There are a few websites I regularly check to see if there's an interesting conference coming up to which I should submit an abstract. These are:
ACI: International conferences
After attending a few conferences, I now also receive calls for abstracts in my mailbox regularly.
Over the past two years, I've attended the following conferences:
Structural Faults and Repair
This is a conference specialized in repair and strengthening of existing structures. Case studies from practicing engineers as well as academic research are presented. It's organized in the marvelous city of Edinburgh.
fib PhD symposium in Civil Engineering
This conference is organized for PhD students, mainly for PhD students researching structural concrete. Presentations are 20 minutes, followed by 10 minutes of discussion - so there is plenty of time to go in-depth. It's also a great place to practice presenting skills among your peers.
ASCE Structures Congress
Eight parallel tracks, featuring all topics related to structural engineering... This conference bundles a vast amount of expertise and information into a few days' worth of time - planning your schedule ahead is a must! I learned a lot on bridge engineering, as I chose to mainly attend the sessions in the bridge engineering track.
This conference is entirely focused on structural concrete - and I was very pleased to find several entire sessions dedicated to the problem of shear in concrete. Again, with several parallel tracks, planning your schedule in advance is required.