Parking Garage

Liberty Center Office Building (675 Randolph Street)

This 13-story, 353,000 sf Class "A" office building is occupied by the Federal Government’s Defense Advanced Research Projects Agency (DARPA) in Arlington, VA.  The building is located within the larger Liberty Center complex, which is a 5.35-acre, mixed-use development with two office buildings, a residential tower with retail, and structured below-grade parking.  The development is certified at the Gold level under the LEED-ND (Neighborhood Development) pilot program.

Designed to meet the Department of Defense minimum Anti-Terrorism Force Protection (ATFP) standards, the building has an 82-foot secured perimeter and is surrounded by a sizeable lawn separating it from the surrounding buildings within the complex.

Embassy of Nigeria

SK&A provided structural engineering services for the Nigerian Embassy’s new chancery building.  In addition to three above-grade levels of office and meeting space, the chancery includes below-grade parking for 90 cars.

Designed to U.S. Department of State standards, the building is a modern structure with a stone-clad exterior and a soaring, light-filled atrium/lobby with a curtain-wall of glass.  SK&A’s services included consultation from the schematic design through construction administration phases.

733 15th Street, NW (The Woodward Building)

Complete restoration and conversion of a circa 1910 steel and concrete-framed 11-story office building (including one basement level) into a residential apartment building.  Historic restoration activities included modifying floors constructed of terra cotta flat arches with concrete fill, and rehabilitation of the multi-wythe brick façade.  The façade materials also included stone at the lower levels and terra cotta at the uppermost levels.  Several columns were removed in the basement to facilitate parking.  Hydraulic jacks were used to pre-deflect six new steel transfer girders at the ground floor used to replace the columns.  Stairs were reconfigured throughout, terraces added to the roof, and two vehicular elevators added to access the below-grade parking.

The project was awarded the 2009 Outstanding Project Award for Excellence in Structural Engineering by the Structural Engineers Association of Metropolitan Washington. 

Promenade Plaza Rehabilitation

SK&A provided plaza restoration services at the Promenade Towers apartment complex.  The spacious, elevated plaza includes an Olympic-sized swimming pool and is bordered by the two high-rise residential buildings all of which sits over a three-story garage.  The plaza/garage structure consists of cast-in-place concrete framing with post-tensioned concrete elevated slabs and was constructed in four sections separated by expansion joints.

Originally constructed around 1972, the plaza and pool included a concrete topping sundeck and several deep planters.  The overall plaza appearance had become aesthetically displeasing due to deteriorating topping slab and planter wall conditions. There were several leaks through the plaza deck, down into the garage space below, and structural distress existed in isolated locations, particularly under the planters.

SK&A performed the initial analysis of the plaza structure to determine allowable load capacities and provided strengthening design once the final landscape concept plan was completed.  The project also required concrete repair, waterproofing, steel/carbon fiber strengthening, and post-tension repair.  All of the strengthening and waterproofing were fast-tracked over a four and a half month period.

2000 N Street, NW Plaza Renovation

This project entailed the renovation and conversion of a hotel facility into a rental apartment complex.  Prior to commencing the general building renovation, repairs to the garage, as well as plaza strengthening and plaza waterproofing were required. Repairs included: waterproofing and repair of the plaza deck over the garage, structural analysis and strengthening of the plaza deck to support the proposed new plaza landscape design, along with full depth wall-to-wall removal; and replacement and waterproofing of the below-grade parking deck.

SK&A’s structural analysis determined that many areas of the plaza slab needed varying levels of reinforcement in both positive and negative movement areas.  Strengthening of the plaza deck involved both carbon fiber reinforcement and the casting of new concrete beams into the plaza deck, which extended both above and below.  A total of 21 new concrete beams were cast into the plaza slab.

Additional work included the installation of new rooftop unit steel-frame supports, masonry planter wall construction, plaza drain installations (determined from plaza deck flood testing results), and the demolition and reconstruction of two balconies to provide a new curved shape matching the plaza design features.

Parc Somerset Repairs

The condominium association of this 18-story, luxury high-rise complex undertook a preventive maintenance approach to offset future (and more expensive repairs) by initiating an exterior repair program.  SK&A completed a comprehensive condition evaluation followed by recommendations for the repair design and preventive maintenance of the balcony, garage, and main entrance of the building.    

Work performed included:

  • Repairs to visible concrete deterioration caused by corrosion of embedded post-tension cables and anchor grout plugs;
  • Repairs to the significantly worn waterproofing membrane top coat in the garage;
  • Installation of the Dryvit system on the balcony soffit of Unit 1403; and
  • Replacement and re-setting of brick pavers caused by settlement at the entrance of the building.   

Montgomery County Garage #31 Peer Review and Waterproofing

Under a task-order contract with Montgomery County’s Division of Parking Operations, SK&A provided peer review services for the design and construction of a four-level parking garage beneath a commercial complex in Bethesda, Maryland. The parking structure is S-3 Occupancy Type I, with post-tensioned concrete slab, supported on columns bore on individual spread footings.  The exterior perimeter is enclosed by concrete foundation walls and interior rooms enclosed with concrete masonry unit (CMU) walls.  A transfer concrete slab located at the mezzanine level supports the mixed-use complex above.

