Fragment Response of Unreinforced Concrete Masonry Walls Subjected to Blast Loading Conditions

Abstract

There are very few methods for predicting the fragment velocity and fragment production of an unreinforced, ungrouted concrete masonry wall. Those that do exist often require large computational resources or fail to predict fragment velocity accurately. A methodology has been developed that accurately and quickly predict the fragment velocity and fragment production of an unreinforced, ungrouted concrete masonry wall. This is an engineering-level analysis tool that can be rapidly implemented and understood. The theoretical background and need for a methodology of this type is discussed. The prediction methodology is compared against two full-scale fragmentation tests conducted in 2019 and four older quarter-scale tests. Reasonable agreement was found between the test results and the energy methodology predictions. As this methodology was developed, it became evident that the negative-pressure time history had a significant impact on the fragmentation behavior. Different methodologies for predicting the negative phase pressure time history were examined and compared. Ultimately no suitable method for predicting the negative phase pressure time history was obtained. The negative phase prediction methodologies and their shortcomings are also discussed and briefly examined.