2015 Award Winner: Parking Structure – Restoration

Walker Parking-Lancaster Parking Authority Garages, Lancaster, PA

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Description:

The Lancaster Parking Authority (LPA) owns five parking garages of various ages located throughout the city of Lancaster, Pennsylvania. In June of 2013, the garages were assessed by Walker Restoration Consultants (WRC). The garages showed typical deterioration for their age and exposure, needing nearly $4.4 million dollars in repair and maintenance over 10 years. The overall garage system is worth over $80 million dollars, so the 10 year repair budget is 5.5% of the system worth. LPA and WRC have effectively managed costs by following the program closely. Furthermore, LPA hired two contractors to work within the five garages during the same construction season on differing scopes of work (waterproofing and structural) in order reduce the schedule and to save construction costs. This ten-year asset management plan created a phased restoration plan which is currently being implemented and is set to carry out through the year 2022.

THE GARAGES

The five parking garages are located throughout the city of Lancaster. They are of precast construction and vary in height and size. They include the Duke Street, East King Street, Penn Square, Prince Street, and Water Street Parking Garages. The 30+ year old Duke Street Parking Garage consists of 5 levels and 439 spaces. The 6 year old East King Street Parking Garage contains 6 levels and 466 spaces. The 40+ year old Penn Square Parking Garage has 4 levels and 755 spaces. The 40+ year old Prince Street Parking Garage has 8 levels and 1150 spaces. The 20+ year old Water Street Parking Garage has 3 levels and 637 spaces. These five garages contain a total of about 26 acres of structured parking.

THE GARAGES’ STRUCTURAL SYSTEM

All of the garages are normal weight, 5000 psi, precast, prestressed concrete structural systems using 10 to 12-foot wide by 60±-foot long double-tee floor slabs. At two garages, Water and King Streets, double-tees are “pretopped” which means the entire 4-inch thick floor slab is poured in the precast plant. At the other three garages, the double-tees are topped with 2-inch thick concrete floor slabs poured in the precast plant and 3 inches of concrete poured in the field. The double-tee to beam connections are a mixture of welded connections and rebar connections depending on the adjacent beam. After these connections are made, the area is filled with field cast concrete until it rises above the floor in a sloped configuration similar to a speed bump. This fill concrete, which completes the structural system, is commonly referred to as a “wash.” These washes are also used as drainage swales to direct water across the floors to drains. Each double-tee is also connected to adjacent double-tees along the 60-foot sides at 5 to 6 foot spacing by welded connections. These double-tee to double-tee welded connections occur about 1-inch below the top of the slab.

One garage, Prince Street, contains a large one-way spiral exit helix. This helix’s structural system is cast-in-place slab, beam and wall construction.

THE WATERPROOFING CHALLENGES

The primary waterproofing tasks in a parking garage are all located within the floor system and are:

  1. Joint sealants along the double-tee 60-foot edges.
  2. Joint sealants and traffic bearing membranes with the washes.
  3. Traffic bearing membranes above the field cast concrete infill within stair treads and landings.
  4. Expansion joints in the decks, stairs and bridges subject to vehicles, pedestrians, and snow plows.

Unique waterproofing tasks also occurred as follows:

  1. At the Penn Square Parking Garage, sealing of the asphalt wear slab used at the first supported level was completed. This was done because the asphalt wear slab and it’s buried asphaltic membrane which covers and protects the concrete floor slabs has deteriorated, requiring an intermediate life extension repair.
  2. At the Duke Street Parking Garage, sealing of the membrane over the electrical room at the entrance and top tier inverted tee beam was carried out. This was done in order to extend the life of the electrical room components and the life of the heavily exposed inverted tee beams.
  3. At the Prince Street Parking Garage, membrane was installed over occupied space. The membrane was sealed in stages in order to permit traffic to travel through the garage. Only half of the membrane was installed at a time so the garage could remain open as there was space for cars to pass adjacent to the membrane installation.

