http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Cracking in reinforced concrete bent caps
xii, 228 leaves : illustrations ; 28 cm.
The objective of this research program was to determine the causes of cracking in the cantilever portion of multi-column reinforced concrete bent caps that exist within the Texas Department of Transportation bridge inventory. This was achieved by studying the relationship between stresses in the longitudinal tension reinforcement, reinforcement detailing, shear resistance, and cracking of the bent cap during service loading through to failure. As a part of this investigation, sixteen full-scale bent cap specimens were constructed and tested under quasi-static monotonic loading. A number of variables were isolated throughout the study including flexural stress levels, reinforcement arrangement, the design critical section, shear resistance and serviceability factors. Strain levels in the main longitudinal reinforcement were monitored, and crack widths were measured and recorded throughout testing. As a result of this investigation, design recommendations were proposed in an effort to mitigate cracking in order to improve durability and reduce maintenance costs of bent caps throughout the lifetime of the structure. Excessive cracking in RC bent caps can be controlled through improved design detailing for both flexure and shear. For flexure, designing for demands at the column centerline provides overstrength at the column face. This overstrength at the column face can reduce the effective reinforcement stresses during service conditions and reduce cracking. Enhanced shear strength should also be provided within the bent cap negative moment regions. Shear reinforcement should be specified such that proper ductility of the bent cap is assured. Specifically, the nominal shear strength should exceed the factored shear loading as well as the required shear to develop flexural overstrength in the bent cap, using f[] = 1.25f[]. In addition, adequate side face reinforcement in the web flexural tension zone can help reduce cracking at serviceability load levels. Attention to these details are expected to be effective in limiting cracks in RC bent caps at cantilevered locations.
Issued also on microfiche from Lange Micrographics.
Includes bibliographical references (leaves 96-98).