Phillip S. K. Ooi

• Doctor of Philosophy
• Professor at University of Hawaiʻi at Mānoa

The resilient modulus ( M r ) is typically interpreted as the average of the last five secant slopes of the cyclic stress-axial resilient strain curve from repeated loading triaxial tests. It is not uncommon to then fit mathematical models to the secant M r to derive model parameters ( K i , more commonly known as K 1 , K 2 , and K 3 ) that are the...

31 undisturbed cohesive silts with plasticity indices ranging from 3 to 55% were tested in an erosion function apparatus to obtain their erodibility curves. The critical shear stress (τcr)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usep...

Rockfalls and landslides commonly occur in the Hawaiian islands. When these events occur along a thoroughfare, they can result in the loss of lives, cause significant damage to infrastructure, and force full or partial road closures, resulting in traffic congestion and commuting delays, sometimes for months. The Hawaii Department of Transportation...

Nuclear density gauges (NDG) have been widely used for field compaction control. However, their shortcomings include the burden of licensing with nuclear regulatory agencies, gauge maintenance, storage and transportation restrictions, requirement to wear dosimeters, and radiation safety training. A recently developed low-activity NDG (LANDG) altern...

A power model (ε = A. NB) to estimate permanent strain (ε) from single-stage repeated load triaxial (RLT) tests can simulate both shakedown and incremental collapse. When the exponent B < 1, the ε versus load cycle number (N) plot concaves downwards, resembling that of a material that shakes down. When B > 1, the same plot concaves upwards, mimicki...

When subjected to ambient daily temperature fluctuations, a 109.5 ft-long geosynthetic reinforced soil integrated bridge system (GRS-IBS) was observed to undergo cyclic straining of the superstructure. The upper and lower reaches of the superstructure experienced the highest and lowest strain fluctuation, respectively. These non-uniform strains imp...

A 109.5-Ft-long Geosynthetic Reinforced Soil Integrated Bridge System (GRS-IBS) in Hawaii was instrumented to measure superstructure strains, vertical pressures below the footing, lateral pressures behind the end wall and modular block facing, and lateral displacements of the facing. Field surveys were also performed to measure the bridge footing s...

Obtaining the particle size distribution (PSD) of fine-grained soils in hydrometer testing has several shortcomings, particularly long test duration, whereas a laser diffractometer can provide a soil’s PSD relatively expediently. PSDs of the finer fraction of several Hawaiian soils using laser diffraction were compared with those from hydrometer te...

The scour rate found by the cohesive soil-erosion function apparatus (SRICOS-EFA) method provides more accurate and realistic scour predictions than the Richardson and Davis equation, which tends to overpredict scour, especially in cohesive soils. Scour of cohesive soil occurs more slowly than scour of cohesionless soils. The time-dependent nature...

Nearly 60% of bridge failures in the United States are caused by scour. When water flows in a channel, there is a critical value of riverbed shear stress; below this value, scour will not take place. This critical shear stress is an important parameter in scour prediction. However, a standard method to estimate the critical shear stress does not ex...

Four pairs of large-scale instrumented geosynthetic reinforced soil (GRS) square columnswere load tested to study the effects of varying reinforcement strength to spacing ratio, to discern the lateral pressures during construction and during load testing, and to derive shear strength parameters of the GRS composite. Each pair was identical in every...

The geosynthetic reinforced soil (GRS) performance test (PT), also called a mini-pier experiment, was developed by the Federal Highway Administration (FHWA) to evaluate the material strength properties of GRS composites built with a unique combination of reinforcement, compacted fill, and facing elements. The PT consists of constructing a 1.4-m squ...

A database of load tests performed on geosynthetic reinforced soil (GRS - reinforcement in this study is of the extensible variety) was developed using results of recent load tests performed on large scale GRS structures at the Federal Highway Administration's Turner Fairbank Highway Research Center as well as results from the literature. The measu...

FOREWORD The use of geosynthetic reinforced soil (GRS) for load bearing applications such as bridge abutments and integrated bridge systems (IBS) has expanded among transportation agencies looking to save time and money while delivering a better and safe product to the traveling public. GRS has been identified by the Federal Highway Administration...

The pressure for pavement and geotechnical engineers to incorporate sustainability into engineering projects has led to a rise in the use of recycled concrete aggregate (RCA) as fill and in pavement sublayers. Although the use of RCA has many economical, environmental, and engineering advantages, an oversight in quality control can lead to the use...

With a rise in virgin aggregate consumption, the use of recycled materials has become an attractive solution in earthwork and pavement construction. An understanding of the behavior and characteristics of recycled materials is necessary before they are used in practice. In this study, the behavior of recycled concrete aggregate (RCA) during compact...

Utilization of crushed recycled concrete aggregate (RCA) in highway projects has become increasingly common due to many advantages both environmentally and economically. To understand its behavior more, a series of repeated load triaxial tests were conducted to assess the permanent deformation (PD) characteristics of RCA, a basaltic virgin aggregat...

The role of an aggregate base course layer in a flexible pavement system is to distribute loads to a stress level that can be sustained by the underlying subgrade. When a pavement is analyzed as a layered, isotropic elastic system, it is not uncommon to see tensile stresses at the bottom of the base course layer upon application of a wheel load. Te...

