Are you sure you meant to write 40% acrylamide?

i meant the acrylamide/bis (37.5:1, 40% solution) but the gel should be 16% thank u 

I have routinely run 10, 15, and 20% mini-gels as well as 10-20% gradient large-format gels. Usually use 150 V for mini-gels and 25 mA/slab for large gels. Large gels finish (dye reaches bottom of plates) in 5-6 h. If the bands have stopped moving, the problem is not likely with the gel. Check your buffer levels, power supply, cables, and lid.

Thank you for your suggestions Pr Allen 

I am using 16% tricine gels too and everything seems OK. I use 150V constant volt for 2 hrs.

What protocol are you using for the buffer composition?

P.S. I am using the protocol from Haider et al., 2012 (Single buffer system)