Reinforcement of buckled webs of plate-girder and box-girder bridges

If one attempts to prove the buckling safety of plate-girder and box-girder bridges which were constructed before the introduction of DASt-Ri.012 [1] using DASt-Ri. 012 or DIN 18800 Part 3 [2], he will find out that large areas of these bridges do not have enough buckling safety. The first question to be asked is: How can one reinforce the calculated buckled webs of these bridges to increase their resistance of buckling? This question recently gains more and more importance because many bridges are involved for example the Sinn bridge along the highway A 7, the Hase bridge in Spessart and the Danube bridge Sinzing near Regensburg along the highway A 3 [3] just to mention a few. This article presents some measures to improve the resistance of buckling. Using the buckling field of one existing bridge the effect of one appropriate strengthening in the pier area will be pointed out.