Lightweight Concrete Bridges for California Highway System


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Title: Lightweight Concrete Bridges for California Highway System

Author(s): James E. Roberts

Publication: Special Publication

Volume: 136


Appears on pages(s): 255-272

Keywords: bridges (structures); creep; highways; lightweight aggregates; lightweight concretes; moisture content; shrinkage; static loads; structural steels; Construction

Date: 1/1/1993

Describes the use of expanded shale lightweight concrete for both older bridge widenings and new bridge construction on the California State Highway System in the past 30 years. Examples of major projects illustrate the durability and reliability of a properly designed and constructed lightweight aggregate bridge. Cost comparisons of lightweight aggregate structures bid in competition with structural steel and normal weight concrete alternative structures highlight the economic viability of this material. The outstanding performance of these lightweight bridges under heavy traffic and the close competition in bidding suggests that lightweight aggregate is a material that should be considered in future bridge designs, especially in earthquake country, where dead load is such an important factor in seismic design. The known consistent creep, shrinkage, and modulus properties of lightweight aggregate remove any doubts about performance, as certain structures have demonstrated. Industry advances in controlling moisture content have reduced considerably the handling and finishing problems of earlier years.