Joseph Wartman

ENGINEERING PROPERTIES OF CRUSHED GLASS-SOIL BLENDS

This paper reports on a laboratory study to evaluate the feasibility of using crushed glass to improve the engineering characteristics of fine-grained, marginal materials (e.g. kaolin, quarry fines) and conversely, to explore the extent to which soil blending could enhance the cohesive behavior of crushed glass (CG). Several basic physical and mechanical properties of two different soil-glass blends increased by 50% to 100% by the addition of fine-grained soils; however, this was accompanied by a 20% to 45% reduction in frictional strength. When considering the addition of CG to marginal soils to improve their strength characteristics, the results show a significant amount of frictional strength was added to the fine grained soils through addition of CG.

Engineering Analysis of Ground Motion Records from the 2001 Mw 8.4 Southern Peru Earthquake

The Mw 8.4 23 June 2001 Southern Peru earthquake generated intense ground motions in a large region encompassing southern Peru and northern Chile. The earthquake was recorded by seven strong motion stations with peak ground accelerations ranging from 0.04 g to 0.34 g for site-to-fault distances ranging from about 70 km to 220 km. At this time, there are no other strong motion records for an earthquake of this magnitude. Hence, the strong motion data set from this earthquake is unique and of particular interest to engineers dealing with seismic design in subduction regions. This paper presents an engineering analysis of the strong motion records. Shear-wave velocity profiles were measured using Spectral Analysis of Surface Waves methods at four stations. Measured shear-wave velocities are high, indicating that all sites classify as stiff soil sites (Site C) according to the International Building Code classification scheme. The strong motion set is characterized by strong high frequency content at large distances from the fault. Site response contributed at least in part to the observed high frequency content in the ground motions. In general, current attenuation relationships for spectral acceleration underpredicted the observed ground motions.

Investigation of the performance of the New Orleans regional flood protection systems during Hurricane Katrina: Lessons learned

The recent flooding and devastation of the greater New Orleans region during hurricane Katrina represented the most costly peace-time failure of an engineered system in North American history. Extensive investigations and analyses have been performed by several major teams in the wake of this disaster, and some very important lessons have been learned. Many of these have very direct and urgent applications to levee systems in other regions throughout the U.S., and the world. Lessons include the importance of proper evaluation of risk and hazard; so that appropriate decisions can be made regarding the levels of expense and effort that should be directed towards prevention of catastrophe, and the levels of post-disaster response capability that should be maintained as well. The making of appropriate decisions, given this information regarding risk levels, is then also important. Also of vital importance are numerous “engineering” lessons regarding analysis, design, construction and maintenance; hard-won lessons with applications to flood protection systems everywhere. We must now do everything possible to capitalize upon these; and to prevent a recurrence of this type of catastrophe in the future. 1 Professor, Dept. of Civil and Environmental Engineering, University of California at Berkeley, Berkeley, California 94720. Email: seed@ce.berkeley.edu GSP 161 Embankments, Dams, and Slopes Copyright ASCE 2007 Geo-Denver 2007: New Peaks in Geotechnics Redistribution subject to ASCE license or copyright. Visit http://www.ascelibrary.org

VARIABILITY AND SCALE-DEPENDENCY OF RECYCLED RUBBER TIRE MATERIALS

This paper presents a variability study of several engineering properties of recycled rubber tire pieces based on a comprehensive literature survey of experimental test programs. The unit weight, cohesion, internal friction angle, Youngs modulus of elasticity and Poissons ratio were evaluated and compared to engineering property variability of natural soils. In addition, a series of regression and residual analysis were performed to investigate the presence and significance of scale-dependency on the engineering properties of rubber tire pieces. The results of the variability analysis show that unit weight and Poissons ration have the lowest values of coefficient of variation whereas the shear strength parameters ad he elastic modulus have the highest. From the regression analysis, cohesion and Youngs modulus showed the greatest sensitivity to changes in maximum tire particle size. However, these results are based on statistics that have limitations when used for interpretive purposes. A non-statistical investigation based on geotechnical theory was used to further evaluate the scale-dependency of the shear strength parameters. Using Mohr-Coulomb failure theory and assuming that the cohesion component of strength is justifiable neglected, the analysis showed a scale-independent relationship which is consistent with the statistical findings for internal friction angle.

