 |
The
Old Main Post Office was completed in 1932. With hundreds
of train movements and thousands of passengers using the
rail system daily, the Amtrak Station under the Old Main
Post Office is a vital link between home and work for
many Chicagoans. This 73-year old structure has survived
the age of steam and coal fired trains and remains in
relatively good conditions despite years of exposure to
diesel locomotive exhaust. The ingress of carbon dioxide
has reduced the pH of the parent concrete leading to severe
corrosion of the structural reinforcing steel. This condition
posed a serious risk to both passengers and trains alike.
The main challenge facing the engineer was determining
the most effective methods of removing and replacing the
damaged concrete. Several means and methods were explored
over a two year period leading up to the development of
the project specification. Ultimately, the engineer selected
low velocity spray applied mortar for the replacement.
The contractors developed a plan to complete the work
in a specified time, without shutting down the train station
or creating disruption to commuters. All of the smaller
equipment and manpower for each night’s work was
loaded onto a converted school bus with folding platforms,
and pulled to the work area on railroad tracks. The materials,
mix water, and spray equipment were placed on a flatbed
rail car and towed in behind the school bus. After the
completion of each shift of work, the converted school
bus drove out of the station and back to a staging area
roughly one mile away.
The Old Main Post Office Plenum Ceiling Repair project
was a complicated endeavor with many obstacles. By fostering
a successful “partnership” between engineer,
general contractor, subcontractors, and material supplier,
the project was successfully completed on time and on
budget.
|
|
Owner
United States Postal Service
Chicago, Illinois
Project Engineer/
Designer
Parsons Brinckerhoff
Chicago, Illinois
Repair Contractor
Allied Waterproofing, Inc.
Lyon, Illinois
Material Supplier/
Manufacturer
Degussa Building Systems
Shakopee, Minnesota
|
LOGIN
