Hybrid Joint NS-LL Type: A Stretchable Device with Excellent Water Stopping Properties

The main shock of the Kumamoto earthquake that occurred in the early hours of April 16, 2016, caused the Aso Ohashi Bridge to collapse, significantly impacting local transportation. Following recovery efforts, the New Aso Ohashi Bridge was opened in 2021. In the New Aso Ohashi Bridge, structures that can accommodate future fault displacements have been incorporated, such as the use of a steel simple box girder bridge over the fault. Additionally, the expansion joints installed at the bridge's seams are designed to follow fault displacements. Our bridge expansion joint, the "Hybrid Joint LL Type," has been adopted for this New Aso Ohashi Bridge, contributing to the safety and functionality of the bridge while accommodating large displacements. Japan is a country prone to earthquakes, and bridge design requires ensuring safety against Level 1 seismic motion (earthquakes occurring during the service period) and Level 2 seismic motion (maximum class earthquakes). Moving forward, our company will continue to provide technologies that support the safety and security of social infrastructure.

This time, Crittec Industries has implemented changes to the product specifications and expanded the application conditions for the bridge expansion device "Hybrid Joint" in the "LL type (LL-125, LL-150, LL-175)." With this specification change, we have improved workability and made it possible to accommodate a wider slab gap than before. ■ Main Changes 1. Change in Anchor Rebar Arrangement To further enhance the structural stability of the product, we have optimized the arrangement of the anchor rebar. 2. Expansion of Applicable Slab Gaps By reviewing the design and structure, we have expanded the range of applicable slab gaps for each model. This increases flexibility in product selection during design and allows for adaptation to a wider range of bridge conditions. ■ Changes to Applicable Slab Gaps The numerical values for the applicable conditions (applicable slab gaps) before and after the changes for each model are as stated in the PDF of the release. ■ Future Developments With this specification change, the LL type has evolved into a product that can meet more severe conditions and diverse design needs. Our company will continue to promote technological development that contributes to the longevity of infrastructure.

Crittec Industries Co., Ltd. published a newspaper advertisement (black and white, full-page 15 columns) for the bridge expansion device "Hybrid Joint" in the February 26, 2026 issue of the Sankei Shimbun Tohoku 6 Prefectures edition. In Japan, the number of bridges over 50 years old is rapidly increasing, making the longevity of bridges a critical issue. The expansion devices, which are considered a cause of bridge damage, require high water-tightness and long-term durability. Our expansion device "Hybrid Joint" offers multiple types tailored to different bridge types and conditions. Among them, the "Hybrid Joint 3LII type" has demonstrated a durability of 100 years in fatigue loading tests conducted by a third-party organization. It has successfully passed 12 million cycles of repeated loading at a maximum load of 260 kN, confirming performance equivalent to a 100-year design service life for bridges. We have numerous delivery records in the six Tohoku prefectures and can accommodate a wide range of bridge types, including steel and PC bridges. The special website linked to the advertisement allows for the review of detailed materials and inquiries or requests for documents. Please make use of it for comparing and considering bridge renewal and repair plans. Crittec Industries will continue to contribute to the longevity of bridges nationwide, starting with the Tohoku region.