Virtuoso Performance-Alliance Riggers and Constructors, Ltd.

Carlsbad Performing Arts Center, Carlsbad, N.M.

Structural Class IV (Over $2.5 Million)

Erector: Alliance Riggers & Constructors

Fabricator: W&W | AFCO Steel LLC

Detailer: W&W | AFCO Steel LLC

Structural Engineer: HKN Engineers

Architect: NPSR Architects

Construction Mgr./GC: Jaynes Corporation

Contract Value: $3.7 Million

Tons of Steel: 738

Alliance Riggers & Constructors Ltd. welcomed a few big challenges when it won the bid to erect 738 tons of steel and 61 precast-concrete panels needed to build the new Carlsbad Performing Arts Center in Carlsbad, N.M.

Its first challenge was logistical.

To complete its part of the project, the Alliance crew of 25 would be working about 170 miles from home for about six months. Also, Alliance would have to transport about 65 truckloads of cranes, forklifts, service trucks, and other equipment from its El Paso, Texas, headquarters to the jobsite.

The second challenge was that the construction would take place on a highschool campus during the school year. That meant work had to stop when the students moved from class to class during the day, heavy lifts would be made when nearby classrooms were empty, and steel would be hung during off hours when possible.

The third would be working on an extremely tight site to tilt up cast-on-site concrete panels that stood up to 79 feet tall, measured 8 to 22 feet wide, were 8 inches thick, and weighed up to 225,000 pounds with rigging. This was further complicated by the need to immediately install structural steel that tied each concrete panel in shortly after it was erected, particularly the tallest ones.

Alliance Riggers’ final challenge was doing it all using a single access point, since the new performing arts center sits between three other buildings, one of which is just 15 feet away.

Owned by Carlsbad Municipal Schools, the facility covers 79,000 square feet, seats 1,100 guests, and is a venue for all of the Carlsbad community’s performing arts.

Vital Planning and Communication

A major key to the project’s success was meticulous planning and frequent, clear communication between Alliance, general contractor Jaynes Corporation (which also cast the concrete panels), the project’s owner, the architect, the engineer of record, and the steel fabricator.

Alliance began by using AutoCad and 3D Lift Plan as it bid the job in 2022, more than a year before the physical work started. “You can’t even bid a job this complex without a solid plan,” said Alliance co-owner and CEO Phil Cordova.

As Alliance developed the panel- and steel-erection layouts in AutoCad and 3D Lift Plan, the information could be transferred into Jaynes’ building information management (BIM) system so everyone on the project team stayed on the same page.

During both planning and execution, Alliance used 3D Lift Plan to run though each significant crane lift, including the wall panels, structural steel in the stage area, roof trusses, and grand stair. It used AutoCAD to do all of the panel layouts and placements, including the crane path, and cut sections to show crane clearances.

Cordova said that in addition to the planning, continual clear communication and cooperative relationships between all entities was key to the project’s success. “This cooperation enabled everyone to make the adjustments that are typically needed as a job progresses, whether it was the GC, the engineer of record, or the steel fabricator, everyone worked together smoothly.”

Anthony Ortiz, Alliance Operations Manager, gave one example of how the erector’s strong relationship with steel fabricator W&W | AFCO Steel benefited the job.

“From contract receipt to completion, the team at W&W was always accessible and ready for any change,” said Ortiz. “For example, on short notice we decided to oversize the embeds on the concrete wall panels as redundancy. W&W made the changes just a week before placement.”

In addition, smooth coordination between W&W and Alliance was vital to proper sequencing throughout steel erection. Said Ortiz, “There was no spare space on the jobsite, so we used part of the student parking lot as our laydown area. It was about a quarter mile from the erection site, and students were using it. So W&W could only deliver a load of steel when no students were in the lot, and each load could include only the pieces we would erect in the next few days.”

Using In-House Fleet

Alliance brought a full cast of its own equipment from its El Paso headquarters to the Carlsbad project site.

The big star of the show was an 825-ton capacity Liebherr LR 1750 lattice-boom crawler crane with 253 feet of boom. Its reach and capacity were needed to upright the tallest and heaviest precast concrete panels, to set roof trusses and heavier pieces of structural steel, and to pick and place other cranes and equipment on the site.

Other lifting equipment in the cast included a 110-ton capacity Liebherr LTR 1100 teleboom crawler crane, a 60-ton Grove teleboom crawler crane, a 13,200-pound capacity Magni RTH 6.35 rotating telehandler, and a 26,500-pound capacity Merlo P120.10 fixed-body telehandler.

Alliance also had its Tadano AC 250 all-terrain crane on site long enough to assemble the LTR 1750 crawler crane.

The LTR 1100 primarily set structural steel; the Grove crane set miscellaneous steel including stairs and exterior loose-steel work; the Merlo P120.10 fixed-body telehandler shook out steel at the laydown yard, carried it a quarter mile to the building site, and hung low-level steel, and the Magni RTH 6.35 rotating telehandler set lighter steel and also handled four long temporary braces that supported each precast concrete panel until it was secured in place by structural steel.

Placing Panels and Steel

As each tall panel around the stage was set into place, Alliance connected four temporary braces to hold the panel upright until it was locked permanently into place by structural steel. Each of those extra-long braces connected to the panel at a height of more than 40 feet and weighed 1,000 to 1,600 pounds, far too much to manhandle. So, Alliance lifted each brace into position using the Magni RTH 6.35 rotating telehandler equipped with a winch.

As the LR 1750 placed the building’s concrete wall panels in a carefully planned sequence, the Magni rotating telehandler and the 110-ton capacity LTR 1100 teleboom crawler crane set perimeter structural steel and columns to lock them in place. To ensure safety, Alliance closely coordinated the movement of each piece of equipment, every brace, and each piece of panel reinforcing steel. That included monitoring weather and wind speeds.

When panel placement and perimeter steel erection had been completed on all but the closeout panels, the LR 1750 traveled out of the building and set up on a crane path, from which it reached over the building to set three trusses, each 120 feet long and weighing 35,513 pounds with rigging.

Each truss arrived on site as three pieces, which Alliance spliced together on the ground before the LR 1750 set it in final position.

The truss sections were first bolted together before their top and bottom chords were welded to those of the mating section with full-penetration welds. The splices were made on extremely cold days, so Alliance’s welders preheated all the connections, and each weld was verified by an on-site inspector.

When the trusses were in place, the LTR 1100, the Magni RTH 6.35, the Merlo P120.10, and the 60-ton Grove crane erected the rest of the structural steel, roof decking, four catwalks, and a grand stair. In all, they set 588 tons of structural steel, 85 tons of miscellaneous steel, 50 tons of decking, and about 15 tons of joists.