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  1. Answer the questions to part III:

1. Was excavation of the site simple?

2. What was below the asphalt parking lot?

3. Why was the construction schedule set back about a month?

4. Who was excavation and foundation constructor?

5. What obstacles were in the basement of the Old Garden?

6. Why were explosive charges small?

7. How were the holes for the charges drilled?

8. What was just chipped away?

9. What did the workers use when they were as close as 20 ft to the subway?

10. Why was the subway entrance different from others?

11. What part of the old Garden structure was retained?

12. What is the function of the exterior tube?

13. What is the shape of the arcade?

14. What materials are used for the arcade?

15. How are the sections connected?

16. What materials are used for the arcade’s vaulted ceiling?

17. How are the tube’s loads transferred?

18. What is Richard F. Rowe?

19. Where is the rigid frame interrupted?

20. What provides a setback for exterior lighting equipment?

  1. Read part IV and answer the questions after it. Make sure you can explain the following terms and word combinations from part IV.

Project engineer

Core bracing

Tight bay spacing

Chamfered corner

To splice on at midspan

To form Ts

Field-welded

Wedding cake pattern

Shop-welded (on to one side) beam stubs

Gravity load

Curved masonry

Part IV. Bracing. Gary R. Steficek, SOM's project engineer for the commercial tower, adds that not all of the core bracing continues to the top of the building, either. Some of the bracing stops at the 16th floor, some stops at the 40th and the rest continues to the 50th floor. Tight bay spacing was needed at the corners to help transfer the wind loads around the corners of the building. There are four 11-ft-wide bays at each end and alternating 19-ft and 11-ft bays in the center. Each end bay has a chamfered corner. Columns that had beam stubs spiced on at midspan to form Ts were used between the 11-ft-wide bays. "The [horizontal] stubs were welded on in the shop where it is a lot easier to make a moment connection," says Steficek. Mosher Steel Co., Houston, fabricated the structural steel for the theaters and commercial tower. Steficek adds that the stubs could not exceed 5-ft because they had to be transported through tunnels into New York City. That meant that for the 19-ft-wide bays, stubs could only be shop-welded onto one side of the columns and additional beams for the frame had to be fieldwelded.

The steel framing that surrounds the tube in a wedding cake pattern at the building's base does not add to its stability. Steficek explains that the 18 floors of framing around the base of the tube carry only their own gravity load. The curved masonry on the exterior that is designed to mirror the arcade inside is six stories high. Steficek adds that the floor area varies from about 45,000 sq. ft at the base to about 25,000 sq. ft on the upper floors.

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