Julie M. Davis | STRUCTURAL OPTION
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| JULIE DAVIS |
| BUILDING STATISTICS |
| THESIS ABSTRACT |
| TECHNICAL ASSIGNMENTS |
| THESIS RESEARCH |
| THESIS PROPOSAL |
| PRESENTATION |
| REFLECTIONS |
| FINAL REPORT |
| SENIOR THESIS E STUDIO |
Note: While great efforts have been taken to provide accurate and complete information on the pages of CPEP, please be aware that the information contained herewith is considered a work-in-progress for this thesis project. Modifications and changes related to the original building designs and construction methodologies for this senior thesis project are solely the interpretation of Julie Davis. Changes and discrepancies in no way imply that the original design contained errors or was flawed. Differing assumptions, code references, requirements, and methodologies have been incorporated into this thesis project; therefore, investigation results may vary from the original design. |
City Vista | Building 2 | Building Statistics 460 L. Street Washington DC. 2001 General Info
Architecture: City Vista is a 2 building luxury mixed use complex located in downtown DC. Building one contains retail, residential, 1 acre green roof, and a roof top pool. Building 2 is strictly residential and connects to building 2 with a glass bridge the architect uses vertical and horizontal elements to create a more intimate setting for shoppers and residents. Building 2 skyline is a powerful horizontal statement though the use of a roof overhangs. This horizontal element is counteracted with protruding glass and crème colored brick vertical components throughout the building’s façade. At ground level the building narrows for a more intimate appearance. Buff and grey face brick, champagne metal panels, and glass walls compose the building’s facade. (The site is highlighted in red)
Building Envelope: The Vista is a Cast in place concrete building; typical wall construction is 4" metal gauge studs, 1/2" sheathing, air space, and face brick, and floor to ceiling glass curtain wall construction. The penthouse uses 8" CMU wall construction with metal panels. Four concrete shear walls are also used around the elevator core and other various locations. Typical roof construction is a post tension roof slab covered with ridged polystyrene insulation sealed with a standing seam metal roofing system. The pedestrian bridge connecting Building 1 and 2 is steel construction with a composite slab and flat asphalt roof. Building Systems Structural System -Foundation System : Building 2 is 4” slab on grade construction with 6x6 W2xW2 WWF, vapor retardant layer, and 6" ASSHTO #57 granular material, with a deep foundation system. Augured 16” diameter cast in place piles are drilled at a depth of 60-65’ below grade. This foundation system was chosen due to the median to stiff clay located up to 22’ below grade. Piles have an assumed service capacity of 125 tons and typically are reinforced with 1 #8 x 15’-0” LG. Piles under shear walls are reinforced at 25’ with 4-#8 vert. and #4 ties. The slab is thicken at interior CMU walls and location of increased service loads. Grade beams at a width of 1’- 0” are placed around the buildings perimeter at varying depths. - Pedestrian Bridge: The Pedestrian Bridge connects building 2 to Building 1A and 1B. The bridge is to have a minimum clearance of 14' from grade. The footers serve double purpose, supporting the crane until construction is over then serving as the bridge footings. The bridge is supported by (4) W12x58 columns that tie into W24x55 concrete incased girder with full moment connection. The floor slab is 3 ½” of lightweight concrete on a 2” 20 gage galvanized metal deck. The roof is a 1 ½” 20 gage metal roof deck with insulation and rubber asphalt topping. -Framing System : Building 2 is a flat slab system with a central core. The slab is a two way post tension system, supported by a grid of (52) cast in place concrete columns. (4) Concrete shear walls are used for lateral stability, three of which surround the elevator shaft (i.e. the central core). Cold form metal studs are used for most wall construction with the exception of stairwells, mechanical rooms and storage areas which are masonry construction. -Shear Walls: Shear walls footings are to be reinforced at a depth of 25’-0” with vertical bars and ties. Typical shear wall reinforcing is #4@12” vertical and horizontal, 8#8 in the middle, and #3 ties in various arrangements. - Post Tension Slab : The tendons are unbounded and span in both directions with a minimum of (2) tendons above columns . Banded and uniformed distributed tendons are used. Bundles size varies but restricted to a minimum of 4 tendons per bundle. The 7 ½” slab is reinforced two-ways with #4@24” bottom mesh reinforcement and #5 top bars at various locations, rebar is also provided around the perimeter. Tendons stressing will be done with a hydraulic jack, anchorage blockouts are grouted and tendons cut 1” from slab edge, stressing sequence is as followed; Balconies are conventionally reinforced with #4 @ 12” O.C and 2-#5 top & bottom Electrical System Building 2 is feed by (2) 3000A 208/120V systems. The first services the lobby via sub panels, and the second services the condos via a 3000 amp bus duct. The panel boards services corridor lighting, fire alarm equipment, and mechanical rooms. The bus duct feeds into a 120/208volts , 3 phase, 600 amps, meter center at each floor and then is send to indivdual120/208 volt, 125 amp, 1 phase panel board which service each apartment. A 4 cycle 230 KW diesel emergency generator with a 50 gallon fuel tank is located on the roof. The generator operates the fire alarm system, fire pumps, elevators, and emergency lighting in the event of a power outage. Lighting System All indoor public areas are lit by fluorescent 120V parabolic recessed lighting fixtures and wall sconces. The pedestrian bridge’s architectural features can be seen at night by the 150W T10 halogen pendant fixtures. Condo units are equip. with a combination of fluorescent and incandescent surface and track lighting by Sea Gull Lighting. Fluorescent lighting is used in the kitchen, a combination of (2) bulb 32W T-8 fixtures and track lighting with canopy style magnetic transformers are used. All other fixtures are incandescent with varying wattages depending rooms use. Mechanical System On the roof are (2) 100% outside air rooftop units containing a indirect gas furnace, condensing unit, and compressor. Each unit is 208v/3 phase and pushed 4000 cfm of outside air. Pubic areas are serviced with 208v/3 phase split system heat pumps with cooling, reverse cycle heating and electrical heating capability. Residential units are serviced with thru the wall gas heating units. Cooling in residental units is accomplished by these units as well. Each individual unit is 208v/1 phase with variable CFM depending on the unit size. Fire Protection The building is 100% sprinkled with an automotive wet and dry sprinkling system. Dry system is located in areas not heated (i.e. loading deck). Stairwells have a 2 hr fire rating and should be sprayed from top and bottom. Upon detection of smoke, water, and heat the fire alarm system is activated and unlocks fire access doors, turns off corridor electrical units, and activated pressurized fans for towers. Building 2 construction has mostly a 2 hour fire rating. Transportation Building 2 has (2) elevators located in the building’s central core, Both elevators are electric traction elevators with a capacity of 3,500 lbs. Elevators are controlled by the fire system and are equip with emergency power. There are also (2) stairwells located at each end of the building. Construction Managment City Vista is design -bid-build with Davis Construction as the prime construction. Truland systems Corporation did all electrical and fire protection work and Miller and Long performed all concrete work. Construction began in December 2005 and is set to end in December 2007. A tower crane was used during construction and footings are contained within the building foundation system. Telecommunications Telecommuications is provided in each residental unit. |
