2012年，明尼苏达大学决定复活旧的主要供暖厂，这是一个由1912年建造的蒸汽发生厂，在密西西比河银行的前石灰石采石场，进入了新的和创新的东西。在其几十年的使用中，该设施经历了几种装修来解决大学的增长。However, the Old Main Heating Plant’s latest iteration would be the most impressive: retrofitting an outdated steam plant that once used seven coal and gas-fired boilers to generate steam into an efficient, state-of-the-art, combined heat and power plant. With the installation of a jet engine-driven turbine and a massive heat recovery system, the Main Energy Plant would address the University of Minnesota’s increased demand for power and steam and help the university progress toward its goal of reducing campus emissions by 50 percent by 2020.
旧主要的环境评估和修复
为了踏上这种节能探险，大学首先需要解决主楼内的危险物质，毗邻退役的焚烧炉建筑和泵房，以及整个遗址的受影响的土壤。manbet体育滚球布劳恩Intertec由明尼苏达大学保留，以帮助评估危险材料，并在包括焚烧炉建筑物中的旧主体设施。在外面，布劳恩Inmanbet体育滚球tertec与大学合作，准备环境响应行动计划/建设应急计划，以解决整个网站的知名和未知的影响。
最终，整体环境修复项目从七个锅炉及其相关管道中取出了含石棉的隔热材料;从陈旧的加热设备控制面板和其他仪器中恢复超过500磅的液体汞;去除近10,000平方英尺的汞催化聚氨酯地板;去除铅涂料;拆除了前焚烧炉设施，这些设施也含有烧伤的医疗废物的灰烬;拆除了两座前泵房建筑，也需要恢复大量的燃料油，并且由于该网站被后悔支持新的通道道路，因此填埋数千吨的受影响的土壤。在整个网站分级努力中，保留了Braun Intertec以提供全日制观察manbet体育滚球，因为受到影响的土壤得到修复，并解决了其他环境影响。
Laying the Groundwork: Geotechnical Evaluations
Before construction of the Main Energy Plant and installation of the new co-generation systems could begin, the university and its design team needed to better understand the site’s soil and groundwater conditions. As the geotechnical engineer for the project, Braun Intertec undertook an extensive historic review of the past evaluations on the site. This review resulted in the development of a final geotechnical program to address the support of new features inside the combined heat and power plant as well as construction of the new access road, which replaced a difficult to navigate switchback drive and the massive retaining wall that would support the limestone and soil bluff created by the Mississippi River and the quarry. Inside the building, the evaluation showed that a combination of high-capacity spread footings could be used where the sandstone bedrock was shallow and deep micropiles were needed where the old river channel was found.
New Tricks for Old Structural Steel
Once the geotechnical review was complete, the project advanced to the renovation of the Old Main facility. One of the many challenges that surfaced during this project was concern that the 1910 era structural steel may not be weldable as new structural steel was added to the plant. Fortunately, Braun Intertec had just finished working with similar era structural steel on theUniversity of Minnesota’s Northrop Auditorium renovation project, another historically significant structure on campus. Braun Intertec ultimately implemented a testing program with the knowledge gleaned from the Northrop Auditorium project to address the welding concern. This testing program found the chemical makeup of the old structural steel was not compatible with modern-day welding techniques. If exposed to welding heat, the old steel would become brittle and lose its load carrying capacity. In order to maintain the structural integrity of the Old Main building, our engineers worked with the design team to develop a modern-day plate bolted to the old steel detail to allow new structural steel to be added to the interior.
Braun Intertec和建筑团manbet体育滚球队面临的另一个挑战是，建筑物的后壁在1911年倒在旧采石场的脸上。布朗Intertec使用混凝土取芯器通过混凝土墙来核心，结果高达四英尺厚。通常，在墙后面发现了一个空隙。将一台小型摄像机插入核心孔中以录像到墙壁上的空隙和背面的条件，然后再重新密封另外100年左右。
Keeping It Up to Code: Special Inspections and Testing
The plant, constructed under the guidelines of the Minnesota State Building Code, also required special inspections and testing. Braun Intertec was retained to provide these services which included soil testing, concrete testing, reinforcement placement observations, structural steel observations and testing, micropile installation observations and testing, structural masonry observations and testing, shotcrete observations and testing, post-installed anchor observations and testing, fireproofing inspections and testing, intumescent paint observations and testing, bituminous testing, roofing observations, rock anchor observations and testing, and ongoing geotechnical consulting services.
节能效果
Completed in 2017, the Main Energy Plant is expected todouble the energy efficiency output of the old plant，节省明尼苏达大学估计每年营业成本200万美元。综合的热量和发电厂还将减少碳排放量估计10％至13％，有助于大学实现其可持续性目标。
This project has received several notable awards for its extraordinary achievements including the 2017 Minnesota Brownfields ReScape Award for Environmental Impact; the 2018 Minnesota Construction Associations’ Award of Excellence for Green/Sustainable projects; the 2018 ACEC/Texas Engineering Excellence Gold Award for Energy project and a 2018 National Recognition Award at the National ACEC Engineering Excellence Awards competition.