The objective of the peer review was to determine if the plans and specifications for the garage’s design were in compliance with applicable building codes, Montgomery County’s design standards and other industry standards. At the review’s conclusion, SK&A advised the County on deficiencies observed in the critical areas of design, waterproofing, structural calculations, MEP calculations and life safety.  The study also included the review of construction documents through issuance for permit (regarding code requirements) and constructability of the proposed five-level subterranean garage. In reviewing the construction documents, similar projects were used as a basis for comparison.

Waterproofing aspects of the project included the review of design and specifications for: vehicular traffic-bearing waterproof membranes on elevated garage decks; foundation wall waterproofing; under-slab draining system; and water-tight street-level expansion joint systems. Additional waterproofing consulting provided ranged from air and moisture barrier design to subterranean drainage design.

To view a live camera of the project under construction, click here.

Montgomery County Garage 49 Rehabilitation

The Garage 49 post-tensioning repair project involved the performance of major structural and waterproofing repairs to the five-level cast-in-place concrete post-tensioned structure.  The combination of poor design and construction details resulted in severe cracking and deflection of the elevated decks of the parking structure. 

The visible signs of distress led the owner, Montgomery County, to conduct a condition survey in 2004 that included physically exposing and examining a section of the post-tensioning system across a 60-ft wide section of the elevated deck from column-to-column, along a construction joint.  Exploratory work revealed areas where over 40% of the uniform cables across the slab section had failed due to structural design deficiencies and corrosion-related deterioration. 

The survey led to the installation of emergency shoring along construction joints throughout the garage until a thorough repair program could be performed.  SK&A's services included:

  • Concrete repair and renovation
  • Caulking and sealing
  • Reinforcement repair
  • Waterproofing and protection
  • Capital planning and budgeting
  • Project management
  • Structural evaluation and repair

Highlights of the project included the installation of new pour strips along existing construction joints, while tackling unforeseen conditions and additional repairs to anchor strips and cables within almost every repair phase.  The post-tensioning cable replacement work was challenging due to temporary stressing required on sections of tendons actively being repaired to ensure that the structure could adequately support vehicular traffic and remain open and in use as the repair work was being performed. 

The project was awarded the Concrete Repair Project of the Year in 2007 by the International Concrete Repair Institute’s Baltimore-Washington Chapter.

Democracy Center Plaza Repairs

SK&A provided repair and renovation services for this office complex project.  The complex has three unattached, matching buildings facing each other surrounding a central plaza with outlying parking lots and a parking garage below.  The plaza’s landscaping appears as an X-shaped courtyard between the buildings.  The northwest and southwest legs of the X (flanking Building #2) have large continuous planters with paver-topped walkways lining each side.  The other legs also have paver-topped areas as well as isolated planters. The plaza slab surrounding the buildings is a conventionally reinforced concrete slab, supported on concrete beams and columns.  The garage has concrete-encased steel columns located around the building perimeters.  An approximately 25’ wide asphalt driveway is located on three sides of the plaza and is designated as the service lane. 

The plaza renovation included the complete removal of the existing pavers, planters and waterproofing, the repair of structural elements below the old waterproofing, and the replacement of topping materials.  Work also included concrete steel column encasement repairs, removal and replacement of concrete ramps and topping slabs supported by CMU piers, and painting, priming, and fireproofing of steel beams.

In addition, SK&A replaced existing soil beneath the pavers with crusher-run fill, performed architectural precast concrete repairs within planter pre-cast panels, removed and replaced planter CMU walls abutting buildings and planter precast coping stones in order to install rubberized asphalt waterproofing. New plaza expansion joints were installed, and existing concrete bollards replaced. Lastly we cleaned and flushed the existing drains and installed new planter drains to promote bi-level drainage as well as provided waterproofing protection and project management services. 

Capitol Plaza Green Roof Addition

SK&A’s Repair & Restoration Division evaluated the adequacy of an 11-story office building’s roof structure to accommodate a green roof retrofit.  Built atop of a two-level parking garage, the building is approximately 153,344 SF including plazas, while the new green roofs account for 11,000 SF.  Structural evaluation included providing detailed structural analytical computations to evaluate the roof’s capability of supporting the green roof addition plus required service loading, such as snow load, live load and snow drifts. Additionally, certain areas of the main roof and penthouse roof frame were evaluated to receive solar equipment. SK&A determined that the roofs were adequately designed to support the anticipated loads from the green vegetative roofing assembly in addition to the multiple load combination. 

SK&A categorized the scope of work needed for the green roof addition and provided roof plan view drawings for initial cost estimates. Following the survey, SK&A prepared plans and specifications for inclusion in the application package for DDOE’s Green Roof Rebate for Targeted Large Retrofit Program, designed and specified the green vegetative roofing system, provided structural waterproofing details to integrate the system application with those of the manufacturer standard details and prepared selective demolition and removal of the existing roofing assembly only to the extent to accommodate the new application.