STANDARD TECHNICAL STOP CIRCUIT CONSTRUCTION METHODS
In construction activities, a term that people in the profession often use is underground circuit. So what is a stop circuit? How is the standard technical stop circuit construction method performed? All will be revealed in the article below, let's refer to Hung Nghiep Phu right away!
1. What is a stop circuit?
1.1. Concept of circuit stop
Stop joints are interruptions in concrete construction located at certain locations. At these locations, the next layer of concrete is poured when the previous layer of concrete has hardened.
Mạch ngừng chính là vị trí gián đoạn trong thi công bê tông được bố trí ở một số vị trí nhất định.
In construction, the stop joint is the weakened position of the structure of the monolithic reinforced concrete. Therefore, the size of the stop joint must be as optimal as possible: the stop joint length is the shortest; the stop joint is as straight and has as few bends as possible; the stop joint surface must be perpendicular to the structural axis so that the stop joint surface area is the smallest.
1.2 Origin of stop joints
When the previously poured concrete at this position turns into a solid state, new concrete must not be poured because it will break the joints formed in the concrete mortar. Therefore, you need to let the old concrete layer stabilize in the concrete mold and completely solidify before pouring a new layer.
It is because of the above activities that concrete stop joints are formed at the temporary stop position. Stop joints affect the overall bonding of the concrete, so you need to continuously perform construction to avoid them.
In case of having to stop the joint, its position must be in a structural area with small internal forces, not causing danger to the structure at the joint section. You should add reinforcement to the joint to limit the weakening caused by them. Therefore, the size of the joint must be reduced to the maximum level as follows:
- The joint should be as straight and as bend-free as possible.
- The joint surface must be perpendicular to the structural axis so that the joint surface area is the smallest.
2. Technical standard circuit construction method
2.1 Downtime
-
The stop joint is the boundary between the old concrete layer and the new concrete layer. During the construction phase, these two concrete layers will have two different strengths (R1: strength of the old concrete layer. R2 strength of the new concrete layer).
If the stop time is too long, R1 > R2 limits the adhesion between the two layers before and after. If the stop time is too short, R1 is very small, during the construction of the second concrete layer, it will cause cracks or chips in the poured concrete layer due to beams, traffic, or steel reinforcement...
The most suitable stop time is t = (20 ÷ 24)h, at which time the poured concrete layer will reach a minimum strength of R1 = 25kg/cm2.
Khi đổ bê tông mới, mạch ngừng cần phải được xử lý kỹ lưỡng để hai lớp bê tông mới và cũ bám dính vào nhau.
2.2 Circuit break location
- Requirements for creating stop joints: Stop joints must be flat and perpendicular to the direction of compressive force applied to the structure.
- For vertical stop joints: there must be a mold to create stop joints
- For horizontal stop joints, they should be placed 3cm to 5cm lower than the end of the formwork.
- The stop joint must be arranged in a convenient location for construction at the following locations:
- At the location where the direction of the force is changed.
- At the location with small internal forces, pay attention to small shear forces.
- At the location where the structure has a sudden change in cross-section.
- For compressive structures: The stop joint can be stopped at any location convenient for construction. Because when subjected to compression, the concrete layers will be pressed together, so it does not affect the working capacity of the structure.
- For flexural structures: The stop joint location does not affect the load-bearing capacity of the reinforced concrete structure. However, it should not be placed at the moment location; there is a tendency to separate the two concrete layers separated by the stop joint in the tensile zone.
- Shear structures: Causing the two concrete layers to slide on each other, which is very dangerous for the structure. Therefore, the stop joint must be placed at a location with small shear force.
2.3 Circuit Breaker Handling
When pouring concrete, the stop joint needs to be carefully treated; so that the two layers of new and old concrete adhere to each other. Normally, construction units use some of the following measures:
- Clean and water cement on the surface of the old concrete layer; before pouring new concrete.
- Rough the surface, chisel out all the substandard concrete parts; especially in the vertical stop joint, then water cement. For horizontal stop joints, after roughening; apply a layer of high-grade cement mortar about 2/3cm thick before pouring new concrete.
- Use adhesive additives for stop joints.
- Pre-place steel mesh at the stop joint position when constructing the previous concrete layer.
3. Some factors affecting the number of concrete joints
- The level of load-bearing structure such as: short span, water permeability, etc.
- The capacity of the concrete mixer or mixing station.
- The construction site (Places with frequent traffic jams, densely populated areas).
- Human resources, equipment for a concrete pouring session, backup plans for equipment.
During the construction process, construction workers do not recommend too many concrete joints. Pouring concrete in one block is still preferred. In addition, you should also pay attention to the quality of the joints before pouring the next layer of concrete because cracks often appear at this location.
4. Introducing a reputable design & construction consulting service provider
The importance of construction units is undeniable, their reputation will ensure the quality and aesthetics of your project. Currently, there are many units providing design and construction services to meet the increasing construction needs in our country. Therefore, finding a reputable unit is not easy and requires you to spend time researching. In the selection process, you need to research carefully and ensure that the accompanying unit must have high expertise, many years of experience, have a clearly signed contract, transparent costs,... To help customers save time searching, Hung Nghiep Phu Construction Investment Co., Ltd. is confident that it will be the best choice for you.
Hung Nghiep Phu Construction Investment Co., Ltd. with the mission of providing the best solutions and services, building a prosperous community with customers, Hung Nghiep Phu is gradually affirming its brand through sincere cooperation, with a leadership team with ethical capacity, creativity, high expertise and strategic vision. Hung Nghiep Phu owns a team of skilled, highly qualified employees who will bring customers the best quality technology.
Hung Nghiep Phu Construction Investment Co., Ltd. - specializes in constructing civil and industrial works. We look forward to accompanying customers in construction projects as well as continuous procedures such as planning diagrams, applying for construction permits, completing procedures, applying for fire prevention and fighting certificates, ... If you have any questions or are in need of design, completing procedures, please contact us immediately for free consultation!
>>> See more:
_____________________
CONTACT INFO:
Facebook: Công ty TNHH Đầu tư Xây dựng Hưng Nghiệp Phú (興業富)
Hotline: 1800.3368 (Miễn phí)
Website: xaydunghunnghiepphu.com
Gmail: kinhdoanh01@xaydunghungnghiepphu.com
Address: No. 2034D, Group 22, Phuoc Thai Hamlet, Thai Hoa Ward, Tan Uyen City, Binh Duong Province
------
Source: Compiled from the Internet
