Seismic Design of Pipe-pin Connections in Concrete Bridges

Seismic Design of Pipe-pin Connections in Concrete Bridges
Author: Arash Esmaili Zaghi
Publisher:
Total Pages: 546
Release: 2010
Genre: Concrete bridges
ISBN:

Telescopic pipe-pin two-way hinges are used in concrete bridges to eliminate moments while transferring shear and axial loads from integral bridge bent caps to reinforced concrete columns. The hinges consist of a steel pipe that is anchored in column with a protruded segment that extends into the bent cap. In the absence of experimental and analytical studies, design of pipe-pin hinges has been based on pure shear capacity of the steel pipe. The primary objective of this research was two folds: (1) to investigate the seismic performance of the current detail of pipe-pin hinges and propose necessary modifications and (2) to develop a reliable design method for pipe-pin hinges that reflects their actual behavior. This research was comprised of comprehensive experimental and analytical studies of pipe-pin connections and their components including a shake table study of a two-column pier model. The experimental component of the study included three sets of test models: (1) six push-off specimens to evaluate the bearing strength of concrete against the steel pipe, (2) six pure shear specimens to determine the yielding and ultimate shear capacities, and (3) a two-column 0.2-scale bridge pier model incorporating pipe-pin hinges that were designed based on the proposed guideline. The pier model was used to evaluate the new design method under earthquake excitation. The experiments showed that the lateral failure mechanism is typically controlled by concrete diagonal tensile cracking of the column in combination with flexural yielding of the steel pipe as opposed to pure shear, although the pure shear failure mode should be considered when a large amount of lateral steel is used in the column. Another possible mode of failure is bearing failure of the concrete around the pipe in heavily reinforced columns. The shake table experiment of the pier model confirmed that the proposed design method meets the safety and performance requirements under seismic loading. The analytical studies consisted of (1) a stick model in SAP2000 that was developed for pipe shear key subassemblies, (2) detailed nonlinear FE models using ABAQUS that were used to performed an extensive parametric study in order to shed light on different aspects of the behavior and generate the required data for the design guideline, and (3) a model in OpenSees that utilized a macro model for the pipe-pin hinges. The experimental and analytical results helped identify the means to improve the performance of current pipe-pin hinge details. The pipe studs and spiral around the can proved to be unnecessary and were eliminated in the proposed standard detail. A thicker tapered hinge throat was suggested to solve the problem of local concrete damage to the throat and column edges. As a possible extension of pipe-pin application, a study was conducted on pipe-pins combined with isolation and damping systems. The analytical modeling of these details showed that modified connections can reduce the demands on the structure by dissipating a major portion of the earthquake energy.

Experimental and Analytical Seismic Studies of Bridge Piers with Innovative Pipe Pin Column-footing Connections and Precast Cap Beams

Experimental and Analytical Seismic Studies of Bridge Piers with Innovative Pipe Pin Column-footing Connections and Precast Cap Beams
Author: Ali Mehrsoroush
Publisher:
Total Pages: 1518
Release: 2014
Genre: Electronic books
ISBN:

The use of prefabricated structural elements is an integral part of many accelerated bridge construction (ABC) efforts. Connections of these prefabricated elements to the rest of the structural system is critical to the performance of the structure under service loads and extreme events such as earthquakes. Two types of novel joints were developed in this study: 1) base pipe pin connections to substantially reduce the moment transfer between the column and footing, and 2) pocket connections to provide structural continuity at column-cap beam joints. The pipe pin consists of two steel pipes to transfer shear and a tension member to transfer uplift forces. Pocket connection is formed by extending the column into a pre-fabricated pocket in a precast cap beam and grouting the space between the column segment and the pocket. The primary objective of this research was to investigate the seismic performance, response, and behavior of base pipe pins for both cast-in-place (CIP) and precast construction, to study the performance of column-cap beam pocket connections to be utilized in ABC, and to develop a reliable design guideline for base pipe pins. This research was comprised of comprehensive experimental and analytical studies. The experimental portion of the study was conducted at the University of Nevada, Reno Large Scale Structural Laboratory including three sets of tests: 1) cyclic loading test of a large-scale two-column bent model, and 2) two direct pull tests of CIP and precast pipe pin connections. The bent model was composed of a precast engineered cementitious composite (ECC)-concrete column, a conventional CIP reinforced concrete column, a precast cap beam, and two single footings. The columns were connected to the footing and cap beam utilizing pipe pin and pocket connections, respectively. Direct pull tests were carried out to investigate the failure mode of the pipe pins under direct tension and determine the ultimate tensile capacity of the pins. The proposed pipe pin connections were found to be successful even under high drift ratios. Test results revealed that pipe pins needs to be designed for shear forces that exceed the column design shear due to reversed friction under large base rotations. Direct pull tests of the pipe pins showed that the dominant failure mode of the connection under pure tension was rupture of the tension member and all the other connection elements remained damage free. The pocket connection using corrugated steel pipes with a column embedment length of 1.2 times the column diameter performed well in forming the plastic hinge when conventional concrete was used in the embedded region. However, longitudinal bars in the precast column with embedded ECC debonded at 4% drift ratio. The analytical study consisted of 1) elaborate finite element (FE) modeling of the pipe pin connections and footings under direct tension, 2) FE study of the two-column bent, and 3) analytical modeling of pipe embedded in the footing (pipe shear key). ABAQUS and OpenSees were used in the analyses. The analytical models were evaluated based on correlation with experimental data, and were then used to investigate the effects of different parameters on the seismic performance of pipe pins. Results of the parametric studies along with the experimental observations led to an iterative procedure to determine seismic demands and methods for designing pipe pins. This was followed by development of design and detailing methods and illustrative examples.

