Welcome to Alexis Pacella's AE Senior Thesis e-Portfolio



Building Statistics: Part I

Building Name: Lexington II at Market Square North
Location: Washington D.C.
Corner of 8th Street and E Street
Functions: Residential Tower with 3 stories of
underground parking and retail
Size: 72,000 sf
Levels: 12 Stories above grade and 3 underground parking levels
Construction Dates: Completed 2002
Cost: $10,000,000- $50,000,000
Project Delivery Method:


Project Team:
Owner: Square 407 LP; a Joint Venture of Gould Property Company and Boston Properties
      Http://www.bostenproperties.comn/site/index.aspx
Architect: Studios Architects
      http://www.studiosarch.com/
General Contractor:The Clark Construction Group
      http://www.clarkconstruction.com
Structural Engineer:The Thornton Tomasetti Group; formerly James Madison Cutts
      http://www.theTTgroup.com
MEP: Engineering Design Group
      http://www.ghtltd.com/



Building Statistics: Part II

Architecture:
Hailed as an “exclusive and private environment with unsurpassed style and service; you have found your new home” at the Lexington II residential tower. Located in the Historic Penn Quarter of Washington DC, Lexington II is part of a stylish new development called Market Square North. Located off of Pennsylvania Ave, between the White House and the Capitol, Lexington II is in close proximity to many other prominent DC areas, such as The Mall, The Smithsonian, and the Shakespeare Theater.

The Lexington II consists of 49 individual apartments varying between one bedroom, two bedrooms, and studios apartments. All apartments feature over-sized windows, walk-in closes, and spacious ceramic baths. Interiors are finished in fine materials including Italian marble, French limestone, granite and cherry. Some apartments also feature French balconies, terraces, and bay windows. A luxurious main lobby with full concierge service is provided. A reception room is also available.

Lexington II also includes three below grade levels, which are utilized as parking and retail space. The below grade levels connect Lexington II via tunnel to the rest of the Market Square North development.




Building Envelope/ Facade:

While the Market Square North complex is outfitted in granite and glass with a solid masonry base and lighter glazed windows on the top levels, Lexington II is designed to compliment it and relate to the other buildings located in the Historic Penn Quarter. Lexington II is a has an non-loading bearing exterior brick cavity wall featuring pre-cast stone trim and pre-cast concrete accents. Punched windows are in a grid like pattern along the exposed exterior walls. (Two sides of Lexington II abut to other buildings in Market Square North.) A typical wall sandwich consists of facebrick, a 1 and 7/8" airspace, 15# building paper, 5/8" exterior gypsum sheathing, 3 and 5/8" 16 galvanized metal studs located 16" on center, 3" batt. insulation with an R value of 19, and a 1/2" gypsum wallboard,

A steel and glass canopy defines the entrance to Lexington II. The main entrance is set of double glass doors opening up into a vestibule with a second set of doors leading into the lobby. The other building entrances are directly connected to adjoining buildings, the under-grade parking areas, and retail space, which opens exteriorly to the street.

                               


The roof of Lexington II has no special features expect for a mechanical penthouse which houses the elevator equipment, a cooling tower, and a backup generator. Roof construction is a ballast, filter fabric, rigid insulation, separation sheet, and fluid applied membrane waterproofing. The penthouse enclosure around the backup generator is made of 2" exterior insulation and finish system (E.I.L.F.), #15 building paper, 5/8" exterior gypsum sheathing, 3 and 5/8" metal studs 16" on center, and 1/2" gypsum wallboard. The cooling tower is enclosed by 2" E.I.L.F and an 8" CMU wall.



Zoning and Location History:
Lexington II is located in downtown Washington DC at the corner of 8th Street and E Street, a few streets back from Pennsylvania Avenue. This central location places the Lexington II in Washington DC’s Historic Penn Quarter. Being in the Historic Penn Quarter, Lexington is located close to many sites of national significance; such as the White House, Capitol Building, Mall, Smithsonian, Shakespeare Theater, and MCI Arena as well as numerous other upscale restaurants, galleries, and theaters. Being such an historical rich area, the Historic Penn Quarter was declared a national historic site on September 30, 1965 by the Secretary of the Interior. October 15, 1966 the site was added to the National Register of historic Places. Currently the block Lexington II is located on is governed by the Pennsylvania Avenue Development Corporation, first established in Oct. 27, 1972. More detailed information on the Pennsylvania Avenue Development Corporation can be found at http://www.nps.gov/paav/pa_visit.htm.

