Engineering Commons^™

Fiber-Based Seismic Damage And Collapse Assessment Of Reinforced Concrete Single-Column Pier-Supported Bridges Using Damage Indices, Yu-Fu Ko, Jessica Gonzalez

Mineta Transportation Institute

Near-fault earthquakes can have major effects on transportation systems due to the structural damage they impose on bridges. Therefore, it is imperative to assess the seismic damage of bridges appropriately, and this research focuses on reinforced concrete (RC) bridges. This research advances the seismic performance assessment of RC single-column pier-supported bridges with flexural failure under near-fault ground motion by use of ductility coefficients and damage indices. The methodology included modeling fiber-based nonlinear beam-column elements to simulate the damage development process of RC bridge piers under earthquake loadings, considering the global buckling of longitudinal steel bars, examining the cracking and spalling …

Cascadia Subduction Zone Earthquake Vertical Ground Acceleration Investigation And Potential Impact On Bridges In The Pacific Northwest, Rachel Caroline Bassil

Civil and Environmental Engineering Master's Project Reports

The effects of vertical ground accelerations during subduction zone earthquakes currently are not sufficiently understood. There are numerous case studies and evidence that effects of vertical ground accelerations can significantly impact the performance of bridges during a seismic event, but most previous research has been focused on shallow crustal earthquakes. Current bridge design codes provide little guidance for accounting for vertical ground accelerations in seismic design, in part because additional information is needed about the characteristics of vertical ground motions during Cascadia Subduction Zone (CSZ) earthquakes in the Pacific Northwest.

For this study, recorded seismic data from recent subduction zone …

Development Of Deep Shear Wave Velocity Profiles And An Approach To Generate Site Signature Consistent Pseudo Shear Wave Velocity Profiles In The Mississippi Embayment, Ashraf Kamal Himel

Graduate Theses and Dissertations

This dissertation details the development of a surface wave method (SWM) technique to generate deep shear wave velocity profiles (VS profiles), applying this technique at 24 sites across the Mississippi embayment and developing an approach to generate pseudo site signature consistent VS profiles from velocity functions and fundamental frequency. In the presented SWM technique, active and passive source surface wave measurements are inverted along with fundamental frequency to develop a site signature consistent VS profile. Multiple transformation methods, including MSPAC, HRFK and FK are used to resolve experimental dispersion data from surface wave measurements. SWM VS profile at the Central …

Seismic Performance Design Criteria Of Existing Bridge Bent Plastic Hinge Region And Rapid Repair Measures Of Earthquake Damaged Bridges Considering Future Resilience, A K M Golam Murtuz

Dissertations and Theses

The main objective of this research was to evaluate the seismic performance of existing sub-standard reinforced concrete (RC) bridge column-spread footing subassemblies and to quantify the material strain limits through a full-scale experimental program. A total of six column-footing test specimens with pre-1990 construction details were subjected to reverse cyclic lateral loading, utilizing a conventional three-cycle symmetric loading protocol and a protocol representing the demands expected from a CSZ earthquake. Additionally, the tests were designed so that variable axial loading could be applied to simulate the secondary load effects experienced during an earthquake in a column that is part of …

Implementation Of A Novel Inertial Mass System And Comparison To Existing Mass-Rig Systems For Shake Table Experiments, Alvaro Lopez, Peter Dusicka

Civil and Environmental Engineering Faculty Publications and Presentations

Shake table testing is one of the more effective experimental approaches used to study and evaluate seismic performance of structures. Reduced-scale models can still result in large-scale specimens where incorporating the required inertial mass effectively and safely can be challenging. This study proposes a new system of arranging the mass in the experiments that combines the realism of mass participation during earthquake excitation when supported by the shake table with laboratory practicality considerations of the mass positioned off the specimen. The characteristics and dynamic motion equations for the proposed system are described and applied to shake table experiments involving large-scale …

Rapid Repair Of Seismically Vulnerable Bridge Columns Following Earthquake Induced Damage, Gregory H. Norton

Civil and Environmental Engineering Master's Project Reports

The Cascadia Subduction Zone (CSZ) earthquake has a high probability of occurrence within our lifetime, threatening bridges across the Pacific Northwest. Damage is expected to be geographically spread throughout the region and will have a nearly simultaneous impact on transportation through several important corridors. While bridge repair and replacement will ultimately be needed, priority will be placed on resuming mobility such that repairs will need to be implemented quickly. In an effort to anticipate this need, a repair method is being developed for rapid repair with the goal of achieving semi-permanent installation that also considers the different bridge damage states …

Seismic Design Coefficients For Speedcore Or Composite Plate Shear Walls - Concrete Filled (C-Psw/Cf), Shubham Agrawal, Morgan Broberg, Amit H. Varma

