摘要 應用輕質骨材混凝土於梁構件設計，不僅可減小構材斷面，增大結構跨度，提高結構空間使用效率，亦可因此減低基礎設計需求，進而減低工程造價，並提高設計之效率，鋼筋輕質骨材混凝土梁應用技術之突破，不僅可確保結構之安全，對設計之競爭力亦將有所提升。 有鑑於輕質骨材混凝土尚屬於未開發完全階段，因此本文針對輕質骨材混凝土與常重混凝土梁構件受剪力、彎矩及扭矩之承力行為作比較。受剪力之梁試體分別以不同之跨深比作為剪力試驗之參數，本文於混凝土工程設計規範與解說(土木401-86a)中，修正其最大剪力限制對跨深比較小之深梁太過嚴苛之規定，因此於本文中針對規範公式4-28提出修正，以符合深梁之實際抗剪強度；於受彎矩之輕質骨材混凝土梁試體則以不同之鋼筋比作為彎矩試驗之參數，針對極限彎矩強度、降伏彎矩強度、開裂彎矩強度、及有效等值應力塊區域本文分別對其進行預測以及與常重混凝土梁試體之試驗結果作比較，其結果顯式輕質骨材混凝土梁於受彎矩之情況下其行為近似於常重混凝土梁；於受扭矩之輕質骨材混凝土梁試體則以不同之縱向與橫向鋼筋量作為扭矩試驗之參數，用以比較扭矩強度與扭轉角於不同鋼筋體積比時之差異，並比較輕質骨材與常重混凝土梁試體受扭矩後之結構行為有何差異。 ABSTRACT Reinforced concrete is commonly used in the constructions of building and bridge structures. In general, the structural weight of such designs is large which might hamper its competitiveness when earthquake-resistant efficiency is concerned. In order to enhance the efficiency of such design, reduction in structural weight is essential. This study is focused on the flexural and torsional behavior of reinforced concrete beams using light weight aggregates. A series of tests on light weight reinforced concrete beams subjected to bending and torsional load, respectively, were conducted to obtain their structural responses. Test results show that the load-deformation relationship of light weight reinforced concrete beams is similar to that of the normal weight reinforced concrete beams. However, calculations on the shear capacities of light weight reinforced concrete beams indicate that there exists discrepancy between the ACI design equations and the test results. The discrepancy varies when the ratio between shear span and depth of the member is altered. Recommendation on the calculation of shear strength of light weight reinforced concrete beams is proposed in this study for engineering practice. Further investigation on the behavior of members subjected to torsion validates that the relationship between torsion and twist angle of light weight reinforced concrete beams is similar to that of normal weight members. Test results also confirm that the achievable twist angles at which members reach the crack and ultimate states are smaller for reinforced concrete beams using light weight aggregates.
