Is one player allowed to build the same building more than once in Puerto Rico? If so, do the bonuses stack, so that a player building both Large Markets would get +4 for trading? I wasn't able to find anything in the rulebook that specified this either way. My play group ruled that you can't build the same building multiple times, on the grounds that some of the bonuses seem overpowered if you can double up on them (e.g. Harbor), and other bonuses make no sense if applied more than once (e.g. Construction Hut). Is there any official rule on this?
According to the rules for the online version on BrettspielWelt, "no player may build a building more than once."
And you can confirm this by looking at the official rules from Rio Grande, page 8: