Details:

Creators:
Schmitz, Michael E. ; Parsons, Robert L. ; Ramirez, Guillermo ; Zhao, Yuan
Schmitz, Michael E. ; Parsons, Robert L. ; Ramirez, Guillermo ; Zhao, Yuan Less -
Corporate Creators:
University of Kansas. Dept. of Civil, Environmental and Architectural Engineering
Corporate Contributors:
Kansas. Dept. of Transportation
Subject/TRT Terms:
[+]
Bridge Abutments Computer Models Drainage Material Finite Element Method Flowable Fill Geotechnology Highways I42: Soil Mechanics Laboratory Tests Lateral Pressure Literature Reviews Settlement (Structures) Soils Trench Backfill
Publication/ Report Number:
K-TRAN: KU-02-6
Resource Type:
Tech Report
Geographical Coverage:
United States ; Kansas
United States ; Kansas Less -
TRIS Online Accession Number:
978483
Edition:
Final Report
Corporate Publisher:
University of Kansas. Dept. of Civil, Environmental and Architectural Engineering
Abstract:
Use of Controlled Low-Strength Material (CLSM) behind bridge abutments has become common practice to avoid the problem of settlement when using compacted soils. CLSM solves the settlement problem within the fill but raises separate concerns. The lateral pressures that CLSM exerts on the bridge abutment are not well understood. Another concern is the potential for clogging of the drainage material on the bridge abutment. This could occur if the fly ash, cement, or water paste flows through the drainage fabric and hardens. Research was performed in a series of laboratory tests and finite element analyses to determine the lateral pressures generated by CLSM. The effect of CLSM on drainage material was also evaluated in the physical tests. For the physical testing an apparatus was constructed that was 6 ft tall, 2 ft deep, and 2 ft wide. One wall of the apparatus was instrumented with pressure cells at varying heights. Drainage material was also placed on the instrumented wall. The apparatus was then filled with CLSM. Fill was placed in the apparatus and pressures recorded with time. Lateral pressures in all studies peaked immediately after CLSM placement at pressures approaching full fluid pressure before dropping sharply to near zero. Pressures tended to decline most slowly at the center of the fill, which was consistent with observations of previous researchers. Finite element analyses were conducted for several CLSM-wall configurations, including the laboratory apparatus and an actual bridge design provided by the Kansas Department of Transportation with a series of loading configurations. Results from the finite element analyses predicted full fluid pressure when the fill was placed and 25-35% of the full fluid pressure after curing. These results were also consistent with previous field observations. Settlement within the fill should be minimal based on the literature review and finite element analyses. However, the potential for settlement in the foundation soils below the fill is not addressed by the use of CLSM and may still be significant. Comments on how settlement of foundation soils could be addressed are included in Chapter 7. Based on the results of the literature review, physical testing, and computer modeling, it was recommended that the fill be modeled as a fluid during placement and that a much reduced equivalent fluid pressure be used for estimation of lateral pressures after curing. Recommendations were also made regarding the possibility of wall rotation away from the fill, which could enable fill in a fluid state to migrate into a gap between the abutment and lower lifts of fill that had set up and potentially cause higher than expected lateral pressures. No recommendations for changing the specifications for the drainage material were made as it performed very well in the physical testing.
Format:
PDF
Funding:
C1293, RE-0289-01
Collection(s):
US Transportation Collection
Main Document Checksum:
[+]
urn:sha256:b5077876a880a44f8c99efddf10584a95a3ba2028a0ef0c8c87b1c58dcb42d40
Download URL:
https://rosap.ntl.bts.gov/view/dot/39896/dot_39896_DS1.pdf
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