The city of Spokane is seeking public input on the design of the envisioned pedestrian-and-bike bridge it hopes to build eventually to connect the University District to commercial, medical, and residential areas south of it.

Preliminary cost estimates for the bridge range between $11.3 million and $12.2 million, says Katherine Miller, the bridge project's manager and a senior engineer with the city. Those figures include design work, right-of-way purchases, and construction costs, though she adds that the actual cost of the project likely will change once a study on the project is complete.

Miller says the project's team recently selected two final design schemes for the bridge and has posted sketches and three-dimensional images of them on a blog outlining the project.

At that website, udbridgestudy.blogspot.com, members of the public can take a survey about which design for the bridge they prefer and can leave comments about it, Miller says. The survey and comment feature will be open until the end of this month, she says, adding that as of late April, about 250 individual responses have been gathered.

While the bridge project still is in the study phase, Miller says a bridge planning committee hopes to present a final design scheme based on the public's comments to the City Council and Spokane Mayor Mary Verner in June. If approved, the committee would complete an environmental evaluation of the bridge and a cost estimate for the final structure, after which the project would be prioritized with other plans the city has for future development of the U-District, she says.

The need for the bike-and-pedestrian bridge originally was determined back in 2004 when the city put together its University District Strategic Master Plan, Miller says.

"That effectively was when it became a priority to look into further," she says. "The city obtained some federal money to do a type, size, location study, which is what we're in the process of right now."

That grant for that study is about $390,000, she adds. Miller and Verner's bridge advisory committee have been working for about a year with a team of contracted consultants that are being paid with that grant money, she says.

So far, Miller says, the planning committee has determined the location and size of the bridge, and the current phase of the study focuses on determining the type and design of it.

The two final design choices for the pedestrian-and-bike bridge have the same approach scheme, Miller says, with both stairs and ramps providing access to the elevated bridge that would cross the Burlington Northern Santa Fe railroad tracks and the currently under-construction Martin Luther King Jr. Way. The possibility of a future mass-transit system that could parallel that corridor also was taken into consideration during the creation of the designs, she says.

The plans for the north and the south bridge landings both feature public green spaces, low-maintenance landscaping, lighting, and seating areas, as well as space to construct public transit shelters. The ramps at each access point were designed with cyclists in mind and to be compliant with the Americans with Disabilities Act.

Miller says the approach areas to the bridge also were designed to integrate with either of the final two bridge schemes.

Of those plans, one features an arch-style bridge with an S-shaped bridge deck that diagonally crosses the railroad tracks and the street. The other design is what's called a cable-stay bridge, which features a tall, narrow arch in the middle of the structure with cables extending from it down to the sides of the straight-angled bridge deck to hold it up. Miller says each bridge would be about 400 feet long.

One of the main objectives of constructing the U-District bike and pedestrian bridge is to create a safe, non-motorized connection from the Riverpoint Campus, Gonzaga University, and surrounding neighborhoods to the Sprague Avenue business corridor and Spokane's medical district south of it, says the project's blog.

The site also says the bridge could help stimulate economic development in the Sprague area. The project's advisory group is working with the East Sprague Redevelopment Study to ensure that the bridge complements its goals for future development there, the site says.

A third goal of the project is to create a visible architectural element through the bridge design that's noticeable and could become somewhat of a city landmark, the site says.

Miller says the planning committee had held a public comment session last October to narrow the possible designs for the bridge from around seven to the two final options. During that time, a specific location of the bridge also was determined, she says.

On the Sprague side, it will start at an extension of south Sherman Street which currently ends about a block south of the railroad tracks. The north approach will be situated in the southern end of the Riverpoint Campus where currently there is a campus parking lot that's located directly west of the Washington State University Spokane bookstore.

The lead project consultant is KPFF Consulting Engineers, of Seattle, but several Spokane-area companies also are involved, Miller says. Those local participants are Taylor Engineering Inc., MW Consulting Engineers, landscape architect Sherry Pratt Van Voorhis PS, the Spokane offices of GeoEngineers Inc. and LMN Architects; and Northwest Dynamics Inc., of Coeur d'Alene.

The schematic images featured on the project's blog site were created by LMN Architects and KPFF Consulting Engineers, Miller says. A blueprint for the project hasn't been completed yet, but that design and engineering work would begin after Mayor Verner and the City Council have approved the final design option, she adds.

Miller says it's not clear at this time when the city would start constructing the bridge, and that the project likely would be broken up into phases as funding is secured, through state or federal grants and city allocated funds.

Spokane's U-District stretches from Interstate 90 on the south to about Sharp Avenue on the north. The west and east edges of the District are Division and Hamilton streets. It encompasses an area that includes a number of businesses and residential properties clustered around the Gonzaga and Riverpoint campuses.