In　order　to　reduce　seismic　response　of　fixed　piers　in　irregular　continuous　bridges　and　improve　the　overall　seismic　resistance　performance　of　bridges,　locking　ball　devices　were　installed　between　the　sliding　piers　and　girders　of　bridges.　These　devices　allowed　the　sliding　piers　to　share　seismic　load　from　the　superstructure　with　the　fixed　pier,　according　to　the　potential　seismic　resistance　capacity　of　sliding　piers.　A　shake　table　test　and　a　simulation　of　the　finite　element　model　of　a　three-span　irregular　continuous　bridge　were　conducted.　Then,　taking　a　typical　five-span　irregular　continuous　bridge　as　an　example,　the　seismic　resistance　mechanism　and　the　influence　of　locking　ball　devices　on　the　seismic　responses　of　sliding　piers　were　analyzed.　Optimal　designs　of　locking　ball　devices　were　studied　to　protect　sliding　piers.　The　results　show　that　locking　ball　devices　installed　on　sliding　piers　can　effectively　reduce　the　seismic　response　of　the　fixed　pier,　but　they　may　increase　the　seismic　response　of　the　sliding　piers　installed　with　locking　ball　devices,　and　that　of　the　irregular　continuous　bridge　as　a　whole.　Both　the　acceleration　threshold　and　the　lock　gap　of　the　locking　ball　device　strongly　influenced　the　seismic　resistance　effect.　The　main　parameters　of　the　locking　ball　devices　should　be　optimized　based　on　the　structural　characteristics　of　the　bridge,　so　as　to　obtain　a　better　seismic　resistance　effect.　Adjusting　connection　stiffness　of　locking　ball　device　can　reduce　the　seismic　response　of　the　short　sliding　pier　and　can　protect　it,　but　changing　the　lock　gap　is　not　an　effective　way　of　protecting　the　short　pier.　It　is　necessary　to　optimize　the　arrangement　of　the　locking　ball　devices.