Construction is Under Way!
September 12, 2008
The diversity of activities has increased and progress remains positive at the Mirabella at South Waterfront jobsite, now twenty weeks along. The jobsite is visible at lower center-left in the above photograph, taken from the 15th floor eco-terrace of the OHSU Center for Health & Healing.
A bird’s-eye view of the Mirabella construction site from the northwest shows the increased diversity of activities on the jobsite. Placement of driven grout pilings, approximately 50% complete at this time continues at the northern half of the site. Completion of driven grout pilings at the southern half of the site has allowed the commencement of the placement of reinforcing steel and formwork, followed by structural concrete (the first major pour is visible above; photo taken Sept 12) for pile caps and grade beams. Together with the driven grout pilings and (soon to come) slab-on-grade, the pile caps and grade beams make up the structural foundation for Mirabella at South Waterfront.
About a week before the above photo was taken, the earthen site access ramp (visible at the bottom center-right in the above photograph) was reconfigured for the final time from the mid-block of Curry Street to the western end of Curry Street at Bond Avenue. This reconfiguration allowed placement of driven grout pilings at the former location of the access ramp. Following completion of all driven grout pilings (mid to latter-October), the earthen site access ramp will be removed and all equipment and materials will access the site (until the ground floor is in place) via assistance from the tower crane.
A portion of the first major concrete pour at the Mirabella at South Waterfront site is visible in the above photograph. The pile caps and grade beams shown above are located along the River Parkway (eastern) edge of the site, near the southeast corner of the site. Approximately 100 cubic yards of structural concrete were placed on this day, Sept 12, 2008.
Following the placement of structural concrete, the top surface of a pile cap is troweled smooth. Reinforcing steel surrounding the perimeter of the pile cap is bent at a 90-degree angle to allow subsequent tie-in to the reinforcing steel for the pending slab-on-grade. The vertical reinforcing steel extending from the center of the above-shown pile cap will be tied-into reinforcing steel to comprise a structural column.
Once the structural concrete has set (approximately 24-hours), the wood formwork is stripped (removed), and re-used elsewhere on the Mirabella site. Wood materials that cannot be re-used are recycled.
The second major concrete pour is underway in the above photograph, taken Sept 17, 2008 and looking toward the southwest across the site. Shown to the left of the boom truck (used to facilitate precise placement of the pumped concrete throughout the site), is the large mat footing surrounding the pit for elevators 5 and 6, which will serve Mirabella’s podium (the six story portion of the building on the southern side of the site). In the foreground (lower left in the photo), the pile caps and grade beams poured on Sept 12 have received compacted back-fill around their perimeter edges.
