Bridge structural testing and reinforcement treatment?

With the continuous development and progress of China's economy and transportation industry, highway bridges at all levels of the traffic load is increasingly heavy, due to the shortage of funds in the construction of many bridges, flood relief capacity is low, the design load is low, subject to the constraints of the technical conditions at the time, the design and construction management of the bridge is mostly more sloppy, the bridge construction of the majority of the use of materials and equipment is more outdated, resulting in the current stage of the many bridges are present. Certain defects, affecting the normal transportation, to the development of the national economy has been adversely affected.

A common method of bridge structure inspection

Many bridges in the construction of social development is slow, coupled with the lack of foresight of some bridge designers, after the bridge is put into operation, the construction of the management system has long been neglected, the bridge's management costs have been taken up for no reason or misappropriated, the overloading of vehicles is not strictly examined, and the bridge's technical condition is not observed in a timely manner, which has led to the occurrence of various diseases, seriously damaging the many highways and bridges, and the bridge has been severely damaged. Various diseases occurred, which seriously damaged the normal operation of bridges. Various adverse factors finally led to many bridges to shorten the actual service life, and even some bridges have become dangerous bridges, seriously affecting people's lives and property safety, in order to strengthen the bridge structure of the detection and reinforcement treatment is imperative.

The bridge structure inspection is a scientific experiment to test the bridge structure directly. The main task of the bridge test is to analyze the performance of the bridge structure after loading the measured parameters through a planned, analyze and evaluate the performance of the structure, and correctly evaluate the bridge structure's bearing capacity and use conditions. Bridges in the use of the process will often appear a variety of damage, the relevant departments need to find the bridge in a timely manner in the existence of the damaged links, and timely repair, regular inspection of the bridge goods maintenance is to ensure that the normal operation of the bridge is an important part of the link. At this stage, the commonly used bridge inspection methods include three kinds, namely, half-breakage detection, no-breakage detection, half-breakage and no-breakage combination and load test. Bridge inspection methods are mainly aimed at detecting problems such as strength and internal defects of concrete. Usually, the nondestructive testing of concrete beams includes two kinds of strength and integrity testing, and the nondestructive testing of concrete beams is based on the ultrasonic method and rebound method, which traditionally test the strength of concrete.

Two, the bridge structure reinforcement treatment

The bridge structure reinforcement treatment method needs to be strictly in accordance with the different causes of bridge damage to take different measures, usually, the bridge structure reinforcement treatment methods include the following.

1. Extracorporeal prestressing reinforcement method

The extracorporeal prestressing reinforcement method is mainly applied to the limit state of the normal use of the beam bridge exceeding the limit state of the structure, the technicians through the bridge body to apply extracorporeal prestressing, so that the bridge to reduce the structural cracks, reduce the beam under the deflection, so as to improve the structural stress state of the various cross-sections. Usually, the advantage of extracorporeal prestressing reinforcement method is that after using prestressing reinforcement, it can ensure that the prestressing is permanently preserved, and the prestressing can be dismantled, so this largely expands the scope of use of extracorporeal prestressing reinforcement method, on the one hand, it can be used as a permanent reinforcement measure to improve the bearing capacity of the bridge, and on the other hand it can be used as a temporary reinforcement for the passage of heavy vehicles; in addition, the extracorporeal prestressing In addition, extracorporeal prestressing reinforcement method can make the bridge adjust and improve the force condition of the original structure of the bridge under the condition of small increase of self-weight, and enhance the crack resistance and stiffness of the bridge structure; and under the condition of small increase of self-weight, it has less influence on the force condition of the bridge foundation, which can save the cost of bridge reinforcement. The principle of extracorporeal prestressing reinforcement method lies in the fact that by installing additional steel girders outside the bridge body and connecting them with the reinforced girders by anchoring and applying prestressing, the distribution of internal force in the original structure is changed and the stress level of the original structure is reduced, which in turn improves the load carrying capacity of the bridge and reduces the deformation of the bridge structure.

2. Reduce the weight of the arch reinforcement method

There are three ways to reduce the weight of the arch, one, the use of prefabricated reinforced concrete T-beam, hollow plate or micro-curved plate and other lightweight deck system to replace the previous bulky web arch system: two, the web arch of the gravity cross-walls hollowed out, or converted into reinforced concrete columns; and three, gradually lowering the bridge elevation, to reduce or completely Elimination of materials on the arch. Reducing the self-weight on the arch reinforcement method is aimed at improving the carrying capacity of the bridge, is a means of adjusting the distribution of the constant load on the arch, mainly for the main arch ring deformation is too large, through this method in order to adjust the arch axis and the line of pressure; the use of reducing the self-weight of the building on the arch is mainly for some double curved arch bridge foundation bearing capacity is low, through this approach to reduce the bridge on the foundation bearing capacity requirements.

3. Outsourcing concrete reinforcement method

This reinforcement method is mainly applicable to arch bridges, foundations, piers, piers, steel bridges and girder bridges, etc., is to increase a part of the constant load on the bridge structure, in order to ensure the success of the outsourcing of concrete reinforcement, in the formulation of outsourcing of concrete dimensions should be taken into account outsourcing to build the structural bearing capacity of the following. Outsourcing concrete reinforcement method of the construction process includes the following aspects, in the construction process construction personnel must be strictly in accordance with the relevant provisions of the construction, first of all, the use of concrete reinforcement of the compressed freshly poured concrete thickness should be not less than 150mm, and to ensure that the original concrete surface chiseled into the depth of the concave-convex depth of not less than 6mm of the rough side of the use of shotcrete construction should be greater than 50mm, and the thickness of freshly poured concrete should be greater than 40mm.

Secondly, the configuration of the concrete stone should use crushed stone or harder pebbles, the maximum particle size should not be greater than 20mm; In addition, the bond surface of the connecting reinforcement area should be greater than 0.2% of the area of the bond surface. Again, in the use of steel and steel plate reinforcement should ensure the effective transmission of force, and should ensure that it can *** with the participation of the original structure of the force. Finally, when using steel reinforcement, the diameter of the U-shaped hoop should be consistent with the original hoop diameter, closed hoop diameter should be greater than 10mm, reinforced force steel and the original member of the net distance between the force steel should be less than 20mm, the use of short bars welded, hoops using the U-type or closed hoops.

4. Steel plate paste reinforcement method

The so-called steel plate paste reinforcement method is the use of anchor bolts or binder to paste the steel plate anchored in the concrete structure of the tensile edge or the weak parts of the steel plate instead of additional reinforcement steel, in order to improve the durability of the bridge structure and the bearing capacity. The steel plate paste reinforcement method is mainly applicable to the main beam of the bridge due to the increase in traffic caused by insufficient bearing capacity, or the main beam of the girder plate bridge transverse cracks and so on.

The detection and reinforcement treatment of bridge structure is a complex and detailed work, which requires the relevant technical personnel to have comprehensive knowledge in various aspects, and to combine theory and practice to ensure the effectiveness of bridge detection and reinforcement work, extend the service life of China's bridges, and promote the long-term sustainable development of the national economy.

This article describes the content of "bridge structure inspection and reinforcement treatment". Welcome to visit Zhongda Consulting for more information.

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