Fred Klaiber - Academia.edu (original) (raw)
Papers by Fred Klaiber
Transportation Research Record: Journal of the Transportation Research Board, 2005
Accurately and effectively assessing the safe load-carrying capacity of bridges is a common probl... more Accurately and effectively assessing the safe load-carrying capacity of bridges is a common problem that bridge owners face. Diagnostic testing can be especially beneficial for bridges that are part of an aging, rapidly decaying infrastructure. In addition, diagnostic testing can ...
In June 1996, a series of field-tests were conducted on twin bridges carrying I-680 over county r... more In June 1996, a series of field-tests were conducted on twin bridges carrying I-680 over county road L34 in Beebeetown, Iowa. The west-bound bridge was damaged by an over-height load. The load fractured a portion of the bottom flange and web of the first two beam lines of the 11-beam structure. A majority of the strands were exposed in the pro-cess but no strands were severed. Several strands appear lax. The eastbound bridge is undamaged. The Iowa DOT decided to replace the two damaged beams due to uncertainties regarding their capacity and long term serviceability. Prior to removal of the beams, the westbound and eastbound bridges were load tested. Results from the tests are still being interpreted but the bridges do appear to behave differently. Re-sults indicate that the differences may be only partially due to damage; the other causes being differences in end restraint of the center span and participation of the barrier rail in edge stiffening. Grillage models of an undamaged br...
The problem of an aging and rapidly decaying infrastructure is an issue facing many agencies char... more The problem of an aging and rapidly decaying infrastructure is an issue facing many agencies charged with maintaining a fully functioning transportation system. Numerous bridges of marginal condition must frequently be posted, resulting in detours with increased travel time and distances. However, when tested, these bridges often exhibit strength and stiffness characteristics beyond traditional codified parameters and beyond calculated rating procedures. The use of diagnostic load testing for the purpose of load rating has become an accepted practice for addressing these bridges by many public agencies. Commercial equipment and analytical tools, like the Bridge Diagnostics, Inc. (BDI) system, have simplified the process of testing, modeling, and rating bridges. This paper presents a current effort at Iowa State University to evaluate and document the applicability, ease-of-use, and accuracy of a system for load rating of bridges through physical testing. To illustrate the use of the...
A major bridge problem in the United States is the corrosion of reinforcing steel and the subsequ... more A major bridge problem in the United States is the corrosion of reinforcing steel and the subsequent deterioration of the surrounding concrete due to deicing salts. There have been efforts in the past to alleviate these problems by using reinforcement that will not corrode, including clad steel reinforcement, fiber-reinforced polymer (FRP) reinforcement, and non-corrosive MMFX steel reinforcement. Another innovative concept is the steel-free bridge deck, which has been developed in Canada. These decks are free of internal steel reinforcement and rely on the internal arching action of the concrete slab, when the slab is confined in both the longitudinal and transverse directions. Using shear studs for composite action between the concrete deck and the steel girders provides longitudinal confinement, while steel straps welded to the top flanges of the girders at regular intervals provide the transverse confinement. FRP reinforcement is included transversely and longitudinally in the d...
Every year many prestressed concrete (P/C) girder bridges in Iowa are damaged by overheight vehic... more Every year many prestressed concrete (P/C) girder bridges in Iowa are damaged by overheight vehicles. Traditional P/C girder repair strategies include welded steel jackets, internal strand splices, and external post-tensioning. Unfortunately, these types of repairs are both labor intensive and vulnerable to future corrosion. One possible alternative to these traditional repair techniques is to repair/strengthen impact damaged P/C girders with carbon fiber reinforced polymers (CFRP). These types of materials have the advantage of large strength/weight ratios, excellent corrosion/fatigue properties, and are relatively simple to install. This paper will present experimental results from one of the three damaged P/C girder bridges that were repaired using CFRP. The results from testing this bridge before and after being repaired with CFRP will be presented. Data from these tests verified that CFRP is an effective method for repairing/strengthening damaged P/C girder bridges. of the auth...
