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Book Performance of Circular Reinforced Concrete Bridge Columns Under Bidirectional Earthquake Loading

Download or read book Performance of Circular Reinforced Concrete Bridge Columns Under Bidirectional Earthquake Loading written by Mahmoud M. Hachem and published by . This book was released on 2003 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt: Describes the dynamic testing of 4 circular reinforced concrete bridge columns. The specimens were divided into 2 pairs, with each pair subjected to a different ground motion. Within each pair, one specimen was subjected to one component of the ground motion, while the other was subjected to 2 components. Two analytical studies were carried out for a wide array of column heights, diameters, and axial load intensities. The columns were subjected to large suites of ground motions scaled to match on average the design response spectrum.

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 Seismic Performance of Well confined Concrete Bridge Columns

Download or read book Seismic Performance of Well confined Concrete Bridge Columns written by Dawn Ellen Lehman and published by . This book was released on 2000 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Experimental and Computational Evaluation of Reinforced Concrete Bridge Beam column Connections for Seismic Performance

Download or read book Experimental and Computational Evaluation of Reinforced Concrete Bridge Beam column Connections for Seismic Performance written by Clay Joshua Naito and published by . This book was released on 2001 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Experimental Study and Analysis of Retrofitted Flexure and Shear Dominated Circular Reinforced Concrete Bridge Columns Subjected to Shake Table Excitation

Download or read book Experimental Study and Analysis of Retrofitted Flexure and Shear Dominated Circular Reinforced Concrete Bridge Columns Subjected to Shake Table Excitation written by Patrick Laplace and published by . This book was released on 2001 with total page 468 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 Experimental Study and Analysis of Retrofitted Flexure and Shear Dominated Circular Reinforced Concrete Bridge Columns Subjected to Shake Table Excitation

Download or read book Experimental Study and Analysis of Retrofitted Flexure and Shear Dominated Circular Reinforced Concrete Bridge Columns Subjected to Shake Table Excitation written by Patrick N. Laplace and published by . This book was released on 2003 with total page 882 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Earthquake Resilient Bridge Columns Utilizing Damage Resistant Hybrid Fiber Reinforced Concrete

Download or read book Earthquake Resilient Bridge Columns Utilizing Damage Resistant Hybrid Fiber Reinforced Concrete written by William Dean Trono and published by . This book was released on 2014 with total page 199 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modern reinforced concrete bridges are designed to avoid collapse and to prevent loss of life during earthquakes. To meet these objectives, bridge columns are typically detailed to form ductile plastic hinges when large displacements occur. California seismic design criteria acknowledges that damage such as concrete cover spalling and reinforcing bar yielding may occur in columns during a design-level earthquake. The seismic resilience of bridge columns can be improved through the use of a damage resistant hybrid fiber reinforced concrete (HyFRC). Fibers delay crack propagation and prevent spalling under extreme loading conditions, and the material resists many typical concrete deterioration mechanisms through multi-scale crack control. Little is known about the response of the material when combined with conventional reinforcing bars. Therefore, experimental testing was conducted to evaluate such behaviors. One area of focus was the compression response of HyFRC when confined by steel spirals. A second focus was the tensile response of rebar embedded in HyFRC. Bridge columns built with HyFRC would be expected to experience both of these loading conditions during earthquakes. The third focus of this dissertation was the design, modeling, and testing of an innovative damage resistant HyFRC bridge column. The column was designed to rock about its foundation during earthquakes and to return to its original position thereafter. In addition to HyFRC, it was designed with unbonded post-tensioning, unbonded rebar, and headed rebar which terminated at the rocking plane. Because of these novel details, the column was not expected to incur damage or residual displacements under earthquake demands exceeding the design level for ordinary California bridges. A sequence of scaled, three dimensional ground motion records was applied to the damage resistant column on a shaking table. An equal scale reinforced concrete reference column with conventional design details was subjected to the same motions for direct comparison. Compression tests showed that the ductility of HyFRC is superior to concrete in the post-peak softening branch of the response. HyFRC achieved a stable softening response and had significant residual load capacity even without spiral confinement. Concrete required the highest tested levels of confinement to achieved comparable post-peak ductility. Tension tests showed that HyFRC provides a substantial strength enhancement to rebar well beyond their yield point. Interesting crack localization behavior was observed in HyFRC specimens and appeared to be dependent on the volumetric ratio of rebar. The damage resistant HyFRC bridge column attained its design objectives during experimental testing. It exhibited pronounced reentering behavior with only light damage under earthquake demands 1.5 to 2.0 times the design level. It accumulated only 0.4% residual drift ratio after seven successive ground motions which caused a peak drift ratio of 8.0%. The conventional reinforced concrete column experienced flexural plastic hinging with extensive spalling during the same seven motions. It accumulated 6.8% residual drift ratio after enduring a peak drift ratio of 10.8%.

