The design-build team had to provide a comprehensive durability analysis for the proposed consulate building in Dakar, Senegal. The environment included both corrosive soils as a marine coastal exposure at elevated temperatures and the desired life needed to be 100 years using ordinary Portland cement concretes, since fly ash, ground granulated blast furnace slag, silica fume and other pozzolans were not available. Furthermore, only black steel reinforcing bars were available.
TCG determined the exposure parameters for the elements in the ground water, in soil above the ground water and for the airborne coastal exposures. To perform the service-life analysis, the Stadium® software from SIMCO Technologies, Inc. was employed. This enabled modeling the elemental shapes and environment exposures for chloride ingress and the formation of other potential failure mechanisms such as sulfate attack. Then for maximum practical concrete cover over the reinforcing bars the estimated life before corrosion initiation and damage due to propagation of corrosion was determined. Supplemental protection systems including membranes, surface treatments and corrosion inhibitors were then recommended to meet the 100-year design life.
In addition to the life cycle analysis, TCG provided guidelines to minimize cracking due to thermal and drying shrinkage, which could compromise the predicted performances. Curing recommendations were presented to further insure that the concrete properties were not compromised.
B.L. Harbert, Page Southeriand Page, and Ehlert/Bryan Inc.
U. S. Department of State
The durability recommendations from TCG made us confident that this consulate wilt be durable and meet the demands of the State Department. TCG was professional and timely in their services. We are working with them on other projects.