3 notable bridges

Da Nang is amongst others well known for its amazing bridges over the Han River. The old now named Nguyen Van Troi Bridge is built during Frensh colonial era. Park Your car or motorbike and stroll over the bridge watching the anglers. At the given waypoint You can see nearby to the south the new Tran Thi Ly Bridge with its tremendous prestressed concrete pylon and red steel ropes, which from afar appeares more like a huge harp. In some distance to the north You can see the yellow dragon of the Rong Bridge.

To make an entry in the Online-Log, You have to go to Tran Thi Ly Bridge and Rong Bridge and do some investigations to determine a password. Both bridges were inaugurated at the same day, the 29th March 2013, the 38th anniversary of Da Nang's liberation.

1. The construction of Tran Thi Ly started in 2010. For Rong Bridge it started 1 year earlier. But what for both are the exact day = DD and month = MM ???
You can find it on site, but beware of the traffic ! ! ! The amount of motorbikes and their speed can be dangerous.

2. Having found day and month, determine the following integer values
x = DDMM  for Tran Thi Ly Bridge
y = DDMM  for Rong Bridge

3. Now calculate    z = x + y
z is a 4 digit number and the password for making Your Log.
Have a nice time :)