Wow, this sounds intense. What are you looking for when you inspect?
Defects mostly. We use the information from site to determine remaining asset life and recommend repairs to be done and when to do them.
For reinforced concrete we look for cracking, delamination and spalling as standard. Depending on the environment, we may also check the hardness of the surface. Other testing includes resistivity, impedance measurements and potential mapping of the reinforcement (these allow us to determine corrosion risk, and for impedance measurements an estimation of corrosion rate). We also take samples for detailed testing that may include chemical analysis for chlorides and sulphates. Sometimes we docompressive strength testing. If there is a coating we may test the tensile bond strength of the coating.
Often we are dealing with aged infrastructure and sometimes they have limited or no drawings, so we often need to confirm reinforcement spacing, depth and concrete grade.
Steel is generally more straight forward, involving measure of remaining thickness and weld cracks and identifying any areas of accelerated corrosion. It can get trickier when dealing with certain environments though.
Timber is probably the most complicated, because unlike steel and concrete, you cannot test for timber type if you do not have good documentation (so you may not know exactly what you're dealing with). Timber cracks, blisters, rots and suffers insect damage.
Edit: I should add that we are also starting to see more of the reinforced polymer composites, which I haven't dealt with personally but are also very complicated to assess and predict degradation behaviour.
Edit 2:
This sounds like a job that might not always be enjoyable, but would definitely be interesting. I'm sure you've seen some cool stuff.
The sewage well was pretty interesting actually (albeit a bit gross). It was amazing how many Q-tips there were down there. They were EVERYWHERE. Don't flush Q-tips down the toilet!
