According to the arrangement of the school, I went to Fujian Xintai Construction Co., Ltd. on March 2, 20xx for the construction and management practice of the first phase project of Liyuan Square in Zhangzhou City. This is a good opportunity for me to understand the structure and differences between theory and practice. The tense two-month internship life is over. Under the leadership of the company's chief engineer and the explanation of the on-site engineer, I still gained a lot in the internship process. The following is my harvest and experience in the internship.
First, through this internship, I will have a perceptual knowledge of this major from practice, and lay a solid foundation for future professional study. Not only let us learn a lot of knowledge that we can't learn in class, but also broaden our horizons and increase our knowledge, laying a solid foundation for us to better apply what we have learned to practical work in the future. Through production practice, I can get more in-depth contact with professional knowledge, further understand the importance of reasonably controlling the cost of construction projects, understand the problems existing in the process of project construction management and the difficult problems that conflict between theory and practice, and write an internship report, so that I can learn to comprehensively use what I have learned and improve my ability to analyze and solve professional problems.
Second, through the introduction of the company's chief engineer, I have a basic understanding of the main person in charge of the site and the general situation of the project. Fujian Xintai Construction Co., Ltd., where I worked as an intern, is a first-class construction enterprise. Buildings 4, 5, 7 and 8 of the first phase of Liyuan Plaza in Zhangzhou City, which our company undertook, are located on the north side of the middle section of Nanchang Road, with frame-shear structure, underground 1 floor, 27 floors above the ground in Buildings 4 and 5, and 19 floors above the ground in Buildings 7 and 8, with a total construction area of 192030. During the internship, the project is in the construction stage of pile foundation and basement.
Third, through this internship, I realized that the construction unit should reasonably control the project cost and do the following:
(1) signing of the project contract. A project contract is an agreement between the project construction unit and the construction unit on the rights and obligations related to the project. The signing of the project contract is an important barrier for the construction unit, because the project contract not only clearly stipulates the rights and obligations of the construction unit and the construction unit, but also contains important contents such as quality grade, construction period, materials used, price and payment term, which has a very direct impact on the project cost. If the content of the project contract signed by both parties is complete, the logic is strict, and the rights and obligations of both parties are equal, the final project cost may be reasonable, otherwise, the cost may be low and the construction unit may suffer losses.
2 engineering change visa release. Engineering change refers to the owner's changes to the original drawings according to the needs in the process of engineering construction. Because the original drawings have been changed, it will inevitably lead to the change of engineering quantity and the increase or decrease of the original contract price. In particular, some projects have changed greatly, and the increase or decrease of engineering quantity has changed greatly. The final settlement basis is only based on the change of visa of the representative of the construction unit, so it is particularly important to change the visa clearance. It can be said that whether the project change visa is timely and accurate directly affects the project cost.
(3) Project final accounts audit. Project final accounts refer to the settlement data including all quantities and all prices compiled by the construction unit after the project is completed and accepted. Prepared by the engineering construction unit, the construction unit for preliminary examination. Finally, the construction unit entrusts a qualified social intermediary agency to conduct an audit and issue an audit report. Project final accounts audit is the last link of capital construction management activities and the last level of project cost control, so the construction unit must attach great importance to it.
Four, engineering construction technology experience:
As soon as I attended the blue prints.the design, I understood the main contents of the blue prints.the design.
Before the general project starts, the owner, design unit, contractor and quality supervision unit should all participate in the blue prints.the design, so as to find and solve the problems such as mistakes and contradictions in design, vague concepts in construction and possible difficulties in future construction, and avoid unnecessary losses in construction. The joint hearing should pay attention to the following points:
First, find out the defects and mistakes of the drawing itself. Review whether the drawing design conforms to the relevant national policies and regulations (architectural design, structural design, construction specifications, etc.). ); Whether the drawings and descriptions are clear and the reference standards are accurate; Whether there is any mistake or omission in the construction drawing standard; Whether the size, plane position and elevation of the general plan and the construction drawing are consistent, and whether the relationship between the plan, elevation and section is consistent; Whether the design of each professional post is coordinated.
Second, the feasibility of construction, combined with the characteristics of drawings, in the construction process, study whether the drawings can meet the requirements of drawings in terms of quality, safety, construction period, technology, material supply and even economic benefits, and suggest the design unit to make appropriate modifications when necessary.
Third, whether the geological data are complete and can meet the requirements of the drawings; Whether the surrounding buildings or environment affect the construction of this building, etc. Whether the functional design of construction drawing meets the requirements of the construction unit, etc. , is the main content of the blue prints.the design.
Summarize drawings and other issues to prepare for joint examination, and the technical director of the project will convene relevant personnel to conduct internal preliminary examination. In order to better understand the designer's design principle, I consulted the relevant atlas, made an in-depth study of the drawings, raised many insightful questions, and had a heated discussion with the construction technicians, trying to figure out what I didn't understand. I found that the most important thing is that it doesn't conform to the atlas except the size and reinforcement of the structure, and I found that the doorway on the shear wall is also easy to make mistakes.
