Joseph Bednarz

Building Name: River Tower at Christina Landing

Location and Site: 115 Christina Landing, Wilmington, DE, 19801

Building Occupant Name: The Buccini Pollin Group

Occupancy or Function Type:
Primary Occupancy: Condominium Building
Accessory Occupancy: Enclosed Parking Garage interfaced in lower eight stories

Size (Total Sq. Ft.): Approximately 433,200 Sq. Ft.

Number of Stories Above Grade: 25 stories initially, 27 stories after redesign

 

Primary Project Team:
   - Owner: The Buccini Pollin Group:
     http://www.bpgroup.net
   - Architect: Burt Hill Kosar Rittleman Associates:
     http://www.burthill.com
   - MEP Engineers: Burt Hill Kosar Rittleman Associates:
     http://www.burthill.com
   - General Contractor: Gilbane Construction Company:   
     http://www.gilbaneco.com
   - Civil Engineer: Pennoni Associates, Inc.:
     http://www.pennoni.com
   - Structural Engineers: O’Donnell & Naccarato, Inc.:
     http://www.o-n.com
   - Elevator Consultant: Lerch Bates & Associates, Inc.:
     http://www.lerchbates.com

Dates of Construction:
   - Planned: May 1, 2005 to November, 2006 (18 months)
   - Actual: September 1, 2005 to April 1, 2007 (18 months)

Costs:
Original estimates:
   - Overall Project: $55.5 million
   - Building Cost: $46 million
   - Soft Costs: $4 million (CM fees, permits, site services, laborers) and an additional $5 million of environmental remediation    (contamination due to buried oil tanks from old tannery/oil storage yard)

After value engineering phase (now a 27-story building – two additional floors of condos at cost of additional $2.5 million):
   - Overall Project: $58 million
   - Building Cost: $49 million
   - Soft Costs: same as above

Project Delivery Method:
Originally: Design-Bid-Build
After redesign: Fast Track/Design-Build

 

BUILDING SYSTEM INFORMATION

ARCHITECTURE:

The River Tower at Christina Landing is an integral part of the redevelopment of the Christina River waterfront in Wilmington, DE. Phase one of the riverfront project involves the construction of sixty-three luxury townhouses and a 22-story apartment tower connected by a 2-acre park adjacent to Christina River. Phase two of the redevelopment involves the construction of a second tower, the 25-story River Tower at Christina Landing (the “River Tower”) on what is currently a parking lot for the first apartment tower.

The first floor of the River Tower contains retail space and various management and mechanical rooms on the south side of the building, with the entrance to the parking garage on the northern side of the floor. Floors 2-7 of the River Tower are comprised of a parking garage on the north side and six units on the southern side. The additional spaces required by the parking garage result in a wider base to the building, as the lowest eight floors have a wider footprint than the remaining seventeen floors. The eighth floor consists of a Great Room, Fitness Center, six luxury units, along with an outdoor terrace containing a rooftop pool, spa, garden, and observation deck. The other floors contain eight units a piece, each with master bedrooms and baths. These luxury units range in size from one- and two-bedroom dwellings, each unit having access to its own terrace. The largest units contain dens and multiple terraces.

BUILDING ENVELOPE:

Brick-faced pre-cast panels line most of the exterior walls. The entrances on the eastern and southern side of the high rise possess an aluminum glass curtain wall system. The main entrance on the southern side has a canopy with aluminum composite panel system cladding. On the ground floor, a concrete block recessed wall painted black dominates the western elevation, partially obscured by a green-screen fence. An 8” composite aluminum panel reveal lines the building at its uppermost floors. An aluminum storefront glass system is used on the stair towers. Sliding doors open from the units to individual terraces (some penthouses have even two terraces), which are lined with an aluminum perforated railing systems, consistent with the open spaces of the parking garage. Horizontal and vertical metal panel systems hide the rooftop mechanical systems. The rooftop terrace which houses the pool and observation deck is lined with 6”x6” wood columns with vertical wood infill panels. An expansion joint exists where the edge of the parking garage roof/terrace meets the narrower part of the high rise beginning at level 8. The roofing system will be an adhered membrane/roofing flashing system coated with a water proofing sealer.

CONSTRUCTION:

The owner rejected the original design, so value engineering has been utilized to cut costs in the latest conception. During the redesign process, the owner decided to add an additional two floors of condominiums. Perhaps the cost savings from the redesign made the additional units a viable option, since the new budget is actually larger than the previous one. Because of the readily available drawings and information for the original design (and ongoing design process of the new design), my thesis project will focus on the older conception.