An innovative structural system for pier columns is currently being investigated through a series... more An innovative structural system for pier columns is currently being investigated through a series of laboratory experiments. The columns and connections under investigation are comprised of precast concrete segments to accelerate construction. In addition, some of the columns being investigated employ elastic elements to self-center the columns against lateral loads and structural fuses to control large lateral deflections and expedite repair in the event of a catastrophic loading event. At the time of publication, two cantilever columns with varying component materials and connection details have been tested in the laboratory and two more are in preparation for testing. The columns are subjected to axial and cyclic, quasi-static lateral loads. After sustaining significant damage, the self-centering columns are repaired by replacing the structural fuses and retested to failure to investigate the effectiveness of the repair.
Repairing/replacing deficient bridges is a major challenge for transportation system managers and... more Repairing/replacing deficient bridges is a major challenge for transportation system managers and is magnified for Low Volume Road (LVR) systems where inadequate structures need replacing due to structural and functional deficiencies. To maximize limited replacement funds, some local governments employ in-house forces to reduce construction costs, however most lack the resources to construct traditional bridge systems. The beam-in-slab bridge (BISB) system is a cost competitive alternative designed specifically for LVR systems. Consisting of W sections spaced 24 in. (640 mm) on centers and filled with concrete, the BISB system has been shown to be a sound replacement option, but however in some instances it is not structural efficient. To improve efficiency, composite action was obtained with an alternative shear connector (ASC); a transverse arch was utilized to distribute the wheel loads and reduce the self-weight. Both the section spacing and depth were increased resulting in the...
The use of Railroad Flatcars (RRFCs) as the superstructure in low-volume bridges has been investi... more The use of Railroad Flatcars (RRFCs) as the superstructure in low-volume bridges has been investigated in a research project at Iowa State University. These alternative bridges will enable county engineers to replace old, inadequate county bridges for less money and in a shorter construction time than required for a conventional bridge. A feasibility study completed in 1999 by the Bridge Engineering Center at Iowa State University determined that RRFC structures have adequate strength to support Iowa legal traffic loads. In a follow-up research project, two RRFC demonstration bridges with different substructures and types and lengths of RRFCs were designed, constructed, and tested to validate the conclusions of the feasibility study. Bridge behavior predicted by grillage models was supported by data from field load tests, and thus, design recommendations were developed for determining live load distribution in the RRFC bridges. Moreover, it was determined that the engineered RRFC br...
Researchers at the Iowa State University (ISU) Bridge Engineering Center have developed the modif... more Researchers at the Iowa State University (ISU) Bridge Engineering Center have developed the modified beam-in-slab bridge (MBISB) system as an alternative replacement for use on low-volume roads. The system consists of longitudinal steel girders with a concrete arched deck cast between the girders. Composite action between the concrete and steel is obtained by using an alternative shear connector, also developed at ISU. Other than the nominal transverse reinforcement required for the ASC, the MBISB requires only minimal additional reinforcement. After an extensive laboratory testing phase, two demonstration bridges were constructed and field tested to determine the properties of the design. The demonstration bridges, MBISB 1 (L=50 ft, W=31 ft) and MBISB 2 (L=70 ft, W=32 ft), were constructed by in-house forces using standard construction equipment. The resulting structures saved the bridge owner slightly more than 20% over the costs of conventional designs. Test results indicated tha...
Transportation Research Record Journal of the Transportation Research Board
Although several superstructure design methodologies have been developed for low-volume road brid... more Although several superstructure design methodologies have been developed for low-volume road bridges by the Iowa State University Bridge Engineering Center, no standard abutment designs had been developed. Thus, there was need for an easy-to-use design methodology, generic abutment construction drawings, and other design aids for the more common substructure systems used in Iowa.
Fibre-Reinforced Polymer Reinforcement for Concrete Structures - Proceedings of the Sixth International Symposium on FRP Reinforcement for Concrete Structures (FRPRCS-6), 2003
Black Hawk County (BHC) has developed a precast modified beam-in-slab bridge (PMBISB) system for ... more Black Hawk County (BHC) has developed a precast modified beam-in-slab bridge (PMBISB) system for use with accelerated construction. Individual components of the system have been tested in the Iowa State University Structural Laboratory, and the overall system was tested in the field. Using the BHC system, the bridge superstructure can be assembled in two days and the bridge opened to
Transportation Research Record: Journal of the Transportation Research Board, 2005
Accurately and effectively assessing the safe load-carrying capacity of bridges is a common probl... more Accurately and effectively assessing the safe load-carrying capacity of bridges is a common problem that bridge owners face. Diagnostic testing can be especially beneficial for bridges that are part of an aging, rapidly decaying infrastructure. In addition, diagnostic testing can ...
