SACRAMENTO, CALIFORNIA – The American River Bridge on the Capital City Freeway connects commuters to medical centers, employment opportunities, and activity hubs in downtown and eastern Sacramento. This multi-span, 1.5-mile bridge was constructed in 1954 and widened in 1965 to six 12-foot northbound and southbound lanes, with minimal inside and outside shoulders.

Today, the bridge has a deteriorated concrete deck that is in need of repair and in need of additional lanes to allow pedestrians to cross the American River. Because of this, the California Department of Transportation (Caltrans) spearheaded a $200 million bridge rehabilitation project that includes removing and replacing the existing concrete deck, widening the bridge, and adding a bike and pedestrian path.

Construction began in 2022 and is expected to be completed in 2026. Conco Pumping began working with American River Construction (ARC) to pour the four piers for the bridge that are located in the American River in late 2022 and expects to begin pouring the new deck in late 2023 or early 2024.

 A difficult setup

Due to financial considerations, the project required ARC to install floating work platforms, or barges, to facilitate construction activities within the river. To accommodate this unusual setup, ARC selected Conco Pumping as their concrete pumping contractor. Conco chose two Putzmeister boom pumps for this complicated project: the 39Z-Meter truck-mounted concrete boom pump and 38Z and 36M placing booms that were used in different phases of the job.

ARC and Conco set up the Putzmeister placing boom equipment on a barge and pumped across a 700-foot gangway built between coffer dams from a trussell with a 39Z boom truck equipped with Putzmeister’s high performance pump kit. The 39Z is equipped with the 13 HPD pump kit and was chosen due to its robust design to withstand high-pressure high-rise job site conditions, as well as long-distance pumping that was required for this project.

A close partnership

ARC engineers collaborated with Putzmeister’s engineering department to design and implement a specialized setup, attaching the placing boom to the barge. Once Conco and ARC received confirmation that the plan was viable, it took approximately six days to construct and set up the equipment on the custom-made framework on the barge.

Another challenge faced by Conco and ARC involved building around 700 feet of pipeline to facilitate the concrete pumping from the trussell to four different pier locations. Con Forms provided a delivery line comprising a robust 5-inch, 0.25-inch thick pipe, heat-treated for a high-pressure rating and low wear resistance. Con Forms also supplied all the necessary clamps, hold-down brackets, and diverter valves required to couple and anchor the delivery line to the trussell and gangway, connecting the concrete pump to the placing boom.

Concrete Pours

The Conco ARC team successfully executed three pours for each of the four piers. The initial pour involved a 150-yard slurry seal at the base of the coffer dam, facilitating dewatering and creating a dry area for footing construction. The second pour comprised an 180-yard footing application. The third and final pour necessitated approximately 350 yards of concrete for the pier wall, executed at a continuous rate of around 30 yards per hour over 12 hours starting at 1 am to achieve a consistent flow of ready mix. Undertaking the work during the nocturnal hours capitalized on lower temperatures, thereby reducing the concrete’s set time within the pipeline.