I am not in civil engineering but our office sounds similar. We have time sheets to code our time to whatever project we are working on. If we don't have anything going on at the moment we charge our time to general admin or client development or any number of categories. I get paid for all hours I put in although non-chargeable overtime is frowned upon and banned in some cases. A day golfing with a client is a maximum of 8 hours even if we go out for beers afterwards (cheap employer
).
At the end of the year though your chargeable ratio will have a factor in your bonus and raise potential. In my position however I have some control over how much work I bring in so if my ratio is poor it could be that I turned down work or performed poorly and lost clients.