General Building Site
- Building Name:
- Location and Site:
- Building Occupant:
- Building Occupancy Type:
- Building Size:
- Number of Stories:
- Project Team:
- Dates of Construction:
- Construction Cost:
- Project Delivery Method:
- Block 12
- Rockville, MD
- Federal Realty Investment Trust
- Retail & Residential Apts
- 285,000 Gross SF.
- 4 Total Floors and 2 Sublevels
- Federal Realty Investment Trust
- The Whiting-Turner Contracting Co.
- Design Collective
- Summit Engineers, Incorporated
- SCA Consulting Engineers
- Clinton & Associates
- Datawatch Systems, Inc.
- HLB Lighting Design
- October2012 - May 2014
- $36 Million
- Design - Bid - Build
Block 12 is part of a new 1.7 Million square foot mixed-use community in Rockville, MD. Block 12 will primarily consist of 174 residential units, 13 retail spaces, a fitness and clubhouse area consisting of 1,075 square feet, and a 576 square feet swimming pool on the podium level. There are 3 different unit types in the residential level, which include 33 MPDU, 85 Transitional, and 56 Modern. The residential units vary in quality and options. The transitional unit is considered the standard option, the transitional unit has more amenities and options, but the modern offers more options and offers the best views and locations.
Directly beneath the retail spaces, will be 2 levels of 163 underground parking spaces. The parking level will contain 137 parking spots, while the remaining 26 parking locations will be on the retail level. In addition to the parking spaces, the underground garage will house the main electrical room along with 4 motorcycle spaces.
The swimming pool area on the podium level is open to all the residential levels. The architecture of the open courtyard area also includes private balconies for certain residential units.
National Codes Used:
- 2009 International Building Code
- 2008 National Electric Code
- 2009 International Mechanical Code
- 2009 International Fuel Gas Code
- 2009 International Energy Conservation Code
- 2009 International Plumbing Code
- 2003 & 2009 Life Safety Code (NFPA-101)
- 1991 Fair Housing Act Accessibility Guidelines (FHAAG)
Zoning: Montgomery County
A large portion of the above ground residential exposed façade is composed of masonry, EIFS, stucco, lap siding, and aluminum composite panels. The retail level is comprised of a combination of an aluminum anodized framed glazing system curtain walls and storefronts.
The exterior enclosure was covered with a proprietary zip system, which acts as a barrier that keeps moisture out and reduces air leakage. The underground garage level was completely waterproofed with insulated drainage panels over a trowel applied membrane. The courtyard was waterproofed with hot fluid applied asphalt membrane, while the main residential roof was covered with a PVC membrane.
The owner of the property is seeking LEED Certification for Building 12. Some of the major LEED points opportunities sought in this project are through the green roof system, a waste management plan and an indoor air quality management plan.
The building excavation had to be excavated 10 feet deep, prior to starting the concrete foundation construction. The 16 foot deep excavation left nearly 27,000 cubic yards of uncompacted soil, which had to be safely secured off-site. Nearly 60,000 square feet of vertical soil surface area had to be safely secured, to allow work to continue. To support the excavation walls, over 200 steel H soldier piles were installed with wood lagging boards and 36 tiebacks through drilling operations and grout, as seen on figure 1.1. To prevent sediment and control erosion, scrubbers and tire washers were installed at the two main entrances.
Power is supplied by PEPCO, the utility provider. A transformer, which will be owned by the owner, is located on the parking level and feeds approximately 1500 KVA to the main electrical switchboard. The 3-phase 480/277V low voltage is fed from one location to electrical closets on each residential floor for common power receptacles, lighting fixtures, and card readers in the stairs. Dewatering pumps, supply fans, and exhaust fans are fed by 480V. There is one diesel generator of 250 kW with an auto start of 10 seconds max and minimum fuel storage of 24 hours at rated load. LED’s were installed in wall scones and stairwell light fixtures, as an energy saving initiative. T-5 fluorescent lighting was used in the garage drive aisles and parking areas. For the residential levels a combination of can lights, surface mounted, and pendant lights were used to illuminate the spaces. For the retail and entry hallways, motion sensors and occupancy sensors.
The mechanical system for the parking level is a simple system that circulates air with 3 exhaust fans, which are activated with CO2 sensors. Each ¼ hp fan can circulate 2,700 CFM of air. The retail spaces will primarily utilize 2 810 MBH RTU’s, which will be located on the roof, as seen on figure 1.2. The residential units will be heated by split system heat pumps and cooled with a cooling system. There is 1 air intake shaft and 1 exhaust fan with 6 fans.
The wood frame building sits on spread footings set 3 feet below the slab on grade level with two 12”-13”post tensioned concrete slabs. The cast-in-place concrete podium slab contains 10” drop panels to help distribute the load of the floors above. The slabs are 1.5% - 3.0% sloped to accommodate draining water. The cast-in-place concrete was pumped and poured using concrete barrels, to reach the building’s extremes. The thickest concrete wall is 12”, due to soil pressures at the garage, while the thinnest wood wall is 5” at the residential level.
The structural truss system used is patented by SCA. It was utilized to increase productivity for faster drywall installation on the field. The common residential floors (2-3), contain wood trusses of 20”-24”, and a wood frame to support the residential penthouse and roof. Block 12 holds a 3’ swimming pool on the podium slab. The wood roof system was designed for primarily a flat roof. The typical wood truss sizes vary from 20”- 24”, mostly on corridor. The structural truss system used is patented by SCA. It was utilized to increase productivity for faster drywall installation on the field. The common residential floors (2-3), contain wood trusses of 20”-24”, and a wood frame to support the residential penthouse and roof. Block 12 holds a 3’ swimming pool on the podium slab. The wood roof system was designed for primarily a flat roof. The typical wood truss sizes vary from 20”- 24”, mostly on corridor.
Fire Protection System:
Active fire protection measures are taken by 2hr fire rated shafts and fire rated I-beams. Passive fire protection measures are additionally taken by a wet pipe system in the stairs & residential areas and dry pipe system in the garage & retail slabs. The fire protection material utilized in the parking and retail level was cast iron, while in the residential levels, a non-metallic sprinkler system option was used.
ALL IMAGES/RENDERINGS OF BLOCK 12 WERE GENEROUSLY SUPPLIED BY DESIGN COLLECTIVE. ALL CONSTRUCTION PHOTOGRAPHS AND INFORMATION WERE GENEROUSLY SUPPLIED BY THE WHITING-TURNER CONSTRUCTION COMPANY.