Analysis of Eiffel tower by Aaditi Dhyani
- 2. By: Aaditi Dhyani ID No. : 140501 Civil Engineering (3rd Year)
- 3. A Presentation on Eiffel Tower An in-depth analysis of the Iron Lady.
- 4. Contents: i) Introduction ii) The Builder iii) Construction iv) The structure v) Structural Analysis vi) Maintenance Conclusion Reference
- 5. INTRODUCTION
- 6. • Built for World’s Fair and to celebrate the centennial of the French Revolution. • The tower officially opened May 5, 1889. • “The Iron Lady” was the star attraction with 2 million visitors. • It symbolizes ideals of ingenuity, progress, and beauty. • It was the tallest structure in the world until 1930.
- 7. The Builders
- 8. Gustave Eiffel, a renowned civil engineer of that time, known from his revolutionary bridge building techniques is usually credited with the building of the Tower. He was also known for the construction of the statue of liberty’s iron framework, the Maria Pia bridge or the Garabit Viaduct.
- 9. Civil Engineer Émile Nouguier Architect Stephen Sauvestre Civil Engineer Maurice Koechlin
- 10. Arches added to the design by Stephen Sauvestre. Original pylon design by Koechlin and Nougier.
- 11. The CONSTRUCTION
- 12. Work began in January 26th,1887 with the digging of the tower’s foundations, which were laid in four months.
- 13. The actual metal work started on July 1887.
- 14. The Eiffel Tower’s base is composed of four legs. In these legs are 2 anchor bolts that are each 26 feet long and 4 inches in diameter. One part of Eiffel’s plan for the foundation of the structure was the placement of a hydraulic jack. The hydraulic jack was used to enable the raising or lowing of the platform to make certain it was level.
- 15. All the elements were prepared in Eiffel’s factory in Levallois-Perret on the outskirts of Paris. Each of the 18000 pieces used to construct the tower was specially designed and calculated, traced out to an accuracy of a tenth of a millimetre and then put together to form new pieces, each measuring about 5 meters.
- 16. On site a team of builders, was responsible for the 150-300 workers who assembled the gigantic structure.
- 17. All the metallic pieces on the Tower were fixed by rivets. This was a well known technique at the time of the construction.
- 18. A team of four men was needed for each rivet assembled: one to heat it up, another to hold it in place, a third to shape the head and a fourth to beat it with a sledgehammer.
- 19. The tower is built with wooden scaffolds and small hoists directly fixed to the tower.
- 20. Beginning of second floor- June 1888.
- 21. Above the second floor- September 1888.
- 22. Above the middle floor- December 1888.
- 23. The workers, perched on a ramp just a few centimetres wide, at a steep height for the topmost floor of the tower.
- 24. It took just two years two months and five days to build the Eiffel Tower, a record speed considering the rudimentary means available at that time. The construction work was finished on 31 march 1889. The assembly of the tower was a marvel of precision.
- 25. The Design
- 26. Puddled or wrought iron. • The metal structure weighs 7,300 tons. • Total weight: 10,100 tons. • Number of rivets used: 2,500,000. • Number of iron parts: 18,038. • Cost of construction: 7,799,401.31 French gold francs of 1889. MaterialUsed
- 27. Gustave Eiffel created a two-system foundation for the Eiffel Tower, to protect the reinforced concrete structure from flooding through the Seine river (near the North and East pillars). Foundation
- 28. Top Platform First Platform Second Platform Ground Level Height – 324 m 1430 sq. m. CROSS SECTION 4415 sq. m. 250 sq. m. 276 m. 115 m 57 m Dimensions
- 29. VerticalTransport In June 1889, five hydraulic elevators were installed for the use of visitors. Maintained regularly, they cover a distance equal to two and a half times around the world.
- 30. VerticalTransport A staircase going to the top, has a total of 1792 steps, commemorating a centennial of French Revolution.
- 32. Loads Three types of loads act on the Eiffel Tower: 1. Dead load- its own weight 2. Live load- the weight of people and machinery. 3. Wind load Live Load: A live load of 50 pounds per sq. ft. is taken for the tower. Dead Load: The net weight of the tower is divided into three sections, as shown in the figure.
- 33. This live load acts in combination with the dead load for a total vertical load of: This load acts through the centroid of the Tower, which is located 257 feet above the ground. Wind Load- Along the height of 984 feet, the total force is: The centroid of this force is halfway up the Tower so P, the idealized point wind load, acts at this point. Loads
- 34. Reactions The overall reactions at the base of the Tower are easily found from the wind and gravity loads (dead and live). Overall vertical and horizontal reactions will develop to balance the respective loads. A moment reaction will also develop to balance the horizontal load applied through its centroid a distance l/2 from the support. The reactions at the base of each column, instead of for the Tower as a whole, are necessary to find the internal forces in the individual columns.
- 35. Reactions Each column will logically develop half of the horizontal and vertical reactions found for the entire structure. The wind force will create a higher vertical reaction in the leeward support and a lower vertical reaction in the windward support because the wind alone would create compression in the leeward support and tension in the windward support.
- 36. InternalStresses The values of compressive and tensile stress can be found from the formula: where the force, N, is the total axial force found from both vertical and horizontal loads. The area of each of the two simplified columns is 1600 square inches. The compression forces found at the bases of the Tower’s columns are N = -7,630 kips on the windward side, and N = -15,780 kips on the leeward side.
- 37. InternalStresses The resulting stresses are: on the windward side and: on the leeward side. Because the wind may act on the Tower from any direction, each of the supports must be designed to take the maximum stress of -9.9 ksi. This is also a rough estimate of the maximum stress on each of the actual Tower’s four columns, because the idealization has combined four columns into two twice as large.
- 38. Safetyfactor The safety factor for the Eiffel Tower is the ratio of the ultimate stress and the actual stress. The ultimate stress for iron is about 45 ksi. This is the maximum it can withstand in both tension or compression before it fails or breaks. The value of actual stress, -9.9 ksi, is used with the ultimate stress, 45 ksi, in the safety factor formula: Structures are usually designed with at least a safety factor of two, i.e. only half a building material’s maximum strength is used. Load>4.5 times the actual load
- 39. Efficiency In design, one wants a structure not only to be strong, but stiff, so that deformations cannot occur. If a structure is stressed to the allowable limit, the safety factor is found as usual: The safety factor for wrought iron is about three, so the allowable stress is: An ideal structure has an efficiency of 1.0 or 100% where actual stress equals the allowable. The Eiffel Tower, with a maximum stress of 9.9 ksi, has an efficiency of: The actual structure has a factor of four and a half while the material could withstand a factor of only three.
- 40. MAINTANENCE
- 41. Weight of paint- approximately 60 tons Time required- 15 to 18 months Frequency required- every 7 years. No. of workmen- 25 painters Cost of painting (approx.)- 3 million euros Colour- Bronze
- 42. Conclusion The Eiffel Tower and it’s daring design were quiet ahead of it’s time. Gustave Eiffel received the highest accreditation for the construction of the tower, when it was renamed after him. Numerous aerodynamic researches have been performed on the tower. The massive height of the tower has been useful in the field of telegraphy and telecommunication.