Seismic Performance of Bridge Column-pile-shaft Pin Connections for Application in Accelerated Bridge Construction

Seismic Performance of Bridge Column-pile-shaft Pin Connections for Application in Accelerated Bridge Construction
Author: Mehrdad Mehraein
Publisher:
Total Pages: 1468
Release: 2016
Genre: Electronic books
ISBN:

Bridges with integral superstructures are common in high-seismic regions. The superstructure and substructure are connected using rigid connections in these bridges. However, hinge or “pin” connections may be used to connect columns to pile-shafts to reduce the overall force demand in the integral bridges, leading to smaller and more economical foundations. Additionally, prefabrication of structural elements facilitates accelerated bridge construction (ABC), which could improve the quality and economy of project compared to cast-in-place (CIP). The primary objectives of this research were to investigate the seismic performance of three types of bridge bent connections: (1) pipe-pin connections at column-pile shaft joints for CIP and precast constructions (2) rebar-pin connections at column-pile shaft joint for CIP and precast constructions, and (3) pocket connections to develop rigid joints between precast columns and precast pier caps. This research was comprised of experimental and analytical studies. The experimental portion of the study was conducted on a shake table at the Earthquake Engineering Laboratory at the University of Nevada, Reno including two 1/3.75 scale, two-column bents subjected to seismic loadings. The cap beam in each bent was precast and connected to the columns using pocket details. The pin connections were used to connect the columns to pedestals, which simulated the pile-shafts. The column-pedestal joints were formed using pipe-pins in one bent and rebar-pin in the other bent. The available details of pin connections were modified for utilizing in the bents because the tensile force transfer mechanism and pile-shaft failure modes had not been accounted for in the current practices. A proposed ABC method for pin connections was investigated by constructing one column in each bent as a precast shell filled with self-consolidating concrete (SCC), whereas the other column was CIP. Furthermore, engineered cementitious composite (ECC) was incorporated in one column plastic hinge region of each bent to explore the effects of ECC on the seismic performance of the columns. The shake table experiments confirmed that the proposed design methods meet the safety and performance requirements of the codes under seismic loadings. The analytical studies consisted of: (1) simple stick models for the pin connections that were developed for the bents as design tools, (2) nonlinear finite element (FE) models for the pin connections in OpenSEES that can be utilized for global analysis of bridges with pin connections, and (3) elaborate nonlinear FE models of the bent with pipe-pins using ABAQUS to investigate the microscopic performance and interactions of the components. The analytical models were evaluated based on their correlation with experimental data and were subsequently used in focused parametric studies to address the gaps in the experimental results and provide more insight into the pin behavior under various conditions. Lastly, design procedures and detailing recommendations for column-pile-shaft connections using pipe-pins and rebar-pins were developed and proposed based on the results of the experimental and analytical parametric studies.

Seismic Performance of an I-girder to Inverted-T Bent Cap Bridge Connection

Seismic Performance of an I-girder to Inverted-T Bent Cap Bridge Connection
Author: Richard Manning Snyder
Publisher:
Total Pages: 195
Release: 2010
Genre: Girders
ISBN:

This report presents the research conducted as part of an investigation for the California Department of Transportation (Caltrans) regarding the seismic response and overall moment capacity of precast I-girder to inverted-T bent cap bridge connections for seismic applications. The current design practice, as outlined by Caltrans' Seismic Design Criteria, assumes that the connection between the precast I-girders and the inverted-T bent cap will degrade in a seismic event and shall therefore be designed as a pinned connection, making the precast girder option for seismic bridges inefficient. A prototype I-girder to inverted-T bent cap bridge and a 50% scale test unit was designed in order to investigate the behavior of the as-built girder-to-cap connection region. Additionally, per the request of Caltrans, an improved girder-to-cap connection detail was developed in order to ensure a fully continuous moment connection between the I-girders and inverted-T bent cap.

