The article "Proving 100 Years of Durability" was published in the March 1, 2025 issue of "Bridge Communication." *The full article is available in the related PDF document. Please download and read it. We encourage you to take a look!* <Excerpt from the article> Crittec Industries announced that its main product, the expansion joint "Hybrid Joint 3LII-500," has been proven to have a durability of 100 years through fatigue loading tests conducted by a third-party organization. The 3LII type meets NEXCO specifications. The load support plate and anchor plate are designed as a vertical integrated structure, providing high durability and preventing damage from metal fatigue. In October to November 2024, using a fatigue testing machine at the Construction Machinery Construction Association's Comprehensive Research Institute, a third-party organization, it cleared a maximum loading weight of 260 kN for 12 million cycles. This is based on the assumption that a 25-ton large vehicle ran over the 3LII-500 for 12 million times, equivalent to a 100-year durability. According to the "Road Bridge Design Guidelines," the standard design service life for bridges is 100 years. For newly constructed bridges, there is no need to replace the expansion joints for 100 years. The 3LII type is maintenance-free, eliminating the need for traffic restrictions for sound inspections, thereby reducing maintenance costs and improving safety.

At Crittec Industries, we have developed a low-profile expansion device called the "TS type," with a product height of 75mm, and have begun manufacturing and sales. Given that our product delivery record started with highways, we believed that enhancing the durability of the product was a market need and have been advancing our development accordingly. While this is certainly not incorrect, it is undeniable that this led to somewhat over-specification in product development. For bridges that see a few light trucks passing daily, what is required is cost-effectiveness and compactness of the product rather than durability equivalent to that of highways. Particularly in older bridges, the thickness of the deck is thin, and existing products were too large to fit. Therefore, we have developed the compact TS type product. With a product height of 75mm, it often fits within the thickness of the pavement. In December 2024, we first installed the TS type at the Senami Bridge (Nishitama-gun, Tokyo). Due to the shallow notch depth, the installation was completed in a shorter time compared to conventional products. If you are looking for a low-profile product, please consider us!

The expansion device "Hybrid Joint Type 3LII" from Crittec Industrial has been proven to have a durability of 100 years! A fatigue loading test was conducted by a third-party organization. It successfully withstood repeated harsh loading, clearing the equivalent of 12 million cycles, which corresponds to 100 years. This aligns with the 100-year design supply period for bridges. Since there is no need to replace the expansion device for 100 years, it reduces lifecycle costs. Additionally, as it is a maintenance-free joint that eliminates the need for sound inspections associated with regulations, it also reduces maintenance costs. This is a revolution in expansion devices! The "Hybrid Joint Type 3LII," with its ultra-long-term durability of 100 years, is not a new product; it has already been widely adopted across national highways as a product that meets NEXCO specifications. We encourage you to adopt the "Hybrid Joint Type 3LII," which contributes to the longevity of bridges.

Our company's hybrid joint CS type for bridge expansion devices has been newly adopted by the Metropolitan Expressway Company. As a result, the CS type will be the only approved product for steel deck slabs on the Metropolitan Expressway going forward. The CS type is an expansion device specifically designed for steel deck slabs and has a proven track record, particularly in the Kanto region. On the Metropolitan Expressway, we have primarily supplied the hybrid joint RS type, which is similar to our standard products, the NS to LL types. Until now, we have installed products on steel deck slabs after careful consideration each time, but we have now officially received certification as an approved product through water stop testing and FEM analysis. Since it can now be used on the heavily trafficked Metropolitan Expressway, we will promote it further for use on a wider variety of roads. If you have any projects involving steel deck slabs, please feel free to contact us.

Our product, the hybrid joint 3LII-350 for bridge expansion devices, has passed the fatigue and waterproof tests specified by NEXCO. This product is classified as a "product joint" under NEXCO's classification, with an allowable expansion amount of 350mm and a maximum applicable gap amount of 730mm. Previously, the largest product joint available for use by NEXCO had an allowable expansion amount of 230mm and a maximum applicable gap amount of 415mm, so with this certification, our product is now the largest (according to our research).