The predicted behavior of German underground personnel shelters, equipment, and certain instrumentation was investigated. Data obtained will be used for evaluation and improvement of present design criteria. Nine reinforcedconcrete underground shelters, designed by German engineers, were tested at the 170-, 155-, 110-, 78-, 26-, 11.5-, and 7.2-psi overpressure ranges as determined from average blast-line instrumentation measurements. Reinforcing steel, doors, and ventilation equipment were received and incorporated in the shelters. Preshot and postshot precise location surveys were made to determine the total lateral and vertical motions of the structure as a result of the blast. Blast instrumentation used in the shelters and entranceways consisted of pressure gauges, earthpressure gauges, self-recording pressure gauges, and dynamic pressure gauges. Free-field measurements were recorded along the blast line using U. S. self-recording and electronic pressure gauges and German self- recording pressure gauges. Structural response was recorded by deflection and acceleration gauges, strain gauges, and scratch gauges. Radiation measurements were taken using U. S. gamma-radiation film dosimeters, gamma-radiation chemical dosimeters, neutron detectors, telemetering gamma dosimeters, and German gamma chemical dosimeters. Mice were used as biological specimens in environmental tests in seven of the nine structures tested. In addition to the environmental tests, a series of tests was performed in the nine structures to check for the possible occurrence of dust in the shelters as a consequence of nuclear explosions. Ground shock spectra were recorded for free field conditions and for the interior of a shelter. An experiment was included to investigate the transmission of ground shock acceleration to a simulated body. This test recorded the shock-absorbing characteristics of a commercial product. (auth)