As a key connection structure in modern transportation networks, bridges are readily affected by earthquakes. Abutment failures not only cause the loss of function, but also lead to damage of entire bridge structures. To further research the influence of beam constraints on abutment damage in liquefied ground, in this paper, we investigate earthquake damage to the Shengli Bridge in the 1976 Tangshan earthquake, use UWLC software to conduct a numerical simulation analysis of the earthquake damage to the Shengli Bridge, and compare our results with the actual seismic damage. We found the numerical simulation results to be generally consistent with those of the actual seismic damage, which indicates that the UWLC finite element software has a good fitting ability. We numerically simulated the influence of the restraint force of the beam and the thickness of the liquefied layer on abutment damage modes with and without a pile foundation. The results show that under earthquake action, bridge abutment breakage is more serious. Unlike the gravity abutment with no pile foundation, we found the damage modes of abutments with a pile foundation to be forward-collapse failure, mainly because the pile foundation restricts the horizontal movement of the abutment bottom. The post-seismic displacement of abutments with a pile foundation is less affected by the restraint force of the beam than that of abutments without a pile foundation. For the gravity abutment, the liquefied sand layer has a certain filtering effect on the middle and high seismic-wave frequency bands, which reflects the damping effect of the liquefied layer. For pile-foundation abutments, the damping effect is not obvious due to the pile-soil-platform interaction.