The Experts below are selected from a list of 33 Experts worldwide ranked by ideXlab platform
Y-s Siow - One of the best experts on this subject based on the ideXlab platform.
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Investigation of Two Bridge Alternatives for Low Volume Roads - Phase II. Volume 2 of 2, Concept 2: Beam in Slab Bridge
2000Co-Authors: F W Klaiber, T J Wipf, J C Nauman, Y-s SiowAbstract:This project continues the research which addresses the numerous bridge problems on the Iowa secondary road system. It is a continuation (Phase 2) of Project HR-382, in which two replacement alternatives (Concept 1: Steel Beam Precast Units and Concept 2: Modification of the Benton County Beam-in-Slab Bridge) were investigated. In previous research for concept 1, a Precast Unit bridge was developed through laboratory testing. The steel-beam Precast Unit bridge requires the fabrication of Precast double-tee (PCDT) Units, each consisting of two steel beams connected by a reinforced concrete deck. The weight of each PCDT Unit is minimized by limiting the deck thickness to 4 in., which permits the Units to be constructed off-site and then transported to the bridge site. The number of Units required is a function of the width of bridge desired. Once the PCDT Units are connected, a cast-in-place reinforced concrete deck is cast over the PCDT Units and the bridge railing attached. Since the steel beam PCDT Unit bridge design is intended primarily for use on low-volume roads, used steel beams can be utilized for a significant cost savings. In previous research for concept 2, an alternate shear connector (ASC) was developed and subjected to static loading. In this investigation, the ASC was subjected to cyclic loading in both pushout specimens and composite beam tests. Based on these tests, the fatigue strength of the ASC was determined to be significantly greater than that required in typical low volume road single span bridges. Based upon the construction and service load testing, the steel-beam Precast Unit bridge was successfully shown to be a viable low volume road bridge alternative. The construction process utilized standard methods resulting in a simple system that can be completed with a limited staff. Results from the service load tests indicated adequate strength for all legal loads. An inspection of the bridge one year after its construction revealed no change in the bridge's performance. Each of the systems previously described are relatively easy to construct. Use of the ASC rather than the welded studs significantly simplified the work, equipment, and materials required to develop composite action between the steel beams and the concrete deck.
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INVESTIGATION OF TWO BRIDGE ALTERNATIVES FOR LOW VOLUME ROADS - PHASE II. Volume 1 of 2 Concept 1: Steel Beam Precast Units
2000Co-Authors: F W Klaiber, T J Wipf, J C Nauman, Brent M. Phares, M E Fagen, Y-s SiowAbstract:Recent reports have indicated that 23.5% of the nation's highway bridges are structurally deficient and 17.7% are functionally obsolete. A significant number of these bridges are on the Iowa secondary road system where over 86% of the rural bridge management responsibilities are assigned to the counties. Some of the bridges can be strengthened or otherwise rehabilitated, but many more are in need of immediate replacement. In a recent investigation (HR-365 "Evaluation of Bridge Replacement Alternatives for the County Bridge System") several types of replacement bridges that are currently being used on low volume roads were identified. It was also determined that a large number of counties (69%) have the ability and are interested in utilizing their own forces to design and construct short span bridges. In reviewing the results from HR-365, the research team developed one "new" bridge replacement concept and a modification of a replacement system currently being used. Both of these bridge replacement alternatives were investigated in this study, the results of which are presented in two volumes. This volume (Volume 1) presents the results of Concept 1 - Steel Beam Precast Units. Concept 2 - Modification of the Beam-in-Slab Bridge is presented in Volume 2. Concept 1, involves the fabrication of Precast Units (two steel beams connected by a concrete slab) by county work forces. Deck thickness is limited so that the Units can be fabricated at one site and then transported to the bridge site where they are connected and the remaining portion of the deck placed. Since Concept 1 bridge is primarily intended for use on low-volume roads, the Precast Units can be constructed with new or used beams. In the experimental part of the investigation, there were three types of static load tests: small scale connector tests, "handling strength" tests, and service and overload tests of a model bridge. Three finite element models for analyzing the bridge in various states of construction were also developed. Small scale connector tests were completed to determine the best method of connecting the Precast double-T (PCDT) Units. "Handling strength" tests on an individual PCDT Unit were performed to determine the strength and behavior of the Precast Unit in this configuration. The majority of the testing was completed on the model bridge [L=9,750 mm (32 ft), W=6,400 mm (21 ft)] which was fabricated using the Precast Units developed. Some of the variables investigated in the model bridge tests were number of connectors required to connect adjacent Precast Units, contribution of diaphragms to load distribution, influence of position of diaphragms on bridge strength and load distribution, and effect of cast-in-place portion of deck on load distribution. In addition to the service load tests, the bridge was also subjected to overload conditions. Using the finite element models developed, one can predict the behavior and strength of bridges similar to the laboratory model as well as design them. Concept 1 has successfully passed all laboratory testing; the next step is to field test it.
