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Book Seismic Performance of Reinforced Concrete Bridges Allowed to Uplift During Multi Directional Excitation

Download or read book Seismic Performance of Reinforced Concrete Bridges Allowed to Uplift During Multi Directional Excitation written by Andres Oscar Espinoza and published by . This book was released on 2011 with total page 666 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract Seismic Performance of Reinforced Concrete Bridges Allowed to Uplift During Multi-Directional Excitation by Andres Oscar Espinoza Doctor of Philosophy in Engineering - Civil and Environmental Engineering University of California, Berkeley Professor Stephen A. Mahin, Chair The behavior of bridges subjected to recent moderate and large earthquakes has led to bridge design detailed for better seismic performance, particularly through wider bridge foundations to handle larger expected design forces. Foundation uplift, which is not employed in conventional bridge design, has been identified as an important mechanism, in conjunction with structural yielding and soil-structure interaction that may dissipate energy during earthquakes. Preventing uplift through wider foundations looks past the technical and economical feasibility of allowing foundation uplift during seismic events. The research presented in this thesis is part of a larger experimental and analytical investigation to develop and validate design methods for bridge piers on shallow foundations allowed to uplift during seismic events. Several analytical and some experimental studies have been performed to assess rocking and or uplift of shallow foundation systems, however they have evaluated systems with a limited range of footing dimensions and seismic excitations. As such, there is an uncertainty in the information needed to base a performance evaluation and develop design methods. The purpose of this study is to investigate, through experimental and analytical studies, the seismic performance of uplifting bridge piers on shallow foundations when considering different ground motions and footing dimensions. As well as to identify key differences in performance evaluation criteria for conventional and uplifting bridge pier systems. The experimental study dynamically tested a single reinforced concrete bridge column specimen with three adjustable footing configurations grouped by footing dimension, and tested for various combinations of one, two, and three components of seismic excitation. Groups one and two evaluated uplifting systems where the column was limited to elastic loading levels while group three considered inelastic column loading levels. All test groups remained stable and exhibited some rocking and or uplift during testing. Analytical models were developed and validated using the experimental testing results to predict local and global footing and column response. Reliable estimates of forces and displacements during elastic and inelastic response were achieved. To assess the seismic performance of a range of bridge pier systems allowed to uplift a parametric investigation using the validated analytical models was performed in which the column was modeled per conventional design criteria to ensure adequate strength and flexural ductility. The parameters varied include footing width, ground motion excitation, and elastic or inelastic column response. Response of the uplifting bridge pier systems was found to be sensitive to the structural periods, magnitude of excitation, and footing width.

Book Experimental and Analytical Seismic Studies of a Four span Bridge System with Composite Piers

Download or read book Experimental and Analytical Seismic Studies of a Four span Bridge System with Composite Piers written by Fatemeh Kavianipour and published by . This book was released on 2013 with total page 1350 pages. Available in PDF, EPUB and Kindle. Book excerpt: Funded by the National Science Foundation through the Network for Earthquake Engineering Simulation (NEES) research program, a major multi-university research project has been in progress at the University of Nevada, Reno. This study describes the study of one of the three large-scale bridge models that were tested to failure on three shake tables system. This model was supported on fiber-reinforced polymer (FRP) composite piers implementing accelerated bridge construction (ABC) techniques. The bridge was a quarter scale model of a 4-span bridge with continuous reinforced concrete superstructure and a drop cap, two-column pier design. Each pier utilized different unconventional FRP details. The purpose of using these innovative details was to improve the seismic performance of the bridge. The first pier consisted of cast-in-place concrete-filled glass FRP tubes with ±55 degree fibers. The second pier consisted of two segmental reinforced concrete columns wrapped with layers of unidirectional carbon FRP sheets to provide confinement and shear reinforcement. Only nominal hoops were used to hold the longitudinal reinforcement, as FRP jacket and tube were sufficient in providing confinement and shear required reinforcement. The third pier had the same configuration as that of pier 1 but the columns and footing were precast. The top connections in piers 1 and 3 consisted of pipe-pin joints to facilitate ABC and provide hinge behavior. The objectives of the study presented in this document were to evaluate the biaxial seismic performance of this bridge system incorporating composite piers, investigate the performance of each detail and compared them to each other and to conventional ones, determine the influence of abutment-superstructure interaction on the response, assess the performance of a bridge model incorporating ABC techniques, evaluate sufficiency of analytical modeling of the performance of composite material and details, and to conduct parametric study of different variations of the bridge model to study the effect of several important factors such as near-fault earthquake effects and the variations in the configuration of the bridge model. large-scale 4-span bridge model was designed, constructed, and subjected to simulated earthquake loading on three shake tables. The simulated shake table motions were the modified 1994 Northridge, CA ground motion recorded in Century City and were applied to the bridge model in ten runs with increasing amplitudes. Over 380 channels of data were collected. Compared to conventional reinforced concrete bridges, experimental results showed superior performance under extreme seismic loading even under lateral drift ratios exceeding 9%. Extensive post-test analytical studies were conducted and it was determined that a computational model of the bridge that included bridge-abutment interaction using OpenSees was able to provide satisfactory estimations of key structural response parameters such as superstructure displacements. The analytical model was also used to conduct parametric studies on response of the bridge model and its variations under near-fault excitations. The effects of changing the column section properties were also explored. It was found that concrete-filled FRP tube piers and CFRP wrapped post-tensioned segmental piers reduce residual displacements compared to their conventional reinforced concrete counter parts even under impulsive near-fault motions.

