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8/17/20 - At month 24 of the 36-month project:
Structures: Abutment # 1:
This structure has been built and is now supporting the last nine girder beams (see photos). The existing steel beam pilings were wrapped with rebar, concrete forms were placed, and concrete was poured to create the abutment. The last nine girder beams were set between Pier # 1 and Abutment #1 this past week (completed on Friday August 14th).
Bridge Decking and Overhangs:
Crews continue installing galvanized steel deck pans across the girder beams and building overhangs to accommodate the sidewalks (five-feet wide on each side).
Thousands of shear bolts are being welded to the tops of the girder beams. These serve to prevent the concrete deck slab from sliding and will tie the nine-inch thick concrete deck slab to the support beams.
Soon, a sub-contractor crew will begin placing a grid system of epoxy coated steel rebar across the girder beams and deck pans. A quantity of almost 1.5 million pounds of steel rebar is required.
Within the next few months, an engineered sequence of concrete pours to create the deck slab will begin, requiring almost 3,400 cubic yards of concrete (an average concrete truck contains 10 cubic yards).
9/21/20 - At month 25 of the 36-month project:
The Lewallen Bridge replacement project continues, with a contract completion date listed by TDOT as August 31, 2021.
Here is a description of the work currently being performed:
- Galvanized Metal Deck Pans
Deck pan installation is complete across the entire bridge (see photo). These sheets of metal serve as permanent concrete forms. A nine-inch thick concrete slab will be poured over the deck pans. The concrete slab will serve as the driving surface.
- Bridge Deck Overhang
The bridge deck overhang system is complete. This formwork allows the concrete deck slab to extend beyond the traffic lanes and the edges of the outside steel girder beams, providing for 5.5 feet wide concrete sidewalks poured on top of the bridge deck slab, with the concrete bridge parapet wall being poured on top of the sidewalk.q
- Shear Bolt Studs
Welders continue to install thousands of shear bolt studs on top of the steel girder beams (see photo). These studs are spaced about six inches apart and they serve as dowel pins to prevent the concrete slab from sliding, connecting the slab to the steel girder beams.
- Epoxy Coated Steel Rebar
A sub-contractor crew is on-site, making good progress installing the
1.5-million-pounds of steel rebar, creating a grid system across the bridge deck. This work is currently more than 50% complete (see photos).
- Concrete Bridge Deck
Approximately 3,400 cubic yards of concrete will be pumped to create the bridge deck. The contractor estimates that concrete pouring will begin in late October-early November 2020.
The bridge deck length is 1,136 feet and the width is between 77 feet 8 inches and 101 feet 8 inches.
Long Range Completion Goals
Here is a sequence for the last stages of completion, once the concrete bridge deck, sidewalks, and parapet walls are complete:
1. A road connection will be built at the south end of the new Lewallen Bridge, aligning it with Clinch Avenue, near Carden Farm Drive.
2. Thirty-eight LED streetlights will be installed to illuminate the new bridge.
3. Traffic control signs and pavement markings will be installed on the new bridge.
4. Northbound traffic only will be re-routed onto the new bridge. The contractor estimates that this could take place as soon as late spring 2021, winter weather permitting.
5. A road connection will be built between the north end of the new bridge and the intersection of State Route 61.
6. The new bridge will be opened for traffic in both directions.
7. The old bridge will be demolished.
8. Riverside Drive will be re-built from SR 61 to Meadowbrook Street, including a new parking area, new concrete sidewalks, and excavation to install a new storm sewer system.
9. Lakefront Park facilities impacted by the bridge construction will be restored.
10/19/20 - At month 26 of the 36-month project:
Crews continue preparing the bridge deck for concrete:
Bridge Deck Drains
Drains spaced at engineered intervals are being installed where the drain gutter meets the concrete curb/sidewalk. This is time consuming work, as the recently installed deck rebar steel must be trimmed away to make room for the drainage structure, which must be set at the proper elevation.
Epoxy Coated Steel Rebar
A sub-contractor crew continues installing the 1.5 million pounds of steel rebar, creating a grid system across the bridge deck. The deck rebar work is currently about 90% complete.
Concrete Bridge Deck
In preparation for the bridge deck concrete pour, crews will be erecting a concrete screed machine, which will extend across the entire width of the bridge deck. This machine must be built to very precise specifications, with several dry runs required to make sure it is running at the correct elevations. The screed machine rests on rails that will be installed on top of the outer most concrete forms. It uses augers to distribute the concrete mix, and then large floats will level and finish the concrete surface.
The contractor estimates that concrete pouring will begin in the next 4-5 weeks. Approximately 3,400 cubic yards of concrete will be pumped to create the nine-inch thick bridge deck. The finished concrete deck will be the driving surface for bridge traffic.
