South Gate Bridge Structural Condition Assessment And Retrofitting Technology

The arch bridge is a kind of ancient type bridge. On the development process of the bridge, the ancient arch bridge has a more important historical status than the girder bridge. By the the 60 to 70 ages in 20th century, the double arch bridge played a vital role. With the development of society, the bridge runs under the long-term of overload conditions and long years of aging, deformation, cracks, damage, etc. So far almost all the double arch bridges have some degrees of disease, so that they are need to be reinforced and reconstructed to restore or increase its carrying capacity and to extend its life. In this paper, the main work and research results are as follows:1 .Not only the complete on-site investigation and data collection of the South Gate Bridge, but also the assessment and the load test were conducted.2.Through the comparation between the test results and the theoretical results, it is conducted that the carrying capacity does not meet its requirements, and it need to be reinforced.3.Toward the South Gate Bridge's characteristics of the disease, the method of increasing the cross-section is utilized to reinforce it. After numerical calculation, it is concluded that not only the stress state of the arch but also the bridge's overall force performance are obviously improved after reinforced. Its carrying capacity, crack width and deflection all can meet the requirements. It is illustrated that this reinforcement technic is feasible, reliable and economical, which has obvious social and economic benefits.4.The calculation formula of the bolt anti-shear and anti-pull-out are derived, which provide the basis of the theoretical calculations for old bridge reinforcement in the future, and can change the practice of setting up the bolt by experience at the current to ensure that the reinforcement may be more reasonable.5.The formula derived is applied to the reinforcing engineering works. The anti-shear and anti-pull-out capacity of the combination of the old and the new concrete surface is calculated for the actual arch ring to be reinfored.And some analysis and discussion of the reinforcement were carried out, a number of specific methods and measures for strengthening the implementation were also provided.