few key points on the nose. Let’s focus on this point. First they had to insert a plane and touch this point. One can easily measure the Z location of this point. Now we have two more coordinate measurements pending, X and Y. It is clear that the point on the nose lies between these two plumb lines. This allowed them to easily measure the X coordinate value. The same technique was used to measure the Y coordinate value. To reconstruct a nose, they had to mark and measure many such points. If you want to scale the nose up two times, simply multiply all these values by 2. At the other end, a wooden skeleton is waiting to be covered with plaster. The workers started to cover the nose with plaster, but they had to conform to the scaled up measurements of the points. When you complete the plaster work conforming to the data values, the nose is scaled accurately. Thousands of such data points were transferred to scale up the whole model. One can easily cross check the scaling operation with the help of double measurement.
It is believed that Bartholdi did two more scaling operations to reach the final full-sized model, each time adding more details to the statue. They were not able to contain the final Plaster model in their studio. Instead, they split the statue into many pieces.
Now comes the magic of the repoussé operation. From the final plaster model, the workers
fabricated a wooden skeleton. This wood skeleton conforms to the shape of one section of the garment. Thin copper plates were placed against the wooden skeleton and then hammered. This way, the copper plates achieved the exact same shape of the plaster model. Since the hammering was done from the inside, the other surface was smooth, free from hammer marks.
The French workmen made a total of 300 such copper plates. Now, the challenge was how to connect the different plates perfectly and strongly. For this, they used the riveting technique. Here is an interesting question for you. On the clothes of the Statue, you can easily see overlapping copper plates and tiny rivets. However, we don’t see any overlapping or rivets on the face. This is true even on the hands and feet. In these regions, all you can observe is a tiny line. How is this possible? As shown, the normal riveting method results in rivet heads on both the sides. To give the statue an elegant look, the engineers used countersunk rivets in these regions. Since the sheets were not overlapping, they had to add an extra copper strip, then do the riveting work. This technique prevents outer projections of the rivets. This amount of care was given by the engineers to give the statue a polished look.
The riveted copper plates were supported by iron armature strips. The next big question is how to erect these pieces vertically so that even a strong wind force will not collapse them. These plates need strong internal support. Bartholdi, who had no idea how to build a support skeleton for the Liberty lady’s skin, approached the most popular architect of that time Eugène Viollet-le-Duc. Eugène Viollet-le-Duc’s solution was a set of masonry walls which comprised many compartments.These compartments would be later filled with sand and the copper skin would cover the whole structure. This structure definitely is incredibly strong against the wind force. Batholdi thought his engineering problems were over. However, in 1879 passed away without leaving a detailed engineering plan of his structure.
This time Bartholdi approached none other than Mr. Gustave Eiffel, the man who would build the Eiffel tower years later. Eiffel’s structure was totally different from Eugène Viollet-le-Duc. It was slender and modern.
These four giant beams which taper towards the top are the main central pylons inside Eiffel’s structure. The structure was reinforced with horizontal and inclined bars. Look at the way he designed a supporting structure for the hand of the statue. The main columns of the central pylon were fitted with a set of girders. These girders were kept on the pedestal. Now, starts the long journey of tension bars. They get connected with a set of lower girders which are embedded with the pedestals. By tightening these huge nuts of tension bars, the entire iron structure of the statue will be bonded firmly with the pedestal. Eiffel made the iron structure super strong - what a genius! As we already learned, flexible flat bars connect the copper skin to the strong iron frame. This way, Mr. Eiffel ensured that his structure would sway slightly when it is windy outside.
In this miniature model of the Statue of liberty, I have used thick bars to connect between the central core and the skin of the statue. When I shoot a bullet on this, this statue is just topples. In the second model I have used thin and flexible bars. As you can see this statue survives a topple. The vibration of skin was able to absorb energy from the bullet. Please note, to make the bullet heavy, we added a steel ball in between.
However, here they faced another problem: an electrochemical reaction between the iron and copper. If they are directly connected, the metal will corrode in just a few years. Eiffel solved this problem by inserting shellac coated asbestos pieces between these metals.
In Paris, the Statue is achieving its final shape and beauty. However, in New York, they are facing a major financial crunch to build the pedestal of the statue. Moreover, the transfer of construction equipment and materials to the island was another massive challenge. In Paris, the completed statue, without a pedestal, patiently awaits her final destination. Work in New York on her pedestal was progressing extremely slowly.
In January of 1885, Bartholdi took a chance. He decided to prepare the Lady Liberty for travel. It took almost half a year for workers to carefully take apart the statue. They packed the Statue of Liberty into 214 wooden crates and loaded them onto a French Navy ship.
