Western_Michigan_University_CCE

LESS

 

 Current Project

NEESR: Near Collapse Performance of Existing Reinforced Concrete Frame Buildings

 

Real-Time Hybrid Simulation with Online Model Updating

 

Completed Projects

 

Integration Algorithms for Real-Time Hybrid

 

Cyclic Testing of two HGA10 connectors for CLT panels

 

NEESsoft: Seismic Risk Reduction for Soft-Story Woodframe Buildings

 

Evaluation of Earthquake Analysis Procedures using a Steel Frame Building

 

Effects of Friction Damper on Seismic Response of a Steel Frame Structure

 

US-China Distributed Test

 

Structural Design of a Steel Industrial Building Seismic Design of a Steel Concentrically Braced Frame

 

 

Project Navigation:

Real-time Pseudodynamic Hybrid Simulation Applying Actuator Delay

 

Pseudo-Dynamic Testing of a Scaled Specimen Using General Similitude Laws

 

Incremental Dynamic Analysis of a Steel Moment Frame

 

Health Monitoring System of a Bridge Structure Using Wireless Sensor Network

 

Development of Versatile Hybrid Testing System for Seismic Evaluation


 

Investigation of Damage Detection Methods with a Wireless Sensor Network

 

 

 

    Current Projects    
  NEESR: Near Collapse Performance of Existing Reinforced Concrete Frame Buildings    
     

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01/2012~12/2014

National Science Foundation

Adam Mueller

Master Thesis

Mehrdad Sasani, Ph.D. Northeastern University

Xiaoyun Shao, Ph.D. Western Michigan University


Description: This project utilizes the unique hybrid simulation capability provided by the NEES facilities to integrate the physical experiments on four sets of three columns of four buildings and the numerical simulation of the remaining reinforced concrete frame structure. The goals of the project are to determine the effects and important characteristics of triaxial as opposed to unidirectional seismic ground motions on column failure and collapse mechanisms, to develop reliable analytical modeling tools and methods for collapse analysis and to develop system level acceptance criteria and procedures for collapse analysis of reinforced concrete structures.

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Real-Time Hybrid Simulation with Online Model Updating

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1/2014~Current

Adam Mueller, Bilal Ahamed Mohammed

Description: Current hybrid simulation practices often use a fixed numerical model without considering the possible availability of a more accurate model obtained during hybrid simulation through an online model updating technique. To address this limitation and improve the reliability of numerical models in hybrid simulations, this study describes the implementation of an online model updating method in real-time hybrid simulation (RTHS). The Unscented Kalman Filter (UKF) was selected as the model updating algorithm and applied to identify Bouc-Wen model parameters that define the hysteresis of the experimental substructure, and the identified parameters were therefore applied to the numerical substructures during the hybrid simulation. 

 

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Completed Projects

Integration Algorithms for Real-Time Hybrid Simulation (RTHS)

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1/2014~6/2014
Carlos A. Santana
Master Project
Description: In this work, the description of the ground motions and its implications are shown first. Then, the novel technique known as “Hybrid Simulation” (HS) is described with its overall features, and right next, the explanation of several tools (algorithms) used to decipher the dynamic problem seeing several different approaches and concepts. All these tools are fully HS-compatible and their implementations are portrayed including testing validations. 
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Cyclic Testing of two HGA10 connectors for CLT panels

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2/2014~9/2014
Brenda Hodgell
Undergraduate Research Project
Description: Cross Laminated Timber (CLT) is a building material that was developed in the 1990’s that was initially used primarily in Europe. Slowly it has been gaining popularity as a building material in the United States, but it is not commonly used. CLT can be used as a steel or concrete substitute for framing. It is composed of three or more layers of lumber that are adhered together. The layers are stacked crosswise to increase durability. CLT has a number of advantages including low material weight with comparable strength, good seismic performance, versatility, made of renewable resources, and easy installation due to prefabrication. 
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NEESsoft: Seismic Risk Reduction for Soft-Story Woodframe Buildings

