Master of Science, University of Toledo, 2010, Civil Engineering

Pavement management is a process that helps to maintain a pavement network in a safe and serviceable condition in a cost effective manner. A key component of an effective pavement management system is its ability to predict the remaining service life of pavements. Remaining service life of pavements can be predicted using the present pavement condition and the latest rehabilitation action performed on that particular pavement. Survival curves are often developed to obtain remaining service life of a pavement family. The objectives of this study are to determine the average service life of pavements and to predict their remaining service life. Remaining Service Life is defined as the projected number of years until rehabilitation is required. The pavement condition data in the form of Pavement Condition Rating (PCR) were used to develop Kaplan-Meier survival curves for different PCR thresholds. PCR 60 was considered as the terminal condition and the average service life of pavement network was calculated as the area under PCR 60 survival curve. Derived performance curves for all the survival probabilities were developed between pavement age and PCR using the Weibull approximation of the Kaplan-Meier survival curves. Derived performance curves were employed to determine the remaining service life of individual pavements based on current age and PCR. PCR curves were also developed for individual PCR thresholds between RSL and pavement age by using the Weibull approximation of the Kaplan-Meier survival curves to better understand the relationship between RSL, PCR and pavement age. Average service life of the pavement network and remaining service life of individual pavements obtained from this study can be used to assist in pavement rehabilitation decision making and budget allocation.

Committee: Eddie Chou PhD (Committee Chair); Azadeh Parvin PhD (Committee Member); George Murnen PhD (Committee Member) Subjects: Civil Engineering; Engineering; Transportation

Doctor of Philosophy, The Ohio State University, 2019, Earth Sciences

Tide gauges record relative sea level (RSL), i.e. the vertical position of the sea surface relative to the adjacent land mass or relative to the seafloor under the gauge. A tide gauge cannot distinguish between a rise in sea level or subsidence of the land or seawall or pier that supports the gauge. Absolute sea level (ASL) refers to the level or height of the sea surface stated in some standard geodetic reference frame, e.g. ITRF2008. Since satellite altimeters make a geometrical measurement of sea level, this constitutes a determination of ASL. Satellite altimeters suffer from instrumental drift and thus need to be calibrated using tide gauges. This requires us to estimate the rate of RSL change at each tide gauge and convert this into an estimate of the rate of ASL change. This is done using a GPS station located at or near the tide gauge, since it can measure the vertical velocity of the lithosphere – often referred to as vertical land motion, VLM – which allows us to exploit the relationship ASL = RSL + VLM. This goal has motivated geodesists to build dozens of continuous GPS (or CGPS) stations near tide gauges – an agenda sometimes referred to as the CGPS@TG agenda. Unfortunately, a significant fraction of all long-lived tide gauges – especially those in the Pacific - have also recorded non-steady land motion caused by earthquakes. Rather than simply delete such datasets from the agenda, this thesis explores a new analytical method, based on the concept of a geodetic station trajectory model, that allows us to compute RSL and ASL rates even at tide gauges affected by regional earthquakes. We illustrate this method using two tide gauges (PAGO and UPOL) and three GPS stations (ASPA, SAMO and FALE) located in the Samoan islands of the Southwest Pacific. In addition to managing the impact of large regional earthquakes, we also seek new approaches to reducing noise in RSL rate estimates by suppressing the higher frequency sea level changes associated with ocean (open full item for complete abstract)

Committee: Michael Bevis (Committee Chair); C.K. Shum (Committee Member); Loren Babcock (Committee Member); Michael Barton (Committee Member) Subjects: Earth; Geological; Geophysical; Geophysics; Geotechnology; Ocean Engineering; Oceanography