F W Klaiber - One of the best experts on this subject based on the ideXlab platform.
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Investigation of Two Bridge Alternatives for Low Volume Roads - Phase II. Volume 2 of 2, Concept 2: Beam in Slab Bridge
2000Co-Authors: F W Klaiber, T J Wipf, J C Nauman, Y-s SiowAbstract:This project continues the research which addresses the numerous bridge problems on the Iowa secondary road system. It is a continuation (Phase 2) of Project HR-382, in which two replacement alternatives (Concept 1: Steel Beam Precast Units and Concept 2: Modification of the Benton County Beam-in-Slab Bridge) were investigated. In previous research for concept 1, a Precast Unit bridge was developed through laboratory testing. The steel-beam Precast Unit bridge requires the fabrication of Precast double-tee (PCDT) Units, each consisting of two steel beams connected by a reinforced concrete deck. The weight of each PCDT Unit is minimized by limiting the deck thickness to 4 in., which permits the Units to be constructed off-site and then transported to the bridge site. The number of Units required is a function of the width of bridge desired. Once the PCDT Units are connected, a cast-in-place reinforced concrete deck is cast over the PCDT Units and the bridge railing attached. Since the steel beam PCDT Unit bridge design is intended primarily for use on low-volume roads, used steel beams can be utilized for a significant cost savings. In previous research for concept 2, an alternate shear connector (ASC) was developed and subjected to static loading. In this investigation, the ASC was subjected to cyclic loading in both pushout specimens and composite beam tests. Based on these tests, the fatigue strength of the ASC was determined to be significantly greater than that required in typical low volume road single span bridges. Based upon the construction and service load testing, the steel-beam Precast Unit bridge was successfully shown to be a viable low volume road bridge alternative. The construction process utilized standard methods resulting in a simple system that can be completed with a limited staff. Results from the service load tests indicated adequate strength for all legal loads. An inspection of the bridge one year after its construction revealed no change in the bridge's performance. Each of the systems previously described are relatively easy to construct. Use of the ASC rather than the welded studs significantly simplified the work, equipment, and materials required to develop composite action between the steel beams and the concrete deck.
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INVESTIGATION OF TWO BRIDGE ALTERNATIVES FOR LOW VOLUME ROADS - PHASE II. Volume 1 of 2 Concept 1: Steel Beam Precast Units
2000Co-Authors: F W Klaiber, T J Wipf, J C Nauman, Brent M. Phares, M E Fagen, Y-s SiowAbstract:Recent reports have indicated that 23.5% of the nation's highway bridges are structurally deficient and 17.7% are functionally obsolete. A significant number of these bridges are on the Iowa secondary road system where over 86% of the rural bridge management responsibilities are assigned to the counties. Some of the bridges can be strengthened or otherwise rehabilitated, but many more are in need of immediate replacement. In a recent investigation (HR-365 "Evaluation of Bridge Replacement Alternatives for the County Bridge System") several types of replacement bridges that are currently being used on low volume roads were identified. It was also determined that a large number of counties (69%) have the ability and are interested in utilizing their own forces to design and construct short span bridges. In reviewing the results from HR-365, the research team developed one "new" bridge replacement concept and a modification of a replacement system currently being used. Both of these bridge replacement alternatives were investigated in this study, the results of which are presented in two volumes. This volume (Volume 1) presents the results of Concept 1 - Steel Beam Precast Units. Concept 2 - Modification of the Beam-in-Slab Bridge is presented in Volume 2. Concept 1, involves the fabrication of Precast Units (two steel beams connected by a concrete slab) by county work forces. Deck thickness is limited so that the Units can be fabricated at one site and then transported to the bridge site where they are connected and the remaining portion of the deck placed. Since Concept 1 bridge is primarily intended for use on low-volume roads, the Precast Units can be constructed with new or used beams. In the experimental part of the investigation, there were three types of static load tests: small scale connector tests, "handling strength" tests, and service and overload tests of a model bridge. Three finite element models for analyzing the bridge in various states of construction were also developed. Small scale connector tests were completed to determine the best method of connecting the Precast double-T (PCDT) Units. "Handling strength" tests on an individual PCDT Unit were performed to determine the strength and behavior of the Precast Unit in this configuration. The majority of the testing was completed on the model bridge [L=9,750 mm (32 ft), W=6,400 mm (21 ft)] which was fabricated using the Precast Units developed. Some of the variables investigated in the model bridge tests were number of connectors required to connect adjacent Precast Units, contribution of diaphragms to load distribution, influence of position of diaphragms on bridge strength and load distribution, and effect of cast-in-place portion of deck on load distribution. In addition to the service load tests, the bridge was also subjected to overload conditions. Using the finite element models developed, one can predict the behavior and strength of bridges similar to the laboratory model as well as design them. Concept 1 has successfully passed all laboratory testing; the next step is to field test it.
