A 3-year research effort related to the study of heat-straightening repair for damaged steel bridge girders is summarized. Two majorareas are emphasized: laboratory behavior of heat-straightened plates and rolled shapes. During the laboratory investigation of flat plates, a number of parameters were studied, including vee angle, depth of vee, heating temperature, plate thickness, and jacking forces. The msot important parameters influencing the amount of straightening per heating cycle were vee angle, temperature, and jacking force. The patterns of behavior during the straightening process are plotted to illustrate the effects of each of these parameters. In a similar fashion, a laboratory study of rolled sections was conducted. In addition to the same parameters as those affecting plate behavior, this study showed that cross-section shape affects heat-straightening behavior--a factor heretofore unreported in the literature. It appears that rolled shapes can be grouped into three basic modes of behavior depending on the shape and location of the vee. Results of thesetests are plotted showing how the shape of the member can affect the straightening process. Recommendations are given for factors to consider in the heat-straightening repair of bridge girders. This paper appears in transportation research record no. 1319, Bridge and hydrology research 1991.
Samenvatting