Reaching Permanent Grade and Caisson Installation *Completed*

Along the south wall, an excavator begins excavation of the last tier.

Overlooking the construction pit from the south shoring wall, Project Superintendent, Max Klingler, points toward the western wall where
excavation of the final level is underway. After all the sides have reached final grade, work can commence on the foundation and the
substructure. The last six-foot tier on the south wall, on which the Project Superintendent stands, attained foundation
grade in mid-October 2016.

The southeast corner of the construction pit has been excavated exposing the final tier at permanent grade. Final excavation will  continue along the
south shoring wall and the rest of the perimeter. Once the perimeter has reached the bottom level, the center of the pit will be excavated.

As the last cutback continues along the south shoring wall, a front loader levels out the southeast corner to meet permanent grade in preparation
of drilling a 41-foot hole in which to lower a 45-foot  rebar caisson.

Surveyors begin measuring for the placement of the first caisson.

A surveyor uses a laser as his partner stakes out the site.

The center stake is where the caisson hole will be drilled.

While the auger is being attached to the shaft, work continues on the south shoring wall in preparation of shotcrete.

A closeup of the auger being attached to the drill shaft.

The auger is being aligned with the spot where the hole is to be dug.

The drilling has begun.

The auger nears the bottom of the hole.

After the three holes have been dug, a flatbed truck delivers the rebar caissons (center), which will be lowered along the south shoring wall.

After the three holes are dug, proper precautions are made to prevent an accident.

To avoid any mishaps, two teams go over the final instructions before the caissons are lifted from the truck.

Cables are being attached to the rebar at specific points to allow for proper balance as each caisson is lifted from the truck.

With proper balance achieved, a caisson is lifted from the truck.

With the first caisson safely on the ground, the second is being lifted from the truck.

After the first two caissons were lowered into their holes, a steel cover is being lifted from over the hole. An iron worker on his knees at the right is
adding the last of many wire ties to the rebar.  The large cylinder on which the supervisor rests his hand is called a deadman (a weight) to which
a worker is tethered as they work around deep holes.

The caisson is properly strapped for lifting into the whole. The crane operator is waiting for the instruction to make the lift.

A top view of the deadman, which is about to be used.

Two ironworkers tethered to the deadman work around the hole prior to the rebar caisson being lifted into the hole. The worker to right is
holding the rope, which will help stabilize the caisson as it is lifted into the hole.

While the shoring wall rebar crew works on the last level section, the last caisson is lifted over the hole.

Another twelve feet to go till the caisson rests on the bottom of the hole. Note that the workers are still tethered to the deadman.

Once the caisson is set, the crew no longer have be tethered to the deadman. In the photo above, two ironworkers rush to ready a rebar caisson
“skeleton” (piling) prior to a cement pour.

With the caisson leveled a cardboard sheathing is placed over the top of the caisson, which is used to form the cement.

The cement truck arrives and is setting up to fill the hole.

Looking at the south shoring wall as the iron workers prepare the last level for shotcrete. The cement truck (lower left) continues to fill the caisson hole.

A surveyor marks an H-beam column indicating where the concrete foundation floor will meet.

After the cement has cured for a few days the cardboard sheathing can be removed and the horizontal rebar stabilizers can be cut off.

The caisson to the left, which is buried approximately 40-feet deep rises nearly four feet off of permanent grade. Once the bottom is graded and all the underground ducting is in place, a four-inch concrete mat will be laid. After other ducting and pipes are laid per the specs and reinforcement rebar has been installed a four-foot concrete foundation will be poured. The red arrow in the photo to the left points to the survey marking (4′ 10 1/2) on the H-beam, which is enlarged in the photo to the right. This horizontal mark was scribed on all H-beams surrounding the pit.

The last cutback on the west shoring wall and a portion of the north shoring wall were cut deeper than the stipulated depth and then recompacted.

To meet the final (permanent) grade, the soil must be excavated and compacted to meet the mark illustrated above. After the compacted soil meets
the level of the line, the permanent grade in the pit will have been reached.

Soil engineers perform one of the many periodic compaction tests with a nuclear density gauge.

A grader and scraper make their way along the north wall as the last tier are exposed and the soil compacted.

Heavy equipment makes the final adjustments to the permanent grade.

An excavator (left center) works from a narrow dirt pad as the pit widens to the permanent grade aided by the heavy equipment to the right.

Flags (overlooking the north shoring wall) on the Medical Center campus are framed by the excavator boom. The excavator loads dirt from
the narrow ramp near the bottom of the pit.

A scraper, a Padfoot roller, and an adjustable grader blade make final elevation adjustments to the permanent grade.

An excavator makes adjustments to the ramp at permanent grade.

On permanent grade, a cement truck and a concrete boom pump feeds cement into one of the five caissons positioned along the north shoring wall.

A closeup of the concrete boom pumper truck. The last cutback to the north shoring wall (at right)  is now exposed and will be prepared for shotcrete.

Three caissons with their cardboard sleeves were filled with concrete. The top of the caisson will be leveled to meet to foundation floor level.

A closeup of a recently poured caisson. The concrete crew in the background level and smooth out the top of the caisson.

After the caissons have cured for a few days the cardboard sheathing is removed and the horizontal support bars are cut off