Method for pre-stressing a steel structure, and steel structure pre-stressed using said method

A method of reinforcing at least one steel girder configured for bearing loads and bending moments in a steel structure comprising:

• attaching opposing ends of at least one flat carbon fiber-reinforced polymer (CFRP) band mechanically by clamping by friction forces to at least one steel girder of a steel structure with end anchorages configured to secure the at least one flat CFRP band, no adhesive applied to the at least one steel girder, and the at least one flat CFRP band not being glued on the steel girder by adhesive and having no direct contact with the steel girder, wherein the at least one steel girder is configured for bearing loads and bending moments in the steel structure;
• disposing at least one lifting element between the at least one steel girder and the at least one flat CFRP band in a region between and in alignment with attached opposing ends of the at least one flat CFRP band;
• extending the at least one lifting element substantially perpendicular to the at least one flat CFRP band with the end anchorages securing the at least one flat CFRP band, thereby pre-stressing the at least one flat CFRP band in a direction perpendicular to the at least one steel girder;
• and
• securing extension of the at least one flat CFRP band resulted from pre-stressing in the direction perpendicular to the at least one steel girder by one or more supports or latches between the steel girder and the at least one flat CFRP band,
• thereby the at least one flat CFRP band having a target tensile stress achieved therein being supported by the one or more supports or latches and the target tensile stress in the at least one flat CFRP band being transferred to the at least one steel girder, and by virtue of a geometry of the at least one flat CFRP band being pre-stressed perpendicular to the at least one steel girder between the attached opposing ends thereof that are aligned with the at least one lifting element wherein no shearing force occurs at locations of the steel girder where the opposing ends of the at least one flat CFRP band are attached, the at least one steel girder in at least a region thereof corresponding to thus pre-stressed at least one flat CFRP band being effectively stabilized and reinforced and having an enhanced capacity of bearing loads and bending moments.

A method of reinforcing steel girders configured for bearing loads and bending moments in a steel structure comprising:

• attaching opposing ends of at least one flat carbon fiber-reinforced polymer (CFRP) band mechanically by clamping by friction forces to each of a plurality of steel girders of a steel structure with end anchorages configured to secure the at least one flat CFRP band, no adhesive applied to the plurality of steel girders, and the at least one flat CFRP band not being glued on the plurality of steel girders by adhesive and having no direct contact with the plurality of steel girders, wherein the plurality of steel girders are configured for bearing loads and bending moments in the steel structure;
• disposing at least one lifting element between each of the plurality of steel girders and respective at least one flat CFRP band in a region between and in alignment with attached opposing ends of the respective at least one flat CFRP band;
• extending the at least one lifting element substantially perpendicular to respective at least one flat CFRP band with the end anchorages securing the respective at least one flat CFRP band, thereby pre-stressing the respective at least one flat CFRP band in a direction perpendicular to respective steel girder;
• and
• securing extension of the respective at least one flat CFRP band resulted from pre-stressing in the direction perpendicular to the respective steel girder by one or more supports or latches between each of the plurality of steel girders and the respective at least one flat CFRP band,
• thereby the respective at least one flat CFRP band having a target tensile stress achieved therein being supported by the one or more supports or latches and the target tensile stress in the at least one flat CFRP band being transferred to the respective steel girder, and by virtue of a geometry of the respective at least one flat CFRP band being pre-stressed perpendicular to the respective steel girder between the attached opposing ends thereof that are aligned with the at least one lifting element, wherein no shearing force occurs at locations of the respective steel girder where the opposing ends of the respective at least one flat CFRP band are attached, the respective steel girder in at least a region thereof corresponding to thus pre-stressed respective at least one flat CFRP band being effectively stabilized and reinforced and having an enhanced capacity of bearing loads and bending moments.