COVID-19. Although the department has shut down due to the COVID-19 situation, we thought it would be helpful to continue to supply information about the progress of various construction projects—at least to provide as much information as we can get. Here is an update as of Friday, March 20. At this writing we don’t know whether or how COVID-19 is going to affect progress of construction.
New Tower. The concrete floor of the west side of the eighth floor of the tower was poured last Tuesday. The east side of the eighth floor has been partially prepared for pouring concrete this week, but this may not happen on schedule depending on safety precautions required for workers on the job. Nevertheless, the view from the roof of Chamberlin Hall on the other side of University Avenue shows that the new tower now almost completely obscures Daniels and is beginning to rival both Shain and Daniels in height.
Bubble Deck. The upper floors of the new tower are almost completely made of “bubble deck:” biaxial hollow-slab concrete construction. Bubble deck was invented in the 1990s in Denmark and has been more widely adopted in Europe than the United States so far. By replacing significant volumes of concrete with hollow plastic spheres, the mass of a poured-concrete floor can be reduced by about 35%.
Bubble deck works because the top of a floor slab must resist compression, while the bottom of the slab has to resist tension. The middle of the slab contributes little to structural integrity. Even though the hollow plastic spheres replace much of the concrete in the middle of a slab, the slab provides the same strength. Pouring a bubble deck is trickier than a normal deck and must be done in two stages. Unless the rebar-sphere combination is tied down it can float on the concrete. On at least one occasion consultants from other firms have come to our site to see how Miron Construction handles its concrete pours that involve bubble deck.
Bubble deck is important in our building because the weight of non-bubble-deck floors would have exceeded the capacity of the trusses that span the two large lecture rooms in the sub-basement. Bubble deck is important in general because it saves concrete: One kilogram of recycled high-density polyethylene (and the air inside it) replaces 100 kilograms of concrete. Saving concrete in turn saves energy: 100 kilograms of concrete requires about 116 kJ to manufacture. Each plastic sphere replaces about 68 kg concrete and there are thousands of spherical voids in the floors in our building. So, we’re helping recycle plastic and saving lots of energy as well!
Chemistry Learning Center. Work on the new home for the Chemistry Learning Center continues on schedule for occupancy in mid-May. Offices and teaching spaces have taken shape with walls and painting complete and some whiteboards installed. Floors and ceilings are not yet finished, nor are heating and ventilation. Nevertheless, assuming construction can continue during the COVID-19 shut down, the CLC will be in its new space this summer.
Fire Sprinkler Project. Work is scheduled to begin on the fifth floor this week, with a walk-through Monday morning to check that all labs and offices have been secured. Both the fifth floor and the third floor have been secured for fire-protection work that we hope can continue while the department is shut down.
This information is up to date as of Friday afternoon. Email bulletins will be provided as needed.
John Moore and Bob McMahon