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LOW-VOLUME ROAD BRIDGE ALTERNATIVE
Transportation Research Record, 2000Co-Authors: Brent M. Phares, F W Klaiber, T J WipfAbstract:Recent reports indicate that a significant number of the nation's bridges are either structurally deficient or functionally obsolete. A large number of these bridges are on the secondary road system and fall under the jurisdiction of county engineers with limited budgets and engineering staff. In response to this problem, a bridge replacement system was developed for simple span bridges with minimal to no skew that county engineers can design and build with limited resources. The bridge system involves fabrication of Precast Units consisting of two steel beams connected with a thin reinforced concrete deck. The Precast deck thickness is limited to reduce the weight of the Units so that they can be fabricated at one site and then easily transported to the bridge site. Multiple Units are then connected on site to give the desired width of bridge, after which a reinforced cast-in-place concrete deck is placed over the entire bridge. Development of the design methodology for the steel beam Precast Unit bridge consisted of four phases. During the initial phase, small-scale bridge components and a full-scale model bridge were constructed and tested in the Iowa State University Structural Engineering Laboratory. These specimens were tested under a variety of loading configurations under service and ultimate loads. After completion of the laboratory testing, finite-element models of the laboratory bridge were developed and validated with data collected during the first phase. The validated finite-element model was then used to extrapolate analyses of common bridge configurations. The results of the analytical investigation were then combined with classic bridge engineering principles into a design methodology that is easy to use and understand. Although it is not discussed in detail, a demonstration project in which this concept was used has recently been completed and tested.
T J Wipf - One of the best experts on this subject based on the ideXlab platform.
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Investigation of Two Bridge Alternatives for Low Volume Roads - Phase II. Volume 2 of 2, Concept 2: Beam in Slab Bridge
2000Co-Authors: F W Klaiber, T J Wipf, J C Nauman, Y-s SiowAbstract:This project continues the research which addresses the numerous bridge problems on the Iowa secondary road system. It is a continuation (Phase 2) of Project HR-382, in which two replacement alternatives (Concept 1: Steel Beam Precast Units and Concept 2: Modification of the Benton County Beam-in-Slab Bridge) were investigated. In previous research for concept 1, a Precast Unit bridge was developed through laboratory testing. The steel-beam Precast Unit bridge requires the fabrication of Precast double-tee (PCDT) Units, each consisting of two steel beams connected by a reinforced concrete deck. The weight of each PCDT Unit is minimized by limiting the deck thickness to 4 in., which permits the Units to be constructed off-site and then transported to the bridge site. The number of Units required is a function of the width of bridge desired. Once the PCDT Units are connected, a cast-in-place reinforced concrete deck is cast over the PCDT Units and the bridge railing attached. Since the steel beam PCDT Unit bridge design is intended primarily for use on low-volume roads, used steel beams can be utilized for a significant cost savings. In previous research for concept 2, an alternate shear connector (ASC) was developed and subjected to static loading. In this investigation, the ASC was subjected to cyclic loading in both pushout specimens and composite beam tests. Based on these tests, the fatigue strength of the ASC was determined to be significantly greater than that required in typical low volume road single span bridges. Based upon the construction and service load testing, the steel-beam Precast Unit bridge was successfully shown to be a viable low volume road bridge alternative. The construction process utilized standard methods resulting in a simple system that can be completed with a limited staff. Results from the service load tests indicated adequate strength for all legal loads. An inspection of the bridge one year after its construction revealed no change in the bridge's performance. Each of the systems previously described are relatively easy to construct. Use of the ASC rather than the welded studs significantly simplified the work, equipment, and materials required to develop composite action between the steel beams and the concrete deck.
