The Council on Tall Buildings and Urban Habitat has designated the 284-ft-tall Ascent in Milwaukee as the world’s tallest timber and concrete hybrid structure. The 25-story Ascent has broken height and size records both for pure timber and composite timber and concrete structures anywhere—but by only 4 ft in height.
The 488,000-sq-ft residential building barely exceeds the height of the world’s tallest pure-wood building—Mjøstårnet, a 122,000-sq-ft mixed-use building in Brumunddal, Norway, completed in March 2019. Measured in meters, Ascent is 86.6 m, Mjøstårnet is 85.4 m and the timber-concrete hybrid mixed-use building, HoHo, in Vienna, is a close third at 84 m.
After Ascent, the second tallest timber-concrete hybrid in the U.S. is the 39.6-m INTRO-Residential Building in Cleveland, finished this year. The Cleveland building is 30thon the council’s tall timber building list.
Construction of Ascent, designed by Korb + Associates Architects with structural engineer Thornton Tomasetti, began in August 2020. The first tenants began moving in through the 14th floor on July 15. The rest of the building is expected to be finished at the end of August.
Completion was originally set for July 1. “We had supply chain issues,” says Tim Gokhman, managing director for Ascent’s local co-developer,New Land Enterprises，与Wiechmann企业合作。
Construction of the superstructure’s timber frame went “as well if not better than expected,” says Gokhman. Contractor C.D. Smith eventually reached a 5.5-day cycle, decreasing it from the initial 10 days.
Ascent also exceeds Milwaukee’s 85-ft height limit for wood buildings, which is why it took two years to get approvals from the city. In Milwaukee, there was no permitting path for such a tall timber building. There were also no U.S. precedents for grand-scale “supertall” timber-and-concrete building development, financing, insurance, design, detailing, material procurement, fabrication and construction.
Pioneering Tall Timber
New Land considers tall timber a market differentiator for downtown residential development, based on wood’s beauty and growing popularity as a renewable building material.
不过，“从开发商的角度来看，我们都理解并误解了从代码的角度来看，这是多大的，” Gokhman说。
密尔沃基的协作差异模型helped smooth the approval process. Still, to get the nod from building and fire officials concerned about the safety of the structure in a fire, the Ascent team developed and incorporated appropriate studies, tests, evaluations and had industry experts in fire engineering as consultants.
For approval, the city required a temporary standpipe system, installed up the elevator core, in place from the beginning of the timber installation through final occupancy. Also, the permanent fire protection system was operational prior to occupancy.
有两种供水和消防洒水装置的供水，因此，如果一个供应失败，另一个供应可能仍然有效。并且每个活单元内有增强的烟雾检测。
此外，Ascent以石膏混凝土墙壁覆盖物的形式在公共走廊上具有现场混凝土楼梯间和更健壮的防火。
减少d Construction Time
该团队估计使用质量木材的某些结构将施工时间降低了约23％。Ascent由C.D.建造Smith和Catalyst构造使用了严格详细的数字双胞胎。这允许每个光束，圆柱和面板在现场准备好组装，孔的孔可预计在1/16英寸之内。准确性。
坐在六层楼的结构混凝土停车领奖台上的19层木结构居民空间，仅包含超过80,000立方英尺的胶层木制木材，该木材固定在1,150个胶状柱中，有17种不同的尺寸，1,320个尺寸为50尺寸的Glulam横梁36个不同的长度。上升还包含336,000平方英尺的跨层压木材（CLT）。
At a July 20 press conference, Gokhman, talking about the renewable material, said the wood used in the building is replaced by natural growth in North American forests every 23 minutes.
为了抵抗重力负荷，塔是计划中的矮小的L，具有支撑CLT地板膜片的亮膜柱和横梁。像Glulam一样，CLT是通过在压力下将木材粘合在一起以制成层或底层的工程木材。与Glulam的平行层不同，CLT的plies彼此垂直。
该塔的六级讲台具有后张紧的地板板。两个全高混凝土核心抵抗讲台和塔中的横向载荷。基础由162个桩组成，长125英尺，在核心壁下方支撑垫子或柱子下方的桩帽。
迄今为止，259个单位中有100个租赁，这是在预测之前。
Gokhman says the overall experience developing Ascent has been very positive. Barring unforeseen circumstances, New Land plans to do another mass timber high-rise in Milwaukee.
