2013 Session: 209

• Comparison of Sheet Pile Wall Design According to Conventional and AASHTO LRFD Methodologies
  Abstract: Sheet Pile wall design using methods in AASHTO LRFD Bridge Design Specifications (2010) is compared in this study to methods in United States Army Corps of Engineers (USACE) Engineering Manual 1110-2-2504 (USACE, 1994). It will be shown that AASHTO (2010) results in a greater embedment depth, mainly due to a safety factor compounded with Load Factors. Simple modifications to the current AASHTO (2010) code provisions code are suggested which have the potential for large cost savings – while achieving a relatively conservative design compared to conventional design methods (USACE) and typical load combinations. Guidance on the selection of load combinations is also provided. Finally, available centrifuge test data for sheet pile walls subjected to earthquake loading are compared to resulting moment demands derived for both AASHTO and USACE methods.
  Authors: Harden, Chad William
  Authors: Harden, Chad William
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Geotechnology
  Session: 209
  Paper Number: 13-0775
• Design of Geogrid-Reinforced Earth Walls: Transition of Limits and Critical Surfaces
  Abstract: The majority of design approaches or methodologies for reinforced soil walls or slopes are based on separately investigating the internal and external stabilities of the system. The internal stability is examined by satisfying the local stability of reinforcements at each level based on the predetermined critical slip plane (line of maximums) and the tributary area of each reinforcing layer. Recent research aimed at incorporating the contributions of the various elements of reinforced earth walls, some of which are mostly based on statistical correlations. The German code of practice for design/analyses of reinforced earth walls and slopes offers slightly different methodology for analyzing the internal stability of the reinforcement. It is mainly based on investigating numerous circular and random slip surfaces, within and beyond the reinforcement zone (internal and external), while accommodating the axial (resistance) forces provided by all reinforcement layers intercepting these surfaces. This paper presents some of the technical and design considerations and possible improvements on design methodology for reinforced soil walls and slopes. Of particular interest is the use of apparent cohesion concept in design of geosynthetic reinforced soil systems and the transition of limit equilibrium states (mobilization of actual state of equilibrium critical surfaces) for reinforced earth walls. The equivalent cohesion concept was used to transform reinforced soil masses into equivalent cohesive soil masses with friction capacity. Cases of analyses with comparisons between reinforced soil walls and the equivalent cohesive masses were performed and the results revealed very similar results between the two systems in terms of the safety of the walls.
  Authors: Al Mohd, Izzaldin Ayasrah; Ashteyat, Ahmed M.; Malkawi, Abdallah
  Authors: Al Mohd, Izzaldin Ayasrah; Ashteyat, Ahmed M.; Malkawi, Abdallah
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Geotechnology
  Session: 209
  Paper Number: 13-1422
  Practice-Ready: Yes
• Passive Force-Deflection Behavior for Zero- and Thirty-Degree Skewed Abutments
  Abstract: Accounting for seismic forces and thermal expansion in bridge design requires an accurate passive force-deflection relationship for the abutment wall. Current design codes make no allowance for skew effects on passive force; however, small-scale experimental results indicate that there is a significant reduction in peak passive force as skew angle increases for plane-strain cases. To further explore this issue large-scale field tests were conducted with skew angles of 0° and 30° with unconfined backfill geometry. The abutment backwall was 11-ft (3.35-m) wide by 5.5-ft (1.68-m) high and backfill material consisted of dense compacted sand. The peak passive force for the 30° skew was found to be 57% of the peak passive force for the 0° skew case which is in good agreement with the available laboratory and numerical results; however, this may suggest that backfill geometry has some effect on the reduction in peak passive force with respect to skew angle. Longitudinal displacement of the backwall at the peak passive force was found to be between 3% and 5% of the backwall height for both the 0° and 30° skew test which is consistent with previously reported values for large-scale passive force-deflection tests. Heave geometries for both the 0° and 30° tests were quite similar. In both cases the failure geometry extended approximately 4 ft to 5 ft (1.22 m to 1.52 m) beyond the edge of the pile cap and 16 ft (4.88 m) from the face of the cap when measured perpendicular to the backwall.
  Authors: Marsh, Aaron; Rollins, Kyle M.; Franke, Bryan; Smith, Jaycee; Palmer, Katie
  Authors: Marsh, Aaron; Rollins, Kyle M.; Franke, Bryan; Smith, Jaycee; Palmer, Katie
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Geotechnology
  Session: 209
  Paper Number: 13-2665
  Practice-Ready: Yes
• Pullout Resistance Factors for Inextensible MSE Reinforcements Embedded in Sandy Backfill
  Abstract: This paper presents results from a laboratory program of 402 pullout tests of inextensible reinforcements used for Mechanically Stabilized Earth (MSE) walls. Results focus on evaluation of pullout resistance factors for sandy backfill and MSE reinforcement combinations used by the Texas Department of Transportation (TxDOT). This project uses Texas Tech University’s large-scale MSE Test Box with dimensions of 12 feet x 12 feet x 4 feet and an applied overburden capacity of 40 feet of backfill. This test box facilitates pullout testing at a scale not unlike typical field construction. The research design evaluates pullout resistance factors for both ribbed strip and welded grid reinforcements for a variety of independent variables including overburden pressure, reinforcement length, skew or splay angle, level of compaction, grid wire size, and grid geometry including both transverse and longitudinal wire spacing. We use statistical analyses to interpret the data within the context of published AASHTO design guidance for inextensible MSE reinforcements.
  Authors: Lawson, William D.; Jayawickrama, Priyantha Warnasuriya; Wood, Timothy A.; Surles, James
  Authors: Lawson, William D.; Jayawickrama, Priyantha Warnasuriya; Wood, Timothy A.; Surles, James
  Year: 2013
  Document Type: Paper
  Subject: Bridges and Other Structures; Geotechnology
  Session: 209
  Paper Number: 13-2684
  Practice-Ready: Yes
• Pullout Resistance Factors for Inextensible MSE Reinforcements Embedded in Sandy Backfill
  Authors: Lawson, William
  Authors: Lawson, William
  Year: 2013
  Document Type: Presentation
  Subject: Bridges and Other Structures; Geotechnology
  Session: 209
  Paper Number: 13-2684
• Passive Force-Deflection Behavior for Zero- and Thirty-Degree Skewed Abutments
  Authors: Marsh, Aaron
  Authors: Marsh, Aaron
  Year: 2013
  Document Type: Presentation
  Subject: Bridges and Other Structures; Geotechnology
  Session: 209
  Paper Number: 13-2665
• Pullout Resistance Factors for Inextensible MSE Reinforcements Embedded in Sandy Backfill
  Authors: Surles, James
  Authors: Surles, James
  Year: 2013
  Document Type: Presentation
  Subject: Bridges and Other Structures; Geotechnology
  Session: 209
  Paper Number: 13-2684