Geotechnical aspects of the January 2003 Tecoma'n, Mexico, earthquake

Ground failure was the most prominent geotechnical engineering feature of the 21 January 2003 Mw 7.6 Tecomán earthquake. Ground failure impacted structures, industrial facilities, roads, water supply canals, and other critical infrastructure in the state of Colima and in parts of the neighboring states of Jalisco and Michoacán. Landslides and soil liquefaction were the most common type of ground failure, followed by seismic compression of unsaturated materials. Reinforced earth structures generally performed well during the earthquake, though some structures experienced permanent lateral deformations up to 10 cm. Different ground improvement techniques had been used to enhance the liquefaction resistance of several sites in the region, all of which performed well and exhibited no signs of damage or significant ground deformation. Earth dams in the region experienced some degree of permanent deformation but remained fully functional after the earthquake.

Predicting Time-to-Failure in Slopes from Precursory Displacements: A Centrifuge Experiment

Predicting the time-to-failure of slow-moving landslides based on precursory displacements is an appealing concept that could significantly improve our ability to evaluate and manage landslide risk. In this paper, we explore this concept by examining data from a well-documented failure of a submerged, saturated clay slope that occurred during a controlled geotechnical centrifuge experiment. We found that application of a simple linear inverse velocity relationship to the initial portion of the data set produced conservative but nevertheless inaccurate predictions of time-to-failure. Repeating this exercise with data collected closer to failure provided significantly improved the prediction, but at the cost of reduced warning time. A related non-linear model produced an excellent fit over the full time range of observed displacements, but required curve fitting parameters drawn from empirical observations, thus limiting its practical application for predicting the time-to-failure. Still, both models provided a very good basis for understanding and interpreting displacement-time monitoring data, and as landslides progress towards failure, we found that these models are capable of accurately predicting time-to-failure.

Spatial Analysis for Identifying Concentrations of Urban Damage

Disasters resulting from earthquakes, hurricanes, fires, floods, and terrorist attacks can result in significant and highly concentrated damage to buildings and infrastructure within urban regions. Following such events, it is common to dispatch investigation teams to catalog and inventory damage locations. In recent years, these data gathering efforts have been aided by developments in high resolution satellite remote sensing technologies (e.g. Matsuoka & Yamazaki, 2005) and by advances in ground-based field data collection (e.g. Deaton & Frost, 2002). Damage inventories are typically presented as maps showing the location and damage state of structures in part or all of an effected region. In some cases information on the post-event condition of major infrastructure systems such as transportation, power, communications, and water networks is also included. Depending on the means used to acquire data, damage inventories may be developed in days (satellitebased data acquisition) or weeks-to-months (ground-based damage surveys) after an event. Once available, these inventories can be used for a range of purposes including guiding emergency rescues (short-term use), identification of neighborhoods requiring post-disaster financial assistance (intermediate-term use), and support of zoning, planning or urban policy studies (long-term use). An important task when analyzing these inventories is to identify and quantify damage concentrations or clusters, as this information is useful for prioritizing post-disaster recovery activities. Additionally, an understanding of damage concentrations can provide insight to the multiscale processes that govern an urban regions performance during an extreme event. In some cases spatial patterns and clusters can be inferred from damage inventories using simple, qualitative visual assessment techniques. While this may be a satisfactory approach in situations where there is a marked contrast in building performance, its effectiveness is limited when damage contrasts are subtle, and spatial patterns are less obvious. In these instances, more advanced spatial analysis tools such as point pattern analysis can be of benefit. Point pattern analysis (PPA) techniques are a group of quantitative methods that describe the pattern of point (or event) locations and determine if point locations are concentrated (or clustered) within a defined region of study. An early and often-cited example of a semi7

Investigation of levee performance in Hurricane Katrina: The inner harbor navigation channel

The Inner Harbor Navigation Channel (IHNC) sits at the heart of the three main populated regions of New Orleans. As shown in Figure 1, a number of breaches of varying severity occurred along the shores of the IHNC during Hurricane Katrina, contributing to the flooding of all three of the most heavily populated protected areas flooded in this event. This paper presents the results of geotechnical and geo-forensic investigations performed to determine the causes of the various failures along the shorelines of the IHNC. This includes the two massive breaches at the west end of the Lower Ninth Ward, and a number of lesser breaches and partial breaches (distressed sections) along other sections of the canal. There are many lessons here, not just for the greater New Orleans region, but for the nation and for the Profession as well.