11/16/20 - At month 27 of the 36 month project:
Bridge Deck Drains - Complete
The installation of deck drains along the curbs and gutters is complete. This will allow storm water to flow off of the driving surface, into the gutters, and then drop vertically through the drainage structures (see photos).
Epoxy Coated Steel Rebar - Complete
The required 1.5 million pounds of epoxy coated steel rebar is now installed (see photos). Notice the vertical steel rebar pieces along the outside edges of the bridge deck. Once the bridge deck and sidewalk are in place, these vertical extensions will allow the concrete parapet wall to connect to the deck and sidewalk.
Concrete Bridge Deck - Concrete pouring should begin within two weeks.
Photos show the preparation of a concrete screed device that extends across the entire width of the bridge deck. Notice that the screed structure rides on round steel pipe rails. The screed must be adjusted to precise tolerances so the finish grade of the new concrete surface will match the plan specifications. The screed rail will carry several attachments to perform different functions for pouring concrete.
Once a large concrete pump is in place and begins to deliver the concrete mix, augers attached to the screed rail will move back and forth across the bridge deck width and will distribute the concrete. A vibrator attached to the screed rail will remove air voids. Concrete finishing floats and surface rollers will move across the screed rail and will smooth the concrete surface to the proper elevation.
Approximately 3,400 cubic yards of concrete mix is required for the nine-inch-thick bridge deck (note: an average concrete truck contains 10 cubic yards).
Lengths: The concrete bridge deck is 1,136 feet long.
The approach to the new bridge, traveling north bound on Clinch Avenue from South Clinton, adds a 463 feet length of new asphalt. This approach includes a painted median divider (11 wide on the approach narrowing to 8 wide on the bridge deck) which creates a safety buffer to separate opposing traffic..
The south bound approach from State Route 61 adds a 265 feet length of new asphalt between SR 61 and the concrete bridge deck.
Widths - north end: 102.3 feet
This width includes two parapet walls @ 14 each, two sidewalks @ 5.5 each, two drain gutters @ 2 each, two bike lanes @ 4 each, and 7 traffic lanes at 11 each.
south end: 77.3 feet
This width includes two parapet walls @ 14 each, two sidewalks @ 5.5 each, two drain gutters @ 2 each, two bike lanes @ 4 each, four traffic lanes @ 11 each, one painted median divider @ 8.
12-14/20 - At month 28 of the 36-month project:
Concrete Bridge Deck -
The bridge deck concrete pouring construction began on November 24, 2020 and about 20% of the deck has been poured. A completion date for this phase of the bridge project will depend on the upcoming winter weather. Concrete pouring during colder weather presents several challenges, and work schedules often get delayed. To meet TDOT specifications, weather forecasts and future temperatures for several days ahead must be considered when planningw concrete work. In order to pour bridge deck concrete, the temperature must be 35 degrees and rising, with no hard freezes in the near future. The 1,136 feet long bridge deck is divided into ten sections. An engineering plan dictates the sequence that the sections are to be poured. The weight of the poured sections must be properly distributed across the beams and support piers, in a certain order.
The photos show the concrete deck being poured, and the screed device being used to finish the nine-inch thick concrete slab.
Once the bridge deck concrete is complete, crews will begin building concrete forms in preparation for creating the 5.5 feet wide sidewalks and the 4 feet tall parapet walls.
1-19-21- At month 29 of the 36-month project:
Concrete Bridge Deck
Concrete pouring to create the bridge deck floor continues. Cold weather and some COVID-19 problems have created delays for the contractor. Five of the ten bridge deck slab sections have been poured. A total of 3,400 cubic yards of concrete will be used for the deck.
The photos (labeled Jan, 2021) show the south end of the bridge deck. Notice where backfill is taking place adjacent to the bridge, where the bridge approach will be built. Crushed stone and a remote-control sheep-foot vibratory roller/compactor are being used. The stone is applied in six-inch deep lifts, and each individual lift is compacted with the roller. This method eliminates voids in the stone and prevents future settling. At the bottom of the photo, notice the vertical arrangement of green colored, epoxy coated steel rebar, and the wooden concrete form behind the rebar. This is where the 5.5 feet wide sidewalk will be poured, once the bridge deck is complete.
The existing rebar is tall enough to also be used to secure the parapet wall, built above the sidewalk.
2/16/21 - At month 30 of the 36-month project:
Concrete Bridge Deck - Concrete work to create the bridge deck floor continues. Eight of the ten bridge deck sections are now complete.
Sequence of Future Construction - The following sequence of work will take place once the bridge deck floor is complete:
1. Additional concrete pouring is required in order to complete the bridge deck expansion joints.
2. Backfilling at the north abutment is almost complete. The fill will create an elevation for a bridge approach that connects to the existing section of Clinch Avenue (State Route 9) near South Seivers Blvd (State Route 61).
