Competitive Analysis and Value Proposition of Frozen Silt Mats as an alternative to Crane Timber Mats

  • Author / Creator
    Ali, Ghulam
  • The construction industry is adopting the modular construction paradigm with the integration of heavy crane usage. Because of the weight of the modules that are to be lifted, which currently can reach as much as hundreds of tons, ensuring proper ground integrity under the lifting equipment is paramount since its failure can result in dire consequences for the workers and the project. The traditional method of ground support is to utilize timber or steel mats.
    The use of frozen silt (a frozen mixture of water and soil) to prepare crane mats is outside the box idea dispensing with traditional constraints. Artificial ground freezing is a technique used in the construction industry to provide temporary ground support. The mechanical properties of frozen silt are comparable to Coastal Douglas-Fir, but depends upon the temperature attribute. This research contribution aims to investigate the competitive analysis for the use of ice and frozen silt in the form of crane mats to support heavy lifting and hauling. The impact of loading on the crane mats is simulated using ANSYS (FEA platform). Five matting materials (S355, G40.21, Coastal Douglas-Fir, ice, and frozen silt) are investigated using five linear and one non-linear mechanical properties under identical crane loading and boundary conditions.
    The required frozen silt mat surface temperature is considered as −10°C based on the competitive mechanical properties for its practical usage and FEA simulation. The graphical outcome in the form of normal stresses and ground deflection along the crane superstructure slew delivers a conceptual perceptual map for the application of ice and frozen silt in comparison to their traditional competitors (steel and wood). As per FEA simulation, the performance of frozen silt is equal to that of Coastal Douglas-Fir. This similarity promotes the preparation and usage of the frozen silt mat. The conclusion derived from these replications provides a foundation for the estimation of the freezing process in conjunction with ground freezing techniques.
    Based on the loading simulations, this contribution also covers the aspects of freezing methods and energy drainage for the mat temperature attainment. The proposed design of the frozen silt mat is integrated with the traditional means of ground freezing, and the freezing process is studied using ANSYS (FEA). Simulation is performed to attain the bottom-up estimate of ground freezing using indirect freezing (brine chillers) and direct freezing (liquid nitrogen). FEA simulation provides the graphical representation of mat freezing with respect to time-lapse using energy equations and viscosity constraints. The outcome from thermal simulation delivers a baseline for the cost estimation for the alternative crane matting solution in the form of capital, operational, and opportunity cost for this novel approach rather than Coastal Douglas-Fir timber mat ground support.
    Based on the research presented in this thesis, the frozen silt mat within the assumed constraints offers strong practical value as an environmentally-friendly alternative to crane timber mats and is suitable for the climate of North America with good technical and financial industry benchmarks.

  • Subjects / Keywords
  • Graduation date
    Fall 2018
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
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