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The paper investigates the influence of backfill soil, foundation soil, and horizontal joint vertical compressibility on the magnitude of vertical loads developed in steel-reinforced soil concrete panel retaining walls at the end of construction. Measurements of toe loads recorded from instrumented field walls are reviewed and demonstrate that vertical toe loads can be much larger than the self-weight of the facing. In extreme cases, these loads can result in panel-to-panel contact leading to concrete spalling at the front of the wall. Vertical loads in excess of panel self-weight have been ascribed to relative movement between the backfill soil and the panels that can develop panel-soil interface shear and downdrag loads at the connections between the panels and the steel-reinforcement elements. A two-dimensional finite-element model is developed to systematically investigate the influence of backfill soil, foundation soil, bearing pad stiffness, and panel-soil interaction on vertical loads in the panel facing. The results show that an appropriately selected number and type of compressible bearing pads can be effective in reducing vertical compression loads in these structures and at the same time ensure an acceptable vertical gap between concrete panels. The parametric analyses have been restricted to a single wall height (16.7 m) and embedment depth of 1.5 m, matching a well-documented field case. However, the observations reported in the paper are applicable to other similar structures. The general numerical approach can be used by engineers to optimize the design of the bearing pads for similar steel-reinforced soil wall structures using available commercial finiteelement model packages together with simple constitutive models.

Life cycle assessment (LCA) is recognised as a powerful technique to determine the environmental impact component of sustainability assessments of structures in civil engineering projects at the time of design. This paper explains the principal parts and stages in an LCA methodology and demonstrates the approach using the examples of two conventional retaining wall types (gravity and cantilever type) and two mechanically stabilised earth (MSE) wall solutions using steel and polymeric soil reinforcement. The analyses include structures built to four different heights. The LCA methodology was able to quantitatively distinguish between the component environmental impacts of different wall solutions and thus provide a practical numerical score-based tool for designers to choose between candidate solutions. The MSE wall solutions resulted in lower environmental impacts than gravity and cantilever wall solutions as measured by global warming potential, cumulative energy demand, six major midpoint environmental indicator categories, three endpoint damage categories and in terms of overall endpoint scores. The target audiences for this paper are geotechnical and structural engineers engaged in the design of earth retaining\ud wall structures but are less familiar with recent developments in LCA and how LCA can be linked to the design of these systems.Peer ReviewedPostprint (author's final draft

11This paper reports the results of a numerical parametric study focused on the prediction of 12 vertical load distribution and vertical gap compression between precast concrete facing panel 13 units in steel reinforced soil walls ranging in height from 6 m to 24 m. The vertical compression 14 is accommodated by polymeric bearing pads placed at the horizontal joints between panels 15 during construction. The paper demonstrates how gap compression and magnitude of vertical 16 load transmitted between horizontal joints are influenced by joint location along the height of the 17 wall, joint compressibility, and backfill and foundation soil stiffness. The summary plots in this 18 study can be used to estimate the number and type (stiffness) of the bearing pads to ensure a 19 target minimum gap thickness at the end of construction, demonstrate the relative influence of 20 wall height and different material component properties on vertical load levels and gap 21 compression, or used as a benchmark to test numerical models used for project-specific design. 22 The paper also demonstrates that while the load factor (ratio of vertical load at a horizontal joint 23 to weight of panels above the joint) and joint compression are relatively insensitive to foundation 24 stiffness, the total settlement at the top of the wall facing is very sensitive to foundation stiffness. 25The paper examines the quantitative consequences of using a simple linear compressive stress-26 strain model for the bearing pads versus a multi-linear model which is better able to capture the 27 response of bearing pads taken to greater compression. The study demonstrates that qualitative 28 trends in vertical load factor are preserved when a more advanced stress-dependent stiffness soil 29 hardening model is used for the backfill soil compared to the simpler linear-elastic Mohr-30 Coulomb model. While there are differences in vertical loads and gap compression using both 31 soil models for the backfill, the differences are small and not of practical concern. 32 33 Bearing pads; Finite element modeling. 37 38 39 41 42Steel reinforced soil walls constructed with steel strips, bar mats or steel ladders that are attached 43 to steel-reinforced concrete panels are a mature technology. The design focus in guidance 44 documents used by geotechnical engineers is most often on the internal and external stability of 45 the gravity mass formed by the facing panels and reinforced soil zone (e.g., AASHTO 2014). 46 However, the facing column is an important structural component of these systems. It must be 47 designed to carry vertical loads that are greater than the self-weight of the panels. Damians et al. 48(2013) collected data from instrumented steel reinforced soil walls and found that the ratio of 49 measured vertical load to panel self-weight (load factor) ranged from about 2 to 5. These 50 additional vertical loads are the result of downdrag forces generated by backfill soil-panel 51 interface shear due to relative settlement of the backfill plus par...

This paper describes a sustainability assessment methodology and example to select the best sustainable option from candidate conventional gravity and cantilever wall types and steel and polymeric soil-reinforced, mechanically stabilised earth (MSE) walls of different heights. Analyses were carried out using the value integrated model for sustainable evaluations (Mives) methodology, which is based on value theory and multi-attribute assumptions. The paper identifies how indicator issues are scored, weighted and aggregated to generate final numerical scores that allow solution options to be ranked. The final scores include an adjustment based on stakeholder preferences for the relative importance of the three sustainability pillars (environmental, economic and societal/functional). The analysis results show that MSE wall solutions were most often the best option in each category compared to conventional gravity and cantilever wall solutions and, thus, most often they were the final choice when scores from each pillar were aggregated to a final score. However, when cost was weighted most highly of the three pillars, then the conventional wall solutions gave the highest (best) Mives score for walls 3 m high. If environmental issues were the most important concern of stakeholders, then the MSE solutions were the best solution, particularly for walls 5 m high and higher.