COLLAPSE OF TEXAS TOWER NO. 4 269 



It is to be noted that the above computations are for static loading assumptions. 

 A comparison of dynamic eftects would probably show comparatively greater 

 resulting benefits because of the decreased amplitude of the oscillation and 

 also because the natui-al period of the structure will be decreased, making it 

 less likely to coincide with that of the larger waves. 



A byproduct of the new installation is a diminished angle of rotation of the 

 platform in the horizontal plane. Although the introduction of braces on the 

 B-0 and A-C sides was principally for the purpose of giving lateral support to 

 the A and B legs at the points of maximum moment stress, these braces also 

 contribute to (1) the general stiffness of the tower, (2) diminish the angle of 

 rotation, and (3) further decrease possible future wear of pin connections on 

 the A-C and B-C sides. 



OTHER WOEK SPECIFIED 



In addition to the preparation of drawings and specifications for the fabrica- 

 tion and erection of the braces, there was also specified certain other work to 

 be undertaken at the same time and under the same construction contract. 

 This included : 



(1) Torque testing of all of the bolts in the collars which attach the lower 

 ends of the upper diagonals to the main legs on the A-B side. These included 

 the 1%-inch-diameter T-bolts and the 2-inch-diameter main collar bolts. The 

 former were to be torqued to 1,200 foot-pounds and the latter to 1,400 foot-pounds. 

 With these applied torques no turning of the nuts was reported. 



(2) Testing of bolts in the K-braces between the tower platform and the 

 main legs to a torque of 700 foot-pounds was specified. A few bolts turned 

 under this torque. 



(3) Magnafluxing of the welding of the K-braces to the platform and of the 

 lower deck plate to the legs was specified. No defects were found in this welding. 



(4) Further and more complete examination of the loose pins at elevation 

 —26 was, specified in the construction contract. This involved removal of the 

 keeper plates at one end of each of the four pins and measurement of the play 

 between the pins and the pinholes, all to be verified by underwater photographs. 

 In general the play was found to be less than estimated on the previous, less 

 thorough, examination and appear to be a maximum of about one-half inch. 



A complete report on the findings will be rendered under the terms of our 

 title II contract covering the supervision of the construction work. 



FUTTJBE PEECAUTIONS 



As to future precautions and inspection of the tower structure, we consider 

 it advisable to examine all of the new bracing connections at intervals of not 

 more than 1 month or after each relatively heavy storm. The main purpose of 

 such examination would be to discover any cracks, large or small, which may 

 have developed in the welds or plating. At the same time the 1^4 -inch-diameter 

 high-tensile bolts of the new braces should be examined by jarring with a 

 hammer as is done in a rivet test. 



We do not believe that it will be necessary to test any of the old bolts on the 

 underwater collars or the K-brace platform connections unless a very severe 

 storm approaching design conditions has occurred. In such event we recom- 

 mend that the K-brace holts be given a rivet type test. 



Respectfully submitted. 



MoRAN, Proctor, Mueseb & Rutledge, 

 Theodore M. Kuss. 



Senator Stennis. All right, proceed. 



Mr. I^NDALL. Is that when you recommended the installation of 

 the above-water braces ? 



Mr. Kuss. Yes, sir. 



Mr. HuTLEDGE. Sir, this was a confirmation of the recommendation 

 which had been made in May or June. 



Mr. KJENDALL. And they were installed in August 1960 ? 



Mr. Rutledge. Installation was completed shortly after the 1st 

 of August 1960. 



