Two weeks ago, crews on the blue movable scaffolding system (MSS) performed a concrete pour for the road deck on the final segment that the huge machine will construct. To commemorate the blue MSS’ final pour, the video above shows crews managing two concrete pump lines that stretch from the westbound incline over the gap between the approaches and continuously drop concrete onto the exposed rebar.
Pours involve crews deployed in different areas to place, smooth, and texturize the concrete at the same time, and they require that workers constantly keep things moving. In the opening seconds of the video, a worker guides one of the pumps to place the concrete, while another worker uses an industrial vibrator to consolidate it. It is viscous, and – if workers don’t move quickly – it will cure.
When it comes to smoothing the concrete, using traditional floats across such a wide road surface simply isn’t efficient. Enter a Bidwell device that rolls across the concrete after it has been placed to smooth it out. The device is attached to a scaffold on tracks that moves along the span, right behind the workers as they pour. Workers do use floats to smooth the surface that is close to the edge, where the Bidwell cannot reach.
Behind the Bidwell device, a two-person crew on another scaffold drags a concrete broom across the width of the road deck to add a skid-resistant texture to the surface. Sometime before the bridge is opened, the concrete will be paved over with a two-inch-thick polyester overlay. But in the meantime, the surface needs to be skid-resistant for all the construction vehicles traveling on it.
Lastly, a crew member sprays a milky white curing compound on the new concrete to seal it and enable it to cure at the same rate. And that’s how a concrete pour on a large road surface occurs.