无粘结CFRP筋部分预应力混凝土梁刚度及裂缝宽度计算方法

为了推导表达形式统一的无粘结CFRP筋部分预应力混凝土梁刚度及裂缝宽度计算公式，定义了无粘结CFRP筋应力增量与有粘结钢筋应力增量的比值为无粘结CFRP筋等效折减系数。在刚度计算公式中用无粘结CFRP筋的等效折减面积与普通钢筋面积之和与截面有效面积之比这一等效纵向受拉钢筋配筋率替代现行规范中的纵向受拉钢筋配筋率，在裂缝宽度计算公式中用无粘结CFRP筋的等效折减面积与普通钢筋面积之和这一等效纵向受拉钢筋面积替代现行规范中的纵向受拉钢筋面积。从而形成了与现行规范相协调的刚度及裂缝宽度计算公式，按所推导的刚度及裂缝宽度公式的计算结果与试验结果吻合良好。

Calculation methods for stiffness and crack width of concrete beam partially prestressed with unbonded CFRP tendons

In order to deduce the stiffness formula and crack width formula of concrete beam partially prestressed with unbonded CFRP tendons unified in expressions, the equivalent reduced coefficient of unbonded CFRP tendons is defined as the ratio of the stress increment of unbonded CFRP tendons to that of bonded steel bars. If the ratio of longitudinal tension reinforcement in the stiffness formula in current code is replaced by the ratio of the sum of the equivalent reduced area of unbonded CFRP tendons and the area of steel bars to effective cross-sectional area, and the area of total longitudinal tension reinforcement in the crack width formula in current code is replaced by the sum of the equivalent reduced area of unbonded CFRP tendons and the area of steel bars, the stiffness formula and crack width formula in accordance with current code can be developed. The calculated results by using these two formulas are in good agreement with test results.