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7/2011~9/2014

National Science Foundation

Chelsea Griffith

Master Thesis

John W. van de Lindt,  Ph.D. University of Alabama

Xiaoyun Shao, Ph.D. Western Michigan University

WeiChiang Pang, Ph.D.  Clemson University

Michael D. Symans, Ph.D.  Rensselaer Polytechnic Institute (RPI)

Mikhail Gershfeld, S.E. California State Polytechnic University – Pomona

Description: The vision for the NEESsoft project is twofold: To provide a methodology to retrofit soft story woodframe buildings to (1) protect life, safety, and property by avoiding soft story collapse and excessive upper story accelerations, and (2) provide a mechanism by which soft story woodframe buildings can be retrofitted using performance-based seismic design (PBSD) to achieve a level of performance commensurate with stakeholders’ target. This vision will be accomplished through a comprehensive combination of new numerical modeling procedures, hybrid testing for validation of two levels of soft story woodframe retrofit and system level validation to better understand the mechanisms of woodframe collapse and the effect of these two levels of retrofit on system performance.  The project includes the following test phases: Slow hybrid simulation at the University of Alabama (UA), Real Time Hybrid Simulation (RTHS) at UA, Hybrid simulation test at University of Buffalo, and STT at UCSD.

 

Western Michigan University is leading the hybrid testing task essential in gaining a full understanding of soft story collapse mechanisms. Hybrid testing allows seismic evaluation of complex structural systems through substructure system/component testing. Simulation techniques employed in this project will evaluate a full scale wood frame structure with and without various retrofitting options, measuring the margin against collapse, focusing on the effects of a first story retrofit on the upper stories. Experimental methodology is to be developed at WMU’s LESS facility and ultimately carried out on a full-scale model at University of Buffalo’s SEESL facility, where large scale servo-hydraulic actuators will simulate earthquake ground motion and the structure’s dynamic response is recorded.

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Evaluation of Earthquake Analysis Procedures using a Steel Frame Building

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9/2013~1/2014
Mohamed Rusthi
Master Project
Description: Earthquake response of steel moment-resisting frames can be evaluated using currently available finite element software SAP2000 and computational platform RT-Frame2D. The objectives of this master project are; 1) design and analysis of a prototype 3D structure using SAP2000 and conduct compete earthquake analysis according to ASCE 7-10, 2) analyse a representative 2D moment resisting frame from the previous 3D structure and compare the response with the newly developed framework RT-Frame2D, and 3) evaluation of RT-Frame2D in terms of its modeling capabilities, implementation, and output results of the dynamic response. The SAP2000 finite element analysis was performed using a four story steel moment resisting frame building with different earthquake analysis methods provided in ASCE 7-10. And the representative 2D moment resisting frame of the building was analyzed using a newly-developed computational platform RT-Frame2D which uses MATLAB/Simulink environment. Finally, the different modeling options available in RT-Frame2D framework were evaluated by comparing the fundamental period of vibration and dynamic responses such as acceleration, velocity, and displacement. The results when compared with SAP2000 showed that the RT-Frame2D framework is reliable for dynamic analysis. Even though, RT-Frame2D has different modeling options such as flexible connections and panel zone elements, replicating the same models in SAP2000 was not possible. When the responses from flexible connection and panel zone models from RT-Frame2D were compared, the addition of panel zones when there is a flexible connection makes no difference in the responses. On the other hand, models without and with linear panel zone have the same responses. 
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Effects of Friction Damper on Seismic Response of a Steel Frame Structure

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1/2013~12/2013
Christopher S. Sawyer
Master Project
Description: In order to represent the three-story steel frame structure of the Laboratory of Earthquake Structure Simulation (LESS) numerically and maintain stability, a friction damper was designed and installed to the existing very lightly damped specimen. The effect of the friction damper on the seismic response was evaluated through both numerical simulation and experimental investigation. The damping ratio of the structure was increased from 0.277% to 1.699%. Though the desired realistic damping ratio of 2% to 3% for steel structures was not reached, stability was realized in the numerical models. A validated numerical model of both the third and second story substructures were established in MATLAB/Simulink for future development of versatile real-time hybrid simulations at LESS. 
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US-China Distributed Test

