Exiting Arch Bridge Evaluation And Reinforcement

Because of the specific technical advantages such as great span and bearing capacity, locally-produced raw materials, economy construction cost, low maintenance cost and artistic shape, arch bridges are of widespread availability in our country. However, due to the influence of natural environment and some artificial factors, there are common diseases problems have arisen, which have severely weakened the load-carrying ability of these arched bridges that have been used for decades or even hundreds of years. It becomes very prominent to study how seriously the diseases have affected the load-carrying ability of arch bridges and how to assess the load-carrying ability of existing arch bridges. Based on the assessment on more than ten arch bridges in Hunan Province and the impact on the load-carrying ability of them resulted from the deterioration of material performance, this assay has finished tasks as following:(1) Introducing the main diseases and causes of existing arched bridges; generalizing the advantages and disadvantages of the main methods for assessing present bridge bearing capacity.(2) Depending on the field inspection and genetic analysis on diseases of thirteen arched bridges in Hunan Province, making a preliminary structure safety assessment and presenting corresponding maintenance and reinforcement or other treating schemes.(3) Adopting space finite element technique, studying the integrity of existing arched bridges with all kinds of diseases. Calculating the transverse distribution influence line of arch ribs on the crown, generalizing the law on variation of their transverse distribution, and presenting the method of making assessment on globality of existing arch bridges. The analysis indicates that the calculating result of the simple method in this assay can reflect correctly the impact which all kinds of diseases have on the structure.(4) According to the result of field inspection of Zhentou Bridge, establishing non-linear finite element full-scale model of it and analyzing the ultimate bearing capacity of it. The result of study indicates that, after considering the non-linearity of material, the flexibility of the crown is more close to the experiment, and the elastic calculation result is lower. The ultimate bearing capacity of the crown is greater than the quarter and the arch bridge is damaged for the development of four-hinged.(5) Generalizing the influence that deterioration of structure material of reinforced concrete has on the structure. Deducing the bearing capacity descending factor of structure members in large eccentric compression led by the corrosion of steel bars, and presenting the bearing capacity coefficients assessing method on the factors of material regression. The analysis of the bearing capacity of Zhentou Bridge indicates that the calculating result well agree with the finite-element method, and as a simple method, it is of certain practical value.