Back home, the fundraising committee was struggling to come up with funds, and at one point, it seemed that a pedestal for the Lady Liberty was an impossible dream. The savior of the lady Lady liberty Mr Joseph Pulitzer, a newspaper publisher sprang into action at this moment. He launched his own fund-raising campaign in his newspaper: The World. In his editorials, he mocked rich Americans who didn’t contribute to the statue and honored ordinary Americans who donated by printing their names. In just one month, Pulitzer raised $25,000.
On June 17, 1885, with a heroic welcome, the French ship reached New York Harbor with the disassembled Lady Liberty. With no pedestal for her to stand on, the crates were kept in storage. Many other newspapers followed the trend of The World, and public enthusiasm grew considerably. By August 1885, the committee met their goal of raising $100,000.
This truncated concrete pyramid is the base of the pedestal. The weight of the entire statue is carried by a 4.5 meter deep mat foundation. These large granite blocks were the main material used for the construction of the pedestal. You can imagine the effort required to transport the heavy granite blocks to the island via barges and ships. Steam powered cranes and derricks were extensively used to lift the material. The workers started the skillful assembly and concreting of the granite blocks. They left an empty space in the center. This vacant space was to contain the entry area, stairs, and an elevator. At level 6P, they constructed an observation deck.
Once the pedestal was ready, the workers started the assembly of the iron central pylon. In fact, this was reassembly work. Gustave Eiffel made a perfect plan and specification sitting in France to reassemble the iron framework correctly. You will even notice the perfect planning for the construction of double helix stairs. This ladder they are constructing would go all the way to the torch of the statue. We will revisit this later. Under the guidance of his engineering team, the workers completed the assembly work perfectly.
What remains now is the attachment of the copper skin to the flexible bar of the iron frame. For this work, the scaffoldings were no longer needed. The workers had to align holes in both plates before the riveting work. Bartholdi played a major role in reconstruction activities of the statue. He traveled to the US many times for this.
On October 28, 1886, the statue was unveiled to the public amidst huge fanfare. The statue’s face was draped with a French flag and Mr Bartholdi was positioned inside the crown holding it. When Bartholdi dropped the flag, the statue was officially dedicated to the public. Achieving the characteristic green color of the statue took almost 20 years. It is, in fact, a coating named Patina formed by an oxidation reaction with the air. This layer acts as a stable layer protecting copper from further corrosion. During the restoration work of 1984 the authorities had to replace the rusted internal armature bars, but they did not have to do much repairing work on the copper skin. During this restoration work, the authorities replaced the old torch with a more stylish one. The old torch was too badly damaged to restore.
If you want to appreciate the effort put in by the artisans of Bartholdi please have a look at details of the garment worn by the Lady Liberty. The artisans could have easily connected copper sheets as shown. The spectators in the ground could never detect this shortcut work. However the artisans were meticulous and fabricated both the ends of the cloth - obviously a metal work which involves a lot of difficult to join internals.
Climbing the Statue of Liberty is a fun experience. You can use either the elevator or a staircase and reach the first observation gallery. Enjoy a small break here. Climb a few more stairs - Now starts the real climb - the climb through the beautiful helical stairs to reach the crown of the statue. Remember, this time only stairs, no elevator. We have to climb 146 steps to reach the top. If you are tired during this climb, there are few resting points along the way. While climbing up, you may notice another helical staircase above. It will actually be used to climb down, not up. Once you reach the crown, you will be able to enjoy the beautiful view of the waters of New York harbor. Now, let’s explore how to reach the top most point of the statue - the torch gallery. Access to the torch was blocked in 1916 after the Black Tom explosion. If the access was not blocked, you could have enjoyed another amazing climb and view.
The lady Liberty survived Hurricane Hazel, a deadly hurricane in 1954, thanks to Eiffel’s clever engineering. According to our analysis, the hurricane, which blew at a speed of 140 km/hour, may have swayed the statue by 4 inches and the torch by 7 inches. The 1916 Black Tom explosion caused serious damages to the statue. The explosion was measured on a 5.5 Richter scale and there were enormous shockwaves. The shrapnel from the explosion caused serious damages to the skin. It is interesting to note that the torch of the statue remained illuminated during this event. The statue’s glass torch shattered. The arm and internal structure were heavily damaged. After the repair, the authorities decided to permanently shut down the torch gallery to visitors. They might have feared that the repaired structure was not as strong as Mr. Eiffel’s original structure.
Now let’s play a tribute to Mr. Gustave Eiffel by blowing air against his structural design. It was fun to observe the flexing of the bars. Take care. Bye Bye.
In January of 1885, Bartholdi took a chance. He decided to prepare the Lady Liberty for travel. It took almost half a year for workers to carefully take apart the statue. They packed the Statue of Liberty into 214 wooden crates and loaded them onto a French Navy ship.