The District of Columbia Office of zoning also has designations for the block Lexington II is located on. Found on zoning map 10, Lexington II has been given a designation of DD/C-4. DD/C-4 refers to the downtown development district and the central business district. Brief summaries provided from the D.C. Office of Zoning describe C-4 and DD as:
    C-4
       The downtown core comprising the retail and office centers for the
       District of Columbia and the metropolitan area, and allows office,
       retail, housing and mixed uses to a maximum lot occupancy of 100%,
       a maximum FAR of 8.5 to 10.0, a maximum height of 110 feet and 130
       on 110-foot adjoining streets. (Maximum height and FAR depend on
       width of adjoining streets.)
   Downtown Development District (DD)
       Permits incentives and requirements for Downtown sub-areas to a maximum
       FAR of 6.0 to 10.0, and a maximum height of one hundred-thirty(130)
       feet. This district is mapped in combination with other districts.

More detailed criteria can be found on the DCOZ site at http://www.dcoz.dcgov.org/info/reg.shtm.


Major National Codes:
Model Code:
   1996 Edition of the BOCA
Design codes:
    ACI 318-95 ; Reinforced Concrete
    AISC 9th Edition ; Steel design, fabrication, and erection
    AWS D1.1-98 ; Structural Welding
    NDS 1991 ; Wood construction
    ACI 530-95/ ASCE 5-96 ; Masonry Structures

Construction:
Market Square North was a two phase project. The first phase was the completion of the main complex of Market Square North in 1999. Lexington II was built during the second phase of construction and completed in 2002. The cost of Lexington II is between 10 and 50 million dollars for it’s 72,000 square feet. The entire Market Square North project had a construction cost of 70 million dollars and has a size of 570,000 square feet.

**Further construction details will be available pending a reply from Clark Construction, who has been sent a letter via mail asking for a contact within their office.

Structure:
Lexington II is a concrete structure consisting primarily of cast in place concrete elements. The foundation of Lexington II is a 3’-6” MAT foundation resting on top of a 3 inch MAT working slab. The compressive strength of the MAT foundation is 5000 psi. The MAT foundation is resting on undisturbed soil. Along the south wall, where Lexington II abuts a previously built building, HP 14 x 89 reaction piles have been placed 5 feet o.c..

Lexington has a framing plan of concrete beams and columns. The slabs in the substructure are 10” with drop panels 5” deep around two columns in the south of the building. The superstructure has 8” slabs. All concrete has a compressive strength of 4000 psi. A shear wall encompassing the elevators’ shafts spans the entire height of the building.

Transportation:
The vertical transportation system of Lexington is located in a central core of the building. Two passenger elevators operate in the building and both travel the entire height of the building covering its 12 stories and three below grade levels. Two stair wells also run vertically through the building, both travel from the roof level to the underground concourse, one stair way continues to the lowest parking level.

Mechanical:
The mechanical system for Lexington II is an water source heat pump system. This system involves the use of a boiler located in the building's basement, pumps, and a rooftop cooling tower. The cooling tower located on the roof is a 176 ton counter flow blow-thru tower. Fresh air requirements are met by operable windows in the residential units. Fresh air intake units in the roof penthouse provide 100% outside air for corridor spaces. All residential units are equipped with kitchen, toilet, and washer/dryer exhausts.

Electrical/ Lighting:
Each apartment unit is provided a voltage of 120/208. This power is in a phase 1P 3wire system. Located in the roof penthouse is an emergency generator. The incoming electricity is provided by PEPCO vault located outside of the Lexington parking levels. This incoming power is 120/280V and is 3 phase with 4 wires.

Lexington II uses fluorescent lighting in both public and private spaces.

Fire Protection:
The Lexington is provided with a 100% fully sprinklered, automatic wet and dry pipe system. This system utilizes a fire pump, jockey pump, wet pipe sprinkler system, dry pip sprinkler system, and fire standpipe systems as its components.

Plumbing, Telecommunications:
More information will be available on these after contact has been established with engineers from firms other then the structural engineer. Currently letters and emails have been sent to the MEP, architect, and construction companies.


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This Page was last updated on March 15, 2006 , By M. Alexis Pacella and is hosted by the AE Department ©2005