PROJECT #1: Pouring a concrete footing for a bridge
Pouring a concrete footing in standing water requires a special method involving a tremie: a pipe with a cone-shaped feed hopper at the top of the tremie pipe above the water level. The tremie must be made from a rigid metal or plastic material and is generally 20 to 30 cm [8.0” to 12.0”] in diameter.
The equipment: Putzmeister BSF 46X.16H 46-meter truck mounted concrete boom pump
For this project, the contractor needed to pour concrete through standing water in the caisson. To do that, they needed a concrete boom pump with a very long reach. The truck was positioned on the river bank, and the boom needed to reach far enough to pump concrete into the tremie hopper and pipe in the caisson at the bottom of the river bed. The boom also needed to be long enough so that it could be raised up along with the tremie pipe (as the tremie was raised with a crane) while keeping the end of the tremie pipe buried in the poured concrete.
Here’s how the job was completed:
- The crane lowered the tremie pipe into a bridge caisson at the bottom of the river.
- Concrete was poured continuously through the boom and into the tremie pipe.
- The trick to pouring concrete using a tremie is to keep end of the pipe in the wet concrete at the bottom of the caisson, so you’re not dropping the concrete through water.
- As the caisson fills with concrete, displaced water comes out of the top of the caisson. The crane slowly raises the tremie pipe and the boom is raised at the same time (never pulling the bottom end out of the wet concrete).
Expert application tips for pouring through a tremie:
- Use a high slump concrete for tremie application
- Pour at a rate that keeps the concrete from setting inside the tremie pipe
- Be sure to keep the bottom of the tremie pipe buried in the concrete mass as it flows from the boom pump!
PROJECT #2: Building a concrete pedestal for a bridge in the East River, New York City
This project required a large volume of concrete (500 yards) in a single monolithic pour to prevent cold joints that would weaken the structure. To pour so much concrete at once, the contractor needed to create an elaborate setup. This method is widely used now for bridge construction, but it was new and innovative at the time when this bridge was built.
In the bottom left of the first photo below, you can see two 5-inch pipelines running across a barge. The pipelines are transferring concrete from two high-volume trailer pumps positioned on land, to two boom pumps positioned on a barge hundreds of feet out into the river. With this method, the boom pumps are not actually pumping, but only used for distributing the concrete.
Distribution equipment: Putzmeister BSF 46X.16H 46-meter & BSF 42X.16H 42-meter truck-mounted concrete boom pumps
To build this massive bridge pedestal, the contractor used two truck-mounted concrete boom pumps, positioned on a barge close to the construction site, to distribute the concrete that was actually pumped by two trailer-mounted pumps on the river bank. This method saved money because there was no need for an expensive placing boom mounted on a barge.
These truck-mounted boom pumps were chosen because the booms are long enough (46 meters and 42 meters) to reach from the barge to the location of the bridge foundation in the river.
Pumping equipment: Putzmeister BSA 14000 HP D and BSA 1408D trailer-mounted concrete pumps
In addition to the boom pumps used for placement, the contractor used trailer-mounted concrete pumps (positioned on the river bank) to pump a large volume of concrete through 5 inch pipelines and to the distribution pumps.
The contractor completely covered the pipeline with burlap that was kept wet with water, in order to keep the concrete cool and prevent it from starting to set up in the pipeline.
PROJECT #3: Pouring 80-foot deep concrete caisson footings for Global Terminal Jersey City container ship dock
This job required many caisson footings to be filled with concrete to support a new dock for container ships. The contractor used two truck-mounted boom pumps working together to accomplish the work. In the photo below (taken from a crane looking down at the construction site), you can see one concrete boom pump positioned on land, and a second boom pump positioned on a barge.
The equipment: Putzmeister BSF 46X.16H 46-meter & BSF 55.20H 55-meter truck-mounted concrete boom pumps
The concrete was pumped by a 55-meter truck-mounted boom pump on land, which reached out to the barge and plumbed directly into the back of another 46-meter boom pump. The 46-meter pump reached up and over the water to distribute the concrete inside a tremie pipe to fill each caisson footing.
Here at Alexander Wagner Company, we have been providing concrete pumping equipment, supplies and service to contractors in the New York metro area for decades. We’re happy to answer your questions and share our expertise. Feel free to reach out to us anytime!