Arash KhosravifarPortland State University | PSU · Department of Civil and Environmental Engineering
Arash Khosravifar
Ph.D., P.E.
About
36
Publications
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236
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Citations since 2017
Introduction
Arash Khosravifar currently works at the Department of Civil and Environmental Engineering, Portland State University. Arash does research in Geotechnical Earthquake Engineering. His current project is 'Development of a Design Guideline for Bridge Pile Foundations Subjected to Liquefaction-Induced Lateral Spreading'.
Additional affiliations
January 2016 - January 2016
Publications
Publications (36)
Fully-coupled nonlinear dynamic analysis is increasingly used for assessing the seismic performance of pile-supported wharf structures subjected to liquefaction-induced lateral ground deformations. Several numerical challenges exist for analysis of this highly nonlinear soil-structure interaction, which require robust, yet practical, solutions that...
The results of cyclic strain-controlled, constant volume direct simple shear (CDSS) tests and field shaking tests have been evaluated for intact, natural, low-plastic silts from six different fine-grained soils with 54%–100% fines content, 47%–83% silt content, and plasticity indices (PI) ranging from nonplastic to 16. These tests constitute a subs...
A large earthquake is anticipated for the Pacific Northwest of the United States and western Canada from the Cascadia Subduction Zone (CSZ). The earthquake is expected to cause significant damage to infrastructure, including at Oregon’s Critical Energy Infrastructure (CEI) hub which extends for over 9 km and handles 90% of Oregon’s liquid fuel. The...
Nonlinear dynamic analyses were performed to evaluate the effects of ground motion duration on the dynamic response of a pile-supported wharf subjected to liquefaction-induced lateral ground deformations. The numerical model was first calibrated using recorded data from a well-instrumented centrifuge test, after which incremental dynamic analyses w...
Earthquake liquefaction hazards in silty soils are a critical problem in Portland, Oregon and other areas around the world. Recent studies suggest that liquefaction mitigation using microbially-induced desaturation (MID) may provide the capability to mitigate liquefaction potential beneath existing structures in a cost-effective manner. The objecti...
Failure of tailings dams can result in significant spill, loss of human lives, and damages to the environment and infrastructure. Cyclic loadings such as earthquakes and blasting are among the main threats to the stability of tailings dams. Seismic stability analyses of tailings dams are further challenged by the uncertainty and variability of tail...
The results of five centrifuge models were used to evaluate the response of pile-supported wharves subjected to inertial and liquefaction-induced lateral spreading loads. The centrifuge models contained pile groups that were embedded in rockfill dikes over layers of loose to dense sand and were shaken by a series of ground motions. The p-y curves w...
Microbially Induced Desaturation (MID) is an emerging bio-based methodology for mitigating the potential for earthquake-induced soil liquefaction. In MID, a treatment solution typically composed of calcium nitrate and calcium acetate is introduced into the soil to stimulate native denitrifying bacteria. A by-product of the stimulation of denitrifyi...
The interaction of inertial and kinematic demands is investigated using data from five physical models of pile-supported wharves using a large-scale geotechnical centrifuge. The wharf structures in this study were subjected to a suite of recorded ground motions, therefore associated superstructure inertia, and earthquake-induced slope deformations...
Fine coal refuse (FCR) is the waste produced in mining process. FCR can be classified as low-plasticity to non-plastic sandy silt or silty sand. Although FCR consists of appreciable amount of fines content (30% to 60%), there is a high liquefaction potential for hydraulically deposited FCR in impoundments due to its loose and saturated structure as...
The geotechnical properties, cyclic behavior, and liquefaction resistance of in situ fine coal refuse (FCR) have not been sufficiently investigated. This paper presents the characterization of static and dynamic geotechnical properties of in situ coal slurry samples. Representative coal slurry samples were taken from two coal slurry impoundments in...
A constitutive soil model that was originally developed to model liquefaction and cyclic mobility has been updated to comply with the established guidelines on the dependence of liquefaction triggering to the number of loading cycles, effective overburden stress (Kσ), and static shear stress (Kα). The model has been improved with new flow rules to...
Results of a centrifuge test on a pile-supported wharf were used to investigate the time-, depth-, and row-dependent nature of kinematic and inertial loading on wharf piles in sloping rockfill. P-y models were calibrated against recorded bending moments in different piles and different depths. It was found that full kinematic demands and full super...
Effective-stress nonlinear dynamic analyses (NDA) were performed for a large-diameter reinforced concrete (RC) pile in multi-layered liquefiable sloped ground. The objective was to assess the effects of earthquake duration on the combination of inertia and liquefaction-induced lateral spreading. A parametric study was performed using input motions...
