可拆式鋼筋桁架模板截面力學性能試驗和計算方法

史慶軒　楊超望

摘要：

通過對全尺寸可拆式鋼筋桁架模板在施工階段的截面力學性能試驗，研究了其在單調荷載作用下的破壞形態以及受力機理。并分別采用荷載撓度曲線法和極限彎矩法計算了截面特性。分析表明：施工階段可以采用上下弦連續的桁架計算模型，荷載撓度曲線法計算結果與理論值偏差較大，其原因是：試件破壞過程由變形控制，而非強度，以及由于連接件與鋼筋的相對滑移產生的附加撓度，極限彎矩法計算值與理論值較為吻合。在此基礎上，給出了簡支或等跨連續（兩跨）梁計算模型的最大無支撐長度的建議值。

關鍵詞：

可拆式模板；鋼筋桁架；變形；極限彎矩法

中圖分類號：TU398.9

文獻標志碼：A文章編號：16744764（2016）06004608

Abstract：

The crosssection mechanical properties of fullsize detachable formwork with steel bar trusses were tested under construction stage and the failure mode as well as the mechanical behavior were analyzed under monotonic load， and the crosssection properties were calculated using loaddeflection curve method and ultimate moment method. The analysis results showed that truss model with its chords to be continuous and webs can be used during construction， the error was much large between results of loaddeflection curve method and theoretical values， and the reason was that the specimen in failed procress is controlled by deformation， rather than the strength； and the additional deflection was generated by the relative slip between connector and reinforcement； and ultimate moment method were in good agreement with theoretical values. On the base of results， the suggestions were given that the biggest unsupported length under simply supported or continuous beam model.

Keywords：

detachable formwork；steel truss；deformation；ultimate moment method

國外在20世紀20年代就開始使用疊合結構樓蓋形式，60年代壓型鋼板作為永久模板和施工平臺大量應用[12]，Von等[3]提出有效寬度計算壓型鋼板截面特性。中國最初應用的疊合樓板體系為非組合壓型鋼板和組合壓型鋼板，并進行抗彎性能試驗以及采用不同方法計算其截面特性，并對計算結果進行了分析比較等[46]。但壓型鋼板存在明顯的不足，為保留其優勢又能有效地規避不足，鋼筋桁架樓承板應運而生。其中，Lok等[7]從鋼筋桁架夾芯板的抗彎、抗剪、抗扭承載力進行截面特性計算理論研究；童根樹等[811]進行自承式鋼筋桁架樓板的抗彎承載力試驗，采用不同的計算方法確定其截面特性，并對結果進行對比分析，最終確定試件的截面慣性矩I和抗彎模量w。……