Seismic Performance of an I-girder to Inverted-T Bent Cap Connection

Seismic Performance of an I-girder to Inverted-T Bent Cap Connection
Author:
Publisher:
Total Pages: 294
Release: 2011
Genre: Girders
ISBN:

This report presents the research conducted as part of an investigation for the California Department of Transportation (Caltrans) regarding the seismic response and overall moment capacity of precast I-girder to inverted-T bent cap bridge connections for seismic applications. The current design practice, as outlined by Caltrans' Seismic Design Criteria, assumes that the connection between the precast I-girders and the inverted-T bent cap will degrade in a seismic event and shall therefore be designed as a pinned connection, making the precast girder option for seismic bridges inefficient. A prototype I-girder to inverted-T bent cap bridge and a 50% scale test unit was designed in order to investigate the behavior of the as-built girder-to-cap connection region. Additionally, per the request of Caltrans, an improved girder-to-cap connection detail was developed in order to ensure a fully continuous moment connection between the I-girders and inverted-T bent cap.

Rocking Connection Between a Precast Bridge Column and Cap Beam

Rocking Connection Between a Precast Bridge Column and Cap Beam
Author: Bryan Kennedy
Publisher:
Total Pages: 300
Release: 2015
Genre:
ISBN:

Traditional cast-in-place, concrete bridge construction is often a lengthy undertaking, which is burdensome to the motoring public because of the traffic delays that it causes. Precast construction can accelerate the process by moving fabrication offsite, and then rapidly erecting and connecting bridge components onsite. However, designing connections that are both easy to complete and are robust under seismic loading is challenging. This thesis describes a connection that is intended to meet those criteria, and builds on previous work to do so. Experimental, precast, pre-tensioned specimens developed by Davis et al. (2012) showed good seismic performance, but had significant damage at low drift levels. Adding experimental, ductile materials resulted in less structural damage (Finnsson, 2013), but required unconventional construction materials and awkward fabrication. A new precast, pre-tensioned, column-to-cap beam connection has been developed. The design utilizes (1) unbonded prestressing strands to help the column re-center, (2) bonded reinforcing bars to dissipate energy, (3) a baseplate to permit rigid-body, rocking behavior of the column, and (4) a steel tube to confine the column concrete at the rocking interface. The strands are pre-tensioned when the column is cast, so the connection can be completed without any onsite stressing operations. The connection's seismic performance was evaluated with pseudo-static, cyclic testing of one subassembly. The test results showed that the specimen was stiff at low loads, re-centered well, dissipated energy, and was ductile and durable. Damage to the concrete was negligible and the peak moment strength was measured at drifts exceeding 10%. The system offers a method for achieving accelerated bridge construction that also provides excellent seismic performance and uses only conventional construction materials.

Life-Cycle Civil Engineering: Innovation, Theory and Practice

Life-Cycle Civil Engineering: Innovation, Theory and Practice
Author: Airong Chen
Publisher: CRC Press
Total Pages: 2619
Release: 2021-02-26
Genre: Technology & Engineering
ISBN: 1000342085

Life-Cycle Civil Engineering: Innovation, Theory and Practice contains the lectures and papers presented at IALCCE2020, the Seventh International Symposium on Life-Cycle Civil Engineering, held in Shanghai, China, October 27-30, 2020. It consists of a book of extended abstracts and a USB card containing the full papers of 230 contributions, including the Fazlur R. Khan lecture, eight keynote lectures, and 221 technical papers from all over the world. All major aspects of life-cycle engineering are addressed, with special emphasis on life-cycle design, assessment, maintenance and management of structures and infrastructure systems under various deterioration mechanisms due to various environmental hazards. It is expected that the proceedings of IALCCE2020 will serve as a valuable reference to anyone interested in life-cycle of civil infrastructure systems, including students, researchers, engineers and practitioners from all areas of engineering and industry.

