Framingham-based construction firm Perini Corp. has reported third quarter net income of $34.1 million, up 42 percent from the $24 million reported in the same period last year.

For the first nine months of 2008, net income was $87.8 million, as compared to net income of $74.2 million for the first nine months of 2007.

Perini’s acquisition of Tutor-Saliba Corp. was completed Sept. 8, and third-quarter results include one month of operating results for the combined company.

Based on current economic conditions, including the challenges in credit markets that some customers are experiencing, the company said it believes there will be delays in new construction starts in 2009 that will likely impact its financial results for next year, Perini said. Accordingly, the company is lowering its full-year 2009 guidance for revenues from a range of $7.3 billion to $7.8 billion to an estimated range of $6 billion to $6.5 billion