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06/2013~08/2013
NSF through EAPSI program
Adam Mueller
Drs. Shao and Wu

Description: An international geographically distributed hybrid simulation was conducted with physical substructures located at Western Michigan University (WMU) in the United States and Harbin Institute of Technology (HIT) in China. The communication protocol shown below was developed for this project. UI-SimCor was used as the computational driver, and NICON (developed by Dr. Oh-Sung Kwon at the University of Toronto) was used to interface to National Instruments data acquisition.

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Structural Design of a Steel Industrial Building Seismic Design of a Steel Concentrically Braced Frame

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09/2012~07/2013
Bradley Gerbasich
Master Project

Description: This project entailed two separate parts, each with different configurations, design loads, and considerations.  For both Part 1 and Part 2, a SAP2000 model was created to reflect the geometry of the building.  The design loads were assigned to the model utilizing ASCE 7-10 to determine the loading according to the applied loads or given building criteria.  Also, the Loading Combinations found in ASCE 7-10 were utilized within the SAP2000 model to develop the design loads for each individual member.  For Part 1, the design of the steel members utilized both the Structural Steel Design textbook and the AISC Steel Construction Manual.  For Part 2, the design of the steel members utilized both the AISC Steel Construction Manual and the AISC Seismic Design Manual.

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Real-time Pseudodynamic Hybrid Simulation Applying Actuator Delay

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01/2013~05/2013
Adnan Sanchez
Master Project

Description: Real-time pseudo-dynamic hybrid simulation is an experimental method consisting physical testing and numerical simulation with the objective to reproduce dynamic behavior of a structural system.  This project evaluates the compensation techniques necessary for real-time hybrid simulation which include additional error compensation for amplitude mismatch between command and measured, first and second order feedforward predictors to account for inherent actuator delays. The best compensation methods were determined for both linear and nonlinear structural models that would render the least peak error (PE) and the root mean square (RMS).

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Pseudo-Dynamic Testing of a Scaled Specimen Using General Similitude Laws

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09/2011~04/2012
Kevin Phillips
Master Project

Description: Pseudo-dynamic testing is increasingly being used for testing structures that are subject to seismic loadings.  Due to the limited capacity of available testing facilities and also due to economic reasons, testing is often carried out on scaled down models, rather than full scale structures.  The various aspects that are considered, when selecting scale factors for the similitude laws chosen, are explained.  The question of the practicality of scaled down testing on structures is examined using both open and closed loop pseudo-dynamic testing procedures. It was found that the results obtained from pseudo-dynamic testing of scaled models can be considered identical to full scale responses, when used for practical purposes.

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Incremental Dynamic Analysis of a Steel Moment Frame

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12/2011~04/2012
Roger A. Sanchez M.
Master Project

Description: Incremental Dynamic Analysis (IDA) is an analysis procedure by which can be obtained the dynamic response of a structural model exited by several seismic loads where increasing intensities are applied to analyze the structure performance from its elastic behavior to inelastic response until collapse. After the execution of several IDA analyses the results can be summarized on IDA curves to have a graphical representation of the structure’s performance. On this project the procedure to perform IDA analysis is detailed step by step using the software SAP2000 where it is explained how to create the model of a 2D steel frame, define load and masses, assign section properties, define nonlinear properties, add earthquake record data to the model, define time history dynamic analysis case with the required configuration to get the nonlinear response of the model and how to display and export the results. The procedure to perform IDA analysis is executed using time history analysis showing how to scale the earthquake data and run the analysis for several scale factors to get the response of the structure from its linear behavior to dynamic instability. IDA curves are then generated with the data obtained from the sets of dynamic analysis using Microsoft Excel.

