It seems to be very common on 747s. In a short period of time I've flown LHR-LAX-LHR on BA's 744 (as a pax) and there was HEAVY vibration thru the rotation until gear was retracted, both ways. Lufthansa's 744 on FRA-SIN was awful too, but it was worse when leaving SIN, we had to (according to announcement) offload some cargo, to not be overweight. Vibration and rattle, never experienced anything like it. Few bins flew open and some pax were disturbed.