Laser Scanner-Based Hyperboloid Cooling Tower Geometry Inspection: Thickness and Deformation Mapping

Area of Science:

• Structural Engineering
• Geomatics
• Industrial Asset Monitoring

Background:

• Hyperboloid cooling towers are critical, large-scale industrial structures requiring robust geometric integrity for safe operation.
• Traditional geometric assessments often overlook crucial parameters like shell thickness, potentially compromising durability assessments.
• Ensuring the structural health of these aging power plant components necessitates advanced monitoring techniques.

Purpose of the Study:

• To present an original methodology for comprehensive geometric condition assessment of hyperboloid cooling towers using terrestrial laser scanning.
• To incorporate the measurement of internal shell thickness, a parameter typically disregarded in geometric evaluations.
• To validate the proposed method through real-world application on a fifty-year-old operational structure.

Main Methods:

• Terrestrial laser scanning (TLS) to capture high-density point clouds of the cooling tower's internal and external surfaces.
• Utilizing the M3C2 algorithm to estimate the distance between internal and external point clouds for accurate shell thickness determination.
• Innovative analysis of radial deviation distributions to detect shell ovalisation and verification of structural verticality.

Main Results:

• The study successfully determined the actual reinforced-concrete shell thickness and identified geometric imperfections ranging from -0.125 m to +0.136 m.
• A permanent tilt of the tower's axis to the northeast was detected, alongside signs of shell ovalisation.
• No significant advancing deformation of the hyperboloid shell was observed over a two-year monitoring period, indicating stability.

Conclusions:

• The proposed TLS-based methodology offers an end-to-end solution for the geometric assessment of hyperboloid cooling towers, meeting industry standards.
• Incorporating internal measurements and advanced algorithms provides a more accurate and complete understanding of structural condition and durability.
• The findings are crucial for ensuring the continued safe service and effective maintenance planning of aging hyperboloid cooling tower infrastructure.