Building Information________________________
Building Name
Location
Owner
Occupancy
Construction Type
Size
Height
No. of Stories
Total Cost
Date of Completion
Project Delivery Method
[Cannot be disclosed]
Northeast United States
[Cannot be disclosed]
Multi-use - Retail and Business (Type-B)
Type IB - Non-Combustible
651,287 sq. feet
130 feet above grade
11 above grade w/ 4 stories of underground parking
$350,000,000 (est.)
Summer 2016
Design-Bid-Build
Project Team_______________________________
General Contracting / Construction Management
Structural Engineering
Architect
Civil Engineering and Landscape Architect
M.E.P. Engineering
Architecture_______________________________
The Intersection is an 11-story office building with retail space at the ground level and 4 level parking garage below grade. Because of this being primarily used for offices, the bulk of the gross square footage is offices, with just shy of 459,000 square feet of leasable office space. As well, the street level offers almost 23,500 square feet of extra-height retail space, with the rest of the square footage being in the 319 below-grade parking spaces available. The higher office spaces at the 10th floor have direct access to a green-roof rooftop terrace that gives a great view of the surrounding area and an open-air space for the occupants. There is a noticeable step-back in the design after the 9th floor, as the locale in which this was built has a setback regulation in which all structures above a certain height must step back 45-degrees to the edge of the roadway it is enclosed by. The entire structure is topped with an enclosed metal-clad mechanical penthouse that is surrounded by even more accessible green-roofing and terrace space for the occupants.
Codes used in the design of this project:
Building: IBC 2006 w/ Local Amendments
Accessibility: IIC/ANSI A117.1 – 2006 Ed.
Life Safety: NFPA-101
Mechanical: [unknown]
Electrical: NFPA-70
Plumbing: NFPA-13
Structural: ACI 318-05 and ACI 530-05
IBC 2006 w/ Local Amendments
Zoning: Local and county zoning laws
[cannot disclose location]
Building Enclosure - Exterior_________________
For the entirety of the building, the façade is comprised of a glass curtain-wall system. However, not all of the exterior cladding is the same throughout, as it is sectioned. Starting at the street level, most of the areas accessible by the public, including entries and retail spaces, are enclosed in a monolithic glass curtain wall, changing in places to storefront with larger mullions. As you advance up the building, the exterior is mostly of a curtain wall system with uniformly spaced horizontal solar fins. In other areas, there are only vertical solar fins running up the entirety of the façade, and a portion of the façade closer to the rear of the building are actually pre-fabricated panels. These different enclosure setups are varied around the exterior of the building (See image - bottom right).
One standout portion of the building enclosure is an atrium space on the south side of the building, with the space open all the way to the 10th floor. The glazing in this section is supported at each floor by horizontal bowstring trusses that connect to the glazing and span the entire distance of the glass exterior of the atrium. (See image - left)
Building Enclosure - Roofing_________________
Most of the roof of this building is accessible as outdoor terrace spaces, with the only exception being a zone on the north side of the top roof. This area is designed with ballast roofing on rigid insulation on a cast-in-place structural roof slab/deck. All of the roofing types are on top of a structural slab with hot-applied waterproofing and rigid insulation with a base flashing layer. The majority of the roof, as stated previously, is accessible and green-roof with a concrete paver system. The pavers, being the walking surface of the roofs, are simply laid upon slim pedestals attached atop the rigid insulation. All roof drains in areas with pavers are actually not visible, as they are below the pavers, and water can drain through the open joints.
For the vegetated roofing system, a moisture retention mat is placed atop the insulation and is then covered with a filter sheet and buried under a thickness of a specified growing media (soil). Drainage points for these areas are not sub-surface like the paver areas, but the vegetated areas must also terminate a manufacturer-specified distance from the parapet/roof edge. This area is filled in with a specified inorganic drainage material.
The Intersection Office Building was designed to meet the requirements for LEED Gold status upon completion, which it achieved. The main component of green systems is the addition of the aforementioned green-roof systems on the upper terraces. Because of the urban landscape, they also include bicycle storage for the occupants. Points were also awarded for using refrigerant-saving methods, wastewater and runnoff control, and using recycled and regional materials.
Sustainability_______________________________
Structural___________________________________________________
Systems___________________________________
The main structural system used in The Intersection is that of reinforced concrete columns and slabs. The floor system throughout the above grade levels are 11" post-tensioned flat slabs with 8" drop panels at each column location, with banded prestressing tendons running project north-south along column lines, and distributed tendons running east-west through the slab. Lateral loading is resisted by 3 cores of 1'-0" thick cast-in-place reinforced concrete shear walls. At and below grade in the parking levels, the floor is 9.5" thick normally reinforced concrete flat slabs with 5.5" drop panels. In the atrium, there are bowstring trusses suspended horizontally to support the exterior glass. These are suspended by cables from a large truss spanning the atrium, constructed of W14x342 chord members and W14x74 web members. Steel infill beams frame into the truss and to a concrete edge beam with steel decking and concrete make up the roof over the atrium.
Mechanical_________________________________________________
Mechanical systems are split between the lower parking levels and rooftop units. All RTU's are 100% OA and supply air to all above grade levels. VAV boxes are used for air control throughout the building and at each level, as well as in the upper parking levels. Large exhaust fans are used in the parking levels to move air from lower levels. For the sprinkler system that runs throughout the building, the above grade levels are served with a wet-pipe system, while the parking levels use a dry system.
Electrical__________________________________________________
There are 3 main switchboards that distribute power throughout the building located in the lower parking level. In total, over 6500 kVA of power are drawn and used through all 3 switchboards. A 645 kVA - 516 kW generator is also housed in the lower parking levels in case of power shortages or outages. Typical interior lighting consists of 120V/277V 32 watt flourescent lamps with a color temperature of 3500K. Outdoor lighting is all weather-resistant LED's.
Construction________________________________________________
The Intersection was delivered via the Design-Bid-Build method. An older building that used to exist on the same site had to be demolished to make way for the new construction. For the entire project, the construction management cost at bid was $86.5 million, with other diciplines making up the other $213.5 million of total project cost.