Sound Proofing apartment in Residential block !? (plan, floor, build)

[oranabana]

Hi all, first time poster, so please go gentle...

I am looking for some advice on how to best cut down on sound reaching our apartment. The apartment in located on the 14th floor of a 15 floor building. The main concern is the traffic noise from the street below. The apartment faces West and has a full length balcony along the side of the street. This balcony has a half height wall, along its entire length with sliding windows above the wall - again for the entire length.

The ceiling and floors of the whole apartment including the balcony are made from re-enforced concrete. (built in 1995). Since we have two sets of windows (balcony to outside and inside to balcony) we are mainly concerned about noise reaching the apartment in summer, when all windows are open. The windows are going to be double glazed, sliding, with plastic frame. The lower part non re-enforced concrete. The plan is to perhaps use pyramid shaped foam across the whole ceiling of the balcony, but other solutions could be implemented. The height of the balcony is 2.7m

From my research I understand that sound is reflected from concrete/hard surfaces and transmitted by fixed flexing surfaces and best blocked by soft surfaces. I have also seen the pyramid shaped foam padding that is used in sound studios and other sounds sensitive environments - but I believe that this is more for sound insulation, than for sound proofing.

There is a budget for this, and we can get some professional people to do the work. Right now the apartment is stripped of everything (including wall insulation) awaiting re-decoration. So we hope to have some better understanding of how this can be achieved, before the re-decoration starts.

Also thought I could find a forum dedicated to sound proofing, but had not much luck with that.