How We Took A Leaking, Failing, Pre-Cast Parking Garage And Gave It New Life Without Any Significant Disruption of Hotel Operations

A Case Study for Decision Makers

Too often we see parking garage structures that break down and exhibit signs of deterioration. Restruction Corporation engaged in a four phase project to restore the integrity, strength, and performance of a 140,000 square foot garage while maintaining access and service to the adjoining hotel.

This case study will explain the steps taken in order to repair a hotel parking structure in downtown Denver, Colorado.

This Hotel Parking Garage, constructed in the 1970s, was badly deteriorated due to years of water intrusion. Snow melting off vehicles and routine cleaning contributed to the deterioration. Located in downtown Denver Colorado, this 140,000 sf, 5-level, double-tee constructed garage repair project consisted of 4 major work phases.

Phase One: Repair Major Structural Components – Tee Beams and Columns Required Shoring

The first repair phase concerned the precast concrete members of the structure. The repairs were needed due to corrosion of reinforcements in the garage’s double-tee beams, inverted-tee beams, and columns. Due to the anticipated amount of concrete excavation, an extensive shoring scheme was installed. While extensive, the shoring was planned so that work could be completed on all levels within a smaller floor by floor footprint. The shoring scheme allowed traffic egress through all levels preserving a large percentage of the parking revenue generated by the hotel. The shoring plan also allowed safe work access at all levels, expediting the repair construction schedule — another bonus for the owner. These major structural repairs were completed using American Concrete Institute and International Concrete Repair Institute industry standards for reinforcing steel corrosion repairs. The methods included concrete excavation, rebar re-passivation and replacement, shear crack expoxy injection, shear section enlargements and bearing pad removal and replacement.

Phase Two: Removal and Replacement of Structural Topping

The second repair phase of the project was the removal and replacement of the 3”-5” structural concrete topping. It had debonded from the existing double tees and was severely deteriorated. An initial engineering report stated that the lobby level was debonded and all levels needed topping removal and replacement. Restruction Corporation recommended and completed tensile bond testing, in the hopes of saving project costs by eliminating topping removal. After obtaining low bond test results on the lobby level of the structure, full removal and replacement was prescribed. However, good test results did save project costs as the other levels would only require localized topping repairs. Hydrodemolition was the chosen method of removal over the use of jackhammering equipment. By using the 36,000 psi water jets, the team was able to shorten the scheduled repair time, and almost completely eliminate construction noise from impacting hotel operations. Noise elimination allowed the hotel to retain revenue from conference and lodging sales. There were also areas in the topping repair zone where the double-tee flange below was deteriorated and required a full removal and replacement. The hydrodemolition process selectively “discovers” these locations and removes the unsound concrete. This benefit aided construction schedule and cost by reducing inspection and decision-making meetings.The full-depth repairs created a “minefield” of holes in the floor but with proper planning and minimal cost, traffic egress was maintained.

The topping and full-depth repair areas were then replaced with a fiber-reinforced, structural concrete. 500 cubic yards of concrete was placed over the duration of the project.

Phase Three: New Plumbing Lines, Drains, And Urethane Coating

The third repair phase consisted of the installation of new plumbing lines, drains, and a urethane traffic coating. This portion of the work protected the newly repaired structure by mitigating new water intrusion. Existing cracks and joints were routed and sealed in preparation to receive the coating. The use of an epoxy mortar extended with sand was utilized in areas of the garage where there was existing concrete scaling. The heavy duty urethane traffic coating was applied in 3 layers: base coat, intermediate coat, and topcoat. The traffic coating works twofold: it protects the concrete from water intrusion, and creates a wearing course for vehicular traffic that will not damage the waterproofing properties of the coating. Future maintenance costs of the coating are small compared to required structural repairs. New drains and piping were laid out in a cost-effective manner, thereby removing standing water and eliminating safety hazards.

Phase Four: Repainting

The final phase of the project was the repainting of the garage. After years of use, with no full-scale, repainting project undertaken since the parking garage was built, the owner wanted to supplement the new visual appeal of the garage. All of the existing walls, columns, and beams were repainted with different colored accents. The owner selected the color pallet and schemes to compliment the hip and modern themes of the hotel. This parking garage repair project required extensive collaboration between Restruction Corporation, the owner, and the engineer. Prior to starting the project, the owner allowed Restruction Corporation a planning period that was used to find project cost-saving construction methods.The project team held weekly meetings, worked around shutdown times for special events, and collaborated with city officials, thereby minimizing impact to the public. If you need parking garage repairs and have numerous complex operating restrictions, contact Restruction Corporation to save costs without revenue loss.