The site is a former tannery and oil storage yard and some contamination was discovered during site excavation, resulting in environmental remediation fees of $5 million.

ZONING AND HISTORICAL USE:

As mentioned above, the redevelopment site is a former tannery and oil storage yard. The site is now zoned as W-4 Waterfront Residential, Commercial District. A number of variances were required due to the normal height restrictions for an apartment building by the Wilmington. Normally a maximum height of 72’, a variance and an amendment was needed to construct the River Tower. Another variance was necessary when the building coverage of 0.86 building/lot sq. ft. exceeded the normal 0.5 ratio. Finally, the floor area ratio of 5.97 required a variance of the accepted 2.00 ratio.

MAJOR NATIONAL CODES:

Main code: BOCA 1996 with amendments adopted by the city of Wilmington (see zoning for more info)
Fire Protection: BOCA-1999, Philadelphia Fire Protection Code, NFPA-13 Automatic Sprinklers

ELECTRICAL:

The power distribution for the River Tower has both standard 480/277V and 208/120V. Two utility company transformers, one a 408V and the other a 208V, bring electrical service into the building. The 208V transformer feeds into a 208V, 100KAIC switchboard with two 2500A bolted pressure switches. Each pressure switch has TVSS protection and customer metering and supply 2500A residential bus duct risers rated at a minimum of 100KAIC.

The 480V transformer feeds into three main areas. This 480V transformer feeds directly into the fire pump control for fire suppression, and the transformer also sends electrical power into the retail space. The transformer also feeds into the main distribution panel, which is a 3000A, 480V switchboard, 65KAIC minimum rated, with a 3000A bolted pressure switch with GFCI protection, TVSS, utility and customer metering. This main distribution panel itself serves: a 1000A automatic transfer switch which feeds emergency power panels; a 480/277V, 3 phase, 4 wire, 600A MCB, 65 KAIC min. panel for the water booster pumps; a 1000A bus duct riser to the MDP in the penthouse; two 164kW chillers; as well as a 1200A, 480V distribution panel that serves the pool area, corridor lighting, among other things. There is a 480Y/277V, 800kW, 1000kVA emergency generator present to supply power to the fire pump control and critical loads in the building. Two automatic transfer switches, rated at 1000A and 600A, regulate this emergency power.

Some major risers include a 1200A mechanical bus duct and an 800A emergency riser leading to the mechanical penthouse on the 24th floor. Two 2500A residence bus ducts service the 2-15th and 16th-23rd floors respectively. Each condominium unit possesses an individual load center, all rated 208/120V, 1 phase, 3 wire, 125A MCB despite the differences in square footage. These load centers contain circuit breakers for receptacles, garbage disposals, dishwashers, and unit lighting.

LIGHTING:

The outdoor areas immediately surrounding the building will be lit using compact fluorescent triple tube downlights under canopies. Ceramic metal halide spotlights buried within the concrete will run along the setbacks along the perimeter of the building. Metal halide lamps, both surface and pole-mounted, will handle the rest of the exterior ground lighting. The main entrance to the building will be illuminated by recessed halogen PAR38 accent lighting. Recessed compact fluorescent downlights and wall mounted fluorescents will light the connection between the parking garage and main corridors of the ground floor lobby. Pole-mounted ceramic metal halide adjustable spotlights will illuminate most of the pool-area on the terrace level outside the eighth floor. The rest of the terrace will be lit by patio steplights and metal halide uplights for custom columns. The great room will have six pendant compact fluorescent triple tube uplight fixtures even distributed above the room. Halogen downlights will fill in the rest of the lighting requirements of the great room.

The other areas of the building were not within the scope of the bid set that I currently have in my possession.

MECHANICAL:

A constant volume heat recovery air handling unit located on the 23rd penthouse/mechanical level provides forced ventilation to reduce indoor air pollution. Stairwell pressurization fans on the 24th level roof provide smoke ventilation in the event of a fire. 325-ton capacity cooling towers on the same level supply the building with the use of chilled water pumps. Air handlers service the first floor telecommunications room and the elevator equipment room, rated at 900 CFM and 1750 CFM respectively. 400W electric radiant panels heat individual units and rooms such as the fitness center and great room. Two exhaust fans run continuously on the roof and together with natural outdoor air ventilation, maintain natural room pressure. This counterbalances the negative pressure created by the exhaust fans present in each units’ bathrooms.

