In its quest to become the premier residence/hotel in Baltimore’s burgeoning Harbor East, the Four Seasons group enticed nationally renowned chef Michael Mina to put his marque on the food service. Named the “Wit and Wisdom, a Tavern by Michael Mina”, the dining area features an elliptical shaped spirits bar having an elliptical, bell shaped dome, suspended overhead and concentric with the walnut bar top.
Armada Hoffler, builder of several other high rises in the area, had a tight schedule and budget to complete this restaurant fit out so it engaged engineers, Morris & Ritchie Associates, to design the structural frame and supports for the “bell”. After the design was nearly complete “B&B” was consulted by Morris & Ritchie to advise upon the constructability of the design and we told them we could do it.
The lower elliptical ring was comprised of 6×2 tubing, rolled the hard way, with four different intersecting radii, to form a 32’x12’ ellipse. Three different intersecting radii of 6×4 tubing, rolled the easy way, were used to form the upper ring with axes of 22’-6”x4’-0”. Connecting the lower and upper ellipses were 12 tubular ribs, 6”x 4”, rolled the hard way, with two intersecting radii of 12’-1 ¼” and 6’-0 ¼” to form a smooth curve, spaced evenly around the perimeter. In between the structural ribs were 20 gage roll formed ribs, matching our rib geometry, manufactured by Radius Track Company, and installed by Deming Brothers Company. Because all the steel skeleton was to be covered by GFRG (glass fiber reinforced gypsum) that was pre manufactured in panels to the architect’s specifications, B&B’s work had to be precisely fabricated. For that reason we chose fellow AISC member, Chicago Metal Rolled Products, to produce all the radiused tubing.
Specially impressive was the close tolerance of their work and the welding they saved us by doing multiple radii on one of the elements, the ribs.
Since upper and lower ellipses were concentric the shop layed out abcissas and ordinates for both ellipses on one fixture to effect the smooth geometry required of both. Once both rings were fit up and welded the entire double ring and rib assembly was preassembled, using erection lugs that would be used again in the field, to verify final geometry. Due to the size of the lower ring we had to design a splice joint that would allow it to be taken into the final position in the restaurant in two pieces.
Attachment to the underside of the slab above was by hangers from 5 beams epoxied into very specific locations. Because of utilities embedded into the slab, we engaged Tri-State Concrete Scanning to locate anything that would interfere with the drilling for epoxy bolts.
Working points, struck on the floor by Armada Hoffler and locating the extent of the bar, were used to locate the beams in the ceiling, and they were the “beacons” guiding the erection of the bell which began on adjustable positioning stands at floor level. Five of “B&B’s” erectors started at 0530 hrs, drove to the site, took all the pieces into the bar area, began putting the bell together in position on the leveling stands, and by lunch time had the bell located on the work points ready to be final welded. Four days later welding was completed, Deming Brothers had completed the light gage infill, and the GFRG installer began fitting his outer shell panels. Upon completion of the outer GFRG we hoisted the work completed thus far up to elevation for finishing the inner GFRG, lighting, and accessory work.
When having a pint, or more, at that unique bar one will only have to worry about their headache from too much alcohol, but never about the 3 ton “bell” hung over their head by Baltimore’s premier fabricator.
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