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Ground motions and seismic site factors for the design and analysis of infrastructure systems are typically computed based on one-dimensional (1-D) site response analysis, assuming the ground surface is horizontal and the earthquake waves propagate vertically near the ground surface. The 1-D results may not be applicable for sloping ground surfaces and layer interfaces, and therefore, the 1-D results must be adjusted for sloping grounds. In this study, a general framework for developing seismic site factors for sloping grounds and its application for Charleston, SC is presented. The two-dimensional (2-D) site response analysis results of sloping ground were compared with the 1-D horizontal ground results to develop slope adjustment factors. A total of 385 2-D nonlinear finite element simulations of sloping grounds were performed considering seven ground inclinations, 11 shear wave velocity profiles, and five ground motions representative of the area. The results show that the surface responses computed from sloping ground analyses significantly differ from those of horizontal ground analyses. By comparing the 1-D and 2-D results, a set of slope adjustment factors was developed and expressed as an easy-to-use chart. The slope adjustment factor at a project site can be obtained from the proposed chart using site-specific VS30 and ground inclination at a selected period. [ABSTRACT FROM AUTHOR]

This paper presents a quantitative framework to optimise embedded footing performance subjected to extreme historical climate events with respect to the uncertainties associated with site-specific soil and climatic parameters. The proposed framework is developed based on partially saturated soil mechanics principles in conjunction with a multi-objective optimisation algorithm called Non-dominated Sorting Genetic Algorithm (NSGA-II) to develop a robust optimised design procedure. The proposed method was applied to two semi-arid climate sites, Riverside and Victorville, both situated in California, United States. The results show that the proposed method generally improves the embedded footing design compared to conventional methods in terms of cost and performance. Based on the findings, under the extreme climate conditions, the proposed method estimates the average soil degree of saturation within the footing influence zone between 52% and 95%, with a mean value of 63.1% for the Victorville site, and 57% and 90% with a mean value of 81.6% for the site in Riverside. It is also found that the optimal design from the proposed method shows a lower total construction cost, 44% and 19%, for the Victorville and Riverside sites, respectively, compared to the ones designed by the conventional methods. [ABSTRACT FROM AUTHOR]

This article presents the findings of foundation condition analysis performed on the historical coastal fortification, Fort Sumter in Charleston, South Carolina, through coupled numerical modelling of the soil-foundation-superstructure system. The original construction drawings, historical records, and field test results from past and current investigations were used to build and calibrate a representative two-dimensional (2D) cross section incorporating both soil and structural components of the fort. Significant past loadings, identified through historical records, were simulated including initial construction, destruction, repairs, earthquake, and battery construction. Calibration of the numerical model with historical data lends it to become a tool for investigation into the foundational stability of the fort under various loading conditions. The effect of each of the historical loadings on the differential settlement of the foundation was assessed, and it was determined that the foundation is currently in a stable condition but continue to settle slightly which may require further investigation and stabilization to preserve the historical structure. [ABSTRACT FROM AUTHOR]

The static and dynamic behaviours of a retaining wall backfilled with tire aggregate are investigated in this paper through conventional designs as well as coupled finite element simulations. First, a literature survey is conducted to compile the key geotechnical engineering properties of tire aggregate. The data show that the properties vary with the shred size and possess properties desirable to be considered as a retaining wall backfill. Geotechnical designs and computer simulations show significant reductions in structural demand in terms of maximum shear force and bending moment, and construction cost in terms of excavation behind the wall, material required for constructing a retaining wall, and the volume of backfill material when tire aggregate is used as the backfill. The results of a parametric study indicate that the economic advantage is significant even with the highest and the lowest values of the key properties and the parameters of input motion. [ABSTRACT FROM AUTHOR]

A cost- and performance-based robust design optimisation procedure considering the uncertainties in soil properties and wind speed for three typical foundations (raft, pile group and piled raft) for tall wind turbines on clayey and sandy soils is presented in this paper. From the conventional geotechnical designs, it was found that the design is controlled by differential settlement and therefore considered as the response of concern in the robust design optimisation. The robust design optimisation was performed using Non-dominated Sorting Genetic Algorithm II coupled with Monte Carlo simulation to systematically incorporate the uncertainties in the soil properties and wind speed that have a direct impact on the lateral and moment load acting on the foundation. The total construction cost of the foundation and the standard deviation of the differential settlement were considered as the objectives of interest to be minimised. This procedure resulted in a set of acceptable designs presented in a graphical form called Pareto front for each foundation type on clayey and sandy soils. The comparison of Pareto fronts for the three foundations showed that the pile group or piled raft foundation is economical with higher robustness while the raft foundation is economical with lower robustness. Further, the optimum designs of each type of foundation on clayey and sandy soils were determined using the knee point concept from the Pareto front. The easy-to-use Pareto fronts can be used for selecting suitable foundation type and corresponding design variables for a given performance and cost limitations. [ABSTRACT FROM AUTHOR]