Seismic analysis and testing of clay tile walls at the Oak Ridge Y-12 Plant

The recent DOE 6430.1A General Design Criteria has emphasized the importance of determining the adequacy and, hence, safety of both new and old facilities to natural phenomenon hazards such as earthquakes and high winds. In order to meet the criteria, an existing unreinforced clay time wall, which is an integral part of a new facility being placed in an old building, has been evaluated for resistance to seismic events. Part I of this paper consists of the analytical studies. The facility was mathematically modeled and analyzed using a finite element program. The material properties used in the analysis are based exclusively on data available in the current engineering literature for masonry blocks and walls. The results of the analysis conclude that the wall is adequate to meet the seismic requirements per the new criteria, but the results of the testing program described in Part II will eventually need to be incorporated into the analysis. Part II documents the results of a testing program to obtain material properties of the masonry and verify the values used in the analysis of Part I. The fact that most of the available testing data is on brick and concrete block and that the condition of the walls throughout the plants is suspect led to the testing program. The following tests on clay-tile walls, units, and panels were performed: (1) in-situ mortar joint shear strength of existing 12-inch walls, (2) compression strength, (3) tensile strength, and (4) diagonal tension (shear) strength of panels taken from the existing walls. The test results at this time are fairly inconclusive and have high standard deviations. The testing program is ongoing and is currently being expanded