Book Seismic Design and Assessment of Bridges

Download or read book Seismic Design and Assessment of Bridges written by Andreas J Kappos and published by Springer Science & Business Media. This book was released on 2012-04-17 with total page 233 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book focuses on the use of inelastic analysis methods for the seismic assessment and design of bridges, for which the work carried out so far, albeit interesting and useful, is nevertheless clearly less than that for buildings. Although some valuable literature on the subject is currently available, the most advanced inelastic analysis methods that emerged during the last decade are currently found only in the specialised research-oriented literature, such as technical journals and conference proceedings. Hence the key objective of this book is two-fold, first to present all important methods belonging to the aforementioned category in a uniform and sufficient for their understanding and implementation length, and to provide also a critical perspective on them by including selected case-studies wherein more than one methods are applied to a specific bridge and by offering some critical comments on the limitations of the individual methods and on their relative efficiency. The book should be a valuable tool for both researchers and practicing engineers dealing with seismic design and assessment of bridges, by both making the methods and the analytical tools available for their implementation, and by assisting them to select the method that best suits the individual bridge projects that each engineer and/or researcher faces.

Book Experimental and Analytical Seismic Studies of a Four span Bridge System with Innovative Materials

Download or read book Experimental and Analytical Seismic Studies of a Four span Bridge System with Innovative Materials written by Carlos Alonso Cruz-Noguez and published by . This book was released on 2010 with total page 1524 pages. Available in PDF, EPUB and Kindle. Book excerpt: As part of a multi-university project utilizing the NSF Network for Earthquake Engineering Simulation (NEES), a quarter-scale model of a four-span bridge incorporating plastic hinges with different advanced materials was tested to failure on the three shake table system at the University of Nevada, Reno (UNR). The bridge was the second test model in a series of three 4-span bridges, with the first model being a conventional reinforced-concrete (RC) structure. The purpose of incorporating advanced materials was to improve the seismic performance of the bridge with respect to two damage indicators: (1) column damage and (2) permanent deformations. The goals of the study presented in this document were to (1) evaluate the seismic performance of a 4-span bridge system incorporating SMA/ECC and built-in rubber pad plastic hinges as well as post-tensioned piers, (2) quantify the relative merit of these advanced materials and details compared to each other and to conventional reinforced concrete plastic hinges, (3) determine the influence of abutment-superstructure interaction on the response, (4) examine the ability of available elaborate analytical modeling techniques to model the performance of advanced materials and details, and (5) conduct an extensive parametric study of different variations of the bridge model to study several important issues in bridge earthquake engineering. The bridge model included six columns, each pair of which utilized a different advanced detail at bottom plastic hinges: shape memory alloys (SMA), special engineered cementitious composites (ECC), elastomeric pads embedded into columns, and post-tensioning tendons. The design of the columns, location of the bents, and selection of the loading protocol were based on pre-test analyses conducted using computer program OpenSees. The bridge model was subjected to two-horizontal components of simulated earthquake records of the 1994 Northridge earthquake. Over 340 channels of data were collected. The test results showed the effectiveness of the advanced materials in reducing damage and permanent displacements. The damage was minimal in plastic hinges with SMA/ECC and those with built-in elastomeric pads. Conventional RC plastic hinges were severely damaged due to spalling of concrete and rupture of the longitudinal and transverse reinforcement. Extensive post-test analytical studies were conducted and it was determined that a computational model of the bridge that included bridge-abutment interaction using OpenSees was able to provide satisfactory estimations of key structural parameters such as superstructure displacements and base shears. The analytical model was also used to conduct parametric studies on single-column and bridge-system response under near-fault ground motions. The effects of vertical excitations and transverse shear-keys at the bridge abutments on the superstructure displacement and column drifts were also explored.

