After the mortar used in the repointing process has had the required time to cure to perfection, the true reconstruction of the bridge can begin in earnest.
As mentioned in earlier posts, a great many of the original stones were saved to be reused in the reconstruction process. These stones were carefully cataloged as they were removed, marked with their original location (and with which face was outwardly visible), and throughout the rebuild will be set as close to their original position as possible.
All of the fresh stone that has been brought in to replace any original pieces that were not able to be reused, due to damage and erosion over time, has been hand-picked to match the original material the bridge was constructed from.
Check out the Week 8 & 9 Time-Lapse YouTube videos below to see the work in progress!
The first large granite blocks that are hoisted down to the rebuild area (nearly twenty feet below) are the through stones. The through stones are much like the footings on a concrete foundation...they will hold up the etire structure.
The through stones are lowered from the upper landing area and set as close as possible to their position by use of an excavator, however, the need to be put into their final resting place the old-fashioned way: by use of pry bar and brawn.
Once the through stones are set in place, hearting stone is used to fill any voids, thus adding to the overall stability of the structure. Hearting stones are smaller, more easily manageable stones like those seen in the pan in the lower left photograph.
After the through stones are set in place and all of the voids filled with hearting stone, the next step in the process is to begin rebuilding the spandrel walls. As you will notice moving through to Week 10, this is a very meticulous and time consuming process, but the end result will be spectacular.
Much like the previous process of setting the through stones, though on a smaller scale, the spandrel walls are built with larger stones, called face stones (as they are the visible stones on the outer edges of the bridge), and then hearting stones are used to fill any voids.
The beginnings of the spandrel walls are evidenced in the photographs below.