The plaza hardscape at Grange Mutual Insurance headquarters in Columbus, Ohio, is primarily precast concrete pavers (Hanover) arranged to create subtle bands of warm and cool grays with light and medium sandblast finishes. The pavers have a "charcoal' tint, and "Tudor' and "heavy Tudor' finishes. The Tudor finish "very lightly exposes the aggregate, similar to a flamed granite texture," says the manufacturer. Full and half paver modules are randomly arranged, which creates a rich visual affect whether viewed from a distance or up close.

When Grange Mutual Insurance, based in Columbus, Ohio, outgrew its headquarters, the company was faced with the decision to expand the present site or relocate. The easier solution would have been to move to the suburbs, as many corporations have done. Grange decided to maintain its current location within the city and continue to invest in the community and taking advantage of the city's infrastructure, instead of contributing to urban sprawl.

Situated on a three-block property downtown adjacent to High Street, the Brewery District and the historic German Village neighborhood, the Grange headquarters site anchors the downtown's southernmost edge. The headquarters building, a bulky brick structure built in the late 1970s, sat alone at the corner of the site off Front Street, closest to the Brewery District. It was bounded by a landscape that appeared quite suburban, with large expanses of lawn and an eclectic collection of beautiful mature trees interspersed across the site. Although attractive, there was little structure to the landscape, nor connection between the headquarters and its surroundings. The expansion project offered opportunities to remedy the disconnection between indoor and outdoor environments.

Low-profile slabs of Hanover granite add interest to the reflecting pool. The pool wall is cast-in-place architectural concrete.

The Project
The siting, massing and design of the new 11-story, 240,000 sq. ft. office building had the potential to either enhance the community or damage the charm of the site and the adjacent historic districts that bounded it. Landscape architects from NBBJ provided leadership in early urban design studies, which led to the client's decision to minimize building development into the park-like open space to the south. It became apparent that siting the new building tight to the old building, and developing the site toward the Brewery District would best achieve the growth goals, and contribute to the vitality of the recovering neighborhood.

The move to stretch the office tower addition toward High Street spawned the creation of new outdoor spaces that provided connections between indoor activities and the landscape. These spaces include a new plaza, dining terrace, rain garden and service court.The plaza, located at the northeast corner of the site, provides Grange with a much improved presence on High Street, a physical connection to the neighboring Brewery District, and an attractive urban space for staff and visitors to enjoy, extending indoor activities generated from the building's lobby, meeting rooms and cafeteria to the outdoors. The 30,000 square foot plaza has a ratio of approximately 30 percent green space and 70 percent hard surface area. Simple in composition, the plaza is designed to interface harmoniously with the adjacent buildings, and made up of a few basic components: defining cast-in-place perimeter walls and stairs; perimeter planting beds of liriope, purpleleaf wintercreeper, low yew hedges; bosques of "Princeton' elm trees trees; a paved plaza with seating alcoves, and an elegant, low-profile reflecting pool. The plaza is both a viewing and people space. It feels as comfortable with a few people as it does with an event with many people.

The contrasting hardscapes (top) of concrete, pavers and bluestone is on view at the edge of the rain garden. Liriope, purpleleaf wintercreeper and low yew hedges are in the perimeter planting beds of the rain garden. The bottom image is a close-up view of the bluestone.

The plaza was meticulously graded to make the surface appear flat, which was accomplished through the use of unobtrusive slot drains. Materially, the plaza surface consists primarily of precast concrete pavers arranged to create subtle bands of warm and cool grays with light and medium sandblast finishes. A combination of full and half paver modules are arranged randomly, which creates a rich visual affect whether viewed from a distance or up close.

Water is conveyed from roof scuppers through architectural concrete runnels leading to the rain garden. The rain garden slows the erosive forces of stormwater, while enhancing the water quality. The notched concrete weir controls the water flow into the lower basin, where it pools to a depth of 14 inches before percolating to the detention pipes below. Aligned with the notches, crafted rectangular stone planks prevent erosion and provide a contrasting element to the sweeping masses of wetland plants in the lower basin: "Sweet Flag', dwarf horsetail, "Blue Star' and a variety of sedges. The plants were selected for their scale, texture, seasonal color and maintenance qualities to make this a garden that is beautiful as well as functional. Introductions of water-tolerant red maples and swamp white oaks will eventually shade the afternoon sun as well.

