Statue of Liberty

Statue of Liberty

In addition to being a great inspiration and a symbol of freedom and life in a new land, the Statue of Liberty is an example of an engineering challenge in the late 1800s.

The lady with the lamp

Video: Modern Marvels The Statue of Liberty (45 minutes) describes the engineering that went into the design, construction and restoration over more than 100 years.

The Statue of Liberty stands on a small island in New York harbor on a specially-build pedestal. The statue was a gift from the people of France. The sculpture is so big that the French artist Frederic Auguste Bartholdi had to get help from Alexandre Gustave Eiffel (designer of the Eiffel Tower). There is a massive iron pylon and secondary skeletal framework which allows the Statue’s copper skin to move independently yet stand upright. The torch in her hand high above her head was especially challenging for the designers and builders who worked through the steps in the Engineering Design Process to create the Statue.

  • Ask (What? Ask questions, understand the need, identify the problem, define)
    There are many engineering challenges in building the Statue of Liberty. It is huge – total overall height from the base of the pedestal foundation to the tip of the torch is 305 feet, 6 inches. The statue itself is made of copper plates 3/32 inch thick (less than the thickness of two pennies) that were made in France and brought to the United States by ship. The copper statue can’t stand by itself so there is a big iron framework inside to support the structure. It was decided to place the statue in New York harbor on a platform on a small island. Winds of 50 miles per hour cause the statue to sway 3 inches and the torch to sway 5 inches. All this was done in the late 1800s before most of the technologies in use to day were even invented. What were the requirements for the base built in New York harbor?
Structural drawings
  • Imagine (So what? Imagine, brainstorm, explore, discover)
    The structure inside the Statue of Liberty supports the external copper statue. What were some of the ideas Bartholdi and Eiffel tried in preparation to build the statue?
  • Plan (Now what? Plan, design)
    The Statue was reduced to 350 individual pieces and packed in 214 crates for shipping from France to New York. Several times plans were modified because of costs and the funding for the Statue and base. The original engineer on the project proposed a masonry internal structure. After his death before it was built, Eiffel decided to go with an iron truss framework that would allow thermal expansion of the copper. What were the limits on size of pieces of the Statue transported to the United States?
  • Create (Do it. Create, try it out)
    The Statue was completed in France in July, 1884 and arrived in New York Harbor in June of 1885. The pedestal construction was finished in April of 1886 and the Statue was reassemble. photos What problems came up during the construction? How were these resolved?
  • Improve (If this then what? Improve, make it better)
    The Statue of Liberty has been maintained and upgraded over the years. While the statue was closed from 1984 to 1986, the torch and a large part of the internal structure were replaced. Many new materials and technologies have allowed engineers to make modifications that will ensure that the Lady with the lamp will stand in New York harbor as a symbol of freedom for many year to come. How does the new gold film covering the lamp improve on the original design?

The Statue of Liberty, the Golden Gate Bridge, the Giant Buddha of Hong Kong and many other important monuments are protected from corrosion. Thanks to NASA they have all been painted with a special protective paint. It was first invented to protect the Kennedy Space Center’s launch structures from air-salt corrosion, thermal stress, and rocket exhaust.

That’s engineering

  • copper – metallurgy, ductile, oxidation – Copper is easily shaped into complex curves, so it a good material for making the “skin” of a sculpture like the Statue of Liberty. The statue looks very lifelike with fine details in her face. The “drape” of the folds in her robe look like they were made of fabric. Using copper and tools available at the time, the workers were able to make the huge pieces that could be assembled for the final statue. The surface turns green through oxidation after prolonged exposure to the weather in New York harbor. Copper is not very strong, so the statue was designed with an iron framework inside to hold the shape and support the weight of the copper skin of statue.
  • corrosion – process of eating or wearing away gradually usually by chemical action

Engineering ideas

  • materials, steel, copper, truss, armature, galvanic corrosion, curtain wall construction, load bearing, pylon tower, I-beams, low-carbon corrosion-resistant stainless steel, Ferralium, metal halide lamps, elevator, thermal expansion, repousse

Do it
Now it is your turn. Here are some challenges for you to work on…

  • design and build a model statue that uses construction like the Statue of Liberty with an internal framework that supports the sculpture made in a material that does not support its weight

Learn more…