Equations of Young’s moduli of sands as a function of the axial strain amplitude for different types of dynamic loading were developed from a series of resonant column tests. Ottawa 20-30 sand specimens were excited longitudinally with one of three types of loading at three different confining pressures. In the sinusoidal tests, excitation signals were generated by a variable frequency sine-wave oscillator. In the random tests, input signals were generated by a white-noise generator and a pulse signal generator was used in the impulse tests. Input and output signals were analyzed by an FFT analyzer in the random and impulse loading tests. Under each type of loading it was found that the Young’s modulus normalized with the initial maximum Young’s modulus for the different confining pressures could be unified using a normalized axial strain with a reference axial strain for each loading type. Relationships that determine the variation of the Young’s modulus with the axial strain were developed for each type of loading