In June 1996, a series of field-tests were conducted on twin bridges carrying I-680 over county r... more In June 1996, a series of field-tests were conducted on twin bridges carrying I-680 over county road L34 in Beebeetown, Iowa. The west-bound bridge was damaged by an over-height load. The load fractured a portion of the bottom flange and web of the first two beam lines of the 11-beam structure. A majority of the strands were exposed in the pro-cess but no strands were severed. Several strands appear lax. The eastbound bridge is undamaged. The Iowa DOT decided to replace the two damaged beams due to uncertainties regarding their capacity and long term serviceability. Prior to removal of the beams, the westbound and eastbound bridges were load tested. Results from the tests are still being interpreted but the bridges do appear to behave differently. Re-sults indicate that the differences may be only partially due to damage; the other causes being differences in end restraint of the center span and participation of the barrier rail in edge stiffening. Grillage models of an undamaged br...
The problem of an aging and rapidly decaying infrastructure is an issue facing many agencies char... more The problem of an aging and rapidly decaying infrastructure is an issue facing many agencies charged with maintaining a fully functioning transportation system. Numerous bridges of marginal condition must frequently be posted, resulting in detours with increased travel time and distances. However, when tested, these bridges often exhibit strength and stiffness characteristics beyond traditional codified parameters and beyond calculated rating procedures. The use of diagnostic load testing for the purpose of load rating has become an accepted practice for addressing these bridges by many public agencies. Commercial equipment and analytical tools, like the Bridge Diagnostics, Inc. (BDI) system, have simplified the process of testing, modeling, and rating bridges. This paper presents a current effort at Iowa State University to evaluate and document the applicability, ease-of-use, and accuracy of a system for load rating of bridges through physical testing. To illustrate the use of the...
A major bridge problem in the United States is the corrosion of reinforcing steel and the subsequ... more A major bridge problem in the United States is the corrosion of reinforcing steel and the subsequent deterioration of the surrounding concrete due to deicing salts. There have been efforts in the past to alleviate these problems by using reinforcement that will not corrode, including clad steel reinforcement, fiber-reinforced polymer (FRP) reinforcement, and non-corrosive MMFX steel reinforcement. Another innovative concept is the steel-free bridge deck, which has been developed in Canada. These decks are free of internal steel reinforcement and rely on the internal arching action of the concrete slab, when the slab is confined in both the longitudinal and transverse directions. Using shear studs for composite action between the concrete deck and the steel girders provides longitudinal confinement, while steel straps welded to the top flanges of the girders at regular intervals provide the transverse confinement. FRP reinforcement is included transversely and longitudinally in the d...
Every year many prestressed concrete (P/C) girder bridges in Iowa are damaged by overheight vehic... more Every year many prestressed concrete (P/C) girder bridges in Iowa are damaged by overheight vehicles. Traditional P/C girder repair strategies include welded steel jackets, internal strand splices, and external post-tensioning. Unfortunately, these types of repairs are both labor intensive and vulnerable to future corrosion. One possible alternative to these traditional repair techniques is to repair/strengthen impact damaged P/C girders with carbon fiber reinforced polymers (CFRP). These types of materials have the advantage of large strength/weight ratios, excellent corrosion/fatigue properties, and are relatively simple to install. This paper will present experimental results from one of the three damaged P/C girder bridges that were repaired using CFRP. The results from testing this bridge before and after being repaired with CFRP will be presented. Data from these tests verified that CFRP is an effective method for repairing/strengthening damaged P/C girder bridges. of the auth...
