COLLAPSE OF TEXAS TOWER NO. 4 255 



INCREASE IN STRENGTH THROUGH "x"-BRAClNG REPAIR OUTWEIGHED 

 INCREASE IN STRESS THEY WOULD IMPOSE 



Mr. RuTLEDGE. It increased the stress, the forces acting on the struc- 

 ture, but it increased the strength of the structure by an even greater 

 amount than it increased the forces. 



Senator Saltonstall, Well, then, you used the figures — I want to 

 recall them correctly — a 60-foot wave would give how much stress ? 



Mr. RuTLEDGE. Approximately 20,000 pounds. 



Senator Saltonstall. 20,000 pounds per square inch ? 



Mr. RuTLEDGE. Yes, sir. 



Senator Saltonstall. How much did it increase the stress per 

 square inch by putting in these supports above water ? 



Mr. RuTLEDGE. I believe Mr. Kuss has figures on this, sir. 



Is that right ? 



Mr. Kuss. Yes. 



Senator Saltonstall. Mr. Chairman, do you want him to answer ? 



Senator Stennis. Yes, they are both witnesses. 



Mr. Kuss. The installation of those red braces added about 51 tons 

 of horizontal load on the tower as a whole. 



Senator Saltonstall. I cannot hear you, Mr. Kuss. 



Mr. Kuss. The addition of the red braces added 51 tons to the hori- 

 zontal load on the tower from the wave action. Now, the basic loads 

 that this 51 tons were added to were for wind, 418 tons; for wave, 401 

 tons. So that 



Senator Saltonstall. Well, now, 401 tons; how many pounds per 

 square inch ? 



Mr. Kuss. I'll get to that later. 



Senator Saltonstall. Excuse me. 



Mr. Kuss. This is the load on the tower. I'm not talking about 

 the stresses in the legs. 



So this 51 tons additional added about 6 percent to the total hori- 

 zontal force. Now, in turn, what that did to strengthen the tower 

 is this : 



It decreased the bending in the legs to 36 percent of the maximum 

 design bending, original design bending. It decreased the stress in 

 the critical strut — that is, the first horizontal below the red — do you 

 follow me ? 



Senator Saltonstall. It decreased the stress there ? 



Mr. Kuss. It decreased that stress there to 65 percent of what it 

 was before. 



In other words, I am trjdng to point out that this bracing did far 

 more to strengthen the tower than is brought in by the additional 

 wave force. Of course, we knew all this when we put the braces on. 



In addition, of course, it stiffened the tower, but those are engineer- 

 ing facts. 



Senator Saltonstall. Well, now, did the cable bracing down below 

 the water have any effect pro or con ? 



Mr. Kuss. Those cables were not in, sir. Those cables were not in. 



Senator Stennis. The cable bracing was not ever actually put in. 

 It was planned, but the tower collapsed before that Avas carried out. 



