Zhuojin Pipe Fitting Co., LtdTemperature Field Analysis of Ribbed Thin-Walled Square Steel Tube Concrete Columns Under Fire
Literature Overview
Wang Weiwei, Mi Zhenwei, Lv Xuetao, and Zhang Yuzhuo from Liaoning Technical University published their study in Fire Science in 2017 (Vol. 26, No. 2, pp. 93-99), supported by the Liaoning Provincial Department of Education (Grant LJYL033). The research investigates the thermal behavior of ribbed thin-walled square steel tube concrete (STC) columns under standard fire conditions.
Experimental Program and Model Validation
Three full-scale ribbed thin-walled square STC columns were subjected to standard fire exposure tests. A finite element temperature field model was established and validated against experimental results, showing good agreement between predicted and measured temperature distributions.
The temperature field distribution under four-sided fire exposure exhibits biaxial symmetry, with corner regions experiencing the highest temperatures. This is consistent with the geometric concentration of heat flux at corner locations where two heated faces meet.
| Parameter | Influence on Temperature Field |
|---|---|
| Section side length | Major factor — larger sections have lower core temperatures |
| Fire exposure time | Major factor — temperature increases with time |
| Fire exposure mode | Major factor — number of heated faces significantly affects peak temperatures |
| Rib spacing | Minor effect on overall temperature field |
| Steel ratio | Minor effect on overall temperature field |
| Rib presence | Local effect limited to weld points |
Technical Analysis of Rib Effect
The finding that stiffening ribs influence the temperature field only locally near weld points is particularly interesting from a structural engineering perspective. The ribs enhance the local buckling resistance of the thin-walled steel tube under elevated temperatures, but they do not significantly alter the heat transfer characteristics of the composite section. This suggests that the thermal performance is governed primarily by the overall section geometry and fire exposure conditions rather than by local stiffening details.
The thin-walled nature of the steel tube means that heat penetrates rapidly into the concrete core, and the temperature gradient through the wall thickness is minimal. The concrete acts as a thermal mass, slowing the temperature rise at the column core.
Engineering Practice Integration
For fire protection design of steel tube concrete columns, this study provides several important insights:
- Corner regions require particular attention in fire protection design, as they experience the highest temperatures.
- The fire exposure mode (one-sided, two-sided, or four-sided) is a dominant factor in determining the thermal response.
- Stiffening ribs should be designed primarily for structural stability rather than thermal performance.
- Section size is the most effective geometric parameter for controlling core temperature.
From a steel tube manufacturing and welding perspective, the weld points at rib locations represent potential thermal stress concentrations during fire exposure. The differential thermal expansion between the rib and the main tube wall can generate additional stresses at these weld connections.
Study Insights and Outlook
This research contributes valuable experimental data on the thermal behavior of ribbed thin-walled STC columns, a common structural element in modern steel-concrete composite construction. The validated FEA model provides a practical tool for predicting temperature distributions under various fire scenarios. Future research should extend to mechanical property degradation and residual load capacity after fire exposure, as well as the effect of different concrete mixes and steel grades on the thermal and structural response. The combination of thin-wall construction with ribbed stiffening represents an efficient structural solution that warrants continued investigation for fire-resistant design applications.