Case Study: Tuned Mass Dampers for Pedestrian Bridge in Malmö

During the structural design of the pedestrian bridge at Bagers Plats in Malmö, it became obvious that it would require a TMD, as the lowest vertical was calculated to 1.85 Hz.

Vibratec designed a TMD solution: in total 2 TMD’s with a vibration mass of each 340 kg was installed in the mid section of the bridge.

Damping ratio of bridge with blocked TMD: 1.5 %
Damping ratio of bridge with TMD: 9.0 %

Due to the increased damping of the first vertical mode shape, the movements by walking persons are dampened, and the comfort criteria are met.

Application types for Tuned Mass Dampers

Tuned mass dampers are usually implemented in the following typical application types:

Pedestrian bridges and staircases etc. which can be excited by jumping or walking. Primarily this is a comfort problem and not a structural problem.

Office floors and similar being excited either by jumping and walking or machinery may cause discomfort as well as structural problems.

Subsea oil & gas transmission lines. Excitations by wave loads

Tall and slender structures, like bridges, chimneys and towers which can be excited easily by wind causing dangerous situations for the structure.