COLLAPSE OF TEXAS TOWER NO. 4 De 
puters in our missile systems, it is the very same principle upon which 
the all-inertial guidance system works in relating the information ob- 
tained from the accelerometers. 
The suspicions concerning the failure of the upper tier of bracing 
in the A-B plane to function properly were confirmed by diver in- 
spection by Marine Contractors, Inc., East Boston, Mass., under 
Navy contract NBY-22027. In a report dated November 25, 1958, 
it was stated in substance that— 
(a) The pins in the horizontal brace at —23 feet at midpoint in 
the A-B plane were loose (A diagonal) and withdrawn 9 inches 
(B diagonal). 
(6) The Dardelet keeper plates on the B leg were loose and several 
of the studs and nuts were missing from them. 
(c) None of the Dardelet bolts on either side of the collar on the 
A leg were in place, either having sheared off or fallen out and there 
was evidence of vertical motion of the collar on the caisson. 
(zd) In tightening the collar bolts to a certain torque, they would be 
found looser within a day or two. 
(¢) The A leg developed oil leaks which could not be repaired. 
The responsibility for the failure of the Dardelet bolts on the A leg 
was not determinable. Although there was reason to believe that the 
contractor may not have installed these bolts in accordance with the 
plans, there was no way to demonstrate this conclusively. Conver- 
sely, it was possible that the bolts were correctly installed. As for 
the Dardelet bolts on the B leg, no failure was observed but roughly 
half were loose and all were not of design dimensions. The failure 
of the Dardelet bolts on the A leg permitted vertical motion of the 
collar on the A caisson. This movement was applying, and had ap- 
plied for an unknown period of time, exceptional stresses on other 
bracing members, particularly in the A-B plane. 
The 1st Naval District considered this failure of the Dardelet 
bolts a construction deficiency and required the contractor to re- 
place them with T-bolts. Apparently, Dardelet bolts are consid- 
ered by some as nothing more than a temporary device. In the 
fall of 1958, after confirmation of the structural deficiency in the col- 
lar connections of the upper braces on the A-B side, the design en- 
gineers issued the first in what was to become a series of warnings 
on the structural integrity of the tower. By letter dated September 
18, 1958, Mr. Kuss wrote to the officer in charge of construction in part, 
as follows: 
In the meantime and if the collars cannot be tightened and the shear bolts re- 
placed, we are compelled to warn you that a definite hazard exists to the safety 
of the tower and the personnel abeard in the event of a major hurricane pass- 
ing directly over the tower location. 
The work to replace the Dardelet bolts with T-bolts began in Novem- 
ber 1958 but was discontinued when about 50 percent complete because 
of weather. None of the T-bolts were installed until the following 
year and the entire repair was completed in May 1959. In the mean- 
time, with the tower in this condition, it was exposed to five severe 
storms with maximum waves of 33 feet in height and winds up to 90 
miles per hour. The design engineers certified that upon completion 
of the T-bolt installation the tower would be restored to its original 
design strength and in a report dated June 1959, Marine Contractors, 
