How are the first, second and third types of pile foundations of bridges determined?

How are the first, second and third types of pile foundations of bridges determined?

The classification of pile foundations is divided into 4 categories, see "Technical Specifications for Inspection of Construction Pile Foundations" JGJ106-2003 /J256-2003 Article 3.5.1:

Category I: The pile body is complete.

Category II: The pile body has slight defects that do not affect the normal bearing capacity of the pile body structure.

Category III: The pile body has obvious defects, which has an impact on the bearing capacity of the pile body structure.

Category IV: The pile body has serious defects.

Integrity refers to the dimensional changes of the pile body, material density and continuity.

Pile body defects refer to pile body fractures, cracks, mud inclusions, holes, honeycombs, looseness, etc.

Class IV piles should undergo engineering treatment. How is the distance between pile foundations of continuous beam bridges determined?

The distance between pile foundations is determined according to JTG D63-2007 specifications

Chapter 6 concerns the structural requirements for pile foundations, specifically the distance between friction piles should not be less than 2.5 times the pile diameter, and the distance between pile foundations should not be less than 2.5 times the pile diameter. The pile (pillar pile) shall not be less than 2.0 times the diameter of the pile. How are bridge pile foundations and bridge piers distinguished?

Generally speaking, bridge piers are the part of the pier body above the foundation. Piles are the foundation of bridge piers or bridge columns. The two are mainly distinguished according to their structural functions. Bridge piers are columns or walls. It is a force-transmitting component, and the pile is the lower foundation component. When the two are combined, the joint part is the boundary, and the actual boundary is above the cap platform or at the bottom of the pier.

If there is a cap or tie beam: the pile foundation is under the cap or tie beam, and the piers are on the cap or tie beam;

If there is no cap or tie beam: Below the ground line are pile foundations, and above the ground line are piers. The bridge pier is composed of three parts, the lower part is the pile foundation, the upper part of the pile foundation is the cap platform, and the upper part of the cap platform is the pier body. The boundary between the pier body and the pile foundation is the cap. Staking out the bridge pile foundation. How to stake out the pile positions of the bridge.

After converting the pile foundation diagram to absolute coordinates in CAD, query the pile position at any point on the diagram, which is the coordinate to be staked out. Staking out can be done by GPS or total station. Bridge pile foundation. What is bridge pile foundation?

Piles are cylindrical rods buried in the soil. Their function is to transfer the load of the superstructure to the deeper, harder, less compressible soil or rock layers;

< p> Pile foundation - the foundation pile and the cap connected to the top of the pile are composed of the same. If the pile body is completely buried in the soil and the bottom of the cap is in contact with the soil, it is called a low cap pile foundation; if the upper part of the pile body is exposed to the ground and the bottom of the cap is above the ground, it is called a high cap pile foundation.

Bridge foundation - The part of the bridge substructure that is in contact with the foundation is called the foundation; the lowest structure of the bridge. It is located directly on the rock or soil foundation, and its top is connected to the bridge pier or abutment, which is collectively called the bridge substructure.

The function of the bridge foundation is to bear all the loads from the upper structure and transfer them and the loads of the lower structure to the foundation. Therefore, for the safety and normal use of the entire bridge, the foundation and foundation are required to have sufficient strength, stiffness and overall stability to prevent excessive horizontal displacement or uneven settlement.

What is a bridge pile foundation?

The deep foundation composed of piles and pile caps connected to the pile tops (referred to as caps) is referred to as pile foundation.

Pile foundation has the characteristics of high bearing capacity, small and uniform settlement, and can be applied to almost all kinds of engineering geological conditions and various types of projects, especially for buildings on weak foundations. Heavy building (structure). Therefore, pile foundations are widely used in coastal and soft soil areas.

The number and arrangement of piles in the pile foundation should be determined based on the superstructure and load conditions. The pile foundation under the column can be one or a group of piles arranged in a polygonal shape; the pile foundation under the wall is often arranged in rows. When the building load is large and the floor area is small, piles must be arranged in sheets to form a full hall. When the load acting on the pile foundation is mainly vertical load, the piles are all vertical; if there is a large horizontal load, inclined piles must be arranged to resist the horizontal force.

