套箍法加固石拱桥主拱圈的正截面承载力的理论分析

针对石拱桥拱圈加固后的正截面承载力计算问题,提出了考虑加固前截面受力状况及加固材料不同力学性能的计算方法。对加固后的拱圈进行应力应变分析,得出界限破坏的3种形式,对每种界限破坏形式利用截面的协调变形和截面材料的应力应变关系,分析了其极限状态时组合截面的相对界限受压区高度,得出加固后石拱圈最后的破坏模式主要与加固前的初应变及加固层的厚度有关。对应于3种破坏形态从理论上推导出套箍法加固石拱圈在二次受力时的正截面承载力计算公式。计算公式充分考虑了加固前的构件应力水平、加固后截面不同材料组成及构件破坏形态的影响,比现有加固规范的计算取值更趋于合理,为同类加固结构的设计和计算提供了依据。

Theoretical Analysis of Normal Section Bearing Capacity of Stone Main Arch Ring Strengthened by Reinforced Concrete

An analytical method considering the existed stress state in stone arch ring and different mechanical properties of material was proposed to count normal section beating capacity of strengthened stone arch ring.Three limiting destruct forms were found by analyzing stress-strain states of strengthened stone arch ring,the height of relative limiting pressed section was analyzed by accordant section strain and stress-strain function of different material in different limiting destroy states.It is educed that destruct mode of arch ring mainly lies on the existed stress state and thickness of strengthened layer.The theoretical formulas were given to calculate the normal section beating capacity of strengthened stone arch ring according to three destruct modes.The existed stress state before strengthening,different mechanical properties of material after strengthening and destruct modes were considered in the theoretical formulas.It is shown that the analytical method is more rational than the existing criterion and gives a basis to design and analyse same strengthened structure.