Blast Resistance of Polyurea-coated Granite Cladding Walls

Open Access
Author:
Jones, Kendra Diana
Graduate Program:
Civil Engineering
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
June 21, 2013
Committee Members:
  • Dr Daniel Linzell, Thesis Advisor
  • Tong Qiu, Thesis Advisor
  • Zoltan Ivan Rado, Thesis Advisor
Keywords:
  • blast
  • explosive
  • granite cladding
  • polyurea
  • polymer
  • high-strain rate
  • fragmentation
Abstract:
During blast events, a structure’s response is partially dependent on the external, cladding panels, which are directly subjected to extreme pressures resulting from the explosive. Research has shown that the ability of clad building structures to resist damage greatly depends on the high-strain rate behavior of the cladding wall and the subsequent load transfer from the panels to their structural support frames. Cladding panels have the potential to significantly absorb the blast energy, mitigating loads imparted onto the frame. However, as the panels absorb energy, high-velocity fragmentation of the cladding can pose a significant threat to bystanders and the structure itself. Fragmentation is especially prevalent for brittle, granite cladding. To aid in enhancing energy absorption and limiting fragmentation, many researchers have studied the use of polyurea as a coating or interlayer system for metal and concrete structural components. Due to its viscoelastic behavior, polyurea exhibits beneficial mechanical properties at high strain rates. This study evaluates the effectiveness of applying polyurea coating to granite cladding panels with the hopes of reducing blast loading effects on buildings, namely the level of fragmentation and load transfer from the cladding to the support structure. Finite element analyses of polyurea-coated granite cladding walls were performed in LS-DYNA using constitutive models for the granite cladding and polyurea. The modeling approach and analysis method was validated against published blast studies to ensure that reliable results were obtained in the parametric study, where the blast resistance of granite cladding was computationally assessed. The blast size, panel and polyurea coating thickness, and coating location were varied according to construction practice and parameters evaluated in similar studies. The results of the parametric study show that the polyurea coating was effective in limiting the fragmentation of the granite cladding with minimal detrimental effect on load transfer into support connections.