Civil engineering, steel engineering, construction reinforcement works

Old bridge reinforcement technology is a new topic. At present, China's road, rail transportation business was flourishing, many highways have been built and put into operation, there are a lot of highways and other grades of highway under construction will soon put into operation. However, due to the construction quality and other aspects of bridge design, making detection and reinforcement of bridges become necessary, but also because a lot of construction since the founding of the old bridge, due to the time of design, materials, construction and other implications and limitations, vouches cope with the present traffic of fast Meng growth, making the old bridge detection and reinforcement technology is very urgent. In recent years, more and more old bridge strengthening works. According to incomplete statistics, China's roads dangerous bridge, about 4,000 seats, but has yet to see a special bridge strengthening norms. First, the bridge reinforcement tasks and situations (a), the cause of a bridge reinforcement, along with economic development, traffic volume increases, the load rating change. 2, the guiding ideology of the early design focus on saving materials, low safety. Generally caused by thin section, low safety margin, the most typical is the curved arch. 3, the bridge poor durability and long years of aging, such as brick arch bridge. 4, the construction of bridges in recent years, due to improper design or poor quality of construction, there are also reinforcing problems. (II) 1 is difficult, the opening of the bridge has been reinforced bridge, there is the reality of transport needs, because without disrupting traffic reinforcement, so there is traffic interference reinforcement. 2, the structure of limits: the general principles of strengthening the existing structure must be used only to make a fuss in the original structure, has been limited 3, combining old and new architecture is a problem: This contains changes in the new and old architecture transition, including the joint surface of the old and new bridge. 4, the risks are great: because those who want to strengthening the bridge, mostly dangerous bridge, the structure has been in an unfavorable condition, some also in jeopardy. Some of the old bridge lack original design information and construction records, the internal structure is unknown; the existing force, without which it is difficult to determine the limits of its structure, which gives the old bridge reinforcement risks. (C) the reinforcement of technical requirements 1, unit owners typically prefer to scrap the old bridge repair another bridge, except when necessary to use the old bridge and the use of reinforcement measures. 2, due to the design of the old bridge strengthening scheme, heavy workload, low fees, it is generally unwilling to take large design units such design tasks. 3, reinforcing the need for good design bridge theoretical level and basic knowledge of mechanics. When determining reinforcement program to be able to correctly analyze and judge the degree of safety of the old bridge, that is, its structure and internal force size state level. This requires a certain mechanical tests for structural analysis to support. 4, there is a reinforcement of the complexity of the implementation of the program. Reinforcement and treatment methods have a certain experience in the construction of the professional ranks. (Iv), after bridge strengthening political and economic role of bridge strengthening, you can extend the life of the bridge, with a small amount of funding, so that the bridge to meet the traffic demand, but also ease the concentration bridge investment. Strengthening the bridge is not a new project, in general, not the leaders of achievements. But it can be prevented and to strengthen the bridge to avoid the collapse of the bridge caused by material and personal injury, to avoid the competent leadership of political disaster. Second, the strengthening of the program (a) reinforcing the idea of ??a reinforcement and repair and maintenance of the role is different, repair and maintenance of a bridge to maintain normal operating condition of protective and preventive work, and strengthening the force is from the carrier perspective to deal with. 2, the first class demand strengthening, bridges can not afford the original design load requirements, it should be restored to its original carrying capacity by reinforcement. 3, load the original design does not meet the standard of traffic now demands to be raised to a new standard. 4, the bridge through a one-time special heavy loads, require provisional measures by especially heavy load without causing damage to the original structure, after the return to normal. In general strengthening program can consider reducing or increasing the cross-section of internal forces, reinforcement of new materials can be applied. (Ii) strengthening programs and methods currently on the concrete bridge reinforcement methods are: 1, structural reinforcement, such as the use of prestressing, in the tension zone structure paste or additional steel support plate; 2, non-structural reinforcement, such as the closure of cracks or grouting treatment; 3, in recent years, the use of carbon fiber composite materials abroad (CFRP) replace steel reinforcement technology make a fundamental change. Third, strengthening the material and workmanship of carbon fiber composite material is a new material that can replace steel reinforcement used in the bridge, and therefore subject to widespread attention. This material is the most attention in Japan, applications are most widely used. Of this new type of material it is the beginning of 98 years of practical application, the current application and is deepening its research and development. Carbon fiber composite materials (CFRP) features 1, without increasing the dead load and cross-sectional dimensions; 2, does not reduce the clearance under the bridge; 3, the construction is convenient, easy to shape, can be adapted to different component shapes. 4, epoxy bonding, no anchor bolts, the original structure no new damage. 5, according to the force required to paste several layers. 2, carbon fiber composite materials (CFRP) there are three, namely carbon fiber, high polymer fibers, and glass fibers. Fourth, the implementation plan of strengthening the implementation of the program reinforced the need for skilled and have some experience of the construction team to complete. For the process should also be relatively high demand. Fifth, the observation and examination after verification of Reinforced Bridge Reinforcing the need for bridges to detect and observe, to determine the effect of reinforcement. Six bridge reinforcement should form a special specification constantly sum up experience and technological progress to be formed on the basis of special norms bridge reinforcement.