Abstract: Concrete is the major material for infrastructures. A new, simple and inexpensive method to improve the seismic capacity ofimportant structure components is to improve the damping capacity of concretematerial. The damping capacity of the high damping concrete is frequencydependent, but the available viscoelastometer and other dynamic mechanicalanalyzers can not measure the shear damping capacity of a large scale materialsuch as concrete materials. For the high damping shear-type plain concrete bar,using the damping model in complex variables, the shear vibrationequations of motion are derived and then the steady displacement response under a simple harmonicload is obtained through the modal decomposition method. Thetesting formulae for measuring shear damping capacity of large scalematerials are derived and the shear-type damping measuring instrument forlarge scale materials is thus designed. The suggested test theory and instrumentcan be used to study shear damping capacity and mechanism ofhigh damping concrete materials.