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The first challenge on this project was the addition of a 25,000 square-foot open ballroom. Deep, long-span steel joists and joist girders were specified for the roof structural system. Due to the required open ballroom space, no interior columns were used – this resulted in a joist clear-span of over 122 feet. Nearly all of the long-span joists were designed to bear on their bottom chords at one end and cantilever 10 feet beyond the main supports.
When fully completed, the ballroom will have two, track-operated partition walls that can be opened and closed to divide the space into three separate rooms or one large space. The operable partition walls are supported by the long-span joists. Due to the dynamic nature of the partition wall locations, New Millennium designed the steel joists for multiple partition wall conditions, including: 1) both partitions completely opened, 2) both partitions completely closed, and 3) one partition open, one partition closed.
When the partitions are closed and stacked, they are stored in a closet space directly underneath the 10-foot cantilevered steel joist ends. The steel joist cantilevered ends were designed to support the weight of both operable partitions in their fully closed positions. Combined together, the total design weight of both partitions exceeds 40,000 pounds.
Early in the project planning stages, New Millennium met with project managers from New Orleans Iron Works to discuss the major challenges and scheduling. To ensure a quick turnaround, New Orleans Iron Works prepared a steel joist and metal decking fabrication list and requested that New Millennium perform a back-check of the list compared to the structural contract drawings.
One of the biggest challenges proved to be the transport of the long-span steel joists to the project site. Due to the nearly 140-foot overall length of the steel joists, a field-bolted splice was installed to reduce shipping costs from the joist fabrication facility. Normally, steel joists with a field-bolted splice are delivered directly to the project site and assembled there prior to final placement. However, because this project was located in downtown New Orleans, construction storage space was very limited. New Millennium delivered the steel joists to New Orleans Iron Works's fabrication shop, which is located only a few miles from the project site. The steel joists were spliced together at the shop, transported to the project site, lifted off the truck and secured in their final locations. The steel joists never touched the ground at the project site.
This project was successful due in large part to the early collaboration between steel joist and metal decking supplier, steel supplier, and steel erector. The initial project meetings defined all related challenges, enabling the highly proactive design and delivery of a steel joist and metal decking installation that was vital to total-project cost accountability.
Project: Hyatt Regency
Location: New Orleans, LA
Fabricator: New Orleans Iron Works
Description: This project was part of a multi-phase renovation and expansion of the Hyatt Regency Hotel located in downtown New Orleans. Over 5,000 square feet of elevated floor space was replaced with new steel joists and deck, and over 12,000 square feet of new roof was added.
Here are three ways to improve metal decking performance and to cut costs out of your next metal decking project.
Flexible and collaborative engineering during the steel joist and metal decking design phase can remove a range of costs from most any steel project. As owners look more carefully at current inefficiencies in project design and planning, they are seeing a cascading cost effect.
Every ton of steel that can be removed during the steel joist and metal decking design phase can roughly translate to a thousand dollar reduction. This dollar reduction is just for material. A chain reaction of other significant, related costs can also be reduced. These hidden cost areas include transportation, on-site product handling, erection, and clash-based redesign and re-installation.
When New Millennium reduced tonnage on a recent project from 926.77 tons to 848.23 tons, this resulted in the deployment of five fewer trucks. This translated to $6,276 in savings to the project, related solely to the reduction in transportation costs. Based on a $10 per ton estimate for loading and unloading, the client on this project cashed in on savings of $1,700 for product handling.
On the same project cited above, piece count was reduced from 1,841 to 1,571, representing 14.7% reduction in the quantity of pieces to handle and install. While specific numbers were not calculated, based upon the approximate cost of $1 per square foot for erection, the project likely netted 10% in erection savings.
Collaborative and proactive design can also prevent clashes with mechanical, electrical, plumbing and fire suppression runs. For example, if five 30K12 bar joists need to be redesigned and re-supplied, estimated costs can be 2.1 tons at a price (variable based on steel costs) of $2,835, plus $1,025 for freight to the jobsite. Using a nominal cost of $60 per person per hour, all of these costs can quickly accrue. Even such a seemingly minor problem in the midst of a large project can tack on $6,360 to the original project cost.
Time is also big money on a construction site. Just moving a timetable back can result in huge losses to an owner or developer due to lost retail sales or delayed occupancy fees. Since the steel package occurs early in a project, highly collaborative planning here will influence the timetable for all work that follows.
New Millennium Building Systems is a wholly owned subsidiary of Steel Dynamics Inc.