Book Experimental Characterization of Steel Jacket Retrofitted Reinforced Concrete Bridge Column Behavior in Cascadia Subduction Zone Earthquakes

Download or read book Experimental Characterization of Steel Jacket Retrofitted Reinforced Concrete Bridge Column Behavior in Cascadia Subduction Zone Earthquakes written by Sean McGuiness and published by . This book was released on 2021 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt: Research on seismic retrofitting of Reinforced Concrete (RC) bridge columns in the United States (U.S.) was motivated by damage observed following the 1971 San Fernando, 1989 Loma Prieta, and 1994 Northridge earthquakes of California. The research resulted in a retrofitting procedure that consisted of installing steel jackets around RC bridge columns to enhance the lateral deformation capacity. Although the research focused on the development of this retrofit strategy for bridge columns in California, the Washington State Department of Transportation (WSDOT) implemented the program in 1991. Unlike the strike-slip faults in California, seismicity in western Washington is generally dominated by the Cascadia Subduction Zone fault. The 1964 Alaska, U.S., 2010 Maule, Chile and 2011 Tohoku, Japan are examples of mega-thrust long duration earthquakes emanating from a subduction zone fault and producing ground motions with longer durations of strong shaking than strike-slip faults. The research conducted in this study was motivated by the need to assess performance of the existing retrofit strategy when subjected to the expected demands of subduction zone earthquakes. The research conducted herein was an experimental study on the behavior of steel jacket retrofitted bridge columns subjected to demands from long duration earthquakes. Six reduced scale column specimens were designed, constructed, and tested as cantilevers. WSDOT's inventory was characterized to inform the values used for the column parameters, such that the six columns were intended to reasonably cover the range of values for critical parameters. Five of six tests utilized a modified fully reversed-cyclic lateral loading protocol to include additional cycles characteristic of long duration earthquakes. The sixth test used an earthquake protocol, obtained from the response of a single degree of freedom model to a synthetic Cascadia Subduction Zone ground motion in western Washington. Study results indicated stable drifts, including minimal pinching in the load-displacement response indicative of favorable hysteretic energy dissipation, at drifts in excess of the 4\\% expectation set forth in the steel jacket retrofit design guidelines. Total deformation was primarily a result of longitudinal reinforcement bond slip and elongation at the footing-column interface with strength degradation due to low-cycle fatigue fracture.

Book Seismic Behavior of Circular Reinforced Concrete Bridge Columns Under Combined Loading Including Torsion

Download or read book Seismic Behavior of Circular Reinforced Concrete Bridge Columns Under Combined Loading Including Torsion written by Suriya Prakash Shanmugam and published by . This book was released on 2009 with total page 634 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Reinforced concrete (RC) columns of skewed and curved bridges with unequal spans and column heights can be subjected to combined loading including axial, flexure, shear, and torsion loads during earthquakes. The combination of axial loads, shear force, and flexural and torsional moments can result in complex failure modes of RC bridge columns. This study carried out experimental and analytical studies to investigate the seismic performance of circular RC columns under combined loading including torsion. The main variables considered here were (i) the ratio of torsion-to-bending moment (T/M), (ii) the ratio of bending moment-to-shear (M/V) or shear span (H/D), and (iii) the level of detailing for high and moderate seismicity (high or low spiral ratio). In particular, the effects of the spiral reinforcement ratio and shear span on strength and ductility of circular RC columns under combined loading were addressed. In addition, the effects of torsional loading on the bending moment-curvature, ductility, and energy dissipation characteristics were also considered. The analytical investigation examined the development of existing models for flexure and pure torsion. Interaction diagrams between bending, shear and torsional loads were established from a semi-empirical approach. A damage-based design approach for circular RC columns under combined loads was proposed by decoupling damage index models for flexure and torsion. Experimental and analytical results showed that the progression of damage was amplified by an increase in torsional moment. An increase in the transverse spiral reinforcement ratio delayed the progression of damage and changed the torsional-dominated behavior to flexural-dominated behavior under combined flexural and torsional moments"--Abstract, leaf iii.