Bowen Laboratory Research Reports

This report summarizes the results from FEMA P695 analytical studies conducted to verify the seismic design factors for composite plate shear walls – concrete filled (C-PSW/CF), also referred to as Speedcore. ASCE 7-16 provides the seismic design factors, which include the seismic response modification factor, R, deflection amplification factor, C_d, and overstrength factor, Ω_o, for various approved seismic systems. C-PSW/CFs are assigned a response modification factor of 6.5, a deflection amplification factor of 5.5, and an overstrength factor of 2.5 for C-PSW/CFs. These seismic design factors were selected based on the seismic performance of similar structural …

A Predictive Modeling Approach For Assessing Seismic Soil Liquefaction Potential Using Cpt Data, Jonathan Paul Schmidt

Master's Theses

Soil liquefaction, or loss of strength due to excess pore water pressures generated during dynamic loading, is a main cause of damage during earthquakes. When a soil liquefies (referred to as triggering), it may lose its ability to support overlying structures, deform vertically or laterally, or cause buoyant uplift of buried utilities. Empirical liquefaction models, used to predict liquefaction potential based upon in-situ soil index property measurements and anticipated level of seismic loading, are the standard of practice for assessing liquefaction triggering. However, many current models do not incorporate predictor variable uncertainty or do so in a limited fashion. Additionally, …

Post-Liquefaction Residual Strength Assessment Of The Las Palmas, Chile Tailings Failure, Tristan Reyes Gebhart

Master's Theses

Assessment of post-liquefaction residual strength is needed for the development of empirically-based, predictive correlations for earthquake engineering design. Previous practice commonly assigned negligible strengths to liquefied materials for engineering analysis, producing overly-conservative designs. Increasingly available case history data, and improved analytical tools have allowed for more accurate and less overly-conservative estimation of soil residual strength, improving empirical predictive models. This study provides a new case history to the limited suite of (approximately 30) liquefaction failure case histories available for post-liquefaction in-situ strength predictive correlations.

This case history documents the Las Palmas gold mine tailings dam failure, resulting from seismic-induced liquefaction …

Commercialization Of A Small, Lightweight, Low-Cost Seismic Borehole Receiver, Rachel Adams

Theses and Dissertations--Civil Engineering

Herein, conceptualization of a recently patented seismic borehole receiver and its components is developed for commercialization. The device is significantly cheaper, lighter, and smaller than existing technologies on the market. Additionally, it has the potential to achieve better seismic readings than its competitors via patented sensor-to-borehole coupling mechanism. It is the hope that the commercialization of this device will not only provide a more affordable alternative to engineers and geophysicists in the existing market, but the significant cost difference may open new seismic measurement opportunities in the developing world. Its compact size and light weight will increase mobility, allowing investigators …

Girder Load Distribution For Seismic Design Of Integral Bridges, Justin Vander Werff, Sri Sritharan

Faculty Work Comprehensive List

Current seismic design practice related to integral bridge girder-to-cap beam connections allows little or no lateral seismic load to be distributed beyond the girders immediately adjacent to the column. However, distribution results from several large-scale tests have shown that the distribution of column seismic moment typically engages all the girders. An approach utilizing simple stiffness models to predict distribution in integral bridge structures is presented in detail; distribution predictions based on grillage analyses also are compared. The experimental results and the analytical results from the stiffness and grillage models show that current design methods related to vertical load distribution are …

Evaluation Of Collapse Indicators For Seismically Vulnerable Reinforced Concrete Buildings, Nicholas R. Skok

Open Access Theses

Older reinforced concrete buildings can be prone to column shear and compression failures during earthquakes because of inadequate transverse reinforcement. Cities in seismic areas still have large inventories of older and potentially deficient buildings. To analyze every building and estimate its vulnerability in detail is costly. A simple method to rank quickly older buildings according to their seismic vulnerability is needed to help engineers prioritize the use of resources for rehabilitating the most vulnerable buildings.

Four indicators of building damage or collapse were evaluated using numerical analysis and prior data from building surveys: column index (Hassan & Sozen, 1997), R …

Seismic Response Of Stiffening Elastic Systems, Andrew Scott Morgan

Theses and Dissertations

Traditional seismic load resisting systems in buildings are designed to undergo inelastic deformations in order to dissipate energy, resulting in residual displacements. This work explores an approach to eliminate these residual displacements. The systems investigated have low initial stiffness which increases at a predefined displacement, and are therefore called stiffening elastic systems. This thesis begins with an examination of single-degree-of-freedom stiffening elastic systems. A case study is presented which suggests that the benefits from stiffening elastic behavior may be limited to systems which would have long periods if designed traditionally. A thorough parameter study is also presented which indicates the …