THE STRUCTURAL CHALLENGES

Structural repairs are often necessary after failed waterproofing permits water and deicing salts to attack the structure for years, and these garages were no exception. These structural repairs included a large numbers of items, but only those repairs affecting waterproofing are discussed here. The system wide repairs are:

  1. Repairs to welds and spalls at the connections along the double-tee 60-foot edges.
  2. Repairs to deteriorated wash concrete.
  3. At the Water Street Parking Garage, diagonal shear cracking in the spandrel panel was tested to confirm that the cracks were static, not active. After confirming they were static, these cracks were epoxy injected which preserved the beam’s structural integrity.

Unique structural tasks also occurred as follows:

  1. At the Prince Street Parking Garage, an urgent haunch repair at the vehicle entrance was completed in order to prevent both loose concrete from falling or shifting of the double tees above.
  2. At the Duke Street Parking Garage, the top of a number of light pole columns were repaired when water entered the columns at the anchor bolts and caused freeze-thaw damage.
  3. At the Duke Street Parking Garage, numerous spandrel panel connections were repaired using a modified connection since they were determined to be too rigidly connected which caused the connection distress.
  4. At the Duke Street Parking Garage, the clay tile façade infill was modified. The tile was cracking and falling because the clay masonry continued to expand over time which caused cracking when the boundary concrete constrained its growth.

PHASING

These garages are large and are heavily used, so detailed phasing requirements were necessary to allow most areas to remain partially open during restoration to accommodate patrons. Most phasing was defined in the field by LPA staff.

MILES OF JOINT SEALANT, THOUSANDS OF WELDS

Together the five garages contain over 19 miles of double-tee to double-tee joint sealant, which is installed under the key assumption that the joint is non-moving and this assumption is often invalidated when the double-tee to double-tee welded connections break as they rust. Prior to installing sealants, each of the more than 20,000 welded connections between double-tees will be reviewed. When those connections are found to contain broken welds, corroded anchors or that the adjacent concrete had cracked due to overheating during original construction welding, these hidden items will be repaired on a unit price basis.

Nearly all of the expansion joints had failed, were missing, or had heavily damaged block outs. These are being replaced in each phase to reduce costs and inconvenience.

CONCLUSION

These repairs permitted patrons to continue to park in the garages using convenient parking within each construction phase. New, similar, and stand-alone parking garages currently cost between $18,000 and $25,000 per parking space, while these garages will be renovated at a cost near $1,200 per parking space, or 5% to 7% of the replacement cost. The repairs, which were primarily waterproofing in nature, will extend the life of these garages by more than 10 years in a cost-effective manner.

Project Team:

Person/Firm Preparing Submittal
Mr. Gregory J. Neiderer, P.E.
Restoration Department Head
Walker Parking Consultants
565 E. Swedesford Road, Suite 300
Wayne, PA 19087
(610) 995-0260
(610) 995-0261 (Fax)
Email: greg.neiderer@walkerparking.com

Owner
Mr. Larry Cohen
Executive Director
Lancaster Parking Authority
111 North Price Street, PO Box 866
Lancaster, Pennsylvania 17603
(717) 299-0907
Email: lcohen@lancasterparkingauthority.com

Architect/Designer/Engineer
Mr. Jason Gross, P.E., LEED AP
Restoration Consultant
Walker Parking Consultants
565 E. Swedesford Road, Suite 300
Wayne, PA 19087
(610) 995-0260
(610) 995-0261 (Fax)
Email: jason.gross@walkerparking.com

Parking Consultant
Mr. Jason Gross, P.E., LEED AP
Restoration Consultant
Walker Parking Consultants
565 E. Swedesford Road, Suite 300
Wayne, PA 19087
(610) 995-0260
(610) 995-0261 (Fax)
Email: jason.gross@walkerparking.com

Garage 2014 Waterproofing Maintenance Contractor
Greg Cutler
Project Manager
Concrete Protection and Restoration (CPR)
6737 Dogwood Road
Baltimore, MD 21207
(410) 298-2669
Email: gcutler@c-p-rinc.com

Parking Operator/Management
Lancaster Parking Authority
111 North Price Street, PO Box 866
Lancaster, Pennsylvania 17603
(717) 299-0907

Garage 2014 Structural Repair Contractor
Bryan Yarnell
Project Manager
Allegheny Restoration
1165 Garden Street, Hempfield Ind. Park
Greensburg, PA 15602
(724) 925-2556
Email: bryan@alleghenyrest.com

View/Download Project Abstract (PDF)