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.

Structures Under Shock and Impact XVI

Structures Under Shock and Impact XVI
Author: S. Syngellakis
Publisher: WIT Press
Total Pages: 170
Release: 2020-08-19
Genre: Technology & Engineering
ISBN: 1784663999

The increasing need to protect civilian infrastructure and industrial facilities against unintentional loads arising from accidental impact and explosion events as well as terrorist attacks is of major importance. While advances have been made in recent years, many challenges remain, such as to develop more effective and efficient blast and impact mitigation approaches than those that currently exist. The primary focus remains the survivability of physical facilities and the protection of people, as well as reducing economic losses and impact on the environment, with emphasis on innovative protective technologies to support the needs of an economically growing, modern society. The application of this technology ranges from the safe transportation of people and dangerous materials to defences against natural hazards such as floods, wind, storms, tsunamis and earthquakes. Large scale testing is prohibitive and small scale laboratory testing results in scaling uncertainties. Continuing research is therefore essential to improve knowledge on how these structures behave under a variety of load actions, some of which interact making it even more complex and difficult to define. Consequently, more use of advanced numerical simulations for load and structural response calculations is common practice in industry and research. Such calculations can directly be used in design and risk assessment calculations, but also be applied to more simplified design tools and design codes. Whether numerical or analytical modelling techniques are employed, experimental validation is vital for there to be acceptance of the approach to be used. The included papers, presented at the 16th International Conference on Structures under Shock and Impact, highlight new research ideas and results to promote a better understanding of the critical issues relating to the testing behaviour, modelling and analyses of protective structures against blast and impact loading.

Seismic Design and Performance

Seismic Design and Performance
Author: T.G. Sitharam
Publisher: Springer Nature
Total Pages: 406
Release: 2021-03-26
Genre: Science
ISBN: 9813340053

This volume presents select papers presented at the 7th International Conference on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics. The papers discuss advances in the fields of soil dynamics and geotechnical earthquake engineering. Some of the themes include seismic design of deep & shallow foundations, soil structure interaction under dynamic loading, marine structures, etc. A strong emphasis is placed on connecting academic research and field practice, with many examples, case studies, best practices, and discussions on performance based design. This volume will be of interest to researchers and practicing engineers alike.

Seismic Assessment, Behavior and Retrofit of Heritage Buildings and Monuments

Seismic Assessment, Behavior and Retrofit of Heritage Buildings and Monuments
Author: Ioannis N. Psycharis
Publisher: Springer
Total Pages: 490
Release: 2015-05-05
Genre: Science
ISBN: 331916130X

This book assembles, identifies and highlights the most recent developments in Rehabilitation and retrofitting of historical and heritage structures. This is an issue of paramount importance in countries with great built cultural heritage that also suffer from high seismicity, such as the countries of the eastern Mediterranean basin. Heritage structures range from traditional residential constructions to monumental structures, ancient temples, towers, castles, etc. It is generally recognized that these structures present particular difficulties in seismic response calculation through computer simulation due to the complexity of the structural system which is, generally, inhomogeneous, with several contact problems, gaps/joints, nonlinearities and brittleness in material constituents. This book contains selected papers from the ECCOMAS Thematic Conferences on Computational Methods in Structural Dynamics & Earthquake Engineering (COMPDYN) that were held in Corfu, Greece in 2011 and Kos, Greece in 2013. The Conferences brought together the scientific communities of Computational Mechanics, Structural Dynamics and Earthquake Engineering in an effort to facilitate the exchange of ideas in topics of mutual interest and to serve as a platform for establishing links between research groups with complementary activities.

Drilled Shaft Socket Connections for Precast Columns in Seismic Regions

Drilled Shaft Socket Connections for Precast Columns in Seismic Regions
Author: Hung Viet Tran
Publisher:
Total Pages: 119
Release: 2012
Genre: Concrete bridges
ISBN:

Conventional cast-in-place method in bridge construction requires long on-site construction time and substantial labor in the field, which can result in high construction costs and traffic delays. Using precast bridge elements is one solution. However, achieving good connections between precast elements is challenging, particularly in seismically hazardous areas, like the Pacific Northwest, in which the largest forces are developed at the beam-to-column or column-to-footing connections. Therefore, the connections need to be strong enough to resist seismic excitation and easy to construct with high quality. This study adapts the column-to-foundation socket concept to connections between a precast column and cast-in-place drilled shaft. In this connection, the column is precast with a roughened outer surface at the bottom of the column, where it will be embedded in the drilled shaft. Two specimens were fabricated and tested at the University of Washington. The only difference between the two specimens was the amount of spiral reinforcement in the column-to-shaft transition region, which was reduced by half in the second specimen. The goal was to promote failure in the shaft transition region in the second specimen, in order to develop an understanding of the load transfer mechanism there. The response and mode of failure of each specimen was the same as had been anticipated during design. It shows that the new design provides agencies a good method for accelerating bridge construction.

