Readers were so interested in Begin Expressway's unique acoustic walls that appeared in yesterday's post (in my photo facing the opposite direction from this photo by the builders).
So I kept digging and finally found some answers to your questions.
The Gash website has close-ups of the combined retaining/acoustic walls. Take a look.
The engineers explain:
Begin Road connects Jerusalem's entrance coming from 443 highway and its south-west neighborhoods..
Gash engineers designed a three-span bridge and acoustic walls with unique architectural cross-sections.Acoustic barrier semi-roofing shape
The height of the wall and its shape was determined by taking under consideration an acoustic defense line at the edge of the traffic lanes instead of at the margins of the road as usual. As a result the wall's height was lowered from 12-13 meters to 8.5 meters.
Its arch shape was developed in order to reflect the noise sound back to the road.
The structure consists of modules of projecting beams covered with arch-shaped membranes made of 8 cm concrete. The beams also support prefabricated plated serves as a retaining wall for the back landscape's filling.