Document Type

Thesis - University Access Only

Award Date

1993

Degree Name

Master of Science (MS)

Department / School

Civil Engineering

First Advisor

Vernon R. Schaefer

Abstract

In South Dakota bridge approach design has evolved to the use of select granular backfill behind the abutment wall as a strong and free-draining support for reinforced concrete approach slabs at bridge ends. Since 1988 the select backfill has been encapsulated in geotextiles in an effort to prevent erosion of the backfill. Despite modifications to the design of the approach systems, problems continue to occur, appearing as voids under approach slabs, continued differential movements, and cracking and erosion of the approach embankment. The resulting maintenance necessary to correct the problems is expensive. In addition, the use of a select backfill and reinforced approach slabs adds considerably to the original cost of each bridge. The primary problem which has developed is the appearance of voids under the reinforced concrete approach slabs in new and rehabilitated approach systems across the state. The void development has led to distress to concrete approach slabs in the form of transverse and longitudinal crack development, resulting in a decrease of the life expectancy of the system and increased maintenance costs for repair and stabilization of the system. While no immediate threat to the structural integrity of the bridge structure or the approach slab exists, continued traffic loading and water infiltration may lead to sufficient deterioration to necessitate the eventual replacement of the approach system. Maintenance personnel have resorted to mudjacking, the placing of cement slurry in the void space, to stabilize the approach slab and prevent further distress from occurring.

Library of Congress Subject Headings

Bridges -- South Dakota -- Design and construction  -- Models
Bridges -- South Dakota -- Abutment -- Models

Publisher

South Dakota State University

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Rights Statement

In Copyright