Quasi-Static Analysis Of Rocking Wall Systems, Douglas Seymour, Simon Laflamme

Simon Laflamme

Rocking wall systems consist of shear walls that are free to rotate at their base. Their purpose is to mitigate seismic structural damage by constraining the structure primarily to its first mode. This constraint prevents weak story failure, and maximizes energy dissipation by activating plastic hinges throughout the structure. The purpose of this paper is to present a methodology for the design of rocking wall systems. A quasi-static analysis model is used for predicting the seismic mitigation performance of rocking walls. The stiffness matrix is generalized for an N-story simplified structure equipped with this structural system. The model presented enables …

Application Of Mass/Stiffness Eccentricity To Control Response Of Structures Subjected To Earthquake Ground Motion, Bakhtiar Feizi

Dissertations

This dissertation is driven by the concept that engaging more modes in the response of structures can be used to mitigate its translational dynamic response. One such an approach is to engage torsional modes through engineered eccentricity (mass/stiffness eccentricity), thus, introducing coupled translation-rotation response. This idea was first introduced in a paper published by MacBain and Spillers in 2004. As a follow up to the same idea this dissertation was an attempt to investigate and develop the theory concerning the application of mass/stiffness eccentricity to control the translational motion of structures subjected to earthquake ground motion.

Different discrete and continuous …

Earthquake Engineering Simulation With Flexible Cladding System, Jun Jie Li

Masters Theses 1911 - February 2014

This research investigates the interaction between heavy precast cladding units attached to steel framed buildings. Cladding systems are designed as non-structural components and are not expected to contribute to the energy absorption of the primary structure. However, research has indicated that the cladding system may be designed to reduce the response of the primary structure under seismic excitations. The use of flexible connections between the cladding and primary structural frames may be able to provide beneficial effects to the entire structural response. In this study, a series of earthquake engineering simulations were conducted in OPENSEES to analyze the effects of …

Damage Characterization Of Beam-Column Joints Reinforced With Gfrp Under Reversed Cyclic Loading, Aly M. Said

Civil and Environmental Engineering and Construction Faculty Research

The use of fiber reinforced polymer (FRP) reinforcement in concrete structures has been on the rise due to its advantages over conventional steel reinforcement such as corrosion. Reinforcing steel corrosion has been the primary cause of deterioration of reinforced concrete (RC) structures, resulting in tremendous annual repair costs. One application of FRP reinforcement to be further explored is its use in RC frames. Nonetheless, due to FRP's inherently elastic behavior, FRP-reinforced (FRP-RC) members exhibit low ductility and energy dissipation as well as different damage mechanisms. Furthermore, current design standards for FRP-RC structures do not address seismic design in which the …

Shear Modulus Degradation Of Liquefying Sand: Quantification And Modeling, Peter A. Olsen

Theses and Dissertations

A major concern for geotechnical engineers is the ability to predict how a soil will react to large ground motions produced by earthquakes. Of all the different types of soil, liquefiable soils present some of the greatest challenges. The ability to quantify the degradation of a soil's shear modulus as it undergoes liquefaction would help engineers design more reliably and economically. This thesis uses ground motions recorded by an array of downhole accelerometers on Port Island, Japan, during the 1995 Kobe Earthquake, to quantify the shear modulus of sand as it liquefies. It has been shown that the shear modulus …

Behaviour Of Reinforced Self-Consolidating Concrete Frames, Aly Said, Moncef Nehdi

Civil and Environmental Engineering and Construction Faculty Research

Multi-storey reinforced concrete (RC) structural frames represent some of the most congested structural elements. Placing and consolidating concrete in such structural frames imposes substantial challenges. This offers a unique area of application for self-consolidating concrete (SCC) because of its inherent ability to flow under its own weight and fill congested sections, complicated formwork and hard-to-reach areas. Research is, however, needed to demonstrate the ability of SCC structural frames adequately to resist vertical and lateral loads. In the present study, full-scale 3 m high beam-column joints reinforced as per the Canadian Standards CSA A23·3-94 and ACI-352R-02 were made with normal concrete …

Numerical Modeling Of Infill Rc Walls In Seismic Retrofit Of Rc Frames, Mohamed Mohamed Slah El-Din Darwish

Archived Theses and Dissertations

Columns designed and built according to older standards may be subject to damage due to seismic loading during earthquakes as a result of the lack of shear reinforcement and/or insufficient lap-splice length. An experimental program on the use of ifill RC walls in seismic retrofit of RC frames under cyclic loading was conducted in 2002. The output of this experimental work formed the basis for the validation of a numerical finite element model, in predicting forces and displacements. Subsequently the finite element model was used to perform a parametric analysis on the effects of the thickness, overall reinforcement and concrete …