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We are currently offering technical materials from Crittec Industries Co., Ltd. titled "Expansion Device Explanation Series - Types of Expansion Devices." This includes a classification of structures and introduces the characteristics of each with illustrations. [Contents] ■ What is a finger joint? ■ What is a buried joint? ■ Others *For more details, please refer to the catalog. Feel free to contact us with any inquiries.

We are currently offering technical materials from Crittec Industries Co., Ltd. titled "Expansion Device Explanation Series - Structure of Expansion Devices." This includes an introduction to the classification of structures, their respective features, and the locations where they are used, along with illustrations. [Contents] ■ Classification of Structures ■ Features of Butt Joint Type ■ Features of Load Support Type *For more details, please refer to the catalog. Feel free to contact us with any inquiries.

Expansion devices can be broadly divided into three types: by structure, by material, and by function. Each device has different characteristics, such as high shock absorption and ease of maintenance. Therefore, it is very important to understand the merits of each device in order to choose one that fits the environment of the bridge or road where it will be installed. This article introduces the types of expansion devices and explains their characteristics and advantages. By reading the article, you can get a general idea of what types of devices are available. *For detailed content of the column, please refer to the related links. For more information, feel free to contact us.*

The lifespan of a bridge is greatly affected by the water-stopping performance of the expansion device. While it is natural to require the water-stopping performance of the main product (primary water stop), recently there have been increasing cases where the installation of "secondary water-stopping materials" is requested in case the primary water-stopping performance of the main body deteriorates. Therefore, I would like to explain the "purpose" of the secondary water-stopping materials related to the water-stopping performance of the expansion device and provide "introductions to products from various manufacturers." *For detailed content of the column, please refer to the related links. For more information, feel free to contact us.

An expansion joint is a device used to fill the gaps found in bridges and highways. If there are gaps in a bridge, it can cause issues when vehicles pass over it, so these joints are installed to cover the gaps and allow for a comfortable passage. However, although they are referred to as coverings, they are not simply metal plates that cover the gaps. There are other roles that an expansion joint is required to fulfill, and manufacturers produce and handle products that meet the necessary quality and functionality. This article explains the roles that expansion joints play. It also summarizes the types of expansion joints and manufacturers, so by reading it, you should gain a general understanding of the topic. *For detailed information, please refer to the related links. Feel free to contact us for more information.*

It refers to the components installed between the upper structure of the bridge (main girder/main frame) and the lower structure (abutments and piers). Also known as "kutsu," it is called "bridge bearing" in English. These components accommodate the expansion and contraction of the girder due to temperature changes and the deflection caused by live loads, and since they constantly support the bridge girder, they are a very important part. A bridge that connects the upper structure directly to the lower structure without installing bearings is called a rigid-frame bridge. *For detailed information about the columns, please refer to the related links. For more information, feel free to contact us.

The ground cover refers to the foundation of the bridge's railing and the horizontal material that is installed adjacent to the road. In typical roads, gutters are installed to drain rainwater, preventing overflow onto the road surface. This road gutter is similarly installed on bridges, designed to ensure smooth drainage even on elevated roads, with the ground cover fulfilling that function. *For more details, you can view the related links. If you have any questions, please feel free to contact us.*

A PC bridge refers to a bridge constructed using prestressed concrete. It has a higher strength compared to reinforced concrete bridges, making it suitable for longer spans. Additionally, PC bridges are categorized into different types based on their structure, each with its own characteristics. Therefore, it is necessary to install them according to the usage environment, which requires an understanding of each characteristic. This article summarizes what a PC bridge is, including its advantages. It also introduces the differences between PC bridges and steel bridges, so please refer to it as foundational knowledge about PC bridges. *For detailed content of the column, you can view it through the related links. For more information, please feel free to contact us.*

The hybrid joint is an expansion device manufactured by our company. Expansion devices vary in performance and elasticity depending on their type, so it is necessary to choose one based on the bridge or road where it will be installed. However, the hybrid joint can be used in any location and has high durability, allowing for long-term use. In this article, we will introduce the features of the hybrid joint along with product examples and photos. Please use this as a reference when selecting an expansion device. *For detailed information in the column, please refer to the related links. For more information, feel free to contact us.

Rubber joints are one type of expansion device, primarily made from rubber and sealing materials. Basically, the device itself cannot support the weight of a vehicle, so it is often installed in places like sidewalks or areas with low traffic. However, rubber materials are easy to maintain after installation and have the characteristic of reducing the impact on vehicles passing over them. Therefore, it is common for expansion devices to be made not just from rubber alone, but in combination with steel materials. *For more detailed information, please refer to the related links. For further inquiries, feel free to contact us.

