By Tony Heath, Project Engineer
This blog post covers August 21st and August 22nd.
WED, AUG 21: Howdy!
Today was a smooth day at the rain garden as we picked up where we’d left off yesterday morning when the tornado sirens drove us inside. After getting about 1/2″ of rain yesterday, I was worried that the soil in the garden would be overly soft this morning, leading to additional compaction from the construction equipment. Fortunately, the trees had kept the soil drier than I’d anticipated. When excavating near the London Planetree, we were able to keep the back-hoe away from the tree protection area to minimize compaction. The newly installed soil in the south cell did its job well – those areas were completely dry when we arrived on site. As we were excavating for the new sidewalk, we began to uncover some woodier roots around the 10″ depth. Fortunately, we only found a few and we were able to leave them in place with minimal damage.
In the afternoon, once the full length of the sidewalk had been excavated, Josh and Stephanie began placing the stone sub-base, which will underlie the new concrete. I took a video, shown below, of Stephanie placing a load of base material and Josh spreading it. We were able to get the area from the bike racks nearly to the London Planetree placed and tamped down. We will finish the rest tomorrow. Once that’s complete, we’ll notify the concrete finishers that the site is ready for them and they will come set their forms and start pouring. The bridge abutment requires additional excavation along the sidewalk. We thought it would be helpful to lay out the bridge pieces all at once, so we decided not to excavate the additional footprint today and do it towards the end of construction.
Stacey DeLorenzo visited on-site this afternoon to check on progress and to confirm that we’re going ahead with a 4′ extension of the north sidewalk. We also discussed the granite delivery and install date, which will be sometime between Wednesday, 8/28 and Wednesday, 9/4.
THURS, AUG 22: Howdy all,
Today was a slow day at the garden. It was drizzling when I arrived on-site this morning, but it wasn’t enough to slow us down. The south cell continues to sop water up like a sponge and I almost wish it would storm so that I could really see it in action (SPOILER ALERT: it rained on Monday, Aug 26th). The erosion control fabric we installed along the bottom of the swale is continuing to function as well, catching leaves and preventing the bottom of the swale from washing out. The ground was a little softer this morning due to the rain. Thankfully, we had already finished excavating the path for the sidewalk expansion, so we were able to avoid driving the machinery over it and compacting the soil.
Josh and Stephanie spent the morning finishing laying the sub-base for the sidewalk expansion while I staked out the rough limits of the north bridge abutment so that we could excavate that out as well and lay additional stone. The framers will mark it out more precisely when they get to it, but this was just enough so we know where additional stone needs to go. Josh asked Andre, the truck driver, to pick up the mini excavator, which will be used for the majority of the remaining work. We didn’t need it this afternoon because Josh was drilling dowel rod holes in the sidewalk for the concrete finishers, but we’ll start to use it tomorrow.
Tomorrow we’ll use the mini excavator around the edge of the north cell where the decomposed granite will be placed, as well as excavate the area on the north side for the bridge abutment. Once that’s finished, our F&S crew will use the mini excavator for the final piece of mass grading, widening and deepening the two main storage areas in the north cell.
Can’t wait to hear about the rest of the team’s visit to the Lurie Gardens!