There can be an offset if you receive WC benefits.

"How much can family members get?
Each family member may be eligible for a monthly benefit that is up to half of your retirement or disability benefit amount. However, there is a limit to the total amount of money that can be paid to you and your family. The limit varies, but is generally equal to about 150 to 180 percent of your retirement or disability benefit."

http://ssa.gov/pubs/10024.html