A constrained urban site. An ambitious completion deadline. A booming construction market with limited craft labor availability.
Ordinarily, these factors are a recipe for projects fraught with execution headaches and cost concerns, particularly during the construction phase, when anything can happen and often does.
然而，对于丹佛市12层Sova公寓楼背后的设计和建筑团队，这些挑战为将预制技术提升到新水平的机会从字面上和象征性地提升到了新的水平。
除了构成Sova 211单元内部的预制钢板墙板外，上9个级别的外墙利用本地制造的承载板。By shifting an even greater share of field tasks to a controlled, off-site environment typical of prefab projects and then executing a meticulously planned site construction sequence, the team is helping Denver-based developer McWhinney meet the high demand for residences in the city’s Uptown district. The upscale building is set to open in February 2019.
Laura Eathorne, preconstruction department manager for project contractor The Weitz Co.’s Rocky Mountain division, notes that while speed to market is always critical for multifamily projects, a host of issues, such as noise restrictions due to adjacent residences, compounded limitations of the site’s zero-lot line and near-zero laydown space.
“我们研究了许多场景，进行预制结构，外观是最好的选择，”埃索恩说。
Carrying out such a strategy likewise demanded several key ingredients, the most critical of which was a higher degree of upfront planning.
“We had to decide day one if this was the way we were going to go,” says Eric Bottenhorn, director of design for Craine Architecture, Denver.
Because the panels would be delivered with architectural finishes already applied, Bottenhorn says, “relatively small details such as window and vent placement, which typically follow the design, had to be resolved early to be incorporated into the manufacturing process.”
Equally critical was coordination across the design and engineering team, Weitz, and the manufacturers of prefabricated components. Infinity Structures, Alpharetta, Ga., would produce and ship the interior panels, while South Valley Drywall Inc., in nearby Littleton, Colo., would produce the exterior wall units.
“Clarifying roles and responsibilities is particularly critical,” observes Greg Reindl, project manager for SOVA’s structural engineer-of-record, KL&A, Golden, Colo. “There’s a lot going on, and everything needs to fit.”
South Valley’s six-year-old prefab unit had produced load-bearing exterior panels for curtain walls, but CEO Travis Vap says the synthetic finishes specified for SOVA presented a new challenge.
He explains that finished exterior panels typically are left with the areas surrounding the pour spouts exposed until the next floor slab is placed. Crews then clean the area and apply the last finish strips before moving on to the next level.
VAP说：“鉴于Sova的空间限制，我们希望消除尽可能多的脚手架的需求。”“这意味着确保每个细节都是精确和到位的，因此除非细节需要注意，否则我们不必回到外面。”
Eathorne says Revit and other BIM tools proved invaluable in sharing information across the project team as design details were finalized. “Virtually, we built the project 100% before putting a shovel in the ground,” she says.
Rapid Construction
Work at SOVA got underway in April 2017, with excavation and installation of a 45-in.-thick mat slab for underground parking. Three additional 8-in.-thick, post-tensioned levels rise above street level. They provide additional space for parking, a ground-floor lobby and six townhouse units. A 24-in.-thick, post-tensioned transfer slab on Level 4 transitions to the prefab, load-bearing panels, to be delivered separately by Infinity and South Valley.
As SOVA’s lower levels began to take shape toward the end of the year, South Valley began producing 483 exterior panels at its 37,000-sq-ft prefab facility. Averaging 10 ft by 26 ft to accommodate balconies and setbacks, the one-story, steel-framed panels included a mix of 103⁄8-in.-thick units with thin-brick veneer, and a 9-in.-thick version with a textured finish.
在南谷的工具中，有一台定制的机器“ Charles”，该机器命名为VAP的祖父，该机器使用BIM设计信息进行水平，Square和每个面板的平面和1⁄32英寸的凹槽。准确性。
VAP说：“查尔斯可以与一位运营商一起完成通常需要三个人的东西。”他补充说，该机器可以容纳最大15英尺宽的面板。他还估计，将需要150名工人来制作该领域的面板 - 南山谷的制造业人员。
虽然预制被吹捧为治疗the construction industry’s growing craft labor shortage, Vap asserts that his firm’s process is actually building craft skills.
“Our craftsmen can do things better than they ever could in the field, while new carpenters have a valuable training opportunity,” he explains. “Once they learn and master a task, they can move on to the next one.”
As the panels were completed over three months, they were packed and stored in trailers at South Valley’s facility to await jobsite delivery in sync with the construction schedule. Autodesk AutoCAD, Revit, Bim 360 Field and Bluebeam were used to model the loading and trucking process. “Even utilization of the trucks and trailers has to be optimized, or else you risk adding to the shipping costs,” Vap says.
That would prove critical at SOVA, where there was curbside space for only one trailer each from South Valley and Infinity.
“This system allowed us to have product as we needed it,” says Weitz senior project manager Kevin Butts. “There were never any issues with a truck arriving with the wrong panels or loaded in the wrong order.”
外部和室内面板由塔起重机吊起，由密西西比州哈蒂斯堡的MDA Construction安装，该建筑处理了许多Infinity的项目。新利18备用网址尽管该建筑物以楼梯状态上升，但Butts估计要完成每个级别的平均三周，包括外部和内部面板，MEP粗糙，并放置51⁄2英寸的网状板块对于下一个楼层。
Completing the enclosure at the same time as the structure, Butts says, allowed Weitz to get started on inside work long before SOVA’s roof deck was installed in mid-July.
“That’s the point where we’d normally begin a project’s assembly-line phase, installing kitchen cabinets and the like,” he says. “But we’ve been doing that on the lower levels for quite a while, which is what you want to achieve with prefab.”
Although most members of the SOVA design and construction team had at least some experience with prefab construction at the project’s outset, Bottenhorn says the team recognized that an extra level of effort would be needed because the architectural finishes were integrated onto the load-bearing panels.
“As we became more familiar with the program and process, we got more comfortable with it,” he says. Butts agrees, adding that prefab also benefited the SOVA project by allowing for a safer, more professional-looking jobsite, as well as providing savings on everything from dumpsters to parking costs for the specialty contractors’ staff and vehicles.
“This is the way projects should be done,” he says.
