Constructing the Sub-Grade Structural Wall

After the foundation has been poured, preparation begins for the installation of the shotcrete walls, which, when finished, coats the existing shotcrete shoring walls. Over the existing shotcrete shoring wall, a waterproofing membrane called a weep pad will cover the shoring wall. On top of the weep pad, a carpet-like material called Voltex, also a waterproofing material will be installed. After this step is completed, the prefabricated rebar diaphragm will be hung over the Voltex. Once this is completed approximately ten inches of shotcrete will be sprayed on the wall with a high-velocity hose. This featured black and white image depicts the rodbusters as a large crane lifts a prefab section of
rebar on to the northwest shoring wall, which will be anchored to previously positioned rebar.

01.17.17 – 1

After the foundation has been poured, the prefabricated rebar diaphragm walls can be hung over the existing shoring wall. A mockup of the system was made on site for inspection purposes on January 17, 2017. Because the rebar is hung vertically a prefabricated system is less labor intensive on the site.

04.03.17 – 2

After the foundation has been poured and before the stem wall is formed and poured with concrete, Voltex must be installed separating the concrete

from the shotcrete shoring wall.

04.20.17 – 3

One of the fist steps in constructing a sub-grade structural shotcrete wall is to install a waterproofing system over the existing shotcrete shoring

wall. In this photo, laborers are hanging the black dimpled weep pads. Over each soldier pile, a strip of gray Voltex is hung, which must be installed

before the stainless steel galvanized boot is inserted over the bearing plates. This process allows for a tighter waterproofing seal.

04.26.17 – 4

Looking at the north shoring wall one can see the steps in the waterproofing process.

04.26.17 – 4

Looking at the north shoring wall one can see the steps in the waterproofing process.

04.21.17 – 5

One of the fist steps in constructing a sub-grade structural shotcrete wall is to install a waterproofing system over the existing shotcrete shoring wall. Once all of the Voltex is installed a waterproofing sealant will be applied around the edge of each boot.

05.30.17 – 6

It takes two men to slide the boot up a wooden ramp. How they get the boot over the bearing plate is shown in the following video.

05.30.17 – 7 Video

It is said, “necessity is the mother of invention.” When the installation of the galvanized boot was first tested it took three workers: two to hold

the boot up to and over the bearing plate while the third forced the boot up against the shoring wall with a long two-by-four as a lever. Someone decided

this method would be too time-consuming and would be very difficult. A unitary triple-screw pusher was fabricated, to set the boot flush against the

shoring wall with a pneumatic tool, which does the trick–thank you very much!!!!

06.06.17 – 8 Video

The previous video illustrated how a galvanized boot filled with a waterproofing material was installed over a bearing plate that was only a few feet off of the foundation slab.

Once the bearing plates reach a height of five feet or higher a hydraulic boom must be used as illustrated in this video.

05.30.17 – 9

The unitary triple-screw pusher holds the boot securely and flush with the shoring wall while the flanges are nailed to the shoring wall.

04.21.17 – 10

A closeup of what the dimpled weep pads look like. This same material was placed between the compacted earth and the shoring wall.

05.24.17 -11

The northwest section of the shoring wall has been covered with a Voltex water sealing material. A polyurethane type foam (light blue) is cut to size to fit along the top of the stem wall to separate the finished shotcrete wall from the concrete stud wall. The diaphragm rebar will be hung on the  Nelson Stud Nails. Note how each and every strip is aligned and brought together creating a very tight seam. Just like the blue polyurethane foam, the Voltex serves as a break between the shotcrete shoring wall and the structural wall. Each wall will be independent of the other with the exception the tie to the Nelson Stud Nails, which are welded to the soldier piles. The soldier piles are common to both walls.

04.26.17 – 12

The west wall is now ready for rebar, which is being offloaded and stacked on the foundation slab.

05.26.17 – 13

The structural wall, depending on sections, will range from 10 inches to 16 inches thick. In this photo, Alex is marking a transition point where the thickness of the wall will change.

01.24.17 -14

A closeup of a Nelson Stud Nail (AKA Nelson Embed Nail).

 04.13.17 – 15

Attached to this boot is a geotechnical instrumentation sensor system which is tied to the anchor nail and bearing plate. Such systems in this project are used for monitoring the movement of selected soldier piles around the pit.

04.26.17 – 16 Video

Today, the rebar was delivered for the sub-grade structural wall. The rebar diaphragm will be constructed on the slab and then hung via a crane on the Nelson Stud Nails. Once the diaphragm is securely anchored, the shotcrete will be applied to what will then become the structural wall.

04.26.16 – 17

The Medical Center and the Children’s looms tall over the pit as a large crane lowers the structural rebar to the foundation slab below. This west and

the northwest walls are ready for the rebar rodbusters to begin work.

05.30.17 – 18

Today, the rodbusters began running rebar for the structural wall on the northwest section of the existing shoring wall.

06.06.17 – 19

Rodbusters continue to add rebar to the outside of the structural wall mat.

06.06.17 – 20

A closeup of the two layers (front and back sections) of rebar mats being strung (vertically and horizontally) and tied to reinforce the structural wall.

There is a science to the spacing of the rebar and the rodbusters must follow the engineering specs when hanging the rebar.

06.06.17 – 21 Video

Rodbusters are laying out rebar on the foundation slab, which when completed will be lifted by crane to be attached to the western wall. A rodbuster has climbed the

rebar to position and tie a vertical length.

06.06.17 – 21 Video

Rodbusters are laying out rebar on the foundation slab, which when completed will be lifted by crane to be attached

06.08.17 – 22 Video

A view from above illustrating how the galvanized bearing plate covers are anchored to the shoring wall.

06.08.17 – 23 Video

A GoPro video showing some of the rodbusters tying vertical and horizontal members of rebar to the structural wall and corner column and structural wall.

06.27.17 – 24

The Shadows Can Do It!!

The lighting was just right down in the pit as the steel workers began to hang the rebar of another section of the structural wall. To the left, out of

the frame of this photo, the shadows of two workers were projected on the shoring wall as they stood on the platform of a hydraulic boom lift

from above while their co-workers were guiding and wiring the rebar from below. The following video illustrates the scene.below.

06.27.17 – 25 Video

This video illustrates how the outer section of the structural wall rebar is hung. It takes four workers on the ground, two up on the hydraulic lift, a crane operator,

and director down in the pit. On a couple of occasions, you will hear him holler out a signal to the crane operator.

06.27.17 – 26 Video

This video illustrates how the outer section of the structural wall rebar is hung. It takes four workers on the ground, two up on the hydraulic lift, a crane operator,