[{"data":1,"prerenderedAt":62},["ShallowReactive",2],{"q-110180-arch_structure-36":3},{"question":4,"neighbors":27,"sameNumber":46,"prev":35,"next":38},{"id":5,"classKey":6,"session":7,"year":8,"subject":9,"number":10,"groupStem":11,"ownStem":12,"stem":12,"options":13,"answer":18,"answerKind":20,"answerS":11,"answerNote":11,"images":21,"explanation":23,"withheld":11,"deepChars":24,"freq":25,"indexable":26},"arch-110180-801-0102-036","architect","110180",110,"建築結構",36,null,"圖示結構 A、C 為鉸端，B 為鉸接，則 A 點處水平反力為何？ 60 kN 9m 3m 3m",{"A":14,"B":15,"C":16,"D":17},"10 kN","20 kN","30 kN","40 kN",[19],"A","single",[22],"\u002Fimages\u002Farch-110180-801-0102-036.png","本題考點：三鉸拱的水平推力——先由整體平衡求垂直反力，再取半拱對中間鉸 B 取力矩（鉸處彎矩為零）求水平反力。\n【正解理由】依題圖所示，A、C 兩支承同高、相距 3 m + 3 m，B 為頂部鉸，位於跨中正上方 9 m，60 kN 集中載重作用在 B 點。結構與載重左右對稱，整體垂直平衡得 Ay = Cy = 60 \u002F 2 = 30 kN。取左半拱 AB 為自由體，B 為鉸，對 B 取力矩為零：Ay × 3 m − Ax × 9 m = 0，Ax = 30 × 3 \u002F 9 = 10 kN（A 點水平反力指向拱內，即拱對支承向外推）。故選 A。\n【逐項排除】\n(A) 符合。由 B 鉸彎矩為零，Ax = 60 \u002F 2 × 3 \u002F 9 = 10 kN。\n(B) 不符。20 kN 與正確值不符；水平推力由垂直反力乘以半跨、再除以拱高求得，拱高 9 m 遠大於半跨 3 m，推力只有垂直反力的三分之一。\n(C) 不符。30 kN 是 A 點的垂直反力 60 \u002F 2，不是水平反力；題目問的是水平推力，必須再用 B 鉸彎矩為零的條件換算。\n(D) 不符。40 kN 與正確值不符；本題水平推力受到拱高與半跨的幾何比例控制，計算結果為 10 kN。\n【演算步驟】\n整體垂直平衡（對稱）：Ay = 60 kN \u002F 2 = 30 kN\n左半拱對 B 取力矩：Ay × 3 m − Ax × 9 m = 0\nAx = 30 kN × 3 m \u002F 9 m = 10 kN\n【記憶點】三鉸拱水平推力 = 垂直反力 × 半跨 ÷ 拱高；拱越高，推力越小。",538,1,true,[28,31,34,37,40,43],{"number":29,"session":7,"stem":30},33,"有一簡支梁承受均布載重如圖所示，若梁自重不計，下列何者所得之最大正彎矩值與此梁相同？",{"number":32,"session":7,"stem":33},34,"圖中構架 ABCD 之 A 點固端彎矩為何？ 3m 2 kN 4m 10 kN-m …",{"number":35,"session":7,"stem":36},35,"下圖的結構中，關於支承 A、B 點之反力的敘述何者錯誤？ 60°",{"number":38,"session":7,"stem":39},37,"根據鋼筋混凝土「單筋矩形梁」之斷面極限彎矩強度分析，若鋼筋混凝土梁斷面在「平衡應變狀…",{"number":41,"session":7,"stem":42},38,"混凝土構架的耐震撓曲構材縱向鋼筋在梁柱交接面（梁端）及其他可能產生塑鉸位置，其壓力鋼…",{"number":44,"session":7,"stem":45},39,"鋼結構梁柱接頭中強度減弱型接頭（如下圖 A 之圓弧切削式接頭）以及強度增強型接頭（如…",[47,50,53,56,59],{"number":10,"session":48,"stem":49},"114180","由鋼骨構造所形成的特殊抗彎矩構架系統（SMRF）、同心斜撐構架系統（CBF）及偏心斜…",{"number":10,"session":51,"stem":52},"113190","下列關於結構系統與構件行為之敘述，何者正確？",{"number":10,"session":54,"stem":55},"112190","RC 結構特殊抗彎矩構架系統的韌性設計原則，下列敘述何者錯誤？",{"number":10,"session":57,"stem":58},"111180","下列圖示之 A、B、C、D 為四種不同配筋量（超量、平衡、稍微低量、不足量配筋）的 …",{"number":10,"session":60,"stem":61},"109180","矩形鋼筋混凝土梁斷面計算其彎矩強度時，混凝土受壓區之應力常簡化成一等效矩形壓應力區塊…",1791863205120]