A rendering of RTC Partnership’s planned 23-story mixed-use project at 1760 Reston Pkwy. in Reston. (Courtesy of Fairfax County)

Reston Town Center is primed to get a new gateway in the form of a 23-story mixed-use project being planned for Reston Parkway by RTC Partnership LLC.

The proposed building’s height has already been approved by the county and would be taller than anything currently in Reston Town Center. The project would replace an existing 61,000-square-foot office building at 1760 Reston Pkwy., often known as the Town Center Office Building.

Though the overall project still requires review by the Reston Association of homeowners and the Fairfax County Planning Commission, RTC already has approval for a 418,000-square-foot office and retail building. Richard Whealen, managing partner of the ownership group, said the building’s distinctiveness should set it apart from other offices nearby, some starving for tenants.

“Despite the fact that office vacancies are relatively high along the Dulles Toll Road corridor, the time is right for a high-end office tower in Reston,” Whealen said in a press release.

The plans have attracted increased attention because of the property’s prominent location on Reston Parkway at Bowman Towne Drive, where Fairfax County planners have called for a signature office structure. The building’s design, by Reston-based Polleo Group, is more contemporary than many other Reston buildings.

Polleo has designed residential projects such as the mixed-use Spectrum development in Reston and Kennedy Row, a multifamily residential project on East Capitol Street in the District.

The first five floors would consist of retail and parking, with offices on the 18 stories above. On the sixth floor, the developers plan an outdoor 38,000-square-foot terrace (and green roof) that they envision featuring outdoor seating from a restaurant on that floor.

“Hopefully these features will attract a high-end restaurant that could have both indoor and outdoor seating with a striking view of the Reston Town Center and surrounding properties,” Whealen said.

Whealen and his partners have not announced any financing or tenants for the building or a firm construction timeline, although RTC holds termination options for many of the leases in the existing building, giving the company flexibility to begin demolition.

If they decide to begin building the project without either, the developers will join a handful building speculative office projects in Northern Virginia or planning them for coming months. In Tysons Corner, Lerner Enterprises has begun an office project and Macerich Group plans to begin one soon. In Rosslyn, Monday Properties is building a speculative office tower in Rosslyn and the JBG Cos. plan one.

Like those projects, RTC envisions 1760 Reston Pkwy. as a property that will be accessible to Metrorail. The Wiehle Avenue station, on the Silver Line, is expected to be complete in 2014 and is a 10- or 15-minute walk from the property.