Natural Hazards and Disaster Management

Biography

Biography: Hesham Ali

Abstract

The State of Florida maintains 40,000 lane-miles of paved roads. The design of such roads calls for a 3 foot clearance between the pavement base and the ground water table for multi-lane roads and a 2 foot clearance for rural 2-lane roads. The purpose of this clearance is twofold: First, allow for dry conditions during construction to facilitate placement and compaction of subgrade and base layers. Second, budget for a capillary rise of 24” and fluctuating ground water table and ensure dry subgrade conditions during the life of the road, which is essential for a good subgrade support, as characterized by the Subgrade Resilient Modulus. The objective of this effort is to quantify the effect of ground water table rise, caused by Seal Level Rise, on pavement structural capacity. Examine, at a network level, a set of strategies that can help with the SLR challenge over the next 30 years. It is envisioned that maps of roads be prepared on the basis of base-water clearance. Then use time forward projection of ground water table rise rates to determine the time frame in which FDOT would have to address the pavement deficiencies. Three scenarios will be considered for the rate of SLR; Low, Moderate and High.

X GIS Map of Base-water Clearance.

GIS maps can be presented in terms of: The deficit in base-water clearance and; the deficit in structural capacity, as determined in equivalent single Axle load. For instance, as a result of the reduction in subgrade modulus, the remaining life of a pavement section can be computed in ESAL: Loss of vehicle miles traveled as a result of reduced capacity. This will be computed by converting the axle count into vehicles and multiplying by the mileage and; cost estimate of cost of increasing the pavement structural capacity so as to eliminate the structural deficiency.