There are several mistakes you are doing.
TimeSpan is used to calculate the difference between two dates / times. You SQL query returns a single value - Test1Time.
This is probably either a string or a single date/time. So you don't need to use TimeSpan, and you normally won't store a Time Span in your database. Instead you would store a single date/time and use Time Span for example, to calculate the difference between the value you have saved in the database and the current date/time.
Assuming you have fixed that, First, to convert DateTime into TimeSpan use this:
TimeSpan span1 = new TimeSpan(tm1.Now.Ticks),span2 = new TimeSpan(tm2.Now.Ticks),span3 = new TimeSpan(tm3.Now.Ticks);
To add them three, you need :
TimeSpan total = span1.Add(span2);