COLLAPSE OF TEXAS TOWER NO. 4 135 



FUNCTIOlSr AND USE OF DARDELET BOLTS 



Mr. Kendall. Now, you have been discussing the repairs with the 

 use of these Dardelet bolts, Commander. Is it not true that Dardelet 

 bolts are customarily used for a temporary repair? 



Commander Foster. I could not answer that precisely. In my 

 evaluation of the brace, I considered the bolt in the problem. 



Mr. I&]NDALL. I am discussing now, generally the question of what 

 is the function of a Dardelet bolt and what it is used for. Is it not 

 true that customarily and generally, they are used for a temporary 

 fix? 



Commander Foster. I do not believe that is true, sir. 



Mr. Kendall. Do you know whether it is true or not ? 



Commander Foster. I would not hesitate to use them in permanent 

 work. In fact, I would use them in preference to an ordinary struc- 

 tural bolt. 



Mr. Kendall. So you say they are used for a permanent fix ? 



Commander Foster. Yes, sir. 



Mr. Kjendall. Now, after the tower was upended, Commander, I 

 believe that the permanent platform was floated in and jacked up 

 prior to the legs being embedded and prior to any stiffening of the 

 legs with concrete ; is that correct ? 



Commander Foster. That is correct. 



Mr. Kendall. Was that a factor which was taken into considera- 

 tion in calculating the original stresses? 



Commander Foster. I was not involved in the project during the 

 calculation of the original stresses, sir. I really do not know, but I 

 would not — I am not in a position to say. 



Mr. Kendall. Will you describe by reference to the model that you 

 have before you the damage which was sustained by the tower legs, or 

 to the tower legs, from the platform ? 



Commander Foster. As it stands now, the dishing 



Mr. Kendall. Just for my information, what do you mean by dish- 

 ing, Commander ? 



Commander Foster. These legs, or caissons, are cylindrical. If you 

 can imagine taking a cylinder and pushing inward on it, a slight in- 

 ward deformation occurs. 



Mr. Kendall. You mean a dent ? 



Commander Foster. Not precisely a dent ; a flattened effect. 



Mr. Kendall. Go ahead now and show where this happened and 

 describe them. 



Commander Foster. Right at the waterline on the C, and B, and 

 the A leg, as the tower now sits. 



Mr. Kendall. Of what height and of what depth were they ? 



Commander Foster. They were approximately — they varied, but 

 approximately 10 feet in height, approximately 6 feet in width, and 

 I think the maximum was about 10 inches indentation in depth. 



Mr. Kendall. Did that injury give you any particular concern? 



Commander Foster. It did at the time; more a feeling of what 

 might have happened than what actually did. 



Actually the injury was assessed to not be too serious. It M-as re- 

 inforced inside and repaired in that way. 



