An Experimental Study of the Feasibility of Identifying the Impact Damages of Reinforced Concrete Piers Using a Modal Frequency Method

Table 3

Impact scheme 1.

Impact times	Drop height (m)	Car quality (kg)	Axial pressure (kN)	Drop hammer quality (kg)	Friction coefficient	Theoretical speed (m/s)	Measured average velocity (m/s)	Speed change rate (%)
1	4	1200	250	166	0.12	1.124	1.114	−0.890
2	6	1200	250	166	0.12	1.376	1.335	−2.980
3	8	1200	250	166	0.12	1.589	1.563	−1.636
4	10	1200	250	166	0.12	1.777	1.770	−0.56