Precast concrete was optimally implemented in this innovative structural project, which involved constructing a BEBO-type arched culvert over the Blough River on Route 389, 125 km from Fermont, in the Côte-Nord region.

Combining performance and elegance, this patented and standardized structural solution benefits from its speed of installation. The Blough River culvert consists of 34 BEBO-type arches (68 half-arches installed in two sections) and footings. All of the elements that make up the structure were manufactured in the factory under controlled conditions. This approach ensures uniform quality and increased precision while contributing to the overall sustainability of the work.

To carry out the work, an additional challenge, the temporary diversion of a significant watercourse, was necessary. Clever production logistics combined with an efficient installation sequence allowed this project to evolve at an astonishing speed despite the constraints linked to its geographical position and terrain characteristics.

BEBO arches are gaining ground in engineering and infrastructure construction. This precast concrete arch system, used for the construction of short-span bridges, tunnels, culverts, and other underground structures, is appreciated for its technical as well as aesthetic advantages, providing both functionality and visual appeal.

Note: the name BEBO is taken from the word “BEtonBOgen,” which means concrete vault.

The use of the BEBO construction system in constructing the Blough River culvert in the Côte-Nord region showcases the incredible versatility of precast concrete. This system, undoubtedly the structural solution par excellence in this project, demonstrates its adaptability and resilience.

The BEBO Arch utilizes the soil-structure interaction between the arch, its reinforced concrete foundation, and the fill surrounding it to create a high-quality, durable bridge solution. The soil-structure interaction allows for less concrete and reinforcement than a traditional portal structure. In addition, the arch helps avoid soil compaction problems when approaching the structure since the transition from the embankment is more gradual. Finally, BEBO eliminates maintenance related to expansion joints on short-span bridges.

Typically, BEBO arch spans range from 3.7m to 31m and offer geometry with span-to-swing ratios as low as 10:1. The system's versatility makes it attractive for many applications. BEBO arches come in three types: elliptical (E), circular (C) and (T). The letter T means top since the foundation is in a high position compared to other types of structures.

The Blough River culvert is elliptical. The span of the arches is 16.5 m. The culvert comprises 34 arches (68 half-arches installed in two sections) and footings.

BEBO's advantages in this project can be observed on several levels, including the three main ones: economy, speed, and quality.

Economically, the arch sections are thin, which has reduced the amounts of concrete and reinforcement required compared to traditional structural solutions, such as gantries, box culverts and short-span bridges.

Regarding speed, the culvert structure was manufactured in the factory following pre-established design codes, thus speeding up the execution of the structural design. The thinner structures made transportation more accessible and, therefore, faster installation.

As for quality, the structure stands out for its durability, requiring no maintenance. It is characterized by the absence of a visible bridge deck, transition joints approach slabs, or movable supports, making it a masterpiece of ingenious aesthetics. Its refined design has received a very favourable reception from the authorities.

In addition, this initiative is part of a broader approach to promoting sustainable construction practices. By favouring corrosion-resistant materials and optimizing the use of resources, precasters are actively engaged in reducing the environmental footprint of their projects. This ecological approach is not only limited to the preservation of the culvert but also contributes to the protection of riparian ecosystems, thus reinforcing the commitment of stakeholders to responsible and environmentally friendly construction.

Project Parameters

• Project size: 63 meters long culvert, 16.5 meters span
• Concrete quantity: 420 m3, 1360 m2, 1000 T.M. (arches) and 475 m3, 490 m2, 1140 T.M. (footings)
• Reinforcing steel quantity: 53 tons of steel (arches) and 26 tons (footings)