Stress distribution under crawler crane timber mats

• Author / Creator

  Avoine, Remi

• In the construction industry, it is common practice to use timber mats beneath crawler cranes to redistribute heavy loads over large surfaces and allow the stresses on the soil to fall within allowable design limits. The distribution of stresses beneath the mats is generally assumed to be uniform, which implies that the crawler and mats are regarded rigid. This can lead to non-conservative designs for the soil. A 3D elastic finite element model was developed in Abaqus in order to question that assumption. Ten different crawlers were tested on four distinct soils: Sand Fill, Native Sand, Clay Till and Sand & Gravel. In particular, a specific model of crawler, constructed by Liebherr, and used by our industrial partner PCL, was examined. It was found that considering the crawler as a rigid body can lead to significant underestimated stresses, with a relative error from 10% to 50% depending on the crawler’s size and soil type. When stress distributions obtained with Abaqus were compared with the stress distributions calculated by our industrial partner, it was found that they underestimated the stresses by about 37%. It was also determined that the typical assumption made in beam theory that an I-beam’s rigidity is the only parameter to play a role in loads’ redistribution, was acceptable if its dimensions were comprised within a finite range. Finally, a new method to design timber mats was derived using finite element analysis.

• Subjects / Keywords

  • stress distribution
  • mat
  • crane
  • interaction soil structure
  • soil bearing pressure

• Graduation date

  Spring 2019

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-8d4j-mq73

• License

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