How to establish ties with the industry as a young engineering professor? Next January, I will start as an assistant professor in a respected university. My field of work is civil engineering, and I have diplomas (Masters, PhD) in the engineering studies (Hydraulics, Geotechnical, Construction, ...). What I lack, however, is an experience in the field since I have devoted my time to academia.

I am clueless as to how I could establish ties with the industry: consulting firms, labs, ... Many professors in my field are expert consultants, and are renowned in the community of engineers, even though their main activity is research.
First, Congratulations!

Second, I see you are in Canada.  

The first thing you should do is join your local Canadian Society of Civil Engineering chapter.  Become a member, and attend their events (this may include dinner meetings, speakers, tours, etc.).  Talk to people: start with "Hi, I'm Dr. X and a new professor in Civil Engineering at the U of X, where do you work, what do you do?" Get to know the local executive of the CSCE, offer to do a talk about what you do.

Attend the CSCE conferences.  There are many practitioners there who are presenting on their most technical and most research-y work.  Get to know them, they might like to collaborate.

Next, make sure you are on the mailing list for the local chapter of your provincial engineering association.  Go to their events.  Offer to do a talk for them (at lunch meetings, annual events, etc.).  They also likely host professional development workshops, another great way to meet practitioners.

At these events and though your colleges and students, find out which consulting firms do projects that are closest to your research area.  Find people that work there at local engineering events.  Great ways to get to know a firm as a researcher is "Hey, I am teaching a class on (insert topic here) do you have any interesting case studies I could use to illustrate (insert concept here)."

Finally, (as Mad jack says) in engineering programs in Canadian universities, students often must complete a capstone design project.  Find out how your department handles that, and if you will be involved.  Perhaps volunteer to mentor a group.  Then at local meetings you can say "next year I will be mentoring some fourth years students doing a capstone project in (insert discipline here), do you guys have anything interesting coming up that would be suitable for a fourth year group to tackle?"  Then make sure your students do a damn good job.