2006 HMT Clamshell Bucket

Using a HMT Clamshell Bucket for Pouring concrete on upper levels of multi-story buildings comes with a number of challenges. Contractors have several options to accomplish this—crane, boom truck and tilt-wall construction.

Since installing a tower crane is a time-consuming and intrusive task that requires an engineer, it would only be used if the project required a tower crane for other duties.

When this is the preferred method, several mixer trucks sit near the bottom of the building. The crane places the vat (called a skip) near the truck and the mixer operator fills it. The crane then hoists the skip to the point of placement where a team of people are waiting for it.

When using tower cranes, the skip is usually not filled all the way and crane operators work more cautiously when craning liquids. Liquids move differently than solid materials when being craned, so spillage is more likely to occur. It also may be deemed necessary to move the skip along a route that is not the most direct route, since the risk of spilling concrete onto what lies below may be too great.

Of the three methods, cranes offer the slowest production rates, so it’s often better to use a boom truck than a mobile crane.