Steel Tubular Concrete Column with Prefabricated Prestressed Beam Composite Structure for High-Rise Industrial Buildings

Literature Overview and Industry Context

This paper by Hong Qi and Yang Haifeng from Shenzhen Special Zone Construction Engineering Group, published in China Cement (2025, Issue 10, pp. 95-97), addresses a structural engineering challenge that has become increasingly pressing as industrial facilities evolve from low-rise single-story buildings to multi-story and high-rise configurations. The traditional prefabricated concrete frame structure system is limited in its ability to accommodate the large story heights, heavy floor loads, and wide spans characteristic of modern industrial plants, particularly in sectors such as electronics manufacturing, pharmaceutical production, and automated warehousing. The authors propose a composite structural system combining steel tubular concrete (CFT) columns with prefabricated prestressed concrete beams, designed to meet these demanding performance requirements while maintaining the speed, cost efficiency, and quality advantages of prefabricated construction.

Structural System Configuration and Design Principles

The proposed system integrates three key structural elements: steel tubular concrete columns as the primary vertical load-bearing members, prefabricated prestressed concrete beams as the horizontal spanning elements, and specialized connection nodes that transfer forces between the two components. The steel tubular concrete column combines the high compressive strength and ductility of the steel tube with the fire resistance and cost-effectiveness of the internal concrete fill. The prestressed concrete beam provides high stiffness and crack resistance for the floor system, while the prefabrication ensures dimensional accuracy and reduces on-site labor.

The concept of "shuttering-free" construction is central to the system's value proposition. By designing the beam-column connections to be self-supporting during erection, the need for temporary formwork and shoring is eliminated or significantly reduced. This not only accelerates the construction schedule but also reduces the cost associated with temporary works, which can represent 15-25% of the total structural cost in traditional systems.

Connection Node Design and Load Transfer Mechanism

The most critical aspect of this composite system is the beam-column connection node, which must transfer vertical loads, horizontal shear forces, and bending moments between the prestressed beam and the CFT column. The authors emphasize that the reliability of this connection is paramount for the overall structural performance. Several connection configurations are discussed, including bolted steel end plates welded to the CFT column with the prestressed beam bearing on or connecting to the end plate, and embedded steel connection plates cast into the prestressed beam that are bolted to the column.

The load transfer mechanism involves multiple interaction paths. Under gravity loading, the prestressed beam transfers its reaction force to the connection node, which then distributes the load axially into the CFT column. Under lateral loading (wind or seismic), the connection must also resist shear and moment, requiring either a rigid or semi-rigid connection design. The CFT column provides excellent ductility under cyclic loading due to the confinement effect of the steel tube on the concrete core, which enhances the concrete's compressive strain capacity and prevents brittle failure.

Engineering Application and Practical Considerations

The authors apply the system to a specific high-rise industrial plant project, analyzing the structural performance under various loading conditions. Several practical considerations emerge from this application:

• The CFT column diameter must be selected to accommodate both gravity and lateral loads while providing sufficient stiffness to limit inter-story drift. Typical diameters range from 500 mm to 900 mm for industrial applications with story heights up to 10 meters.
• The prestressed beam design must account for the long-term deflection under sustained loads, which is critical for maintaining floor flatness in precision manufacturing environments.
• The connection detail must be designed for ease of field assembly, as the prefabrication philosophy requires rapid erection with minimal on-site fabrication.
• Fire protection of the steel tube is inherently provided by the concrete fill, but the connection hardware (bolts, end plates) may require additional fire protection treatment.

The authors propose specific measures to further reduce structural costs and accelerate construction, including the use of high-strength concrete (C60 or higher) in the CFT column to increase the compressive capacity, the adoption of high-strength prestressing tendons (1860 MPa grade) to reduce the beam depth, and the implementation of modular connection details that can be pre-assembled off-site and bolted in place.

Critical Reflection and Development Outlook

While the system offers clear advantages in terms of construction speed and structural efficiency, several challenges remain. First, the connection between the prestressed beam and the CFT column is inherently a hybrid connection involving both concrete and steel components, which complicates the fatigue performance assessment under repeated loading (e.g., from heavy machinery vibration in industrial plants). Second, the thermal compatibility between the steel tube and the concrete fill must be considered for structures exposed to significant temperature variations, as differential thermal expansion can induce additional stresses at the connection. Third, the system's applicability to seismic zones requires careful detailing of the connections to ensure ductile failure modes and adequate energy dissipation capacity.

The broader significance of this work lies in its contribution to the ongoing trend of industrial building intensification. As land costs increase in urban areas, the conversion of single-story industrial facilities to multi-story configurations is becoming economically necessary. The proposed CFT column with prefabricated prestressed beam system represents a viable structural solution that bridges the gap between traditional heavy steel frame construction and lightweight prefabricated concrete systems, offering a balanced combination of strength, stiffness, ductility, and constructability.

Summary

This paper presents a practical and well-motivated composite structural system for high-rise industrial buildings that combines the strengths of CFT columns and prefabricated prestressed beams. The system addresses the critical demands of large story heights, heavy loads, and wide spans while maintaining the efficiency advantages of prefabricated construction. For structural engineers designing multi-story industrial facilities, this approach provides a valuable alternative to conventional systems, particularly where construction speed and floor space efficiency are paramount. Further development in connection detailing, seismic performance validation, and long-term durability assessment will be essential to fully realize the potential of this system in demanding industrial applications.