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INVESTIGATION OF TWO BRIDGE ALTERNATIVES FOR LOW VOLUME ROADS - PHASE II. Volume 1 of 2 Concept 1: Steel Beam Precast Units
2000Co-Authors: F W Klaiber, T J Wipf, J C Nauman, Brent M. Phares, M E Fagen, Y-s SiowAbstract:Recent reports have indicated that 23.5% of the nation's highway bridges are structurally deficient and 17.7% are functionally obsolete. A significant number of these bridges are on the Iowa secondary road system where over 86% of the rural bridge management responsibilities are assigned to the counties. Some of the bridges can be strengthened or otherwise rehabilitated, but many more are in need of immediate replacement. In a recent investigation (HR-365 "Evaluation of Bridge Replacement Alternatives for the County Bridge System") several types of replacement bridges that are currently being used on low volume roads were identified. It was also determined that a large number of counties (69%) have the ability and are interested in utilizing their own forces to design and construct short span bridges. In reviewing the results from HR-365, the research team developed one "new" bridge replacement concept and a modification of a replacement system currently being used. Both of these bridge replacement alternatives were investigated in this study, the results of which are presented in two volumes. This volume (Volume 1) presents the results of Concept 1 - Steel Beam Precast Units. Concept 2 - Modification of the Beam-in-Slab Bridge is presented in Volume 2. Concept 1, involves the fabrication of Precast Units (two steel beams connected by a concrete slab) by county work forces. Deck thickness is limited so that the Units can be fabricated at one site and then transported to the bridge site where they are connected and the remaining portion of the deck placed. Since Concept 1 bridge is primarily intended for use on low-volume roads, the Precast Units can be constructed with new or used beams. In the experimental part of the investigation, there were three types of static load tests: small scale connector tests, "handling strength" tests, and service and overload tests of a model bridge. Three finite element models for analyzing the bridge in various states of construction were also developed. Small scale connector tests were completed to determine the best method of connecting the Precast double-T (PCDT) Units. "Handling strength" tests on an individual PCDT Unit were performed to determine the strength and behavior of the Precast Unit in this configuration. The majority of the testing was completed on the model bridge [L=9,750 mm (32 ft), W=6,400 mm (21 ft)] which was fabricated using the Precast Units developed. Some of the variables investigated in the model bridge tests were number of connectors required to connect adjacent Precast Units, contribution of diaphragms to load distribution, influence of position of diaphragms on bridge strength and load distribution, and effect of cast-in-place portion of deck on load distribution. In addition to the service load tests, the bridge was also subjected to overload conditions. Using the finite element models developed, one can predict the behavior and strength of bridges similar to the laboratory model as well as design them. Concept 1 has successfully passed all laboratory testing; the next step is to field test it.
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LOW-VOLUME ROAD BRIDGE ALTERNATIVE
Transportation Research Record, 2000Co-Authors: Brent M. Phares, F W Klaiber, T J WipfAbstract:Recent reports indicate that a significant number of the nation's bridges are either structurally deficient or functionally obsolete. A large number of these bridges are on the secondary road system and fall under the jurisdiction of county engineers with limited budgets and engineering staff. In response to this problem, a bridge replacement system was developed for simple span bridges with minimal to no skew that county engineers can design and build with limited resources. The bridge system involves fabrication of Precast Units consisting of two steel beams connected with a thin reinforced concrete deck. The Precast deck thickness is limited to reduce the weight of the Units so that they can be fabricated at one site and then easily transported to the bridge site. Multiple Units are then connected on site to give the desired width of bridge, after which a reinforced cast-in-place concrete deck is placed over the entire bridge. Development of the design methodology for the steel beam Precast Unit bridge consisted of four phases. During the initial phase, small-scale bridge components and a full-scale model bridge were constructed and tested in the Iowa State University Structural Engineering Laboratory. These specimens were tested under a variety of loading configurations under service and ultimate loads. After completion of the laboratory testing, finite-element models of the laboratory bridge were developed and validated with data collected during the first phase. The validated finite-element model was then used to extrapolate analyses of common bridge configurations. The results of the analytical investigation were then combined with classic bridge engineering principles into a design methodology that is easy to use and understand. Although it is not discussed in detail, a demonstration project in which this concept was used has recently been completed and tested.
J C Nauman - One of the best experts on this subject based on the ideXlab platform.
