COLLAPSE OF TEXAS TOWER NO. 4 191 



Mr. French. Did you liave an occasion to conduct a motion study on 

 Texas tower I^o. 4 ? 



Mr. Brewer. Yes, I did. We installed electric accelerometers and 

 strain gages on Texas tower No. 4 in 1958, and throughout that winter 

 in 1958-59 we had recording equipment on board which recorded the 

 sea height, the wind velocity, stresses on the tliree legs, and accelerom- 

 eter motions at three corners of the tower platform. 



Mr. French. Would you tell the cormnittee, please, sir, what the 

 purposes of your study were ? 



Mr. Brewer. The purpose of this study primarily was to determine 

 the miotion of the tower under forces of the sea and air. 



RADAR affected BY TCWER MOTION 



It was the primary concern of the Air Force at this time when they 

 activated the tower, it could be observed physically, that the tower 

 was in motion, and the Air Force was concerned with the fact that 

 these motions, particularly if the}^ were rotational, would throw off 

 the base of the radar search, so that the radar search mechanism in- 

 stead of being on a firm foundation fixed on the earth, would rotate 

 back and forth at an angle and, as a consequence, make, or introduce, 

 an error if you were detecting a bomber in flight. 



As a consequence, it was necessary to determine just exactly how 

 much in temis of angle this platform rotated. 



Obviously, if it was only a few thousandths of a degree, the error 

 would not be great. 



However, if it was on the order of a few tenths of a degree the 

 error would appreciable. 



So that the Air Force then conmiissioned us to determine the tower 

 motions particularly in rotation, how many degrees did it rotate as 

 a function of sea state and wind upon the structure; that was our 

 primary purpose. 



]Mr. French. Did your responsibilities include anything in connec- 

 tion with an analysis of the structure itself ? 



Mr. Brewer. We also were commissioned, secondarily, to measure 

 stresses at the deck, at the juncture of the deck and the leg, that 

 would be at this point [indicating] on the tower, to measure the 

 stresses at that point since they would be the maximmu above w^ater 

 stress, and to report them also as a function of sea height and wind 

 force on the tower, to the Air Force. 



Mr. French. Now, prior to conducting any measurements on the 

 motion of the tower did you have any conferences with any representa- 

 tives of the design firm of Moran, Proctor, Mueser & Rutledge? 



Mr. Brewer. Yes, sir. I believe we had two conferences, one at our 

 preliminary meeting and another where we went into the details of 

 the instrimientation, and the data that we hoped to obtain from our 

 installation on the tower. This occurred in New York at the office 

 of Moran, Proctor, Mueser & Rutledge. 

 _ Mr. Frencpi. In the course of any of those conferences or discus- 

 sions, did you acquamt the design engineers with the method and the 

 instruments which you proposed to use ? 



Mr. Brewer. Yes. At that time, the second meeting, I reviewed 

 the teclmiques that I planned to utilize to measure the tower motions 



