[EarthResearcher333]

Shotcrete Inner Sidewall finishing - Worker using a "guide cable" - Simple pre-alignment with board & anchor for taut cable

A simple, but effective, tightly pulled guide wire (small cable) is being used to assure the proper finish of the shotcrete wall that lines the RCC. Layers of steel mesh and individual vertical reinforcement bars with separate anchor bars were placed prior to this shotcrete wall layer. Earlier images of the "stay in place" fine metal mesh revealed anchors that extend into the wide layer of RCC that was being placed during construction. This adds an additional contribution to a tie-in to the anchorage of the steel mesh, vertical reinforcement bars, and the "drilled then hammered in" anchor bars.

See: Prior post 4250

Prep work with rebar for Inner Shotcrete Sidewall (post 4250)

Fig. 1 Reveals how the upslope alignment of this sidewall layer is carefully maintained by the "guide cable/wire" reference in the finish work. What looks to be a colored wood stud (or a denser material) is being used to hold the guide cable/wire and keep its tension. This approach is effective and can be easily adjusted, repositioned, and aligned. Most likely there is a survey "shoot laser" that is being used to keep this placement of the guide wire accurate to the upslope alignment of the sidewall surface. Another clue to the "laser" is that the board does not have an optical survey "target". Overspray of the shotcrete on the board infers that the board is positioned, and thus the cable, before the shotcrete layer was placed. This would serve as a depth to completion reference in the process of applying the shotcrete..

Fig. 2 Reveals the skill of the concrete workers as the wall is very well finished and clean. There is a significant amount of this work to be done as both sides of the RCC temporary spillway will require this shotcrete surfacing process. The "meet up" date to the upper construction concrete spillway section by the RCC is stated to be the last week of October. This would mean that these workers would be scurrying to finish the inner walls as this happens after the main RCC is emplaced. The other "race" will be the chemically treated 10 to 12 inch hardened RCC layer that still needs to be applied to the RCC spillway horizontal surface. This is also noted to be started when the RCC meets up with the upper construction concrete spillway section.

Note to KC Burke: I'm up late - not early. So you, Abb, and others can be the "early birds"… :)

Fig. 1 Worker carefully finishing shotcrete surface of concrete wall to a guide wire/cable. Simple arrangement allows wire to be repositioned as construction work progresses. No sign of a survey target - indicates wire placed by a laser "shoot" (from a survey position).

Fig 2. Professional finish, including the vertical continuity, of the wall reveals the skill of the concrete workers. Notice the "excess" shotcrete on the plastic. Likely from the finish process of a careful removal of shotcrete to arrive at the final aligned vertical surface.

[EarthResearcher333]

Worker's construction hat shows he is "all-in" on shotcrete. He even keeps a trimmed line on the brim. Does this make it a stronger hard-hat? :)

[mad_as_he$$]

This is truly an epic construction event. Kiewit is now claiming that they have worked more than 500,000 man hours without a OSHA recordable injury. If true, that is an admirable record and their techniques and safety program needs to be studied and shared.

Weather will now become a negative factor.

Rumors persist in the water community about damage to the main spillway structure relating to the floor and the tension bars. Sadly, only time will tell.

[Repeal The 17th]

Just where are we at here?
Is this the temporary sidewall along the temporary section
connecting between the upper and lower spillway sections?
Does this all get ripped out during next year’s construction season?

[EarthResearcher333]

RCC "Football field" stage - Rock Islands gone - Vertical Access Pipe - New construction revelation of sub base rebar in Sidewall slab substructure

The progression of the placement of the Roller Compacted Concrete (RCC) has filled in the "rock islands". The large area resembles a flat stage that a football field could fit within. This gives a perspective on the cubic yards of additional RCC required to elevate their progression to the final upper spillway "joining point". Just think of how many layers of "football field" sized "lifts" of RCC to get to the final grade. A football field is 6,000 square yards (includes the end zones). To elevate the grade in the square footage of this "area", although in a diagonal progression shift of the equivalent "field", a 50 foot fill height is 100,000 cubic yards of RCC. The "height distance to go" is well more than 50 feet. So the math becomes impressive on the work that is to be done.

Another interesting reveal. This photo shows long sections of steel reinforcement bar in the substructure area of the lower Sidewall Slab base. Other photographs in the lower spillway had not revealed this. So, this rebar may be consistent with the construction in all of the Sidewall base OR this rebar is unique to this area (for structural reasons). It's possible that there is more "fill layer" concrete to be placed and that the drain system was being constructed that conflicted with the "fill layer" progression. The photo angle does not reveal any easy height distinguishing differences of the "fill layer" on the other side of the top finish layer slabs verses this inner section.

A vertical "access" pipe is observable in the photo. This access pipe, for inspection and maintenance, connects to the drain system below.

The RCC fill process has reached a stage where the rock islands are covered over. The flat fill area is near a "football field" or more. Long rebar in sidewall slab substructure is a new discovery. Vertical Access Pipe to drains below visible.