The dining terrace, located directly south of the ground-level cafeteria, is an intimately scaled outdoor space with buffered views toward busy High Street. It also has views to the mature landscape of the South Green and the newly developed rain garden. Umbrella tables and chairs encourage people to sit and take a morning break, or have lunch outside. A comfortably wide walk, which is serviceable as a fire lane, draws people along the edge of the rain garden's upper basins, linking to the Wall Street walk corridor and lobby. Preserved trees provide dappled morning shade to the space. Introductions of water-tolerant trees in the adjacent rain garden, such as red maple and swamp white oak, will eventually shade the afternoon sun as well.

A highly visual environmental amenity on the Grange campus is the rain garden, which is situated between the dining terrace and Wall Street path. The rain garden works hand-in-hand with the building's green roofs and a below-grade detention piping system. Water is conveyed from roof scuppers through architectural concrete runnels leading to the rain garden. The rain garden slows the erosive forces of stormwater, while enhancing the water quality. A notched weir, constructed of architectural concrete, controls water flow into the lower basin, where it pools to a depth of 14 inches before percolating to the detention pipes below. Aligned with the notches, crafted rectangular stone planks prevent erosion and provide a contrasting element to the sweeping masses of wetland plants in the lower basin. A variety of wetland plants"?u"Sweet Flag', dwarf horsetail, "Blue Star' and a variety of sedges"?uwere selected for their scale, texture, seasonal color and maintenance qualities to make this a garden that is beautiful as well as functional.

A path cuts through the middle of the south end of the site. It transitions from bluestone and concrete pavers to repurposed brick and poured concrete. Bold arrangements of dwarf bamboo, feather reed grass, black-eyed Susan and Russian sage follow the path in a shifting pattern emphasizing a north-south grain. The path is punctuated with columnar pedestrian lights, and contemporary "Bancal' ipe benches with steel supports.

Another key component of the new campus infrastructure is the reintroduction of Wall Street. The design team established the new corporate lobby on what was formerly Wall Street and reconstructed the street to become the main pedestrian path that connects the new Grange parking garage through the corporate lobby, the rain garden, service court and South Green beyond.

The paving materials transition from bluestone pavers to precast pavers and asphalt as the path moves southward between the service court and rain garden and then to asphalt and repurposed brick pavers from the original street. A bold arrangement of dwarf bamboo, feather reed grass, black-eyed Susan and Russian sage follow the path in a shifting pattern emphasizing a north-south grain. The path is punctuated with columnar pedestrian lights and contemporary benches of wood and steel.

Japanese Pagoda trees (see image on page 82) were specified by NBBJ landscape architects for the main plaza, but the contractor installed a different cultivar that performed poorly and soon had to be replaced soon by "Princeton' elms (pictured). There are also some red maples, swamp white oaks on site (not pictured), along with some existing trees.

In addition to the ground-level site development, three green roofs totaling over 10,000 sq.ft. have been constructed adjacent to the offices at the second and third floors to the south and east. They are densely planted with a diverse palette of visually contrasting sedums to create bold geometric patterns. These green roofs, reduce glare in the adjacent offices, absorb storm water, and reduce the heat island affect, while creating a landscape that benefits the employees in the office tower. Although the client did not pursue LEED certification the design team worked with the client to realize a project that clearly contributes to the vitality of the community, enriches the lives of those who work at and visit the Grange Insurance Headquarters and adds to the built environment in a responsible, sustainable way.

The bluestone hardscape leads to the main building, transitioning to cast-in-place perimeter walls and stairs, with a landscape of "Princeton' elms, "Sebian' yew, creeping liriope, daffodils and a turf mix.

The Grange Insurance headquarters anchors the downtown's southernmost edge. It is situated on a three-block property downtown adjacent to High Street, the Brewery District and the historic German Village neighborhood. A primary design goal was to maintain harmony with the surrounding buildings, homes and nearby park space. To that end, the 30,000 sq. ft. plaza has a ratio of 30 percent green space to 70 percent hardscape.