1300 East Bridge over I-80

 UDOT is rebuilding I-80 and I-215 on the east side of the valley. Included in the project is reconstruction of several bridges. This post is about the 1300 East bridge in Sugarhouse. This, along with the 1700 East bridge, were constructed in a unique way. The new bridge is built next to the existing bridge. When the bridge is completed, the old bridge is demolished and the new bridge is slid into place.

To the east of the existing bridge, abutments for the construction of the new bridge are constructed. The new bridge will be built "at grade", meaning it will be built at the final elevation. This means when the bridge is slid, it will move perfectly horizontally.
Notice the angled break or seam in the rebar. Left of this seam is permanent abutment. Right of the seam is temporary abutment only for construction of the bridge. Once the old bridge is demolished and the new is slid into place, this portion will be demolished.

The thickness of these abutments is shown here, as well as the seam between permanent and temporary abutments. The foundation for the temporary portion is less deep than the permanent one.

At the right end of the abutment wall is a small vertical bump out. Threaded rods will run through this portion which are used with hydraulic jacks to slide the new bridge.
The existing bridge is seen to the left.

The west part of the north abutment wall. Here we see another block through which rods will run when the bridge is slid. Also, we can see here how the new abutment runs under the entire old bridge.

A closeup of the west end of the north abutment wall. A near identical wall is being constructed on the south side as well.

A view showing the thickness of these walls. I estimate they are 3 feet thick.

The new north abutment wall is poured. You can see the permanent left portion has decorative texture cast into the surface. The temporary portion to the left needs no such decoration.
Two holes are seen running through the end block.

The massive steel beams are being installed. These beams sit on a large concrete beam below. There are large blockouts at the bottom of this beam, leaving only small portions of concrete resting against the abutment wall below. These blockouts are still full of wood formwork in this photo.

Closing the freeway for these lifts is done at night to reduce traffic impacts. I think it's worth some lost sleep to come watch.

A group of workers guide each beam end into place. Extreme care is taken to align each beam exactly where it needs to sit. They'll spend a half hour to get it just right.
Two beams, which have been connected with cross-bracing, are lifted at a time. I imagine they do this so they're more stable when placed.

A few days later, all the teams have been placed and more cross-bracing has been bolted on.
Here it's easier to see the blockouts at the bottom of the beam. This creates small blocks which the bridge will slide on.
We also see foam strips get placed along the edges of the steel beam top flange. The concrete deck panels will rest on these foam strips.

The ends of those large steel girders are now encased in concrete, along with the deck of the bridge.
New steel structure goes in north and south of the new bridge. At first, I have no idea what this structure is for.

My questions are answered later on when a new portion of bridge is built. This new portion extends onto those steel supports.
Again, here we see how the main bridge ends rest on small blocks of concrete. Under these blocks will lie low-friction surfaces for the bridge slide.

The eastern edge of the old bridge on the left, with the western edge of the new bridge to the right.

The far north and south ends of the new bridge rest on these pre-cast sections. The white strip shown is a low-friction surface for easy sliding. Once the old bridge is demolished, more of these sections will be added, giving the bridge a straight runway to be slid on.

Large steel guide beams will prevent the bridge from moving north or south on slide day.
On the left we see the large threaded rods running through the base of the new bridge. To my knowledge, hydraulic jacks will push or pull between the bridge and nuts on these rods. When the jacks are maxed out, they are retracted. The nuts are moved and the jacks push the bridge a little more.

Dawn dish soap is used to reduce friction for the slide.

Storm drain pipes are suspended beneath the bridge. After the slide, these will be tied into other drain pipes. The black hoses draped over the side are hydraulic lines for the jacks. They all lead to a control station and pump on the bridge.

The freeway and 1300 East are closed, and the old bridge is taken down. An army of excavators removes the old bridge in a matter of hours.

Slide day! I wish I had a better view. It moves so slow you really have to watch closely to see movement. I'd guess it moves about 3 inches per minute. The intersections on each side have to be reconfigured to fit the new bridge and new freeway ramps. This is the top of the Eastbound I-80 on ramp. The truck at the right is a mini concrete plant. Cement, aggregate, and water are carried on the truck and mixed on-site. This is fast-curing concrete. The ramp needs to be open in a matter of days, so rapid curing concrete is a necessity. Crews work 24 hours a day to get the new bridge and ramps ready for traffic.
Here is a great video of the demolition and slide.

More work on the south intersection. After this asphalt goes down and some striping, the bridge will be open for traffic.

New concrete barriers being poured. The near barrier is done with a slip form machine. A machine takes in concrete and extrudes the shape off the barrier as it crawls along. The far barrier is shaped by formwork. They can't use a slip form machine here due to the short length and the tight radius at the left.

New bridge is open for traffic! 1300 East only had to be shut down for a few days. If they'd used a more traditional method of bridge building, they would have demolished the old bridge and built the new one in place. 1300 East would have been closed for months in that case.

The temporary bridge supports being demolished.

This temporary abutment wall will soon be removed. 

A view of the new bridge in place.

Temporary abutment demolition.

The engineering that goes into something like this is phenomenal.