Back home, the fundraising committee was struggling to come up with funds, and at one point, it seemed that a pedestal for the Lady Liberty was an impossible dream. The savior of the lady Lady liberty Mr Joseph Pulitzer, a newspaper publisher sprang into action at this moment. He launched his own fund-raising campaign in his newspaper: The World. In his editorials, he mocked rich Americans who didn’t contribute to the statue and honored ordinary Americans who donated by printing their names. In just one month, Pulitzer raised $25,000.
On June 17, 1885, with a heroic welcome, the French ship reached New York Harbor with the disassembled Lady Liberty. With no pedestal for her to stand on, the crates were kept in storage. Many other newspapers followed the trend of The World, and public enthusiasm grew considerably. By August 1885, the committee met their goal of raising $100,000.
This truncated concrete pyramid is the base of the pedestal. The weight of the entire statue is carried by a 4.5 meter deep mat foundation. These large granite blocks were the main material used for the construction of the pedestal. You can imagine the effort required to transport the heavy granite blocks to the island via barges and ships. Steam powered cranes and derricks were extensively used to lift the material. The workers started the skillful assembly and concreting of the granite blocks. They left an empty space in the center. This vacant space was to contain the entry area, stairs, and an elevator. At level 6P, they constructed an observation deck.
Once the pedestal was ready, the workers started the assembly of the iron central pylon. In fact, this was reassembly work. Gustave Eiffel made a perfect plan and specification sitting in France to reassemble the iron framework correctly. You will even notice the perfect planning for the construction of double helix stairs. This ladder they are constructing would go all the way to the torch of the statue. We will revisit this later. Under the guidance of his engineering team, the workers completed the assembly work perfectly.
What remains now is the attachment of the copper skin to the flexible bar of the iron frame. For this work, the scaffoldings were no longer needed. The workers had to align holes in both plates before the riveting work. Bartholdi played a major role in reconstruction activities of the statue. He traveled to the US many times for this.
On October 28, 1886, the statue was unveiled to the public amidst huge fanfare. The statue’s face was draped with a French flag and Mr Bartholdi was positioned inside the crown holding it. When Bartholdi dropped the flag, the statue was officially dedicated to the public. Achieving the characteristic green color of the statue took almost 20 years. It is, in fact, a coating named Patina formed by an oxidation reaction with the air. This layer acts as a stable layer protecting copper from further corrosion. During the restoration work of 1984 the authorities had to replace the rusted internal armature bars, but they did not have to do much repairing work on the copper skin. During this restoration work, the authorities replaced the old torch with a more stylish one. The old torch was too badly damaged to restore.
If you want to appreciate the effort put in by the artisans of Bartholdi please have a look at details of the garment worn by the Lady Liberty. The artisans could have easily connected copper sheets as shown. The spectators in the ground could never detect this shortcut work. However the artisans were meticulous and fabricated both the ends of the cloth - obviously a metal work which involves a lot of difficult to join internals.
Climbing the Statue of Liberty is a fun experience. You can use either the elevator or a staircase and reach the first observation gallery. Enjoy a small break here. Climb a few more stairs - Now starts the real climb - the climb through the beautiful helical stairs to reach the crown of the statue. Remember, this time only stairs, no elevator. We have to climb 146 steps to reach the top. If you are tired during this climb, there are few resting points along the way. While climbing up, you may notice another helical staircase above. It will actually be used to climb down, not up. Once you reach the crown, you will be able to enjoy the beautiful view of the waters of New York harbor. Now, let’s explore how to reach the top most point of the statue - the torch gallery. Access to the torch was blocked in 1916 after the Black Tom explosion. If the access was not blocked, you could have enjoyed another amazing climb and view.
The lady Liberty survived Hurricane Hazel, a deadly hurricane in 1954, thanks to Eiffel’s clever engineering. According to our analysis, the hurricane, which blew at a speed of 140 km/hour, may have swayed the statue by 4 inches and the torch by 7 inches. The 1916 Black Tom explosion caused serious damages to the statue. The explosion was measured on a 5.5 Richter scale and there were enormous shockwaves. The shrapnel from the explosion caused serious damages to the skin. It is interesting to note that the torch of the statue remained illuminated during this event. The statue’s glass torch shattered. The arm and internal structure were heavily damaged. After the repair, the authorities decided to permanently shut down the torch gallery to visitors. They might have feared that the repaired structure was not as strong as Mr. Eiffel’s original structure.
Now let’s play a tribute to Mr. Gustave Eiffel by blowing air against his structural design. It was fun to observe the flexing of the bars. Take care. Bye Bye.