Only swinging bells achieve a resonant and musical sound of bells. Nonetheless swinging bells transmit considerable forces into the towers, the horizontal components of which usually cause stresses that are even higher. Especially those ratios coming along with the third vibration frequency often are close to the towers’ eigenfrequencies thus causing dynamically excessive exposures.

Ringing of bells close to the resonance normally leads to an increased exposure of a tower; with exposure over years and decades it is very likely to cause damage. Dynamic analyses of existing towers are therefore recommended if

• structural damage already exists
• deformations of a tower are observed or
• a tower shall be provided with new bells or a new peal respectively.

• With consideration of bell ringing music and structural dynamics aspects: harmonization of the peal of bells to the tower, arrangement of the peal of bells in co-operation with the authorized expert
• (Assistance with) the design of the supporting structure of bell tower and bell supporting structure, construction, analysis, verification
• We also carry out analyses of the musical sound of bells, including the determination of the partial tones and their decay behavior.
• In summary, Wölfel deals with state-of-the-art measurements and analyses, provides professional expert reports and consulting services as to necessary measures by means of data sheets which allow for the direct use by the bell-caster or the structural engineer respectively.

DIN 4178 requires a dynamic analysis for the construction of bell towers.