In a project financed by industry, we tested a steel-lined reinforced concrete vault, using a standard steel vault door modified to resist high blast overpressures. (See slide No. 34.) Slide No. 35 is the completed structure showing the 7-ton steel door, 14-ton steel frame of the door, and 18 inches of reinforced concrete covering the steel liner. The structure was located at the 90 pounds per square inch range. Mr. HOLIFIELD. How much? Mr. SAUNDERS. About 90 pounds per square inch. The damage suffered by the structure was that of stripping off part of the reinforced concrete sides and breaking off the hardware required to open the door. Even though the damage appeared to be quite heavy in slide No. 36, there was no apparent pressure or temperature increase within the vault. Therefore, documents and money in the vault would have been satisfactorily protected. When the combination was reset, the 7-ton steel door was easily opened. Mr. HOLIFIELD. In looking at these structures, the question which occurs to me is why there was no attempt made to take advantage of curving and slanting surfaces rather than flat surfaces. Was it because you were trying to reproduce conventional lines of architecture? Mr. SAUNDERS. Well, I think that most of our shelter structure tests were below ground, that is in the 1957 test series, with the exception of the dome, and, of course, it did have a curved surface and with mounding of earth it would flatten out the slope even more to present a streamlined effect. SLIDE NO. 36.-Damage to vault after blast. Mr. HOLIFIELD. That is what I was addressing my remarks to. That last structure, for instance, a square box sitting out there on the sand, if it had been slightly arched or the corners rounded, I am wondering what the blast effects would have been in relation to a completely conventional-type room. Mr. SAUNDERS. This was an industry structure and it was supposed to be a test of a typical vault which you would find in a bank. Mr. HOLIFIELD. I see. Mr. SAUNDERS. This is the purpose for that type of structure. It was sponsored by the Mosler Safe Co. Mr. HOLIFIELD. I see. Mr. SAUNDERS. A slight design modification would probably have eliminated the stripping off of the sides as it did. Mr. HOLIFIELD. Design of the vault, you mean? Mr. SAUNDERS. No, design of the frame on the front of the building. If they had brought the frame around the front so the pressure would not have gotten into this crack and there definitely was a crack which was established by the photography, the walls would not have been stripped off as they were. As I mentioned earlier, FCDA sponsored the French and West German shelters tested at the expense of the respective Governments to obtain design criteria and make design improvements. Five French and 9 West German structures were tested at predicted pressure locations as shown in slide No. 37. The French structures were located SLIDE NO. 37.-German and French structure locations. as follows: 1 rectangular shelter, 1 circular shelter, and 2 entrance ways at 132 pounds per square inch-these are predicted pressures, and 1 entranceway at 118 pounds per square inch. The West German shelters tested were: 7 rectangular structures located at predicted pressures of 7 to 265 pounds per square inch range, and the 2 circular shelters at the 132 and 198 pounds per square inch range. All of the foreign structures were constructed of heavily reinforced concrete. Foreign supplied doors, ventilation equipment, and reinforcing bars were tested as component parts of the shelter. (See slide No. 38.) Shown here is the French circular shelter under construction. Slide No. 39 is the completed French rectangular underground shelter. The entrances to the shelter are shown on either side of the picture. The air-filtering system is in the center; the tall exhaust stacks are on the left. These structures received slightly less than the 132 pounds per square inch anticipated. The major damage consisted of the destruction of some of the above ground accessories. Slide No. 39 is a preshot view of the French rectangular shelter. Slide No. 40 is a postshot view of the same structure. SLIDE NO. 38.-French circular shelter under construction. |