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Investigation of Two Bridge Alternatives for Low Volume Roads - Phase II. Volume 2 of 2, Concept 2: Beam in Slab Bridge
2000Co-Authors: F W Klaiber, T J Wipf, J C Nauman, Y-s SiowAbstract:This project continues the research which addresses the numerous bridge problems on the Iowa secondary road system. It is a continuation (Phase 2) of Project HR-382, in which two replacement alternatives (Concept 1: Steel Beam Precast Units and Concept 2: Modification of the Benton County Beam-in-Slab Bridge) were investigated. In previous research for concept 1, a Precast Unit bridge was developed through laboratory testing. The steel-beam Precast Unit bridge requires the fabrication of Precast double-tee (PCDT) Units, each consisting of two steel beams connected by a reinforced concrete deck. The weight of each PCDT Unit is minimized by limiting the deck thickness to 4 in., which permits the Units to be constructed off-site and then transported to the bridge site. The number of Units required is a function of the width of bridge desired. Once the PCDT Units are connected, a cast-in-place reinforced concrete deck is cast over the PCDT Units and the bridge railing attached. Since the steel beam PCDT Unit bridge design is intended primarily for use on low-volume roads, used steel beams can be utilized for a significant cost savings. In previous research for concept 2, an alternate shear connector (ASC) was developed and subjected to static loading. In this investigation, the ASC was subjected to cyclic loading in both pushout specimens and composite beam tests. Based on these tests, the fatigue strength of the ASC was determined to be significantly greater than that required in typical low volume road single span bridges. Based upon the construction and service load testing, the steel-beam Precast Unit bridge was successfully shown to be a viable low volume road bridge alternative. The construction process utilized standard methods resulting in a simple system that can be completed with a limited staff. Results from the service load tests indicated adequate strength for all legal loads. An inspection of the bridge one year after its construction revealed no change in the bridge's performance. Each of the systems previously described are relatively easy to construct. Use of the ASC rather than the welded studs significantly simplified the work, equipment, and materials required to develop composite action between the steel beams and the concrete deck.
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INVESTIGATION OF TWO BRIDGE ALTERNATIVES FOR LOW VOLUME ROADS - PHASE II. Volume 1 of 2 Concept 1: Steel Beam Precast Units
2000Co-Authors: F W Klaiber, T J Wipf, J C Nauman, Brent M. Phares, M E Fagen, Y-s SiowAbstract:Recent reports have indicated that 23.5% of the nation's highway bridges are structurally deficient and 17.7% are functionally obsolete. A significant number of these bridges are on the Iowa secondary road system where over 86% of the rural bridge management responsibilities are assigned to the counties. Some of the bridges can be strengthened or otherwise rehabilitated, but many more are in need of immediate replacement. In a recent investigation (HR-365 "Evaluation of Bridge Replacement Alternatives for the County Bridge System") several types of replacement bridges that are currently being used on low volume roads were identified. It was also determined that a large number of counties (69%) have the ability and are interested in utilizing their own forces to design and construct short span bridges. In reviewing the results from HR-365, the research team developed one "new" bridge replacement concept and a modification of a replacement system currently being used. Both of these bridge replacement alternatives were investigated in this study, the results of which are presented in two volumes. This volume (Volume 1) presents the results of Concept 1 - Steel Beam Precast Units. Concept 2 - Modification of the Beam-in-Slab Bridge is presented in Volume 2. Concept 1, involves the fabrication of Precast Units (two steel beams connected by a concrete slab) by county work forces. Deck thickness is limited so that the Units can be fabricated at one site and then transported to the bridge site where they are connected and the remaining portion of the deck placed. Since Concept 1 bridge is primarily intended for use on low-volume roads, the Precast Units can be constructed with new or used beams. In the experimental part of the investigation, there were three types of static load tests: small scale connector tests, "handling strength" tests, and service and overload tests of a model bridge. Three finite element models for analyzing the bridge in various states of construction were also developed. Small scale connector tests were completed to determine the best method of connecting the Precast double-T (PCDT) Units. "Handling strength" tests on an individual PCDT Unit were performed to determine the strength and behavior of the Precast Unit in this configuration. The majority of the testing was completed on the model bridge [L=9,750 mm (32 ft), W=6,400 mm (21 ft)] which was fabricated using the Precast Units developed. Some of the variables investigated in the model bridge tests were number of connectors required to connect adjacent Precast Units, contribution of diaphragms to load distribution, influence of position of diaphragms on bridge strength and load distribution, and effect of cast-in-place portion of deck on load distribution. In addition to the service load tests, the bridge was also subjected to overload conditions. Using the finite element models developed, one can predict the behavior and strength of bridges similar to the laboratory model as well as design them. Concept 1 has successfully passed all laboratory testing; the next step is to field test it.
