COLLAPSE OF TEXAS TOWER NO. 4 99 



Now, the theory of Texas tower No. 2, and the theory from the 

 ground line up, or from the storm line, where the bottom of the ocean 

 waves work, is not to have any more obstruction than you absolutely 

 have to have. Therefore, it is very essential — that is a principle you 

 design on, and the Texas tower No. 2 was designed on that principle. 



Senator Stennis. Pardon me. The reason appears obvious, but you 

 might state it anyway. What was the reason for that ? 



Mr. DeLong, Because if you put bracing in, you will generate the 

 additional resistance against your structure from the ocean waves. 

 Therefore, you want to at all times let the water flow with a minimum 

 of resistance. So therefore, you can only go to depths of water of 

 about 100 feet. After that the size of your column, we will call the 

 legs columns, become so large it becomes uneconomical. 



Then, since you have an ocean floor here, which was roughly 56 

 feet below the water, and you had to accept that and design for it, 

 then you take your next step, where your water is deeper, and in this 

 case tower No. 4 was estimated at 180 feet and it wound up in the end 

 185 feet, but it is pretty difficult to get the water depths exact out there 

 in the ocean, and we make that mistake every day where we are off a 

 few feet. 



So when the design of tower No. 4 was discussed with us, it appeared 

 the only logical design in deep water that, figured costwise and 

 strengthwise, was the K-brace design that tower No. 4 was built on. 

 There were other things that we disagreed with and so forth. But the 

 K-brace structure, as it is known, triangle K-brace structure, is the 

 best laiovv'n method of construction, because when you go into the deep 

 water you start assuming another line of thinking. You say — all 

 right, my ocean floor was minus 56 feet for the Texas tower No. 2 

 design. Now I have to make a new ocean floor, and that is actually 

 what you are doing with the triangle K-brace structure. You make 

 a new ocean floor. So you say to yourself, where am I going to make 

 this new ocean floor?- — because you want to remember now on this one 

 the criteria was, and the assumption or the basic rule was to leave 

 the bracing out of the water motion zone. So then you automatically 

 come to an answer there. We have to keep our bracing below any 

 wave action. That was done. The assumption was made correctly, 

 minus 25 feet or 27 feet. That was proper design. 



Senator Stennis. Below the water ? 



Mr. DeLong. Below the water. 



Senator Stennis. All right. 



Mr. DeLong. Now, this became your new ocean floor. Visualize it 

 as your new ocean floor. Now, what you build here had to be just 

 the same as the ocean floor. It had to be a rigid, fixed structure with- 

 out any possibility of movement, because from here up you follow the 

 same principle except that you have a manmade ocean floor which was 

 now minus 27 feet. Therefore, you could lighten up some of these 

 members that went on top here and not design them exactly as heavy 

 as they were here where your water was deeper. And that was done. 



Senator Saltonstall. Mr. Chairman, if Mr. DeLong is through 



Senator Stennis. No, he is not through, that is I do not think he is 

 through. You may ask a question anyway for clarification. 



Senator Saltonstall. My question is this, Mr. DeLong. You said 

 you went down 50 feet on the embedment for tower No. 2. 



Mr. DeLong. Pardon me, sir — 48 to 50 feet. 



