An insert for use in a mold operation to provide internal cavities and passages within a pre-cast structural component. The insert is a multi-piece elongated tube where the individual pieces slide lengthwise to control the effective cross section. In operation in a form used to cast materials such as concrete, the insert creates a selectively dimensioned passage and is easily discharged from the mold/cast structure during or after the concrete is cured.

An insert for use in a mold operation to provide internal cavities and passages within a pre-cast structural component. The insert is a multi-piece elongated tube where the individual pieces slide lengthwise to control the effective cross section. In operation in a form used to cast materials such as concrete, the insert creates a selectively dimensioned passage and is easily discharged from the mold/cast structure during or after the concrete is cured.

The present disclosure provides a precast column and a method for manufacturing the same, in which the precast column includes a base, a main structure, multiple main reinforcing bars and a concrete structure. The base includes multiple couplers disposed on a bottom mold and multiple stirrups surrounding the multiple couplers. One side of the main structure is connected to the base, and the main structure includes a hollow tube disposed inside the main structure. The multiple main reinforcing bars pass through the main structure, one end of each of which is connected to the corresponding one of the multiple couplers. The concrete structure covers the base, the main structure and the multiple main reinforcing bars.