Repair and Testing of Out-of-Plane Seismic Response of Pocket Connection

Repair and Testing of Out-of-Plane Seismic Response of Pocket Connection
Author:
Publisher:
Total Pages: 0
Release: 2022
Genre: Bridges
ISBN:

Accelerated bridge construction (ABC) has been utilized in precast bridge structures because of its advantage to expedite onsite construction. In ABC, one of the main concerns is the joint connection as it needs to be well designed to maintain structural integrity. Several studies were able to demonstrate the effectiveness of ABC pocket connections for partial and fully precast columns. The pocket connections are designed to have the cap beam longitudinal reinforcements bundled outside the joint allowing the placement of the column uninhibited. On the contrary, this has been an issue for cast-in-place (CIP) construction where congestion of the reinforcements in the joint regions is typical. A recent study at the University of Nevada, Reno (UNR) was conducted by utilizing ABC pocket connection in CIP bridges. The specimen was tested at UNR Earthquake Engineering Laboratory on a shake table in an upside-down configuration using an increasing scaled ground motion. The specimen performed well under out-of-plane ground motion excitations and the ductility of the column was confirmed through typical plastic hinge behavior. In this study, the main objective is to further use the specimen from the recent UNR test to repair the damaged column and to test the repaired specimen using the same loading protocol as the original model. The objective was achieved by developing a repair method using flush cutting and coring of the damaged column. A new column was constructed using the exact reinforcements as the original model. However, the column was cast monolithically in the pocket joint as opposed to the original model where the column reinforcement sat in two different concrete casts with a cold joint at the column-cap beam interface. The repaired column was subjected to the same loading protocol as the original model using the scaled 1994 Northridge earthquake ground motion recorded at the Sylmar Converter Station. The repaired specimen performed well as the plastic hinge zone developed in the column outside the joint, close to the interface of the cap beam, as desired and required by design. The results were compared to the original specimen and the maximum drift ratio for 20% through 450% of the earthquake motion was relatively equal. However, for 550% and 650% of the earthquake motions, the drift ratio in the repaired specimen was significantly larger compared to the original specimen. The high drift ratios were attributed to the slippage of the column in the joint and were validated by an increase in the ratios between the rotations of the original and repaired column recorded at the base. The cap beam remained essentially elastic, i.e. capacity-protected as required, throughout the test which is similar to the performance of the original model. Lastly, recommendations for the repair of CIP cap beam-column emulating ABC pocket connection are provided with special attention to roughen the pocket joint connection to develop a sufficient bond between the two members.

Insights and Innovations in Structural Engineering, Mechanics and Computation

Insights and Innovations in Structural Engineering, Mechanics and Computation
Author: Alphose Zingoni
Publisher: CRC Press
Total Pages: 2223
Release: 2016-11-25
Genre: Technology & Engineering
ISBN: 1317280636

Insights and Innovations in Structural Engineering, Mechanics and Computation comprises 360 papers that were presented at the Sixth International Conference on Structural Engineering, Mechanics and Computation (SEMC 2016, Cape Town, South Africa, 5-7 September 2016). The papers reflect the broad scope of the SEMC conferences, and cover a wide range of engineering structures (buildings, bridges, towers, roofs, foundations, offshore structures, tunnels, dams, vessels, vehicles and machinery) and engineering materials (steel, aluminium, concrete, masonry, timber, glass, polymers, composites, laminates, smart materials).

Application of Accelerated Bridge Construction Connections in Moderate-to-High Seismic Regions

Application of Accelerated Bridge Construction Connections in Moderate-to-High Seismic Regions
Author:
Publisher: Transportation Research Board
Total Pages: 65
Release: 2011
Genre: Technology & Engineering
ISBN: 0309213436

TRB’s National Cooperative Highway Research Program (NCHRP) Report 698: Application of Accelerated Bridge Construction Connections in Moderate-to-High Seismic Regions evaluates the performance of connection details for bridge members in accelerated bridge construction in medium-to-high seismic regions and offers suggestions for further research.