Due to the wide variety of pile foundations, the large differences in construction techniques, and the complex changes in the ground, the pile body may have defects such as shrinkage, expansion, mud inclusion, segregation, and pile breakage during the construction process. Of course, construction After being excavated by machinery, collision will also cause shallow pile body defects. The existence of defects in the pile body will change the normal working characteristics of the foundation pile, thereby causing potential danger to the foundation.

Evaluating the integrity of the pile body through acceptance testing is inevitable to ensure foundation safety. A large amount of practice has proved that the low-strain dynamic testing technology of foundation piles is a very effective means to judge the integrity of the pile body (convenient, fast, economical and with a large number of tests). Bridge Pile Foundation Weekly Diary

The three-month internship has ended. During these four months, I witnessed the construction process of a bridge with my own eyes. During this time I learned a lot and understood the difference between theory and practice. Again, this was the first real building I came into contact with when I entered this profession. Seeing it standing before my eyes, I felt indescribable excitement, indescribable pride, and endless feelings.

Studying in school can only acquire superficial knowledge. Only in internship can you learn more knowledge. Only in learning can progress be made, and only in progress can gains be found. For this internship, I came to the Chengchi Project Department for an internship. During the internship, I laid down the basic skills of my job, which made me full of expectations for my future work. Although the basic skills are not very comprehensive and there are still shortcomings, it makes my work more fulfilling. confidence. Of course, the past has become history, and we still need to work hard to face the future.

After reporting to the project department, he was assigned to work in the first work area of ??the Chengchi project department. Here, my job was arranged to measure. Later I applied to be transferred to the bottom of the dam because I could learn more in different positions. However, working as a field technician was something I had always dreamed of. Being able to come to the Engineering Department, I am very grateful to the company for giving me this new stage, allowing me to show my abilities, expand my own knowledge, and allow myself to absorb more knowledge.

In terms of work, the project department assigned me the position of surveyor at the beginning. The construction of the Damei Super Bridge and the Tianyigou Super Bridge required very strict surveying work. Later, I was transferred to the position at the bottom of the dam. In more than 2 months, the main work completed included bridge deck paving and beam and slab installation. The work of the technicians on the bridge deck paving and beam slab installation construction site was mainly divided into calculation data, inspection application, information and other parts. I have different understandings, but those are just superficial skills and not worth mentioning. Therefore, when it comes to work, I obey the leadership's arrangements and do my job full-time. Only the assigned work is the fastest. Improvement, and finally my job was arranged as a field technician. In my daily work, I gained a deeper understanding and was filled with more sense of passion. It also made myself further enthusiastic, so that I could learn More things will make your daily life more abundant. Work should not just be a simple job, but should be a better way of learning.

Although I have been in contact with the construction site, I often look back on the scene in my memory when I am on site, but there are always differences in this way, and I cannot well describe some of the construction work on site. The process and specifications are well combined, so that when I find a problem, I always feel that there are some discrepancies. Therefore, for existing problems, I have experienced masters on site and colleagues with rich work experience, and I have searched through the Internet. Through many times of communication with their video tutorials, their careful explanations, and my own study, I was able to further clarify the construction site and specifications. Therefore, it is clear that when starting work, there are flaws in one's own knowledge, resulting in some shortcomings due to poor consideration. So far, in half a year of internship, after half a year of humbly asking for advice and careful explanations, the problems existing in my own learning have been solved, so that I can better use my strengths to make up for my weaknesses, check for omissions and improve my cognitive problems. , and also allowed me to further realize that I am just starting out and have limited work experience. I cannot deeply understand the different specifications that need to be applied to each different construction site. Unable to combine the theoretical knowledge learned with practice well. Although the outside world is wonderful, if you don’t have the strength, you will become the wonderful person of others, rather than the wonderful person of others. "Practice is the only criterion for testing truth." The internship is a mirror, which can reflect the results of my study; the construction company carrying out the construction is a mirror, which can reflect the strength of the company; the local construction level is a mirror, which It can reflect the current situation of the development of China's construction industry; the development of China's construction industry is a mirror, which can reflect China's position in the construction industry of various countries around the world! I am happy to have successfully completed the internship, and even more proud to contribute to the development of China's construction industry in the future!

2. Explanation of job responsibilities

The position I am engaged in during this social practice can be said to be a technician.

Technicians must first have strong drawing and calculation abilities, and secondly, the ability to lead and direct workers to perform correct and safe construction. Furthermore, technicians must also have the ability to flexibly handle unexpected problems and correct drawing errors. Technicians can be said to be the soul of the entire project, and every step of construction is inseparable from technicians.