3. Almost 2,400 linear feet of sidewalk will be formed and poured on each side of the bridge, on top of the bridge deck. Sidewalks will be 6 inches thick and 5.5 feet wide.
4. Concrete parapet walls will be formed and poured on top of the sidewalks. Metal handrails will be mounted on top of the walls.
5. Decorative metal street light poles standing eighteen feet tall with decorative lantern-style light fixtures will be installed for bridge lighting.
All street light wiring will be concealed in conduit, hidden inside the parapet walls.
6. Once the new bridge is ready, two lanes of north bound traffic will be re-routed from the existing bridge onto the new bridge. South bound traffic will continue using the existing bridge. During this temporary traffic control phase, approaches will be built on each end of the new bridge, connecting it to Clinch Avenue.
7. When the approaches are complete, pavement markings and traffic control signs will be installed. Soon after, the new bridge will be open for use, and south bound traffic will be re-routed from the existing bridge to the new bridge.
8. Demolition of the existing bridge will begin.
9. A new section of Riverside Drive will be built between South Seivers Blvd. and Meadowbrook Street, which will include new sidewalks and an improved storm water drainage system.
10. Lakefront Park facilities will be restored, including repairs to the:
a. Boat launch ramp
b. Boat dock pier
c. Riverside Drive/Lakefront parking lot
d. Walking trail
3/23/21 - At month 31 of the 36-month project:
Concrete Bridge Deck:
With the exception of one expansion joint assembly, all ten sections of the bridge deck concrete are in place. The following work is now underway:
1. Sidewalk forms with reinforcement steel are being installed.
2. Concrete forms for the parapet wall are being built.
3. Bridge approach aprons are being constructed on each end of the bridge. The concrete pads will extend from the ends of the bridge deck and will connect to a new asphalt transition to Clinch Avenue.
4/27/21- At month 32 of the 36 month project:
The concrete bridge deck is complete, and crews continue forming and pouring the concrete sidewalks and the adjoining parapet walls (see photos). Rather than a solid parapet wall, a decorative concrete wall with openings between columns is being built. Building concrete forms for the decorative style wall is more labor intensive and time consuming, as compared to a solid wall.
Once sidewalks, parapet walls, and street lighting installations are complete, crews will concentrate on building a bridge approach on each end of the project, which will transition to the existing street.
After the approaches and transitions are built, two north bound lanes of traffic will begin using the new bridge.
South bound traffic will continue to use the old bridge until the new bridge is finished and completely opened for all traffic.
Timeline: The contractor has asked TDOT for an extension to the 36-month contract time, which expires on August 31, 2021. TDOT continues to review the request and will make a decision soon on how much additional time could be awarded.
5/25/21 At month 33 of the 36 month project:
Crews working on the Lewallen Bridge replacement project continue with the following areas:
Parapet Walls: Concrete forming and pouring for the Classic design wall continues, with workers concentrating on the north bound side. Just over one-half (600 of 1,200 feet) of the north bound side wall is complete. A separate sub-contracted crew is working ahead of the wall building crew, erecting the steel rebar needed for the wall on the south bound side of the bridge.
Overhang Forms and Brackets: A separate crew is following behind the wall construction crew, performing finishing work to the freshly poured wall concrete, then removing metal overhang brackets that supported the wooden formwork for the sidewalk and wall. They are using a special mobile platform and walk board equipped truck (see photos) that reaches over the new wall and suspends a walking platform for workers.
Storm Water Drainage Installation: Another crew is currently working at the north end of the bridge, assigned to excavation for storm water drainage structure and pipe installation.
Crews will soon begin work on the concrete approach at the south end of the new bridge.
6/28/21 At month 34 of the 36-month project:
Crews working on the Lewallen Bridge replacement project continue with the following areas:
Parapet Walls: The bridge wall on the northbound side is nearly complete. Installation of streetlight poles on top of the northbound wall is currently underway. Crews are now working on the southbound side wall and have completed about 400 feet of the 1,136 feet long wall (see photos of crews assembling forms, and performing finishing work to remove imperfections and form marks from the freshly poured concrete).
Storm Water Drainage Installation: The installation of storm water drainage structures and pipe continues on the north end of the bridge, and similar work has started on the south end. On the southernmost end of the project, a large drill is being used to penetrate rock along the drainage pipe route, where holes will be filled with a blasting agent, to fracture the rock and open a trench for the installation of pre-cast concrete manhole structures and pipes.
Riverside Drive: Excavation crews are preparing the new portion of Riverside Drive beneath the new bridge. The existing roadbed must be removed and undercut at a depth of 5 to 7 feet, to gain the required vertical clearance of 16.5 feet beneath the new bridge girder beams (see photos). Storm water drainage structures and pipe must be installed beneath the new street and parking areas. Much of the new street construction must await the demolition and removal of the old bridge support columns.