Precast Column-footing Connections for Accelerated Bridge Construction in Seismic Zones

Precast Column-footing Connections for Accelerated Bridge Construction in Seismic Zones
Author: Zachary Benjamin Haber
Publisher:
Total Pages: 1224
Release: 2013
Genre: Electronic books
ISBN:

Accelerated bridge construction (ABC) has become increasingly popular in the eyes of state and federal transportation agencies because of its numerous advantages. To effectively execute ABC projects, designers utilize prefabricated structural elements that can be quickly assembled to form functional structural systems. It is advantageous to the bridge designer if these systems emulate the design and behavior of conventional cast-in-place systems. If this can be achieved, typical analysis and design procedures can be used. The difficulty with developing emulative systems is usually encountered in the design and detailing of connections. Substructure connections are particularly critical in seismic zones because they must dissipate energy through significant cyclic nonlinear deformations while maintaining their capacity and the integrity of the structural system. The research presented in this dissertation focused on developing and evaluating earthquake resistant connections for use in accelerated bridge construction. The project was comprised of three main components; testing of five large-scale precast reinforced concrete column models, a series of individual component tests on mechanical reinforcing bar splices, and extensive analytical studies. Column studies included the design and construction of five half-scale bridge column models that were tested under reversed slow cyclic loading. Four new moment connections for precast column-footing joints were developed each utilizing mechanical reinforcing bar splices to create connectivity with reinforcing bars in a cast-in-place footing. Two different mechanical splices were studied: an upset headed coupler and grout-filled sleeve coupler. Along with the splice type, the location of splices within the plastic hinge zone was also a test variable. All column models were designed to emulate conventional cast-in-place construction thus were compared to a conventional cast-in-place test model. Results indicate that the new connections are promising and duplicate the behavior of conventional cast-in-place construction with respect to key response parameters. However, it was discovered that the plastic hinge mechanism can be significantly affected by the presence of splices and result in reduced displacement ductility capacity. In order to better understand the behavior of mechanical splices, a series of uniaxial tests were completed on mechanically-spliced reinforcing bars under different loading configurations: monotonic static tension, dynamic tension, and slow cyclic loading. Results from this portion of the project also aided the development of analytical models for the half- and prototype-scale column models. Results indicated that, regardless of loading configuration, specimens failed by bar rupture without damage to the splice itself. The analytical studies conducted using OpenSEES included development of microscope models for the two mechanical reinforcing bars splices and full analytical models of the five half-scale columns, which were both compared with respective experimental results to validate the modeling procedures and assumptions. Prototype-scale analytical models were also developed to conduct parametric studies investigating the sensitivity of the newly developed ABC connections to changes in design details. In general, the results of this study indicate that the newly develop ABC connections, which utilize mechanically-spliced connections, are suitable for moderate and high seismic regions. However, emulative design approaches are not suitable for all of the connections develop. A set of design recommendations are provided to guide bridge engineers in the analysis and design of these new connections.

Steel Girder-concrete Column Integral Bridges for Seismic Regions

Steel Girder-concrete Column Integral Bridges for Seismic Regions
Author: Justin R. Vander Werff
Publisher:
Total Pages: 368
Release: 2002
Genre:
ISBN:

Bridges with integral connections exhibit improved seismic performance and are useful in providing increased clearances. Integral bridges with steel girders are feasible and provide decreased seismic mass to further enhance seismic performance. However, most bridges in seismic regions that have been built with integral connections have been designed with concrete superstructures and concrete cap beams, and most of the research that has been conducted on integral connections for seismic regions has also dealt with concrete cap and girder sections. For this reason, the National Cooperative Highway Research Program has funded a project investigating the performance of concrete columns and steel superstructures in integral pier bridges under seismic loading. The focus of the project involved the development of a prototype bridge, investigation of suitable connection details and optimum member dimensions, load distribution in the structure, and overall seismic performance. These areas were examined using a combination of analytical and experimental studies. The prototype bridge developed in this study consists of a concrete column; steel, box-shaped cap beam; and steel girders. Two one-third-scale test specimens were developed, constructed, and tested as part of the experimental investigation. Grillage analyses of the prototype structure and test specimens were developed to work out appropriate loading for the specimens, to analyze the load distribution in the structures, and to develop predicted responses for the test specimens. The design of the first test specimen was governed by geometrical constraints based on the necessary depth to provide adequate anchorage length for the column longitudinal reinforcement. The second test specimen was designed to optimize the efficiency of the superstructure by using mechanical anchorage for the column longitudinal reinforcement, allowing the use of a shallower cap beam and lighter girder sections. Both test specimens exhibited satisfactory seismic performance by developing plastic hinges in the columns and successfully retaining strength under inelastic deformations.