The ESAB VAC Working Platforms and Leg Tower Structure is located at the NASA Michoud Assembly Facility in New Orleans, LA. This new platform and leg structure will be used to support ESAB’s new welding machine that opens the door for the core stage of NASA’s new heavy-lift booster.
This massive structure will support the new ESAB weld tool used in the friction stir welding of the large barrel sections for both the oxidizer tank and the hydrogen tank of the Space Launch System (SLS) rocket. It will also validate the other machines’ handiwork by conducting nondestructive tests on the components after they are produced. The structure measures 196-feet tall by 78-feet wide, and has approximately 1,000 tons of structural steel and miscellaneous metals. It is constructed in two separate sections, the platform, and the leg tower support structure.
The assemblies are constructed inside NASA’s existing Vertical Assembly Center (VAC). With confined space, limited clearance, stringent ground pressure tolerances, and with the heaviest lift being upwards of 62-thousand pounds precise planning, sequencing, and coordination were required by all parties for safe and successful erection of the structures and equipment.
The Working Platform is comprised of four concrete slab platforms located around the tool at tank splice points supported by heavy wall pipe columns. The platforms are constructed of large wide flange and truss members for access to the tool, and support of various mechanical units.
The Leg Tower Structure, which is the primary support structure for the weld tool, consists of four triangular 12”x12” Hollow Structural Steel (HSS) truss column sections, each 196’ in length. These tower column sections are supported by ten radius box truss sections constructed from 12”x12”, 8”x8”, and 4”x4” Hollow Structural Steel (HSS) sections. The trusses are completely shop assembled and delivered to the site for a specific erection lift sequence.
The legs are the primary supports for four linear plate sections, which serve as the primary track and guide for the ESAB weld tool. The linear plates consist of 3” thick, 5’-0” wide, by 196’-0” tall plates. There are two 12×45 wide flange sections welded full length to the back of each plate. These beams bolted every 6’-0” back to the tower horizontal truss sections to serve as the primary connection between the linear plates and the tower truss columns. Each 196-foot section is fabricated and delivered to the site in two separate sections. One is 92’-2 ½” long, and the other 77’-6” long. The two sections are then lifted in place with a Liebherr LR 1300 crane and then bolted back to the tower. Each plate section is machined to a specific tolerance for a precise fit-up of the gears, tracks, and stop blocks of the weld tool.
NASA is poised to take their next big step into deep space with the Space Launch System. Standing nearly 400 feet tall, it will be the largest and most powerful rocket ever designed by mankind. It will help take humans back to the moon, and even on newer, more exciting destinations like asteroids and Mars. And just like all the rockets and machinery before it, the Space Launch System will rely heavily on a new advancement in welding. Being involved in the construction and erection of this tool, and being part of a pivotal part in our countries history is a proud accomplishment for Bracken Construction Company.