Gregg Fiegel

Incorporating Learning Outcomes into an Introductory Geotechnical Engineering Course.

The article describes the process of incorporating a set of learning outcomes into a geotechnical engineering course. The outcomes were developed using Blooms taxonomy and define the knowledge, skills, and abilities the students are expected to achieve upon completion of the course. Each outcome begins with an action-oriented verb corresponding to one of six levels of achievement in the cognitive domain (remember, understand, apply, analyse, evaluate, and create). The article includes a listing of outcomes articulated for several course topics. The article also summarises how the outcomes were linked to lesson plans and assignments. Example formative and summative assessment methods and results are presented with the results of teaching evaluations, which indicate that students value this approach to course design. The article concludes with a discussion of how the above approach has been implemented in upper-division courses. Outcomes are presented for a course on earth retention systems.

Evaluation of international roughness index for asphalt overlays placed over cracked and seated concrete pavements

Crack, seat and overlay (CS&O) is a rehabilitation technique that has been used on jointed plain concrete pavements. Only a few studies have evaluated the surface roughness of pavement sections rehabilitated using this technique. The purpose of this paper was to evaluate the roughness of roadway sections rehabilitated employing the CS&O technique. The data extracted from the long-term pavement performance database were separated based on the weather region and analysed. Then, international roughness index (IRI) prediction models were developed. A separate model was developed for pavement sections in California. For sections with bound bases, thick overlays provide a smoother surface (lower IRI). However, the effect of the overlay thickness on the IRI for sections with unbound bases does not appear to be considerable. Prediction models developed in this study are shown to provide adequate predictive capabilities. Sections in California have initial IRI values that are lower than those found for sections in the wet-with-freeze (WF) and wet-with-no-freeze (WNF) regions. However, California sections are predicted to develop higher IRI values over time, when compared to those sections in the WF and WNF regions.

Effectiveness of Water Jetting for Removal of Anomalous Materials from Drilled Shafts

Initial results from a parametric laboratory investigation are described: the investigation was designed to study the effectiveness of water jetting as a means for removal of anomalous materials from concrete drilled shaft foundations. A primary objective for the investigation was to establish relationships between jetting parameters and the removal of commonly occurring anomalous zone materials, including low-strength concrete, slurry-mixed concrete, grout, and clay soil. The experimental work consisted of water blasting test specimens with rotary jets, nozzles, and pumping equipment typically used in construction practice. During testing, material removal rates were measured as a function of jet pressure and standoff distance for specimens with compressive strengths ranging between approximately 5 and 6,500 psi. Water-blasted specimens were cut apart after testing to confirm erosion measurements and to permit inspection of the water-blasted surfaces. The results show that erosion rates and the effectiveness of water jetting are primarily influenced by compressive strength when standard test equipment and jetting pressures are used. The size and angularity of aggregate in the anomalous material do not appear to influence erosion. The greatest erosion was observed for a semicemented material with a compressive strength of approximately 500 psi. Maximum erosion was observed approximately 12 in. from the axis of the jet.

Performance Prediction Models for Cracked, Seated, and Overlaid Concrete Pavements in California

Crack, seat, and overlay (CS&O) is a rehabilitation technique used on jointed plain concrete pavements in California. Although CS&O is widely used, few studies have attempted to develop performance prediction models for pavements that have been rehabilitated with this technique. This study evaluated CS&O performance for surface roughness and transverse reflection cracking. Performance data for CS&O sections in three geographic regions in California were used to develop regression performance models. These models can be incorporated into the California Department of Transportation pavement management system and used to predict future performance, assist with life-cycle cost analyses, and optimize the allocation of resources. The results of a sensitivity analysis suggest that section age is the most significant factor affecting the deterioration of CS&O pavements. Secondary factors include the annual equivalent single-axle load and layer thickness ratio. Section age as an independent variable would include the impact of environmental loading cycles. Other factors related to subgrade conditions, temperature variations, and construction variability could not be investigated because data were not available. However, their impact is inherent to the models.

Water Jetting to Mitigate Defects in Drilled Shafts: Laboratory Investigation

A laboratory investigation was designed to examine the effectiveness of water jetting as a means of removing anomalous (deleterious) material from drilled shafts. One objective of the investigation was to establish relationships between jetting parameters and the removal of common anomalous materials, including low-strength concrete, slurry-mixed concrete, grout, and clay soil. The experimental work consisted of blasting test specimens of anomalous material with water by using rotary jets, nozzles, pumping equipment, and testing procedures in current construction practice. During testing, erosion levels and rates were measured as a function of jetting pressure and standoff distance for specimens with compressive strengths ranging between approximately 5 and 6,500 pounds per square inch (psi). Erosion levels, erosion rates, and water-jetting effectiveness were found to correlate with the compressive strength of the anomalous material. Reinforcing steel bars in a drilled shaft influenced erosion levels and water-jetting effectiveness locally by interfering with the jet path. For jetting pressures around 10,000 to 11,000 psi, erosion was observed to a radial distance of approximately 12 in. from the axis of the water jet for the weakest specimen. The erosion distances observed during the investigation were less than half of the maximum design spacing typically used for drilled shaft access tubes installed for nondestructive testing.