Performance Testing of GRS Test Piers Constructed With Florida Aggregates – Axial Load Deformation Relationships

Details

• Creators:
  Wasman, Scott ; Matemu, Christian
• Corporate Creators:
  Florida A&M University-Florida State University (FAMU-FSU)
• Contributors:
  Herrera, Rodrigo
• Corporate Contributors:
  Florida. Department of Transportation
• Subject/TRT Terms:
  Abutments Aggregates Axial Loads Construction Data Analysis Deformation Friction Geosynthetic Reinforced Soil Geosynthetics Geotextiles GRS-IBS Piers Polypropylene Soil Aggregates Testing Triaxial Shear Tests Woven Materials

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• Resource Type:
  Tech Report
• Geographical Coverage:
  United States ; Florida
• Edition:
  Final Report: 03/30/2020-07/31/2024
• Corporate Publisher:
  Florida. Department of Transportation
• Abstract:
  A series of full-scale axial load-deformation tests on instrumented GRS piers were conducted using materials approved for use in Florida. The piers were designed and constructed following the FHWA and FDOT guidelines for dimensional ratio of height/width = 2, compacted backfill of poorly graded No. 57, well graded RCA-GAB, and a LWA (as a trial experiment), reinforced with biaxial and uniaxial woven polypropylene geosynthetics with a minimum of 4,800 lbs/ft strength spaced 8 inches apart, and confined with 86 lbs segmental facing blocks. The primary objectives were to investigate the behavior of GRS composites specific to Florida design practice, provide accurate stress-strain data for design purposes and evaluate the GRS composite structure axial and horizontal strains under service pressure. Large diameter triaxial tests were performed are appropriate for testing well graded materials. The analysis of triaxial results showed the influence of triaxial specimen on shear strength properties of well-graded RCA-GAB. Conducting triaxial tests on 6-inch diameter specimens led to an increase in the friction angle by 11.4° and 8.5° for peak and residual states, respectively, compared to 4-inch specimens. All GRS piers tested met the FHWA service limit criteria for GRS-IBS satisfactorily. At applied vertical g pressure of 4 ksf (FHWA recommended dead plus live load, with load factors =1), the vertical strain for all GRS piers was below 1%, with lateral strain below 0.51%. The applied vertical pressure needed to achieve 1% vertical strain ranged from 4.1 ksf to 19 ksf for all piers, while the pressure required to reach 2% lateral strain varied from 11 ksf to 32 ksf. Comparison of experimental data with FHWA design methods for GRS-IBS showed that the FHWA ultimate capacity equation consistently underestimated the measured vertical capacity of piers constructed with open graded-No 57 and well graded RCA-GAB backfills when the residual friction angle from large diameter triaxial tests are used. The FHWA equation for lateral displacement accurately predicted the lateral displacement of the facing walls during loading. The assumption of zero volume change was found to hold only below the applied vertical pressure of 4 ksf. The results of the load-deformation tests provide 7 additional values to the dataset of FHWA bearing capacity bias with which new resistance factors were calculated following the AASHTO strength I load combination and using the First Order Second Moment (FOSM) method. For deal to dead + live load ratio of 0.37, resistance factors were calculated to be 0.57, 0.53, 0.44, and 0.37 for reliability indices of 2.33, 2.5, 3.0, ad 3.5, respectively.
• Format:
  PDF
• Funding:
  BED30 977-11
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:e7e4724ee254ba40b465a8f6a2a7437204beaa82b85ccc5f48bcc807d0902e9287a3e581de120df891b3a490390d07d2a7b068764b296215de45dfee66d66996
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/88919/dot_88919_DS1.pdf
• File Type:
  [PDF - 38.80 MB ]