An innovative structural system for pier columns is currently being investigated through a series... more An innovative structural system for pier columns is currently being investigated through a series of laboratory experiments. The columns and connections under investigation are comprised of precast concrete segments to accelerate construction. In addition, some of the columns being investigated employ elastic elements to self-center the columns against lateral loads and structural fuses to control large lateral deflections and expedite repair in the event of a catastrophic loading event. At the time of publication, two cantilever columns with varying component materials and connection details have been tested in the laboratory and two more are in preparation for testing. The columns are subjected to axial and cyclic, quasi-static lateral loads. After sustaining significant damage, the self-centering columns are repaired by replacing the structural fuses and retested to failure to investigate the effectiveness of the repair.
Repairing/replacing deficient bridges is a major challenge for transportation system managers and... more Repairing/replacing deficient bridges is a major challenge for transportation system managers and is magnified for Low Volume Road (LVR) systems where inadequate structures need replacing due to structural and functional deficiencies. To maximize limited replacement funds, some local governments employ in-house forces to reduce construction costs, however most lack the resources to construct traditional bridge systems. The beam-in-slab bridge (BISB) system is a cost competitive alternative designed specifically for LVR systems. Consisting of W sections spaced 24 in. (640 mm) on centers and filled with concrete, the BISB system has been shown to be a sound replacement option, but however in some instances it is not structural efficient. To improve efficiency, composite action was obtained with an alternative shear connector (ASC); a transverse arch was utilized to distribute the wheel loads and reduce the self-weight. Both the section spacing and depth were increased resulting in the...
The use of Railroad Flatcars (RRFCs) as the superstructure in low-volume bridges has been investi... more The use of Railroad Flatcars (RRFCs) as the superstructure in low-volume bridges has been investigated in a research project at Iowa State University. These alternative bridges will enable county engineers to replace old, inadequate county bridges for less money and in a shorter construction time than required for a conventional bridge. A feasibility study completed in 1999 by the Bridge Engineering Center at Iowa State University determined that RRFC structures have adequate strength to support Iowa legal traffic loads. In a follow-up research project, two RRFC demonstration bridges with different substructures and types and lengths of RRFCs were designed, constructed, and tested to validate the conclusions of the feasibility study. Bridge behavior predicted by grillage models was supported by data from field load tests, and thus, design recommendations were developed for determining live load distribution in the RRFC bridges. Moreover, it was determined that the engineered RRFC br...
Researchers at the Iowa State University (ISU) Bridge Engineering Center have developed the modif... more Researchers at the Iowa State University (ISU) Bridge Engineering Center have developed the modified beam-in-slab bridge (MBISB) system as an alternative replacement for use on low-volume roads. The system consists of longitudinal steel girders with a concrete arched deck cast between the girders. Composite action between the concrete and steel is obtained by using an alternative shear connector, also developed at ISU. Other than the nominal transverse reinforcement required for the ASC, the MBISB requires only minimal additional reinforcement. After an extensive laboratory testing phase, two demonstration bridges were constructed and field tested to determine the properties of the design. The demonstration bridges, MBISB 1 (L=50 ft, W=31 ft) and MBISB 2 (L=70 ft, W=32 ft), were constructed by in-house forces using standard construction equipment. The resulting structures saved the bridge owner slightly more than 20% over the costs of conventional designs. Test results indicated tha...
Transportation Research Record Journal of the Transportation Research Board
Although several superstructure design methodologies have been developed for low-volume road brid... more Although several superstructure design methodologies have been developed for low-volume road bridges by the Iowa State University Bridge Engineering Center, no standard abutment designs had been developed. Thus, there was need for an easy-to-use design methodology, generic abutment construction drawings, and other design aids for the more common substructure systems used in Iowa.
Fibre-Reinforced Polymer Reinforcement for Concrete Structures - Proceedings of the Sixth International Symposium on FRP Reinforcement for Concrete Structures (FRPRCS-6), 2003
Black Hawk County (BHC) has developed a precast modified beam-in-slab bridge (PMBISB) system for ... more Black Hawk County (BHC) has developed a precast modified beam-in-slab bridge (PMBISB) system for use with accelerated construction. Individual components of the system have been tested in the Iowa State University Structural Laboratory, and the overall system was tested in the field. Using the BHC system, the bridge superstructure can be assembled in two days and the bridge opened to