The original strong-rock (SR) p-y curves for rock-socketed shafts exhibit a brittle response where the post-peak resistance drops to approximately zero. This brittle response could result in a progressive failure of the rock p-y curves which, in turn, results in excessive pile lengths. This paper proposes a modification to the strong-rock (SR) p-y...
Effective-stress nonlinear dynamic analyses (NDA) were performed for piles in the liquefiable sloped ground to assess how inertia and liquefaction-induced lateral spreading combine in long- and short-duration motions. A parametric study was performed using input motions from subduction and crustal earthquakes covering a wide range of durations and...
Large areas of Iraq are covered with collapsible soils namely gypsiferous soil which is often used as the foundation soil for structures. In particular, the Mosul Dam foundation is comprised of high contents of gypsiferous soils. Intrusion of water through the foundation soil dissolves gypsum which acts as the binding material between soil particle...
We have developed an efficient computational framework for simulating multiple earthquake cycles with off-fault plasticity. The method is developed for the classical antiplane problem of a vertical strike-slip fault governed by rate-and-state friction, with inertial effects captured through the radiation-damping approximation. Both rate-independent...
Inelastic response of extended pile shafts subjected to liquefaction-induced lateral spreading is investigated using nonlinear dynamic analyses (NDA) covering a range of soil, pile and ground motion conditions. Each soil-structure scenario was analyzed for three cases: a baseline case with soil liquefaction and superstructure inertia; a case with l...
An equivalent static analysis (ESA) procedure is proposed for the design of extended pile shafts subjected to liquefaction-induced lateral spreading during earthquake loading. The responses of extended pile shafts for a range of soil, structure and ground motion conditions were examined parametrically using nonlinear dynamic finite element analyses...
In today’s world it is extremely essential that undergraduate civil engineering students have the ability to analyze and solve engineering problems by applying basic principles. In order to do so, it is very important to integrate various fundamental fields to understand the impact of civil engineering solutions in a global and societal context con...
The seismic design of extended pile shafts for the combined effects of dynamic shaking and liquefaction-induced lateral spreading is investigated using nonlinear dynamic finite element analyses (NDA). Results of NDA parameter studies are used to illustrate how inertia and lateral spreading loads combine during shaking. The NDA results are used to e...
About 4 million rural houses of Iran are vulnerable against earthquake. Considering this essential issue, a study on seismic vulnerability of traditional houses is conducted. This paper presents parts of findings of the first stage of this research containing structural classification of rural houses of Iran and their distribution through the count...
Seismic performance of traditional houses of Iran is investigated in this paper. Structural classification of such buildings is carried out regarding their structural elements. Climate and seismicity of Iran is briefly discussed. Then vulnerability of adobe houses and their failure mechanisms in recent earthquakes of Bam (26 Dec 2003) and Dahoeieh-...
Projects
Projects (4)
The overall objective of this research is to develop a design guideline for pile supported wharves under combined effects of liquefaction-induced lateral spreading and superstructure inertia.
This project is sponsored by Deep Foundation Institute (DFI) and National Science Foundation (NSF).
Large areas of Iraq are covered with collapsible soils namely gypsiferous soil which is often used as the foundation soil for structures. In particular, the Mosul Dam foundation is comprised of high contents of gypsiferous soils. Intrusion of water through the foundation soil dissolves gypsum which acts as the binding material between soil particles. This phenomenon results in the formation of collapsible soils which can cause serious damages to the dam structure. The failure of Mosul Dam, with a reservoir as large as 11 billion cubic meter of water, can be catastrophic. In the past, Mosul Dam Authorities have been remediating the soil foundation by injecting cement mortar. This method has been proved not economic; therefore, new, more efficient, methods are desperately needed.
This research study focuses on finding practical methods to remediate collapsibility of gypsiferous soils by improving their geotechnical properties. This study presents remediation of collapsible gypsum-rich soil by grouting. Three types of stabilizer materials were used to make the grout; (1) sodium silicate (Na2 O3 Si) which is well known chemical soil stabilizer, (2) bentonite slurry, and (3) silicone oil. The purpose for using these stabilizer materials is to provide an impermeable layer (waterproofing coat) around the gypsiferous soil particles and to fill the voids that may occur in the soil as a result of gypsum dissolution when subjected to water.
A series of double oedometer (collapse) tests and direct shear tests were carried out for gypsiferous soil before and after remediation by grouting. The results show that treated gypsiferous soil by grouting decreases soil compressibility by reducing volumetric strain and decreases the potential for collapsibility. Also, grouting increases the shear strength of soil at confining stresses smaller than about 250 kPa by increasing the cohesion combined with slight reduction of the internal friction angle.
FLAC models were calibrated for treated and untreated soils studied here to evaluate the behavior of foundations in future stages of this research. The calibrated parameters for soil models are presented here.
KEYWORDS: grouting, compressibility, collapsibility, stabilizer.
