Allowable Bearing Pressures of Bridge Sills on GRS Abutments with Flexible Facing

Fox²,

Shing

2015

Ifcee 2015

The geosynthetic-reinforced soil (GRS) bridge abutment is a new technology that has many advantages over traditional abutment designs, including cost savings, relatively easy and fast construction, and good performance with regard to differential settlements. The GRS bridge abutment is a complex system that includes a lower GRS wall, bridge seat, and upper GRS wall, with the bridge superstructure load applied directly to the backfill for the lower GRS wall. This paper presents numerical simulations of the static response of a typical GRS bridge abutment during construction and service. The numerical simulations include soil-reinforcement, soil-block, block-block, and soil-bridge seat interactions. Analyses were performed in stages to simulate the abutment construction process. A uniform surcharge load was applied on the bridge deck and approach roadway to simulate traffic loads during service. Results for construction and in-service conditions are presented and discussed, with particular focus on wall facing lateral displacements and bridge seat settlements. The effect of bridge load on the deformation behavior of the GRS bridge abutment was also investigated. Numerical results indicate that the abutment has good performance under static loading conditions with relatively small lateral deflection and settlement, and relatively large load bearing capacity. IFCEE 2015

Section: Bridge Seat Movementmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Numerical Study of Deformation Behavior for a Geosynthetic-Reinforced Soil Bridge Abutment under Static Loading

Fox²,

Shing

2015

Ifcee 2015

“…The lateral facing displacements and maximum tensile forces in reinforcement layers at the end of construction are much larger for GRS walls constructed using a heavy compactor than a light compactor. Numerical studies have been conducted for GRS abutments under static loading (Wu et al 2006;Helwany et al 2007;Zheng et al 2014Zheng et al , 2015, and results from these studies show relatively small lateral facing displacements and bridge footing settlements under service loads. However, the effect of backfill compaction was not considered in these numerical investigations for the static response of GRS abutments.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study of the Compaction Effect on the Static Behavior of a Geosynthetic Reinforced Soil-Integrated Bridge System

Geotechnical Frontiers 2017

Fox²,

McCartney

2017

This paper presents a numerical study on the effect of backfill compaction on the static response of geosynthetic reinforced soil-integrated bridge system (GRS-IBS). The numerical simulations were performed in stages to simulate the construction process, and considered soil-geotextile, soil-block, geotextile-block, and abutment-bridge interactions. Backfill compaction was simulated using a temporarily-applied uniform vertical stress to each lift during construction. Simulation results of the GRS-IBS behavior corresponding to various levels of compaction effort are presented and discussed, including lateral facing displacements, settlements, and maximum tensile forces in the reinforcement layers. Results indicate that greater backfill compaction leads to smaller bridge seat settlement and backfill compression, but also results in larger lateral facing displacements.

“…Barrett et al (2013) also presented five successful case studies of MSE abutments in the private sector. Wu et al (2006) studied the allowable bearing capacity of geosynthetic reinforced soil abutments with flexible facing using finite element analysis. The allowable bearing pressures were determined by a limiting displacement criterion and a limiting shear strain criterion.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulations for Response of MSE Wall-Supported Bridge Abutments to Vertical Load

Ground Improvement and Geosynthetics

Fox²,

Shing

2014

In recent years, mechanically stabilized earth (MSE) walls have been proposed as support for bridge abutments on shallow foundations due to significant cost savings over conventional pile-supported designs. This paper presents new research on numerical modeling of a realistic MSE wall-supported bridge abutment using the finite difference program FLAC-2D. MSE abutments are typically subjected to much larger loads from bridge superstructures than conventional MSE walls. An MSE bridge abutment with a flexible wall facing is a complex system that includes granular backfill, reinforcement, concrete facing blocks, and the shallow foundation for the abutment structure. In the numerical simulations, soil-block, block-block, and soil-abutment interactions were simulated using interface elements and soil-geogrid interactions were simulated using cable elements. The MSE abutment is subjected to a vertical bridge load of 200 kPa. Results are presented for static conditions and include lower wall facing displacements, abutment structure settlements, maximum tensile forces in the reinforcement, lateral earth pressures, and vertical stresses under the abutment structure and at the soil foundation level. The numerical results are discussed with regard to practical field applications. 493Ground Improvement and Geosynthetics GSP 238