Book An Investigation of the Effectiveness of Existing Bridge Design Methodology in Providing Adequate Structural Resistance to Seismic Disturbances

Download or read book An Investigation of the Effectiveness of Existing Bridge Design Methodology in Providing Adequate Structural Resistance to Seismic Disturbances written by United States. Federal Highway Administration. Structures and Applied Mechanics Division and published by . This book was released on 1978 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Preliminary Seismic Analysis and Design of Reinforced Concrete Bridge Columns for Curved Bridge Experiments

Download or read book Preliminary Seismic Analysis and Design of Reinforced Concrete Bridge Columns for Curved Bridge Experiments written by Nathan W. Harrison and published by . This book was released on 2011 with total page 542 pages. Available in PDF, EPUB and Kindle. Book excerpt: As part of a Federal Highway Administration (FHWA) sponsored research project to study highway system resilience, a 40 percent scale curved steel plate girder bridge is to be constructed and subjected to earthquake simulation at the Large Scale Structures Laboratory on the University of Nevada, Reno (UNR) campus. The 145 foot long bridge model is to have three-spans, supported on two single-column bents with hammer-head pier caps, and have a subtended angle of 104°. The purpose of the shake table testing is to study the seismic system behavior of the bridge as well as additional bridge components including; conventional columns, isolation, ductile-cross frames, abutment behavior, and the seismic behavior of bridges including the effects of live load. Ultimately design recommendations will be developed from this research. The research presented in this document is the results of preliminary analysis and design of conventional reinforced concrete bridge columns and substructure elements as part of the larger project to examine global seismic behavior of the scaled bridge model. In order to prepare for seismic testing of the scaled bridge model, extensive pre-experimental numerical analysis was performed. Finite element models were developed using SAP2000 and non-linear time-history analysis was performed to investigate the seismic response of the bridge model. Analytical bridge models were analyzed using both 16-inch and 20-inch column diameters and various abutment support conditions. The models were subjected to two levels of horizontal bidirectional earthquake excitation representing a design level earthquake and a large amplitude earthquake intended to cause column failure. Using the results from the analysis, preliminary construction plans were prepared for one set of columns and the adjacent substructure components using the provisions from the AASHTO Guide Specifications for LRFD Seismic Bridge Design. In addition to the investigation into column performance, a parametric study was performed to determine axial response of the bearings at both the abutments and piers when subjected to seismic loading. The numerical analysis showed that system effects due to superstructure-substructure interaction can cause column flexural response that is typically not observed with stand-alone column tests. The effects of bridge horizontal curvature was shown to have a significant impact on the axial performance of the bearings in which the response was not uniform for all bearing at one support location. As a component of the analysis and design, two strut-and-tie models were developed to provide adequate joint detailing in order to ensure capacity protection of the column-to-bentcap connection under multiple cycles of seismic loading.

