- 鄒惠瓊，白洪濤，李 梅
引用本文為探究混凝土箱梁在分層澆筑施工過程中水化熱溫度的發展規律及其溫度應力，對某主跨230 m的大跨度預應力混凝土箱梁橋零號塊水化熱進行了連續觀測，并基于觀測結果和有限元數值模擬計算，分析了零號塊水化過程中底板、腹板和橫隔板的溫度應力發展規律；同時，討論了分層澆筑和整體澆筑兩種不同施工方案對零號塊水化熱溫度應力分布的影響，研究了拆模時間對結構內外溫度的影響程度。結果表明：內外溫差在結構內部產生的溫度應力超過了材料的抗拉強度，從而導致了溫度裂縫的產生；采用分層澆筑施工的零號塊將在上下層混凝土交界面附近形成一條拉應力帶；過早拆模會使混凝土內外溫差迅速擴大，而養護4 d后拆?；炷羶韧鉁夭钕鄬^小，建議零號塊拆模前養護時間不宜少于4 d。 In order to explore the development law of concrete hydration heat temperature of box girder by distinct-layer casting and accurately calculate the temperature stress, the concrete hydration heat in the No.0 block of box girder of a long span (230 m) PC continuous bridge was observed continuously. Based on the field test results and the numerical simulation calculation by FEA, the temperature stress development law of the bottom plate, web and diaphragm were analyzed. Meanwhile, the influence of the construction scheme on the hydration heat temperature stress of the No.0 block of box girder was discussed and the influence of the form removal time on temperature difference was researched. The results show that the excessive temperature difference can cause the excessive temperature stress and the temperature cracks. Besides, the tensile stress field can be formed near the interface between the top and the bottom concrete in the No.0 block of box girder by distinct-layer casting. The research results also show that the form removal time should not be less than 4 days to prevent temperature cracks.
鄒惠瓊,白洪濤,李梅.混凝土箱梁分層澆筑水化熱實測與模擬分析[J].混凝土與水泥制品,2022(6):77-81. ZOU H Q,BAI H T,LI M.Measurement and Simulation Analysis of Hydration Heat of Layered Pouring Concrete Box Girder[J].China Concrete and Cement Products,2022(6):77-81.