A finger joint is one type of expansion device installed at the joints of bridges and highways. It is made of steel and is characterized by its comb-like appearance, and it is a device that has been used for a long time. In this article, we will explain the features of finger joints based on three key points. It summarizes basic knowledge such as appearance and structure, so by reading it, you will grasp the overall outline. *For detailed content of the column, you can view it through the related links. For more information, please feel free to contact us.*

A bridge is a structure built over rivers, valleys, seas, and roads, designed to provide a transportation route across to the opposite bank. Bridges have a long history of development alongside humanity, and today there are various types. Additionally, the characteristics of these bridges differ based on their structures, so construction must be tailored to the environment in which the bridge is installed. This article explains the structures and types of bridges. *For more detailed information, please refer to the related links. Feel free to contact us for further inquiries.*

A bridge girder refers to the part where people and vehicles pass. It is a major component of the bridge and is constructed using materials such as concrete and steel. Additionally, the impact on the bridge girder varies significantly depending on the scale of the bridge and the environment in which it is installed. Therefore, there are various types of bridge girders designed to accommodate these factors, each with its own characteristics. This article introduces what a bridge girder refers to, accompanied by illustrations. It also summarizes the types and structures of bridge girders, so please use it as foundational knowledge about bridges. *For detailed content of the column, you can view it through the related links. For more information, please feel free to contact us.*

The abutments and piers are the substructures that support the superstructure of a bridge. The abutments are also referred to as abutments, and the piers are called piers. Expansion devices are installed between the ends of the girders and the parapets on the abutments. When the ends of the girders are on the piers, expansion devices are installed, but these expansion devices are only placed between the girders and do not affect the piers. *For detailed information on the columns, please refer to the related links. For more information, feel free to contact us.*

At the base of the abutments and piers, foundations are established to transfer the load of the bridge to the ground. The foundations are classified into three types based on their construction, each with distinct characteristics. This article explains the types and features of bridge foundations. Additionally, we have summarized the usage ratios of each foundation and their trends, so please use this information as knowledge about bridges. *For detailed content of the column, you can view it through the related links. For more information, please feel free to contact us.*

Steel deck plates have the advantage of being able to lighten the bridge girders themselves. Additionally, they are valued for their ability to significantly shorten construction periods, but care must be taken when installing expansion devices. This article explains the characteristics of steel deck plates and the key points for installing expansion devices. We also introduce expansion devices that can be used with steel deck plates, so please refer to this as a guide for selecting devices. *For detailed content of the column, you can view it through the related links. For more information, please feel free to contact us.

When an expansion joint is installed, gaps are created around it. The material used to fill those gaps is called joint material (elastic sealant). Joint material is used to prevent water leakage, but on its own, it does not have very high durability. Therefore, depending on the requirements for the bridge, other methods may be used in combination with joint material. This article explains the role and characteristics of joint material for expansion joints, and also summarizes methods to supplement sealants. *For detailed content of the column, you can view it through the related links. For more information, please feel free to contact us.*

The installation of expansion joints differs depending on whether they are newly installed or replacing existing ones. Additionally, whether the device is set up first or later, as well as the type of device being installed, also affects the process, making the steps surprisingly complex. In this article, I have summarized the basic methods of installation based on the new installation of expansion joints. I have also explained the key points and precautions for each installation, so you will have a solid understanding of the overview after reading it. *For detailed content of the column, you can view it through the related links. For more information, please feel free to contact us.

One of the functions required of expansion joints is water-tightness. High water-tightness not only extends the lifespan of bridges but also reduces lifecycle costs, providing many benefits. However, the water-stopping materials that fulfill this role are very susceptible to damage and are a major cause of leaks. Therefore, various measures are being implemented by manufacturers to maintain the water-stopping materials for as long as possible. This article explains the role of water-stopping materials in expansion joints and the types of water-stopping materials. *For detailed content of the column, please refer to the related links. For more information, feel free to contact us.*

The replacement of expansion joints requires thorough on-site investigation and construction tailored to the situation. Since the construction time is limited to one day, schedule management is also very important. Additionally, there are many points to consider that differ from new installations, such as the height of the installation and the area of concrete removal. This article summarizes the flow and key points related to the replacement of expansion joints. Please refer to it as preliminary knowledge before the construction. *For detailed content of the column, you can view it through the related links. For more information, please feel free to contact us.*

The expansion and contraction of a bridge is very important information when selecting expansion devices. Bridge girders expand and contract regularly due to changes in temperature. To accommodate this, expansion devices are installed, making the calculation of expansion and contraction very important. However, the amount of expansion and contraction is not determined solely by temperature changes. It is complex because various conditions, such as drying and deformation due to loads, must be taken into account. In this article, we will clearly explain how to determine the expansion and contraction of bridge girders. We have summarized the key points and main ideas, so you can grasp the overall concept. *For detailed content of the column, please refer to the related links. For more information, feel free to contact us.*

The expansion and contraction devices can be broadly divided into drainage type and non-drainage type. When these devices first started being installed, the drainage type was used, but over time, the non-drainage type has become the mainstream. The difference between the two lies in whether or not water leakage measures are implemented. However, due to the infrastructure development policies set by the government, most manufacturers have started producing non-drainage types. This article introduces the differences between drainage and non-drainage types as well as their usage ratios. Additionally, we have summarized the mechanisms that enhance the functions of the devices, so please refer to that as well. *For detailed content of the column, you can view it through the related links. For more information, please feel free to contact us.

Buried expansion devices, unlike other joints, are not visible from the road. Since they are embedded in the pavement, they are integrated with the road, resulting in minimal noise and vibration. Additionally, maintenance is relatively easy, and over the long term, costs can be significantly reduced. As a result, they are increasingly being installed in small to medium-sized bridges. This article explains the features and benefits of buried expansion devices. We will also introduce the manufacturers producing them, so you can grasp all the details. *For more detailed information, please refer to the related links. Feel free to contact us for further inquiries.*