Book Parametric Study on the Seismic Performance of Typical Highway Bridges in Canada

Download or read book Parametric Study on the Seismic Performance of Typical Highway Bridges in Canada written by Yuling Gao and published by . This book was released on 2015 with total page 131 pages. Available in PDF, EPUB and Kindle. Book excerpt: Earthquakes are one of the main natural hazards that have caused devastations to bridges around the world. Given the observations from past earthquakes, substantial analytical and experimental research work related to bridges has been undertaken in Canada and other countries. The analytical research is focussed primarily on the prediction of the seismic performance of existing bridges. It includes bridge-specific investigations which are mainly conducted using deterministic approach, and investigations of bridge portfolios which are based on probabilistic approach. In both cases, nonlinear time-history analyses are extensively used. To conduct analysis on a given bridge, analytical (i.e., computational) model of the bridge is required. It is known that the seismic response predictions depend greatly on the accuracy of the input of the modeling parameters (or components) considered in the bridge model. The objective of this study is to investigate the effects of the uncertainties of a number of modeling parameters on the seismic response of typical highway bridges. The parameters considered include the superstructure mass, concrete compressive strength, yield strength of the reinforcing steel, yield displacement of the bearing, post-yield stiffness of the bearing, plastic hinge length, and damping. For the purpose of examination, two typical reinforced concrete highway bridges located in Montreal were selected. Three-dimensional (3-D) nonlinear model the bridge was developed using SAP2000. The effects of the uncertainty of each parameter mentioned above were investigated by conducting time-history analyses on the bridge model. In total, 15 records from the earthquakes around the world were used in the time-history analysis. The response of the deck displacement, bearing displacement, column displacement, column curvature ductility, and moment at the base of the column was considered to assess the effect of the uncertainty of the modeling parameter on the seismic response of the bridge. Recommendations were made for the use of these modeling parameters on the evaluation of the seismic performance of bridges.

Book Analytical Investigations of the Seismic Response of Long Multiple span Bridges

Download or read book Analytical Investigations of the Seismic Response of Long Multiple span Bridges written by Wen-shou Tseng and published by . This book was released on 1973 with total page 410 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book NBS Special Publication

Download or read book NBS Special Publication written by and published by . This book was released on 1977 with total page 1000 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Seismic Response of Columns in Horizontally Curved Bridges

Download or read book Seismic Response of Columns in Horizontally Curved Bridges written by Michael John Levi and published by . This book was released on 2011 with total page 1290 pages. Available in PDF, EPUB and Kindle. Book excerpt: As part of a FHWA sponsored research project to study highway system resilience, a two-fifths scale curved steel plate girder bridge was constructed and subjected to earthquake simulation at the Large Scale Structures Laboratory at the University of Nevada, Reno (UNR). The objective of this simulation was to study the seismic system behavior of the bridge as well as additional components including reinforced concrete columns, effects of live load, isolation systems, ductile-cross frames, and abutment behavior. Ultimately design recommendations will be developed from this research. The research that is presented in this document is the results of the design, analysis, and experimental results of the conventional bridge columns and substructure elements as part of the research being conducted at UNR. The design of the substructure elements was completed according to the requirements of the AASHTO Guide Specifications for LRFD Seismic Bridge Design. In addition, the column design was based on the typical column sizes used by the local departments of transportation. The Sylmar recording of the 1994 Northridge, California earthquake was used as the input ground motion in the system. Analytical modeling using SAP2000 was performed on the scaled bridge model to estimate the seismic response of the bridge using non-linear time-history analysis. Numerical analysis was used to check the system at the design level earthquake and at a large amplitude motion intended to cause column failure. In addition, the analytical models were subjected to the testing protocol, ten ground motions with increasing amplitudes, to determine the effect of the loading protocol on the system. The response of the columns during experimental testing met all performance requirements at the design level and maximum considered earthquakes. The effects of shear keys in the system were shown to have an impact on the torsional loads in the system. At the end of the last test, longitudinal reinforcement started buckling in the columns, however; columns had not reached the maximum lateral capacity. Testing was stopped at this point due to shake table limitations.

Book Analytical Investigations of the Seismic Response of Long Multiple Span Highway Bridges

Download or read book Analytical Investigations of the Seismic Response of Long Multiple Span Highway Bridges written by Wen-shou Tseng and published by . This book was released on 1973 with total page 205 pages. Available in PDF, EPUB and Kindle. Book excerpt: