Tsunamis　are　natural　hazards　that　have　damaged　many　coastal　bridges　worldwide　in　recent　years.　As　a　contribution　to　an　important　area　of　coastal　research,　this　study　investigated　tsunami　bore　impact　on　a　bridge　model　with　different　contraction　ratios.　The　time　histories　of　the　horizontal　force,　vertical　force,　and　overturning　moment　on　a　deck-pier　structure　in　a　tsunami　flume　were　measured　by　a　load　cell　at　the　base　of　the　structure.　Results　show　that　different　stages　of　the　flow　motion　were　observed　during　the　bore-bridge　interactions.　The　time　histories　of　tsunami　loads　on　deck-pier　structures　reveal　that　the　horizontal　force　was　characterized　by　four　stages,　the　vertical　force　was　characterized　by　three　stages,　and　the　overturning　moment　was　characterized　by　four　stages.　The　maximum　upward　force　and　the　maximum　overturning　moment　occurred　at　the　same　time　in　the　splashing　stage.　The　maximum　horizontal　force　occurred　in　the　water-accumulation　stage.　The　maximum　downward　force　occurred　in　the　recession　stage.　Tsunami　loads　increased　with　increasing　bore　strength,　and　for　most　bore　strengths,　the　effects　of　the　contraction　ratio　on　tsunami　loads　were　different　for　horizontal　force,　vertical　force,　and　overturning　moment.　Finally,　on　the　basis　of　experimental　data,　equations　for　estimating　tsunami　loads　are　proposed　as　functions　of　the　bore　height　and　the　contraction　ratio.