First, the construction characteristics of expressway bridge in mountainous area
With the continuous development of expressway in China, higher requirements are put forward for the alignment of roads and bridges, which increases the difficulty of bridge construction. Most high-speed bridges are located in complex terrain, with inconvenient traffic, high pier height and large engineering quantity. Therefore, it is extremely important to improve the technical level of bridge construction. As an important part of expressway's construction, the bridge construction in mountainous expressway plays an important role. Therefore, in the bridge construction of expressway in mountainous area, only by accurately grasping the key points of bridge construction technology, combining with the actual situation of the bridge, selecting reasonable and effective construction technology, and accurately applying the construction technology to the construction process, can we give full play to the role of bridge construction technology, ensure the smooth progress of bridge construction in expressway in mountainous area, and thus improve the construction quality of construction units. At present, the construction of bridges in expressway, a mountainous area in China, mainly has the characteristics of long construction period, large investment in machinery and equipment, difficult positioning of piers, and high capital turnover pressure. Therefore, in the bridge construction in expressway, we should pay attention to the above construction points to ensure the safety and reliability of the bridge construction project.
Second, the application practice of bridge construction technology in expressway mountain area.
2. 1 pier concrete pouring technology.
Due to the high piers of the bridge, it is difficult to pour concrete for each pier at the same time. Therefore, the concrete of each pier should be poured separately to make it shape as soon as possible. When pouring pier concrete, the working joints should be reduced to make the joints smooth and tight, so as to ensure the appearance of concrete before and after pouring. It is forbidden to water the pier and pier before solidification to prevent the concrete from setting for too long. In addition, in the process of pouring concrete, a solid platform should be installed and poured by concrete pump. If the distance is too far, it can be transshipped through the secondary pumping station. When pouring, assign special personnel to check the positions and protection dimensions of tie rods, supports, steel bars and templates, to ensure that the embedded parts are located correctly, without displacement or deformation, and to ensure that the water-cement ratio and mixture ratio of concrete meet the requirements. Strengthen vibrating to make the concrete around the formwork full, solid and smooth. When the strength of concrete members reaches 25% to 50% of the expected strength, the side formwork can be removed; If the expected strength is fully achieved, the remaining formwork can be removed. Dismantling the formwork is the same as installing the formwork, so it should be handled with care to avoid deformation and damage of the formwork. After the formwork is removed, focus on the maintenance of the platform and pier, water it regularly from top to bottom with high-pressure pump, or wrap it with health care cloth for health care.
2.2 Bridge substructure foundation treatment technology.
In the construction of bridges in mountainous areas of expressway, attention should be paid to the treatment of bridge foundation, and corresponding treatment methods should be adopted according to the individual characteristics of the foundation. At present, the commonly used foundation treatment methods are: digging out the surface layer or weathered rock covering the foundation surface, in addition, the following construction techniques can also be used for treatment. Firstly, contact grouting, curtain grouting, backfill grouting and consolidation grouting are used for treatment. Secondly, concrete seepage control technology is adopted to effectively block groundwater leakage. Finally, strengthen the weak foundation of bridges in mountainous areas. Although there are many bridge construction technologies in mountainous expressway, the above technologies are professional and necessary. The construction unit should pay attention to and improve these technologies, especially gradually update and develop these technologies in the application process. As a basic project, the bridge project in expressway in mountainous area should be optimized in technology and management, and the technical training, application and renewal of the construction project should be done in time to ensure the construction quality of the bridge project and improve the economic benefits of the construction unit. Technology is the guarantee of construction quality and safety. Therefore, in the construction of bridges in expressway in mountainous areas, relevant management departments and construction units in expressway should strengthen the training, application and popularization of construction technology, so as to promote the smooth completion of bridge construction in expressway in mountainous areas.
2.3 pier construction technology.
Due to the different structural forms of high-speed bridge piers in mountainous areas, traditional construction technology can be adopted when building piers with single structure and low height, and cast-in-place construction can be carried out after formwork erection for one or more times. For high piers, cable-stayed towers and suspension bridges, there are more construction methods to choose from, and the diversification of their technologies is mainly reflected in the differences in structural forms. At present, the construction of high piers and cable towers mostly adopts turnover formwork, sliding formwork and climbing formwork. Some of their characteristics are mainly to divide the piers into several sections and construct them step by step from bottom to top. Slipform construction is adopted to accurately control the external dimensions of the structure to ensure the safety and balance of the construction process. However, to realize sliding lifting, hydraulic equipment is needed, and more capital cost and mechanical equipment are needed. In general, the climbing formwork will be equipped with a climbing frame on its outer side, so the climbing formwork will consume more materials and be equipped with special lifting equipment. In a word, in the process of bridge high pier construction, the appropriate construction technology should be selected according to the actual situation to promote the orderly construction of the bridge.
