The city will spend $80,000 to study how to improve accessibility at some 3,200 pedestrian ramps, sidewalks, and intersections. The study is the first step toward designing a long-term plan for upkeep and improvement of accessible features, and will eventually lead to a wider effort to bring aging city buildings into compliance with the Americans with Disability Act. Under the federal law, municipalities are obliged to make public buildings equally accessible through construction or renovation. “We’ve spent millions over the past eight years to improve accessibility with such projects as the Somerville Avenue, Magoun Square, and Washington Street reconstruction efforts, and in the City Hall ramp rehab and other building upgrades,’’ Mayor Joseph A. Curtatone said in an announcement on the study, “but achieving compliance is an ongoing challenge." The fiscal year 2013 budget also includes funding for a planner who will oversee the accessibility improvements, the city said.