Salt Lake Temple, July - October '23

This is a diagram from the Temple Square website. Most of these photos involve this area of construction. The diagram shows the base isolators either side of the original temple foundation. Above the base isolators is the reinforced concrete transfer beam. The interior and exterior transfer beams are connected to the pipe beams which are already in place beneath the original foundation. The transfer beams will be tied together with tension cables running through the pipe beams. Cable sleeves will be placed in the transfer beam formwork. After it is cast, the cables will be run through the sleeves and tensioned. After tensioning, the sleeves will be filled with grout.
Anyone curious about this process should read the linked page about the renovation. You'll certainly understand these posts more having read it.
templesquare.org

In this photo from July, all the base isolators have been placed on this side of the temple exterior. Plates are bolted to the tops of the isolators off of which large steel shear pins protrude upwards. These will make sure the tops of the base isolators move with the concrete transfer beam which will move with the temple in an earthquake. The base isolators are surrounded by foam blocks which will be removed once the concrete transfer beam is poured and cured.
The soil above the two larger pipe beams running beneath the temple walls has been removed. It's hard to tell, but I believe the interior and exterior transfer beams will be connected through this area, but I'm not sure.
Formwork and rebar for the transfer beam begins to be assembled at the bottom right. This is the Southwest corner of the temple.

Formwork and rebar for the transfer beam is progressing. As a reminder, the ends of the tension cable sleeves is visible in the ends of each pipe beam. These sleeves will be extended through the transfer beam. The temple will sort of float above empty space, with these tension cables helping split the load to the inner and outer base isolators.

Spire stones at the Northwest corner are being replaced after a long absence. All the temple spires have been reinforced with structural steel throughout, up to the very tip. A temporary crane sits atop the structural steel.

Something really fascinating is happening. A bit to the right of center, you can see plywood sheets with squares of styrofoam attached to them. I could be wrong, but I believe these are formwork negatives for the transfer beam tension cables. Notice how these foam blocks are at different angles. I think that the sleeves for the tension cables, once they come out of the pipe beams, will fan out in different directions. The ends of these sleeves will intersect with the face of the transfer beam at odd angles, so I think these blocks will form out a flat opening perpendicular to the ends of the cable sleeves. Pretty cool stuff.

Vertical drilling through the temple walls continues. The white structure to the right of the umbrella is a core drill. Tension cables or steel bars will run through walls the entire height of the temple, tying every block down to the foundation with tension.

Formwork and rebar placement continues. More foam blocks are visible. As you can see, some are at a slight angle, some are steep. It looks like some kind of steel ring is placed on the face of the foam block. These will be cast into the concrete transfer beam.
A pile of beefy rebar sits at the bottom of the picture. These transfer beams have to hold the entire weight of the temple, so the reinforcing steel is immense.

Barely visible at the center of the photo, just above the formwork panel, we can see some of the tension sleeves. It looks like they bend out horizontally at their middle, but they perhaps may not be in their final position. Concrete is weak in tension, so the rebar and many tension cables will hold it together.

I can't explain this one. Atop the larger pipe beam running beneath the temple - it looks like there are sections of similar pipe stacked on top of it. I'm not sure what this is or its purpose.
More base isolators are stacked on the left. Near the bottom right we see rebar rings. I assume these will wrap around the tension sleeves.

A closer look at the large pipe beam. Not sure what's stacked on top of it.

The Southwest visitor pavilion takes shape. These pavilions are much larger than I anticipated them to be.

Some tension sleeves can be seen above and to the right of the workers at the center of the photo. It looks like these are sitting waiting to be put in their proper orientation. It's possible though that there will be tension cables running the length of the beam.

The amount of rebar in these beams is staggering.

The West side of the Southwest visitor pavilion. Steel embed plates are affixed to the upper formwork. I assume roof structure will hang off of these plates.

A view of the Northwest patron entrance building. Foam archways provide a negative around which concrete is poured.

As of the end of October, the transfer beam formwork nears completion.

Northwest of Temple Square in a work zone sits a mock-up for the concrete-window interface. This is probably for the south visitor pavilions. Some kind of pressure test was done to certify the windows meet the requirements, and approval stickers are placed on the windows.

This is the part I'm really geeking out about. This is a mockup for studying the interface of the movable temple structure with the surrounding static structure at ground level. In the event of an earthquake, the temple may move up to 5 feet in any direction, but the surrounding ground will be stationary. There has to be some kind of mechanism to allow for movement while still being safe for anyone standing near the temple. I believe this is the mockup for that system.
The wall in this photo represents the stationary wall surrounding the temple. In the diagram at the beginning, this wall isn't shown, but imagine a concrete wall at the left edge of the diagram. This wall is stationary and affixed to the earth.

It's difficult to see with the wood railings, but on a lip in that exterior wall rests a large steel pan (painted white). The left edge of this pan has a beveled front edge and rests on top of (I assume) the concrete transfer beam or another concrete slab higher up. The beveled front edge can slide up a small metal ramp in the event of seismic movement of the temple.

When the temple-side edge slides up the ramp, the steel pan rotates like a hinge on the lip of the stationary wall.

Another shot of the entire mockup. Perhaps I'll make a diagram of how this works for clarity.

I believe the steel pan will be filled with pavers or whatever kind of decorative concrete work surrounds the temple. Most people will never know that what they're walking on is integral to the seismic protection system for the temple.
Here you can see how the left edge of the pan can slide up metal inclines to allow the concrete beneath to move left or right.

I love this kind of stuff. I can't wait to see how this looks when the project is finished.

Another look at the Northwest patron entrance building.

Much of the solid wall around Temple Square is being replaced with iron fencing. It will be much more inviting and open.
Thousands of people are working to renovate the Salt Lake Temple and Temple Square. I'm grateful for their work.