Timber spread footings, with steel beams on top, are the first phase of construction of a new pod of the elevated station. This is the beginning of the foundation construction for pod A3, erected in 2001-02...the large steel pipe columns which support the structure were later erected at each intersection of the spread footings. Okay, in case you were wondering...the structural steel grade beams are fabricated shapes (differing depending on the location) but nominally 2'-4" deep by 2' wide, fabricated from ASTM A572 Grade 50 (50 KSI, (50 kips per square inch; or 50,000 pounds per square inch yield strength)). The pipe columns are 36", of low-temperature steel (API5LX Grade 50) presumably to resist impact loads, and the exposed bolting is also low-temperature steel (A320 L7). The timber foundations vary in width; they consist of 4x6 inch timbers arranged vertically on 8" or 12" centers, between sheets of 3/4" plywood. If that wasn't enough technical detail, here's a December 2000 ASCE Magazine article about the foundation design and the methods to be used for jacking and leveling the station. Photograph by: Melanie Conner. Caption: National Science Foundation Source: the NSF Antarctic photo library. |