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Health Monitoring System of a Bridge Structure Using Wireless Sensor Network

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02/2011~01/2012
Chee Kian Teng
Master Thesis

Description: Structural Health Monitoring (SHM) of bridge has rapidly become one of the main interests in civil engineering field. The state-of-the-art sensor monitoring technology poses as one of the most efficient and accurate SHM methods. The premise is that changes to structural properties caused by damage will change the way a structure responds to ambient motions. Modal analysis algorithms are applied to the collected vibration responses of a bridge structure (i.e. a bridge) and the structural properties can be extracted. Finally, with the extracted modal properties, damage detection methods can be used to detect and identify the damages developed within the structure under investigation. The study evaluates three output-only modal analysis algorithms with a wireless sensor network (WSN) based on their accuracy and efficiency in extracting modal properties. Output-only algorithm requires only the measured system response (i.e. displacement, velocity or acceleration), while the input, which is the quantification of the excitation force, is not required. The algorithms studied are: Stochastic Subspace Identification (SSI), Auto-regressive Moving Average (ARMA) and Fast Fourier Transform (FFT). These algorithms were used to extract modal properties using acceleration responses collected using WSN from two case studies. The case studies analyzed which are a three degree of freedom (DOF) benchmark structure and a highway bridge in Holland, Michigan. Based on the accuracy and consistency of the modal properties extracted using the algorithms, FFT was determined to be the most accurate and consistent, followed by ARMA and SSI. The extracted modal properties of the Holland Bridge were confirmed by modal frequencies obtained from a Finite Element (FE) bridge model. Recommendations on sensor's placement for future bridge SHM-related projects were provided.

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Development of Versatile Hybrid Testing System for Seismic Evaluation

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08/2009~06/2011

Griffin Enyart
Master Thesis

Description: The hybrid testing method was developed to evaluate the seismic performance of a structural system  by physically testing part of the structure, called a physical substructure, while numerically simulating the rest of the structure using a computer model, named as computational substructure. Instead of building full sized structural specimen, hybrid testing allows researchers to build a complex substructure to be tested experimentally while the relatively simple part of the structure being numerically simulated. Recently versatile hybrid testing system was built at Western Michigan University including a seismic simulator (often called shake table), a reaction/loading system and an advanced controller. Such testing system was used to evaluate the seismic performance of a three story structure whose top story installed with motion mitigation devices (i.e. dampers). The physical substructure is the top story with damper that was installed on the shake table and the numerical substructure is the bottom two story simulated in the computer. The boundary motions between the physical and numerical substructure were numerically simulated and applied to the top story using the shake table. Test results as well as the development of the test system is presented.

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Investigation of Damage Detection Methods with a Wireless Sensor Network

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08/2009~01/2010
Mark Humiecki
Master Thesis

Description: This study evaluates three damage detection methods with a wireless sensor network based on accuracy and efficiency. The three methods assessed are: Modal Assurance Criterion (MAC); Damage Location Assurance Criterion (DLAC); and a method which utilizes the change of the structures flexibility. The concept of each method is discussed and demonstrated with a numerical example of a three story shear type structural model that was designed and constructed as the benchmark structure used in this study. The wireless sensor network adopted here utilizes the Intel Mote 2 pre-configured with the latest tool suite released by the Illinois Structural Health Monitoring Program (ISHMP). The establishment of the wireless sensing network, from software installation to data analysis, is presented. The three damage detection methods are then experimentally validated by using the wireless sensor network to monitor the benchmark structure model. Experimental results are presented and compared to demonstrate the performance of these three methods. The MAC method, with this simple benchmark structure, was determined to be the most accurate and efficient. The flexibility-based method was found to be the least accurate

 

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                               Western Michigan University ---- Department of Civil and Construction Engineering

                               Laboratory of Earthquake and Structural Simulation ---- Last Updated: 12-5-2014