"LE PONT VIERENDEEL. " LIX. 



A short description of the tests may prove interesting. They 

 were carried out during the latter part of 1897, and consisted of 

 two series : During the first test, when 202 tons had been 

 distributed, one of the supports collapsed, and the test load was- 

 entirely removed whilst repairs were effected. The second test 

 consisted in placing a load of 150 tons on the bridge, proceeding 

 gradually from one end to the other. This took eight hours, 

 extended over three days, to put in place The second phase of 

 the test consisted of placing 75 tons additional, but applying it 

 equally from each end towards the centre ; this took three hours 

 ten minutes to put in place. A second additional load of 75 tons 

 was then placed on the bridge in same manner as last load, taking 

 nearly four hours to put in place ; the load then on the bridge- 

 was 300 tons. A further loading of 150 tons was then commenced 

 to be placed in position, proceeding equally from the ends. 

 When 366 tons had been put in place, the first signs of rupture- 

 became evident. This took place when the bridge was loaded 

 with the last test load, from the ends to the third vertical from 

 each end. Rupture, as shown in the photograph, ultimately took 

 place under a gross load of 404 tons, when the load was wholly 

 distributed, with the exception of the fifth vertical from each end. 

 The deflection which took place were as follows : — The bridge- 

 was erected without any camber, and deflected at the centre 

 under its own weight, 13*55 m m. During the first test, under a- 

 distributed load of 152 tons, the deflection was increased by 

 35 m m, and under the 202 tons, when one of the supports failed, 

 the increased deflection amounted to 40 m m. 



During this test the load of 152 tons had rested continuously 

 on the bridge for some two months, and when the whole load was 

 removed for repairs to the support, a permanent deflection, due 

 to the load, was observed of 15 , 5mm = , 6 inches. 



During the second trial, under a load of 304 tons, the total 

 deflection was 61*75 m m = 2*4 inches. 



Professor Vierendeel concludes by saying that he does not 

 pretend to believe that his type of bridge will please everybody,. 



