Summary： With the vigorous development of the construction industry, the application structrual strengthening will be more and more wide, and the new reinforcement technology will be constantly emerging, and the reinforcement technology of the structure will also have a longer development.

In today's developed countries, the degree of urbanization is mostly between 70% and 80%. According to the UN Habitat, by the year 2050, the level of world urbanization will reach 61%, and twenty-first Century will become a real century of urbanization. The process of urbanization in China has entered a stage of rapid development.

It is estimated that by 2020, the level of urbanization in China will reach 60% from 38.9% now, which represents the brilliant achievements of human civilization. However, with the expansion of the scale of the city, the rapid growth of the population, the destruction of the environment is becoming more and more serious, and the natural resources are increasingly scarce, and the living conditions and quality of people are deteriorating. At the same time, the excessive concentration and disorderly construction of buildings make the contradiction between construction and environment increasingly prominent. To control the construction quantity and rational planning of buildings has become a problem that the modern builders must pay attention to. At the same time, it is the task of top priority to improve the life and function of existing buildings. The method of completing this mission is to repair and strengthening the existing structure.

The analysis of the current situation of structural strengthening" textvalue="structural strengthening">structural strengthening in China:

In the developed countries of Europe and America, the investment in building reinforcement and reconstruction has already accounted for more than 1/2 of the total investment of the national construction industry. The Labor Department of the United States in the end of twentieth Century predicted that the building maintenance and reinforcement industry would be one of the most popular industries in twenty-first Century. Since the founding of the people's Republic of China, especially since the implementation of reform and opening up in the late 70s of last century, the number of housing construction and urban facilities has increased dramatically. According to the statistics of relevant departments, the total area of existing buildings in China is at least 10 billion square meters at present, and the vast majority of them are concrete and masonry structures.

During the early years of the founding of the people's Republic of China, a large number of industrial and civil buildings were built for more than 50 years. In some newly built projects, due to the technical and management problems in the investigation, design and construction, there are various hidden dangers of quality and safety in the early stage of the project. For these buildings, if not taken timely reinforcement measures, it may lead to major safety accidents. For this reason, the state has to invest a lot of funds every year for the reinforcement and repair of buildings, which has promoted the development of the building reinforcement and repair industry and formed a huge market space. At the same time, in some existing buildings, the old structure design can not meet the needs of the current use in function, which also stimulates the rapid development of the building reinforcement and repair specialty. Especially with the continuous development of China's economic development and the improvement of people's living standards, the transformation of old cities has become a common topic in large and medium-sized cities in recent years. This has brought unprecedented development opportunities for building reinforcement and rehabilitation.

Method of structural strengthening：

• Prestress reinforcement method

• Enlarging section reinforcement method

• Reinforcement method for changing the force system

• Bonded steel plate reinforcement method

• Reinforcement method of outsourced steel jacketing

• Bonded carbon fiber reinfroced polymer(CFRP) composite strengthening method