Reinforcing the Shoring Walls With Soil Nails AKA Anchor Rods *Completed*

The first level of the south shoring wall has been cut back revealing the face of the embedded soldier piles. After the initial
cutback, a mini-excavator operator cuts the bank back another ten inches exposing three sides of the soldier piles.

A side view of the borehole drilling rig. The slope of the shaft is being checked a final time before drilling begins.

The borehole drilling machine at work: The compressed air ejects the soil out of the hole as the shaft goes deeper into the ground.

The borehole drilling rig operator adds another shaft to meet the depth specification of the next hole.

A closeup of the bit. As the bid goes deeper, the drilling rig sprays a jet of water along with compressed air into the drill hole.

A slope project track borehole drilling rig operator prepares to move the boom to another location.

A closeup of the borehole bit. The engineer checks the angle of the slope as the operator adjusts the angle. For this particular hole, the plans call
for a 30-foot hole at a 15-degree slope. According to the level, the angle is 1.8 degrees off.

A freshly drilled borehole. In this instance, the hole was drilled 53 feet into the ground.

PVC grouting tubes are being inserted into the hole before the prestressing anchor rod is slipped into the hole.

After the PVC grouting tubes are inserted a prestressing anchor rod is carefully inserted into the hole. Note the PVC centralizers properly spaced
along the anchor rod.

The markings on this soldier pile tell the story of this particular hole. This soldier pile is number eleven, the hole is at level C, and the plans call for
a 32-foot hole at a 25-degree slope.

Photo Left: Prestressing steel anchor rods with centralizers. Photo Above: A closeup of an anchor
rod and a centralizer. The centralizer keeps the rod in the center of the drill hole and to prevent the
centralizer from slipping as the rod is inserted, the centralizer is secured to the rod by wire.

After a borehole drilling machine drills an angled hole, the length of the anchor rod, through the soldier pile predrilled flange and into the soil, the
anchor rod is carefully inserted into the drill hole.

The bearing plate with a trumpet (sleeve) as viewed prior to being slid over the anchor rod.

Prior to sliding the bearing plate and trumpet over the anchor rod, the stiffener plate (AKA Kick Plate) must be at the same angle as the anchor rod. The bearing plate with the trumpet is welded at the top to the Soldier Pile and to the stiffener plate at the bottom.

The bearing plate with a trumpet is slid over the prestressing steel anchor rod. For this project, the bearing plates are three sizes in thickness.
The longer the rod, the thicker the plate. The longest rods demand a two-inch thick plate, the one-inch plate is used for the shortest rods, while
the inch and a half bearing plates are reserved for the middle length rods.

The heavy bearing plate with the attached trumpet is carefully being slid over the anchor rod. When this system is complete it must be watertight. Thus the angle at the top of the bearing plate will allow the bottom of the plate to properly seat to the bottom stiffener plate. The top will be
welded to the soldier pile and the bottom will be welded to the angled stiffener plate.

Once the bearing plate is properly seated a large nut is screwed on the rod to hold the plate in place.

The nut is tightened with a sledgehammer.

Sometimes a sledgehammer is used to persuade the bearing plate to line up with the stiffener plate.

Then there are times when an ordinary jack must be used when the sledgehammer won’t do the job.

A welder welds the top of the bearing plate to the soldier pile and the bottom of the stiffener plate.

The excess portion of the rod is cut off to make room for a rubber boot that will be placed over
the plate.

Photo Left: After cutting the rod three-quarters of the way through, a heavy pipe is used to knock off the end piece. Photo Right: The cutoff. The bottle of water is used to cool the blade
of the saw as the anchor rod is cut.

The welder has just inserted a Nelson Nail into the welding gun and is placing a ferrule, a ceramic ring, at the base of the nail. The ferrule is made
of ceramic and serves to concentrate the heat at the area where the nail is welded.

After the shotcrete dries, the Nelson Embed Nails (studs) are welded onto the soldier pile with a special stud welding gun, which provides a 360-degree weld around the nail. These headed nails are used to anchor the shotcrete foundation to the shoring wall. Note the vertical row of nails to the left of the welder.

A Nelson Headed Stud.

The welds on all of the Nelson nails are inspected and it if a nail does not have a complete 360-degree weld, a welder will complete the circle. The welder in this photo is completing the weld on one of the embeded nails.

Various lengths of prestressing steel anchor rods are laid out along with measured PVC grouting pipes.

The PVC grouting pipes are slid into the boreholes outside of the predrilled flange. Another example of how the PVC pipes are positioned to the side of the flange. Notice the black dimpled-weep-pads between the soldier piles.
The weep pads serve to drain water from the soil down the shoring wall to a PVC drain pipe at the bottom of the shoring wall.

Grout is being pumped into the drill hole directly from the mixer hose through a PVC pipe.

The mixing station where the grout is mixed and pumped through through the PVC pipes into the boreholes.

Another method of pumping the grout directly into the PVC pipe from the mixer hose is by pumping the grout from the mixer hose through
a galvanized pipe having a pressure gauge with a shut-off valve at the hose.

Pallets of bearing plates (various thicknesses) with attached (welded on) trumpets.

An illustration of where the prestressing anchor rods was placed in the first tier of the northeast corner. Due to the close proximity of the three anchor rods in this corner, extra bracing is required.

Engineers perform a load test on a soil nail with a Tension Pull Jack.

One end of a caliper is attached to an independent tripod with the other end attached to the tension resistance jack head. As the specified pressure is
applied to the pull jack, the caliper measures the pullout resistance per the applied to the pull jack, the caliper measures the
pullout resistance per the engineer’s specs.

An engineer (sitting) records the resistance as displayed on the caliper.

The yellow check marks on the wall above the soil nail plates indicate that the initial grouting step is complete and ready for the resistance stress
test. After the soil nail passes the test, the engineer sprays the face plate and anchor bolt blue. The anchor rod, which is undergoing the resistance
stress test will fail.

The failed soil nail above indicated by the absent blue paint awaits another test. The initial yellow check mark indicating the soil nail was ready for
the initial stress test was crossed out with red paint. The second yellow check mark indicates that additional grout was shot into the hole
and is ready for the second resistance test.

 After the grout dried another stress test was performed. The blue paint indicates the
soil nail passed the stress test. The next step, the threaded extension will be cut
off just above the nut.

The bearing plates get a final sealant application before the final waterproofing application.

The shoring walls surrounding the project pit. The last tier has been excavated along the south wall. The north, east, and west walls have
one more tier to excavate. This photo taken from the east wall looking west toward the existing Medical Center
complex reveals the enormous size of the project.The new structure will rise approximately ten stories above
the existing building. From the vantage point where this photo was taken, the Medical Center will be
totally obstructed when the new hospitals are completed.