Temperature Load Effect Analysis in Large-Span Steel Tube Arch Hoisting

Literature Overview

This paper by Sun Guofu, Li Shucai, and Zhang Bo, published in the Journal of Shandong University (Engineering Science) in 2010 (Vol. 40, No. 4, pp. 96–101), investigates the temperature load effects on the steel tube arch ribs during the hoisting and installation phase of the Zhijing River Bridge. The research was supported by the National Science Fund for Distinguished Young Scholars (Category A, No. 50625927). Using ANSYS software with parametric design language (APDL), a spatial finite element model was established to analyse the effects of various temperature change conditions and measured temperature distributions on the arch rib installation accuracy.

Technical Background

The installation of large-span steel tube reinforced concrete (SRC) arch ribs is a complex construction process involving the sequential hoisting and positioning of individual segments. Temperature effects during this process can significantly influence the final geometry and stress state of the completed arch. The key temperature effects include:

Temperature Effect	Source	Magnitude	Impact
Solar radiation	Direct sun exposure	Non-uniform surface heating	Differential expansion, camber deviation
Ambient temperature	Air temperature variation	Uniform heating/cooling	Overall dimensional change
Cable temperature	Hoisting cable heating	Localised heating	Segment positioning error
Welding heat	Segment joint welding	Localised high temperature	Residual deformation
Diurnal cycle	Day-night temperature swing	Periodic variation	Cyclic deformation

Nonlinear Temperature Distribution and Linearisation

A critical aspect of this study is the treatment of the nonlinear temperature distribution across the arch rib cross-section under solar radiation. When an arch rib segment is exposed to direct sunlight, the sun-facing surface temperature can reach 60–80°C while the shaded surface remains at ambient temperature (15–25°C). This creates a nonlinear temperature gradient through the thickness of the steel tube wall and the concrete core.

Linearisation Approach

The nonlinear temperature distribution is linearised using the equivalent linearisation principle:

The actual nonlinear temperature profile T(y) is decomposed into a uniform component T_avg and a linear gradient component T_lin(y).
The uniform component produces uniform expansion without bending.
The linear gradient component produces curvature (bending) proportional to the gradient magnitude.
The higher-order nonlinear components are neglected as they contribute minimally to the overall deformation.

Component	Effect on Arch Rib	Design Significance
Uniform temperature (T_avg)	Axial expansion/contraction	Affects segment length and positioning
Linear gradient (dT/dy)	Bending curvature	Causes camber deviation and stress
Nonlinear residual	Higher-order effects	Negligible for engineering purposes

Finite Element Analysis Methodology

The APDL-based parametric model allows systematic variation of temperature parameters to study their sensitivity:

Multiple temperature scenarios – Different solar radiation intensities, ambient temperatures, and wind conditions are simulated.
Measured temperature distributions – Field-measured temperature profiles are used to validate the analytical model.
Construction sequence simulation – The step-by-step hoisting process is modelled with temperature effects applied at each stage.
Cumulative effects – The accumulated temperature-induced deformation over the entire construction period is evaluated.

Key Findings

Finding	Technical Detail	Engineering Implication
Nonlinear solar temperature is the primary factor	Differential heating causes significant camber deviation	Must be accounted for in construction control
Temperature-induced deformation follows predictable patterns	Deformation is proportional to temperature gradient magnitude	Can be compensated through pre-positioning
Cable temperature affects segment positioning	Hoisting cable thermal expansion changes effective cable length	Requires temperature compensation in cable systems
Construction timing influences temperature effects	Daytime vs. nighttime installation produces different results	Schedule optimisation can minimise temperature errors

Connection with Steel Pipe and Welding Engineering

The temperature load effects during arch rib hoisting have direct implications for steel pipe fabrication and welding quality:

Steel Tube Fabrication Considerations

Aspect	Requirement	Rationale
Tube straightness	≤ 1/1000 of segment length	Minimises initial camber error
Tube ovality	≤ 1% of diameter	Uniform thermal expansion behaviour
Material uniformity	Homogeneous chemical composition	Predictable thermal expansion coefficient
Surface finish	Clean, free from scale	Uniform solar absorption
Coating/paint	Reflective or controlled emissivity	Temperature management

Welding Considerations During Hoisting

The field welding of arch rib segments during hoisting introduces additional thermal effects:

Welding heat input – The welding process introduces localised heating that can cause additional deformation beyond the environmental temperature effects. The welding heat input should be minimised while maintaining weld quality, typically through GTAW with controlled parameters (current 150–250 A, travel speed 150–300 mm/min).
Sequential welding – The welding sequence must be planned to minimise cumulative thermal distortion. Symmetric welding from the centre outward is recommended to balance thermal expansion.
Temperature monitoring – During field welding, the base metal temperature must be monitored and maintained within the qualified welding procedure range (typically 20–300°C for structural steel). Excessive preheat or interpass temperature can compound the environmental temperature effects.
Post-weld cooling – Controlled cooling rates (≤ 200°C/min) are essential to prevent hardening and cracking in the HAZ, particularly for higher-strength steels (Q355B and above).

Construction Control Recommendations

Based on the analysis results, the following construction control measures are recommended:

Temperature monitoring system – Install thermocouples at multiple locations on each arch rib segment to measure the actual temperature distribution in real-time.
Pre-positioning compensation – Apply calculated offsets to the segment positioning based on predicted temperature effects during the hoisting window.
Timing optimisation – Schedule critical hoisting operations during periods of minimal temperature gradient (early morning or late afternoon).
Real-time adjustment – Use the measured temperature data to adjust the hoisting cable lengths and segment positions dynamically during installation.
Welding sequence planning – Develop a welding sequence that minimises cumulative thermal distortion while maintaining structural integrity at each stage.

Study Insights and Implications

The research demonstrates that temperature effects, particularly the nonlinear solar radiation-induced temperature distribution, are the dominant factor influencing the installation accuracy of large-span SRC arch ribs. The linearisation approach provides a practical engineering tool for incorporating these effects into finite element analysis and construction control. For steel pipe fabricators and welding engineers, the key implications are: (1) the dimensional accuracy and material uniformity of the steel tubes directly influence the predictability of thermal deformation; (2) field welding procedures must account for the combined effects of welding heat and environmental temperature; (3) the construction control strategy should integrate temperature monitoring with real-time adjustment capabilities. The study's methodology—combining parametric analysis with measured temperature validation—provides a robust framework that can be adapted to other large-span steel tube arch projects with different geometries and environmental conditions. The cumulative nature of temperature-induced errors over the construction period underscores the importance of maintaining tight quality control at every stage of the hoisting and assembly process.