I think the basic process of this construction can be divided into five stages: the first stage is drilling, the second stage is pouring concrete, the third stage is ground beams, and the fourth stage is columns. The fifth stage is capping the beam, the sixth stage is erecting the beam, the seventh stage is tension grouting, the eighth stage is wet joint wet joint, and the ninth stage is bridge deck paving. There are also other facilities such as guardrails, baffles, scaffolding, etc. The technicians have to lay out the wires, spring the wires, level them, guide the workers in correct construction, and work with the foremen to ensure that the welders, steel workers, carpenters, electricians and scaffolding workers can perform correct and orderly construction.

As a technician, I deeply appreciate his hard work and responsibility. The position of technician is very good at training people.

3. Sharing

The formation of every bridge is a process of accumulation. Some people compare the construction process of bridges to the growth process of people. This is a very vivid example. Only a bridge with a solid foundation can support the road to the sky, and a person with a solid foundation can stand tall and strong. Let us share the growth process of this huge bridge.

Step one: drilling

Process flow; measuring and setting out → drilling preparation → drilling excavation → vehicle transporting soil

Construction points:

1. Before drilling construction, the amount of drilling work must be calculated, that is, the amount of drilling work. Based on the project scale, construction period, soil performance and existing mechanical equipment conditions, rotary drilling is selected and a construction plan is drawn up.

2. After the earthwork calculation is completed, the allocation of earthwork can be started. Earthwork allocation is a comprehensive and coordinated treatment of the relationship between the utilization of excavated soil, the disposal of waste and the acquisition of fill soil. A good earthwork allocation plan should minimize the amount or cost of earthwork transportation and facilitate construction.

3. In order to prevent collapse and ensure construction safety, when the depth of hole excavation exceeds a certain limit, the soil wall should be protected by a casing or mud should be added.

4. Commonly used construction machinery for earthwork construction include bulldozers, shovels, single-bucket excavators, loaders, etc. Construction machinery should be selected correctly during construction to speed up the construction progress.

Step 2: Pile foundation

Process flow: C30 concrete cushion→C25 ground beam

Construction points:

1 , This building uses a reinforced concrete structure, and the foundation is a cylindrical foundation.

2 The cylindrical foundation includes a reinforced concrete independent foundation under the column and ground beams. This kind of foundation has good bending resistance and shear resistance, and can be used when the vertical load is large, the foundation bearing capacity is not high, and it can withstand loads such as horizontal forces and moments.

Step 3: Pier columns

Process flow: structural column steel bar binding → measurement and laying out → formwork erection → concrete pouring → watering and curing.

The third step is to tie the beam, the fourth step is to cover the beam, the fifth step is to erect the beam, and the sixth step is to pave the bridge deck...

4. Impact on construction Progress factors

1. Weather factors: Due to rain during the construction process, the construction progress was delayed.

2. Material supply: ①The most basic supply is the supply of water and electricity. ②The supply of cement, stone, sand and other materials affects dusting. ③The supply of gravel affects earthwork backfilling. ④The supply of acetylene and oxygen affects the cutting and welding of electrical and plumber materials. ⑤ The supply of steel bars affects the preparation of materials, thereby affecting the binding of piers, cap beams, and other steel bars. ⑥The supply of iron pipes, fasteners, etc. affects the erection of scaffolding by scaffolders. ⑨ The supply of steel formwork and wood affects the erection of formwork by carpenters.

3. Mechanical factors: Machinery such as cranes are more important. Scaffolding and steel bars need to be hoisted by cranes. If the crane fails, construction will stop.

4. Personnel factors: The number of personnel directly affects the construction speed, but too many personnel will cause a waste of manpower, and too few personnel will slow down the construction speed.

5. Management factors: The technical guidance of technicians and the deployment management of foremen also have a great impact on the construction speed.

5. Construction Safety and Construction Personnel Safety

The factors that affect construction safety are intricate and complex. In addition to the mutual interference and influence of many factors in the construction itself, there are also technical issues in the project, and the quality of the materials. Quality issues, project economic issues, etc. all restrict the safety of buildings from different levels. Engineering safety is not only an engineering technical issue, but also a social and economic issue. It is closely related to people's lives and involves the development of social economy and the progress of human society. Therefore, in every aspect of construction project design and construction, while pursuing the economic and social benefits of the project, we must remember: safety is the eternal theme of project construction! In addition to construction knowledge, what impressed us most was the safety issue. Every construction unit has the slogan "Safety First". As engineering personnel, we should try our best to avoid safety accidents. We should not only strictly enforce rules and regulations, but also instill safety knowledge into employees and be responsible for their life safety.