Crushed recycled concrete aggregate (RCA) has been widely utilized as base and sub-base course and as backfill. Despite the advantages of RCA, one of the potential concerns in some states is that its use can lead to the precipitation of calcium carbonate, or tufa, which can impair drainage and clog filter fabrics, which in turn can lead to prematur...

The demand for pavement construction aggregate is growing significantly. With a rise in aggregate consumption, the use of recycled materials has become an attractive solution in pavement construction from both economical and environmental perspectives. Use of recycled materials in the base course demands understanding of their properties including...

A multistage permanent deformation (PD) test of geomaterials is more economical than the single-stage variety. Only one sample must be tested for the former, whereas several tests on multiple samples are required for the latter. Yet no standards exist for this test in the United States, nor is there a generally accepted procedure for determining th...

Utilization of reclaimed asphalt pavement (RAP) aggregate in highway projects has become common practice in the United States because it has considerable environmental and economical advantages. This study evaluates the resilient modulus (M r) of a crushed RAP on its own, a basaltic virgin aggregate (VA) on its own as well as when the two are bende...

The abutments of integral bridges are traditionally supported on a single row of steel-H-piles that are flexible and that are able to accommodate lateral deflections well. In Hawaii, steel-H-piles have to be imported, corrosion tends to be severe in the middle of the Pacific Ocean, and the low buckling capacity of steel-H-piles in scour-susceptible...

The majority of integral abutment bridges (IABs) in the United States are supported on steel H-piles to provide the flexibility necessary to minimize the attraction of large lateral loads to the foundation and abutment. In Hawaii, steel H-piles have to be imported, corrosion tends to be severe in the middle of the Pacific Ocean, and the low bucklin...

A comparison of the California bearing ratio (CBR) for recycled glass (RG) with other recycled materials and a basaltic virgin aggregate, all having similar gradations, revealed that the CBR of RG is superior to that of recycled asphalt pavement but less than that of recycled concrete and virgin aggregate. Direct shear tests were then run on the as...

This paper presents the specification and estimation of a model based on the mechanistic empirical Pavement Design Guide (PDG) for estimating resilient modulus of fine-grained soils by using common soil parameters and by combining two different data sources: a database developed with Hawaiian fine-grained soils and data extracted from the Long Team...

The characteristic load method (CLM) can be used to estimate lateral deflections and maximum bending moments in single fixed-head piles under lateral load. However, this approach is limited to cases where the lateral load on the pile top is applied at the ground surface. When the pile top is embedded, as in most piles that are capped, the additiona...

The difference between a load test and a proof test is that in a load test, the foundation is loaded to failure, whereas in a proof test, it is usually tested to the design load times the desired margin of safety, and failure may not necessarily be reached. Paikowsky and Tolosko (1999) presented and examined methodologies for obtaining the ultimate...

Three-parameter models have been used to represent the effects of confining and shear stresses on the value of resilient modulus. A new generation of such models allows better characterization of the variation of resilient modulus at low deviator stress. These models can be extended to incorporate the effects of soil type, soil structure, and the s...

Bending moments in excavation support walls and deep foundations are frequently estimated using curvature derived from inclinometer surveys. The basic idea involves fitting a curve or a series of curves to the inclinometer data. The curvature is then estimated as the second difference of the displacement profile. Although many methods are available...

Current procedures for high strain dynamic testing of piles require estimation of the dynamic resistance. This paper presents an innovative method of load testing deep foundations that estimates the pile capacity directly. By placing and monitoring sensitive force sensors near a pile head, a force-time curve can be generated when an impact load is...

Current procedures for high strain dynamic testing of piles require estimation of the dynamic resistance. This paper presents an innovative method of load testing deep foundations that estimates the pile capacity directly. By placing and monitoring sensitive force sensors near a pile head, a force-time curve can be generated when an impact load is...

There has been a recent push toward adoption of in-place soil stiffness as a means of assessing compactness of pavement geomaterials. From a series of low strain GeoGauge stiffness measurements made under controlled laboratory conditions on compacted silts, the variation of stiffness with water content, dry unit weight, degree of saturation, volume...

A single-propped soldier-pile-tremie-concrete wall was constructed as part of the excavation support system for a tunnel jacking project. This wall supported a 14.3-m-high cut with a significant unbraced height (13.4 m) above the excavation subgrade. A limited area of the excavation subgrade next to the wall was jet grouted to provide stability aga...

A single-propped soldier-pile-tremie-concrete wall was constructed as part of the excavation support system for a tunnel jacking project. This wall supported a 14.3-m-high cut with a significant unbraced height (13.4 m) above the excavation subgrade. A limited area of the excavation subgrade next to the wall was jet grouted to provide stability aga...

The analyses and performance of a soldier-pile-tremie-concrete (SPTC) wall with a significant unbraced length is presented. The wall was constructed as part of the excavation support system of the Ramp D tunnel jacking pit built for Contract C09A4 of the Central Artery/Tunnel Project in Boston, Massachusetts. This wall is unique in that it supporte...

The p-y method of analysis models nonlinear behavior, and is an effective method of designing deep foundations subjected to lateral loads. Deflections and bending moments calculated using p-y analyses have usually been found to be in good agreement with field measurements. This paper describes a method of analysis, the characteristic load method (C...

Current procedures for designing groups of piles for lateral loading require the use of a computer or extensive manual computations. This paper presents a simple method (the group amplification procedure) for estimating pile group deflections and maximum bending moments based on the theories of Poulos, and Focht and Koch. The method is applicable t...