PITTSBURGH — Call it collaborative bargaining.

When the Pittsburgh Public Schools and its teachers' union began talks last year for a new contract, the tone was decidedly different from the usual collective bargaining process. Tense face-to-face meetings, lawyers and demands were replaced with a weekend retreat at a downtown hotel, input from principals and teachers, and discussions.

On Monday, the district and the teachers union ratified a new contract that both sides say was the result of a new way to do business. They hailed the 5-year agreement as historic for its length and the inclusion of new incentives for teachers, including a pay-for-performance pilot program that could see eligible teachers pocket up to $8,000 extra a year.

"In a very strong union town, with a very strong teachers' union, we were able to go into a process of being adults who are charged with a responsibility of improving student outcomes and treat that with respect," Pittsburgh Schools Superintendent Mark Roosevelt said Tuesday.

The merit-pay program is voluntary for existing teachers at the top of the pay scale, which is about $77,300 for a teacher with a bachelor's degree in the coming school year. For new teachers, the contract calls for a separate pay scale based on performance.

Called Empowering Effective Teachers, the plan was the basis for a proposal made last year to the Bill and Melinda Gates Foundation. The foundation approved the plan and has given the district $40 million for efforts to improve teacher quality.

The district and union worked on the Gates proposal together, and rolled that into contract talks.

"We approached this in a way where we sat down to resolve problems," said John Tarka, president of the Pittsburgh Federation of Teachers.