The Week of August 6, 2018 — The Week the Isolator Keeper Plates Were Removed

Two of the four keeper plates are highlighted on the Isolator in the featured image —

When the first of the isolators were set, I noticed four vertical plates with two bolts at the top and two bolts at the bottom of the isolator. For all I knew each plate could have been aligned with the four points of a compass. Upon inquiring about the plates were, I learned they were attached by the manufacture per the engineers to stabilize the isolators until sometime after the podium had been completed. Schuff Steel would be making the call as to when the plates would be removed. After the removal of the keeper plates the steel structure would seem to float on the isolators stabilized by the isolator bases and the dampers and damper pedestals all of which are anchored to four feet or reinforced concrete. For several month we wondered if there would be a specific order or pattern to removing the keeper plates. Would they be removed starting in the center and moving out to the four corners or would the procedure begin at the four corners and move to the center? Or would the process start at one of the quadrant outside corners and move quadrant to quadrant? Could the removal be random?

Note: The feature photo introducing this blog is of an isolator after had been set on the base. The keeper plates would remain on the isolators for approximately one year.

The day began with a text from Jack, the assistant job superintendent, who alerted me that the keeper plates would be removed today. Wow, I didn’t anticipate this process so soon.

A concrete field of isolators and their bases all in a row. It is on these isolators that supports the steel structure in the following photo. None of the steel touches the foundation walls. During seismic activity the building will move with the isolators and dampers.

To place this blog in context, we need to remember that the above steel structure rests on 126 isolators on which the massive spline beams are bolted. It is my understanding that according to the specs, the keeper plates can only be removed at a specific point during the construction process. The following first few photographs will take us back a few months to refresh our memory as where the isolators fit in this giant puzzle.

This is the first spline beam that was lowered on to two base isolators. The nodes on each end of the spline beam rest on the isolators. Note that the keeper plates are directly under a cross beam flange to which another spine beam will be bolted.

Standing on the basement concrete floor, approximately eight stories below the metal decking above, Jason removes the third of four bolts on the keeper plate.

With Kenny’s assistance, Jason (background)  maneuvers the keeper plate off of the isolator.

With the keeper plates set aside on the base the isolator stands alone.

Free at last to Resist a Seismic Event Should One Occur

With the four keeper plates removed this isolator joins the others standing independently of the keeper plates. A crew will return to clean all of the isolators and patch the grout.

Meanwhile Other Construction Activities That Happened

This Week on the Site

Level “B”

Although the cranes were down most of the week for the lack of steel, the welders, ironworkers, pipe fitters, plumbers, wall layout crews, electricians, and the MONOKOTE crew were engaged in their skillful labors despite the heat and humidity. To top it off the air quality has not been the best due to the smoke caused by brush fires to the south.

Along with the ironworkers down in the basement, the pipe fitters were laboriously wrestling with a flange for this sixteen inch chilled water pipe.

Just on the backside of a node a welder was grinding away spewing sparks around the wheel and out the backend of the safety guard.

A pipe fitter turns away as his coworker tacks a weld to a pipe.

Toward the northeast section, the plumbers and pipe fitters had been busy competing for space. The smaller diameter pipes near the ceiling are for the fire sprinklers and were installed by the pipe fitters. The larger diameter pipe hanging lower to the ground, and are at a 45° angle were installed by the plumbers and are for industrial waste water. The long galvanized hangers, which are anchored to the structure above, are known as seismic rods and rod stiffening struts. The pipe runs through a stirrup like piece called a clevis hanger. These elements allows the pipes to sway, without bursting, during seismic activity.

Don is threading a rod on which a clevis will be hung to cradle an industrial waste pipe

Every day, I learn something new. For all I knew, the rods were screwed into the inserts above and a clevis in which the pipe would be laid in was screwed on to the rod. That part of the process is correct, but Don explained that there is a rhyme and reason for the height and slope of the pipes. He took out his iPhone and illustrated with a downloaded schematic that certain runs of pipe are to be so many feet from the ceiling and the horizontal distance between pipe runs are also detailed. All of which are dictated by code. Before the concrete on the floor above is poured, threaded inserts are punched through the metal decking as stipulated by the blueprints. Once the concrete is poured, the inserts become part of the structure. The rods and clevis’ in the background are an example of the different heights and widths between the rods.

In a good natured gesture of bipartisanship, plumbers Travis of the north and Daniel (Dan) of the south reach across the work table vowing to work together peacefully at least till lunch. For these two working buddies anything goes after lunch, as long as the work gets done. I can vouch that Dan has a great sense of humor. He has yanked my chain on more than one occasion.

This posse of hanging rods illustrates the various heights, density, and alignment–imagine the number of pipes that will hang from the ceiling. Kinda reminds of the “rings” gymnast use in a routine.

I can’t leave level “B” without mentioning the electricians. While wandering around in the basement, I ran into one or two electrician, they are from the blue hardhat tribe. At the moment, I was more interested in photographing the removal of the keeper plates. Low and behold as I circled around an isolator base to get the best angle to shoot Janson removing the bolts from a keeper plate, I ran into an electrician with his head up a large junction box. From the main electrical equipment room on “A” level another electrician was blowing thick nylon cord through the ducting. The electrician in this photo would pull out sufficient lengths of the cord and tie them together. I did notice that the electricians were communicating with each other via one of the ducts.  Later on, the electrician will use the cord to pull the wire through the ducting and into the junction box. The electrician was so engrossed in what he was doing that I don’t believe he ever knew Jason and I were near him.

Level “A”

Taking a flight of stairs up, I arrived on level “A.” I was particularly interested in the southwest quadrant of the building. When I saw the area last it was a mess. Kind of reminded me of my room when I was a teenager.

Mable, There is a Whole Lot of sparkin’ Goin’ on Around Here.

The two second life cycle of a spark: sparks sparkle, sparks arch, sparks spin, sparks dart, sparks ricochet, sparks sting, and sparks sparkle sparks out. When I arrived on “A” level a sheet metal laborer was cutting sheet metal for a stud header. Of course, I had to take a photo to catch a spark display. Like a snowflake, no spark is the same.

Adam, pipe fitter is up on a lift hanging copper pipe for domestic hot and cold water.

Not far from where Adam was hanging pipe, I came across a section where concrete blocks had been delivered. It appears that block masons will be building a block wall around this room. No doubt this area will be used as a secure room–possibly a satellite pharmacy.

There is smoke in the sky due to brush fires in the local mountains.

This weeks blog ends with the American Flag fluttering over the project as if saluting the newly set columns of the Children’s Hospital.