El Capitolio
Construction on El Capitolio (the Capitol Building of Puerto Rico) began in 1925 in the neighborhood now known as “Old San Juan”. El Capitolio contains both chambers, with the Senate on one side, the House of Representatives on the other, and an array of galleries, friezes and mosaics in between. The building also boasts an impressive rotunda in which Puerto Rico’s constitution (issued in 1952) is exhibited.
Conservation Solutions, Inc. (CSI) was contracted by the government of Puerto Rico to assist a local architect in the investigation of the main terra cotta cornice located at the base of the dome of El Capitolio. A total failure of the structural support steel and anchor system had led to the structural failure of the cantilevered, and now un-reinforced, terra cotta cornice. CSI performed investigative work and partial disassembly of a six-foot section of the cornice in order to prevent its collapse, and to determine the cause and nature of the failure. CSI also worked to gain a better understanding of the materials and techniques used in the construction of the cornice and to provide the architect with various repair solutions, cost estimates, and assistance with the writing of specifications.
The investigation revealed several major problems: 1. the decking and joints between the terra cotta blocks had a network of cracks that provided an ingress point for large quantities of salt-laden moisture; 2. the entire area between the cornice and the decking around the dome was back-filled with “clinker concrete” or “Cindercrete” (a mixture of Portland cement, furnace ash, and large fragments of clinker) and 3. the cornice was constructed using ferrous anchors and ties.
Extreme corrosion of the steel had resulted from exposure to a combination of chlorides in the spray from the adjacent sea, and sulfuric acid formed when saline moisture saturated, and then passed through, the contaminated “Cindercrete.”
Based on the information gathered in the field, research, and consultation with structural engineers it was recommended that all cracked areas of the cornice be dismantled and rebuilt using AISI Type 316, non-corroding stainless-steel rods in a grout injection anchor system by Cintec. In order to retain as much original material as possible, it was recommended that the undamaged areas of terra cotta be stabilized in situ.
After careful examination of the heavily damaged and shattered terra cotta units, it was decided that these elements should be replaced with high quality matching new units from a well-established terra cotta manufacturer.
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