2.4 technical points of bridge formwork engineering.
Bridge formwork construction plays an important role in bridge construction. During the bridge construction in expressway, the construction should be carried out according to the specified construction design scheme. For the pier and abutment structure of the bridge, the processed and assembled steel formwork should be selected for installation. This formwork is assembled by two semicircular formworks, and the height of each formwork is1.5m. After being reworked and manufactured in the factory, its board surface is relatively flat and smooth, with accurate dimensions, convenient disassembly and assembly, tight joints and no deformation after repeated use. Mechanical hoisting can be used if necessary. Before installing the template, carefully check the size of the template. According to the design requirements of the bridge structure, determine the installation position of the formwork, and the installation should be firm and firm, so as to avoid the formwork falling off and slurry leakage when vibrating the bridge concrete and ensure the smooth progress of the bridge construction project.
Three, the quality control measures in the construction of expressway bridge in mountainous areas.
As for the quality control of expressway bridge construction, the author thinks that the division of labor can be clearly defined according to the sub-projects of the bridge, and the quality problems of the project can be avoided by controlling and managing all processes in an all-round way.
3. 1 Strictly implement the quality responsibility system.
In order to ensure the quality of bridges, it is necessary to strengthen regular and irregular inspections of bridges under construction, and conduct monthly inspections and key spot checks on bridges and related surveys and tests. , and monthly evaluation of the project. Strengthen quality consciousness, obey quality supervision, and ensure the overall quality of the bridge to be level and step up.
3.2 Strictly control the quality of raw materials entering the site.
Raw materials are the foundation of bridge quality, so it is necessary to strengthen the inspection and test of raw materials used. Raw materials shall be continuously sampled and tested before and after entering the site. Once unqualified materials are found, they will be refused to enter the site for use, and the hidden dangers affecting quality will be eliminated in the bud.
3.3 Quality control must be supervised throughout.
Quality is no small matter, safety is greater than the sky, and bridge construction can not tolerate any slack and carelessness. Therefore, in the whole process of bridge construction, the quality of the bridge must be controlled before, during and after, and it must be step by step.
3.4 Clear the relationship between project quality management and progress.
In the era of efficiency first, many construction units often pay too much attention to speed and efficiency, while ignoring quality. They often think that as long as the quality of the project is emphasized, the progress and comprehensive benefits of the process will be greatly affected. In fact, paying attention to quality, progress and efficiency is a contradictory combination of mutual supplement, mutual restriction and mutual development. It should be noted that if the quality of the project is not improved, there will be hidden dangers and need to be reworked. Repeated investment will only increase the cost and affect the reputation of the unit. Therefore, ensuring the quality and maintaining the progress can reduce the input of manpower and material resources and ultimately improve the economic benefits.
3.5 Pay attention to design quality
At present, the construction unit and supervision unit strongly demand to improve the design quality. Design quality is closely related to construction quality. In the construction of many bridges, because the geological data in the design documents are inconsistent with the actual geological conditions, the pile length of some pile foundations is inconsistent with the design pile length, and the project that can be completed within the original construction period must be delayed. This not only brings a lot of trouble to the construction, affects the construction progress, but also wastes a lot of manpower, material resources and financial resources.
Third, the conclusion
To sum up, in recent years, with the rapid development of China's market economy, the number of private vehicles in China is increasing, and the requirements for road and bridge construction in China are getting higher and higher. In order to alleviate the traffic tension in expressway, there are more and more road and bridge construction projects on expressway. In order to ensure the construction quality of bridges in expressway, prolong their service life and reduce their maintenance costs, we should pay more attention to the management of bridge construction technology in expressway, improve the quality control of bridge construction technology, and ensure that construction enterprises have an absolute advantage in the market competition. This paper discusses the present situation of bridge construction in mountainous areas of expressway, comprehensively analyzes the key points of its construction technology, and introduces in detail the concrete application of bridge construction technology in mountainous areas of expressway, China.
For more information about project/service/procurement bidding, and to improve the winning rate, please click on the bottom of official website Customer Service for free consultation:/#/? source=bdzd