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 Design Aids for Nonlinear Pushover Analysis of Reinforced Concrete and Steel Bridges

Seismic Design Aids for Nonlinear Pushover Analysis of Reinforced Concrete and Steel Bridges
Author: Jeffrey Ger
Publisher: CRC Press
Total Pages: 396
Release: 2016-04-19
Genre: Technology & Engineering
ISBN: 1439837759

Nonlinear static monotonic (pushover) analysis has become a common practice in performance-based bridge seismic design. The popularity of pushover analysis is due to its ability to identify the failure modes and the design limit states of bridge piers and to provide the progressive collapse sequence of damaged bridges when subjected to major earthq

Seismic Design and Assessment of Bridges

Seismic Design and Assessment of Bridges
Author: Andreas J Kappos
Publisher: Springer Science & Business Media
Total Pages: 233
Release: 2012-04-17
Genre: Technology & Engineering
ISBN: 9400739435

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.

Performance-based Seismic Bridge Design

Performance-based Seismic Bridge Design
Author: M. Lee Marsh
Publisher: Transportation Research Board
Total Pages: 138
Release: 2013
Genre: Technology & Engineering
ISBN: 0309223806

"TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 440, Performance-Based Seismic Bridge Design (PBSD) summarizes the current state of knowledge and practice for PBSD. PBSD is the process that links decision making for facility design with seismic input, facility response, and potential facility damage. The goal of PBSD is to provide decision makers and stakeholders with data that will enable them to allocate resources for construction based on levels of desired seismic performance"--Publisher's description.

Bridge Maintenance, Safety, Management, Resilience and Sustainability

Bridge Maintenance, Safety, Management, Resilience and Sustainability
Author: Fabio Biondini
Publisher: CRC Press
Total Pages: 4119
Release: 2012-06-21
Genre: Technology & Engineering
ISBN: 0203103386

Bridge Maintenance, Safety, Management, Resilience and Sustainability contains the lectures and papers presented at The Sixth International Conference on Bridge Maintenance, Safety and Management (IABMAS 2012), held in Stresa, Lake Maggiore, Italy, 8-12 July, 2012. This volume consists of a book of extended abstracts (800 pp) Extensive collection of revised expert papers on recent advances in bridge maintenance, safety, management and life-cycle performance, representing a major contribution to the knowledge base of all areas of the field.

Seismic Performance of Column-to-drilled-shaft Connections in Reinforced Concrete Bridges

Seismic Performance of Column-to-drilled-shaft Connections in Reinforced Concrete Bridges
Author: Michelle Teng Chang
Publisher:
Total Pages: 248
Release: 2021
Genre:
ISBN:

Drilled shaft foundations are often used to support reinforced concrete bridge columns founded in soft soils or in locations where a small footprint is desired. Increasingly, the shaft is being built with a diameter larger than that of the column, to allow tolerance in the column placement and to facilitate plastic hinge formation in the column rather than in the shaft. The column-shaft connection, which involves a noncontact splice between the column and shaft bars, is a key component in this structural system. However, there is limited research on the behavior of these connections under seismic loads. In order to understand the force-transfer mechanism of column-shaft connections under seismic loading, one quasi-static cyclic experimental test was conducted on a column-shaft subassembly. Measured results were compared with those from three previous experiments performed at the University of Washington. The study found that the amount of shaft transverse reinforcement in the connection region was critical in determining the failure mode of the connection. In specimens with relatively low amounts of transverse reinforcement, including the specimen tested during this study and a previous specimen tested at the University of Washington, the connection failed through a shaft prying failure mode; the specimens developed large vertical cracks between the confined column core and the annular shaft transition region, and the shaft transverse reinforcement eventually fractured at large drift ratios. Therefore, three methodologies for detailing the shaft transverse reinforcement were evaluated, and a new analysis procedure using a strut-and-tie model was proposed. It is consistent with the measured and observed performance of the tested connections, and is applicable to shafts supporting either precast or cast-in-place columns. The new procedure allows engineers to more accurately predict the behavior of a column-shaft connection and prevent an undesirable below-ground failure in the shaft transition region. Lastly, a set of design equations based on the strut-and-tie findings and existing design models is proposed for use in practice.