6. Construction Supervision Organization

Since 1988, my country has begun pilot work on the construction project supervision system in the construction field and gradually implemented it five years later. In 1997, the "Construction Law of the People's Republic of China" stipulated in the form of a legal system: "The state implements a construction project supervision system", thus bringing construction project supervision into the implementation stage nationwide. It is a major reform of my country's engineering construction management system and has had a profound impact on the management of my country's engineering construction. The important contents of construction project supervision are summarized as: "three controls, two managements, and one coordination", which not only controls the investment in project construction, construction period and project quality; manages project construction contracts and information; and coordinates the relationship between relevant units.

Construction products have the characteristics of high value and long service life, and are related to people's life and property safety and healthy living environment. Project supervision companies accept the entrustment of construction units, serve construction units, and supervise and manage the production process of construction projects from the perspective of product demanders. Adopt the management method before, during and after the event to strictly supervise and inspect the quality of materials, devices, components and sub-projects, and the quality of the sub-projects to ensure project quality and use safety.

Relatively formal supervision companies have high-quality personnel, sound corporate management systems, and excellent corporate cultures. Some supervision companies have aging personnel and outdated knowledge, and are no longer able to adapt to today's supervision activities. There are also supervisors who neglect their duties. It is to the benefit of the construction unit that they do not perform their supervisory duties seriously and do not serve the construction unit well. I believe that such irregular and informal phenomena will continue with the opening of the market and the improvement of the legal system. And get solved!

7. A few touches

Touch 1: No matter it is cloudy or sunny, no matter how high the temperature is, construction workers must go to work on time and work under the scorching sun. Some People also suffered from heat stroke, but their wages were not much. Some people said to me: "Kid, study hard! It's easy to make money with knowledge, don't suffer from us." Yes, compared to them, our study and life are simply paradise! We must cherish our time and work hard to learn professional knowledge, otherwise we will not even have a chance to regret it in the future.

Touch 2: The construction unit is divided into many types of work, such as welders, carpenters, electricians, scaffolders, steel workers and small workers who do odd jobs. During construction, each type of work cooperates with the construction, and everyone complements each other. It shows a harmonious and pleasant atmosphere.

Touch 3: The master constantly taught me knowledge and reminded me of what I should pay attention to while at the construction site. I thought that I knew everything when I felt good, so I started to be careless. A construction site master asked me several questions in succession, but I couldn't answer any of them, and those questions were all clearly marked in the specifications. I was told by him that it seemed that I had to be serious when doing things, otherwise very embarrassing things would happen if I wasn't careful.

Touch 4: There are several female workers among all the workers, and they do no less work than men. When I asked her why she didn't do jobs like selling clothes and cosmetics, she said: "That job makes less money, so I do this just to earn more." Looking at her busy figure, I was attracted by her kind of work. Deeply touched by the spirit of not being afraid of hardship. Although she is admired by all workers, she envies me even more because I will not be so tired in the future and will receive more wages than her. Thinking of this, I became more determined to learn professional knowledge.

8. Construction experience and insights:

After entering the construction site, I personally experienced some construction steps, such as dusting, leveling, steel bar bending, stirrup making, and tying and rolling. Reinforcement bars, measuring and setting lines, elastic lines, etc. Through personal experience in construction, I understand that no job is easy. I watched the steel workers making the steel cages quickly and easily, but I couldn't even hold a steel bar with one hand. It seems that we must study professional knowledge seriously. Only by deeply understanding this profession can we make good bridges. If you don't touch the steel bars, you will never know how much the weight of a steel bar will affect you. If you don't practice, you won't understand the complexity of construction. What is the difference between pile groups and single-row piles for bridge pile foundations

Pile groups are arranged in multiple rows or plum blossoms and are suitable for single-pier foundations;

Single-row piles, as the name implies, have only one row and are suitable for Foundation reinforcement under steel structures or culvert load-bearing walls. Bridge pile foundation reinforcement

None