Carpenters "ramp up" in the casting yard
Even though it will be several months before residents see the main span of the new bridge put into place, the structure is already being created. For example, large forms (like the one pictured above) will be used to cast the concrete segments comprising the main span of the bridge. The forms are being built in the casting yard along the unused section of I-35W just north of Washington Avenue. They rise about three stories above the casting beds, which are the curved, ramp-like structures that appear side-by-side on the old freeway. Shortly after the holidays, concrete will be poured into the forms to make the box girder segments that will fit together to form the main span of the bridge. Eventually, there will be eight casting beds and at least four forms. After the first segments are poured at one end of the casting bed, the forms will be removed and placed for the next segment. This method of casting segments is called "longline" casting. A rolling, heated enclosure will help keep the concrete and the workers warm throughout the casting process.
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