Infrastructure Projects - Construction Technology
A Practical Guide to Construction Techniques and Practice
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We will look at several different techniques for placing concrete. This is a concrete pump, a very effective tool. And you can see the discharge arm is articulated, which allows it to get into very difficult areas. They're placing this concrete underneath an existing bridge. It would be impossible to do this with a crane and bucket. This really would be a challenge, except that the concrete pump makes it very simple.
This is a high-rise, concrete frame building and they are placing concrete now in the columns and the walls as an initial operation and then they will follow this by placing concrete on the floor. This looks like an elevator core. The vertical rebar is a wall that, I would say, is enclosing the elevator core. The rebar is in the way of the bucket, so they've constructed some very simple chutes to allow the concrete to reach the wall. They improvise these little devices to help themselves out and it's that kind of know-how that makes for a successful project. |
![]() I'd like you to take note of the formwork. This wall is formed continuously from one end to the other, as opposed to the alternate pours that I showed you previously. This is a different approach to the work. They are, in fact, placing the concrete in one continuous pour. It certainly cost effective to do it that way. But you need to solve the problem of the shrinkage and you still need intermediate bulkheads. I'll show you how they do it in this system. That's a vibrator that the labor is lowering into the concrete to make sure it's completely consolidated. This wall is on the opposite side. This was poured the very same day. Now that the concrete is several hours old, they can begin stripping some material that was forming a keyway. It's a very smart to strip it on the same day. If you come back the next day that concrete is set, and it's much harder to remove.
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