Secondly, through the practice in the construction site, I learned a lot about the technical points of basement construction. Here I summarize the construction technology of concrete for large pile caps.
The concrete construction of large pile cap (core tube) adopts layered inclined plane reverse pouring method. In order to ensure the quality of concrete pouring, in addition to the compactness of concrete, three key technical problems must be solved: first, when concrete is supplied and poured, the internal layers of concrete should be well combined without construction cracks; Secondly, the "three admixtures" technology and thermal insulation control are adopted, and the later strength of concrete is used to reduce the amount of cement, reduce the internal hydration heat of mass concrete, and prevent the concrete structure from cracking due to excessive temperature difference between inside and outside; Third, we should strengthen concrete curing measures to ensure the growth of concrete strength in the later period.
Concrete mix design adopts "three admixtures" technology. Among them, the addition of Grade II fly ash can reduce the peak hydration heat, reduce the dosage of cement, increase the pumpability, ensure continuous pumping and pouring on site, and add UEA expansion agent to prevent cracks from concrete shrinkage and enhance the self-waterproofing ability of the structure. Adding superplasticizer can improve workability, reduce evaporation channels generated by free water and improve concrete compactness.
From the performance of concrete, it can be seen that plastic shrinkage cracks are easy to occur on the surface of concrete, which generally occur before the final setting of concrete, and because of the limitation of steel bars and coarse aggregate, the particles in concrete settle unevenly, and irregular harmful surface cracks will also appear. In order to prevent this kind of crack, when the concrete is poured to the design elevation, it will be vibrated with a vibrator for compaction, and when there is laitance on the surface, it will be leveled with a trowel immediately. Before the final setting and hardening of concrete, use a wood trowel for continuous leveling, seal the concrete surface to prevent bleeding and shrinkage cracks, and at the same time cover and maintain the concrete to avoid the wind and sun, so as to eliminate harmful surface cracks caused by uniform settlement of particles inside the concrete.
In order to avoid cracks caused by excessive temperature difference between the inside and outside of mass concrete, concrete curing adopts thermal insulation and moisturizing composite insulation layer, that is, the concrete surface is covered with a layer of plastic film, the middle two layers of wet sacks, and the upper two layers of dual-purpose plastic films are covered and compacted to prevent rain from wetting the sacks and reduce the thermal insulation effect. Moreover, it is not suitable for water curing before the final setting and hardening of concrete, and covering is beneficial to evaporate water with the water-cement ratio of concrete to achieve the purpose of curing; After concrete pouring for 5-7 days, the concrete is in a cooling state. At this time, the film and sacks are peeled off layer by layer, leaving only one layer of sacks, which shall be watered and maintained by special personnel for not less than 14 days. After this treatment, we carefully inspected the site. No construction cracks were found on the surface of the basement concrete, and the appearance met the quality requirements, indicating that the basement concrete reached the expected maintenance goal.
Although technical measures have been taken to reduce concrete cracks in the mix ratio, due to the large temperature rise of cement hydration heat and poor heat preservation and maintenance at the peak of heat dissipation after pouring, the temperature difference between inside and outside of thick mass concrete such as concrete cap and bottom plate will still be too large, and the surface concrete will shrink too much, resulting in tensile stress exceeding the tensile limit of concrete, which will lead to deep cracks in concrete, even through cracks, making the basement concrete unable to achieve the function of impermeability and waterproofing. In order to ensure that the temperature difference between inside and outside the basement concrete is controlled within 25℃ specified in GB50204-2002, the components with the thickness of concrete structure above 1000 mm can be embedded with circulating water pipes. After concrete pouring, according to the temperature difference between inside and outside the concrete measured by the temperature monitoring system, the circulating water quantity is adjusted to reduce the temperature difference between inside and outside the concrete.
In order to accurately grasp the law of temperature fluctuation of mass concrete, the temperature difference between inside and outside the concrete is strictly controlled within 25℃, and temperature measuring points with different depths are set in the concrete along the height direction, and one temperature measuring point is arranged every m2 on the plane. The selection of temperature measuring points is representative and can reflect the temperature of various parts of mass concrete in the basement. Temperature shall be measured 20 hours after concrete pouring, once every 4 hours, and recorded. * * * will be measured on the first 10 day, and the main content of temperature measurement is to determine the difference between the concrete core temperature and the surface temperature (
To sum up, I have learned a lot of practical knowledge through two months' internship and practice. The so-called practice is the only criterion to test the truth, which allows me to observe the construction process of the basement at close range and learn a lot of applicable and specific construction knowledge, which is often very important basic knowledge that I seldom contact and pay attention to at school. I combine the theoretical knowledge I have learned with practice and keep learning, summarizing and making progress in practice.
I recommend it carefully.