Brent M. Phares - One of the best experts on this subject based on the ideXlab platform.
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INVESTIGATION OF TWO BRIDGE ALTERNATIVES FOR LOW VOLUME ROADS - PHASE II. Volume 1 of 2 Concept 1: Steel Beam Precast Units
2000Co-Authors: F W Klaiber, T J Wipf, J C Nauman, Brent M. Phares, M E Fagen, Y-s SiowAbstract:Recent reports have indicated that 23.5% of the nation's highway bridges are structurally deficient and 17.7% are functionally obsolete. A significant number of these bridges are on the Iowa secondary road system where over 86% of the rural bridge management responsibilities are assigned to the counties. Some of the bridges can be strengthened or otherwise rehabilitated, but many more are in need of immediate replacement. In a recent investigation (HR-365 "Evaluation of Bridge Replacement Alternatives for the County Bridge System") several types of replacement bridges that are currently being used on low volume roads were identified. It was also determined that a large number of counties (69%) have the ability and are interested in utilizing their own forces to design and construct short span bridges. In reviewing the results from HR-365, the research team developed one "new" bridge replacement concept and a modification of a replacement system currently being used. Both of these bridge replacement alternatives were investigated in this study, the results of which are presented in two volumes. This volume (Volume 1) presents the results of Concept 1 - Steel Beam Precast Units. Concept 2 - Modification of the Beam-in-Slab Bridge is presented in Volume 2. Concept 1, involves the fabrication of Precast Units (two steel beams connected by a concrete slab) by county work forces. Deck thickness is limited so that the Units can be fabricated at one site and then transported to the bridge site where they are connected and the remaining portion of the deck placed. Since Concept 1 bridge is primarily intended for use on low-volume roads, the Precast Units can be constructed with new or used beams. In the experimental part of the investigation, there were three types of static load tests: small scale connector tests, "handling strength" tests, and service and overload tests of a model bridge. Three finite element models for analyzing the bridge in various states of construction were also developed. Small scale connector tests were completed to determine the best method of connecting the Precast double-T (PCDT) Units. "Handling strength" tests on an individual PCDT Unit were performed to determine the strength and behavior of the Precast Unit in this configuration. The majority of the testing was completed on the model bridge [L=9,750 mm (32 ft), W=6,400 mm (21 ft)] which was fabricated using the Precast Units developed. Some of the variables investigated in the model bridge tests were number of connectors required to connect adjacent Precast Units, contribution of diaphragms to load distribution, influence of position of diaphragms on bridge strength and load distribution, and effect of cast-in-place portion of deck on load distribution. In addition to the service load tests, the bridge was also subjected to overload conditions. Using the finite element models developed, one can predict the behavior and strength of bridges similar to the laboratory model as well as design them. Concept 1 has successfully passed all laboratory testing; the next step is to field test it.
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LOW-VOLUME ROAD BRIDGE ALTERNATIVE
Transportation Research Record, 2000Co-Authors: Brent M. Phares, F W Klaiber, T J WipfAbstract:Recent reports indicate that a significant number of the nation's bridges are either structurally deficient or functionally obsolete. A large number of these bridges are on the secondary road system and fall under the jurisdiction of county engineers with limited budgets and engineering staff. In response to this problem, a bridge replacement system was developed for simple span bridges with minimal to no skew that county engineers can design and build with limited resources. The bridge system involves fabrication of Precast Units consisting of two steel beams connected with a thin reinforced concrete deck. The Precast deck thickness is limited to reduce the weight of the Units so that they can be fabricated at one site and then easily transported to the bridge site. Multiple Units are then connected on site to give the desired width of bridge, after which a reinforced cast-in-place concrete deck is placed over the entire bridge. Development of the design methodology for the steel beam Precast Unit bridge consisted of four phases. During the initial phase, small-scale bridge components and a full-scale model bridge were constructed and tested in the Iowa State University Structural Engineering Laboratory. These specimens were tested under a variety of loading configurations under service and ultimate loads. After completion of the laboratory testing, finite-element models of the laboratory bridge were developed and validated with data collected during the first phase. The validated finite-element model was then used to extrapolate analyses of common bridge configurations. The results of the analytical investigation were then combined with classic bridge engineering principles into a design methodology that is easy to use and understand. Although it is not discussed in detail, a demonstration project in which this concept was used has recently been completed and tested.