PLUMBING:

A domestic water booster located at the ground floor services the domestic water system in the River Tower. Four storage tankers are connected to the two main water heaters located on the 23rd floor. These water heaters are gas powered. Two cooling towers are located one level above, on the 25th floor. Storm water conductors are located throughout the perimeter of the building to collect rain water runoff. The pool equipment room is located on level 7.5, which can be accessed from the parking garage. The units do not have gas pipe access.

STRUCTURAL:

Apartment Building:
Foundation System: A deep foundation system will support the columns, walls, and slabs. The piles will be HP12x84 steel piles driven to 225 tons with a net bearing capacity of 200 tons. These piles will be grouped at columns and transfer load from columns using pile caps. A typical interior pile cap will be 7’-9”x11’-0” and 38 inches thick, with reinforcement in both directions. An exterior pile cap will be 7’-9”x7’-9” with 4 piles and a depth of 32 inches. Concrete grade beams span from column pile cap to pile cap and support the exterior walls of the building. The first floor slab will be a 12 inch thick concrete slab with #7 reinforcement at 12 inches on-center each way, top and bottom.

Super-structure: The apartment building will have 8 inch thick post-tensioned concrete slabs. The slabs span between columns spaced at 28’-6” in one direction and 23’-0” in the other direction. A typical interior column is 16”x52”, and its reinforcement and concrete strength decreases at upper floors. The exterior columns are 16”x36”. Concrete shear walls (varying 12-16 in., depending on location) provide lateral resistance and are located generally around elevators and stair towers and are scattered throughout the plan. The mechanical penthouse roof will be framed by steel beams spaced at 6 ft. on-center with 1 ½” deep, 22 gage roof deck spanning in between these beams. The mechanical area will be enclosed by metal panels with steel stud support. The cooling tower will similarly be enclosed with metal paneling, with a structural channel girt system to support it.

Parking Garage:
Foundation System: For the parking garage, additional steel piles (80 ton HP12x53) will be added at approximately 20 feet on-center to support the lowest level slab. The exterior columns will have 9’-0”x9’-0”x3’-0” deep pile caps with (5) HP 12x84 piles. The interior walls will have a 6’-0” wide grade beam with HP12x84 piles on each side of the wall, spaced 8’-0” on-center. The slab spanning these piles and columns will be the same as the apartment building slab.

Super-structure: The floor framing of the parking garage will be 34 inch deep pre-topped double tees which span between 45 to 60 feet. An “L” shaped beam makes up the exterior of the building and support the pre-cast tees. These L beams will span approximately 48 feet from column to column. The interior support, including the support of the sloping tees, will be supported by 12 inch thick pre-cast light wall. The exterior pre-cast columns will be approximately 24”x36”. 12-inch thick shear walls located throughout the plan will resist the lateral loads on the parking garage.

FIRE PROTECTION:

The general building classification for River Tower is mostly light hazard, and rated ordinary hazard (Group 1) for the storage and mechanical rooms. Most of the areas of River Tower are protected by an automatic sprinkler system. In addition, there are fire hose valves located at each level of the major stairwells. A fire pump room is located on level 1 to service the fire protection system. Each stairwell has access to a standpipe for immediate access to water. The concrete slabs, beams, and columns provide passive fire protection by their very nature in the parking garage and loading dock areas. Strobes, fire alarms, smoke detectors, and standard equipment are located throughout the building, concentrated mainly in means of egress areas such as stairwells and corridors. The fire alarm system will be fully ADA compliant.

TELECOMMUNICATIONS:

All units shall be wired for cable television and telephone service. Each unit will have multiple Tele/Data access points as well. The units will be expected to have broadband access as well as the latest data access available due to their luxurious nature. This system was not yet clearly detailed as the building is still within the design stages.

TRANSPORTATION:

Because of the dual use of the building, there are two main sets of elevators, as well as two main sets of stairwells. The parking garage is serviced by two sets of exclusive stairwells. The stairwell in the northeast corner leads up to the rooftop terrace where the pool and observation deck is located, providing another means of egress from the building. The other stairwell ends at the seventh floor with the garage. The parking garage also has two elevators where the garage intersects the main tower. These elevators end at the seventh floor with the rest of the garage. A central core of three elevators and a large stairwell services all 25 floors of the building and is located roughly in the center of the structure, where the parking garage bisects the rest of the building. Another stairwell centered on the edge of the southern most wall of the building services all 25 floors.

SPECIAL SYSTEMS:

As River Tower is still in the design phase, there has not been a finished security system detail to reference. Due to the luxurious nature of the units housed in the structure, the security system will undoubtedly be top-of-the-line and highly extensive.