Project Abstracts: 2007 to 2008
Structural Engineering and Mechanics
SST: Polymer Fiber and Waveguide Sensors for Performance-Based Assessment and Health Monitoring of Civil Infrastructure Systems. Tasnim Hassan, K. Peters, and M.J. Kowalsky. National Science Foundation. 08/04 to 07/08
The goal of the project is to develop polymer sensors for health monitoring of civil infrastructure systems. Of specific interest is to develop a sensor that can measure strains in excess of 6% under high strain rates. Although the sensors to be developed can be utilized under a variety of load conditions and structural materials, this research program will focus on application of the sensors to concrete and steel structures subjected to earthquakes loads. The research will develop a data acquisition system that can be utilized in health monitoring and techniques for bonding the polymer sensors to concrete structures.
A Multiscale Study of Ratcheting Failure Mechanisms in Austenitic and Ferritic Steel Welded Joints. Tarek Hassan and K.L. Murty. National Science Foundation. 08/04 to 07/08
The goal of the project is to study multiscale failure mechanisms of austenitic and ferritic steel welded joints subjected to low-cycle fatigue loading. The progressive accumulation of strain with cycle known as ratcheting is believed to result in unexpected failures of defect-free joints. This project will perform low-cycle fatigue tests of welded joints and transmission and scanning electronic microscopy studies of dislocation substructures of the heat affected zone and base metals at various stages of fatigue life. Efforts will be made to develop a model for simulating ratcheting responses of welded joints using both macroscale and multiscale based constitutive models.
Evaluation of a New High Corrosive Resistant Steel Reinforcement for Concrete Structures in the Miditerian Salt Environments. Tarek Hassan and S. Rizkalla. National Science Foundation. 09/05 to 12/07
MMFX is a high strength, highly corrosion resistant steel, ideal for use in civil engineering applications for salt environments such as the miditerian environment in Egypt and high humidity climate such as in North Carolina and many other ocean exposed states. The research will introduce the MMFX steel as a new material has a high corrosion resistance to the engineering community in Egypt for the first time. The proposed research project consists of three major tasks: (1) experimental work, (2) analytical phase, (3) development of design guidelines.
Development of Multi-axial VEPCD-FEP++ and its Extension to Indirect Tension Test. Y.R. Kim and M.N. Guddati. Federal Highway Administration. 09/05 to 12/07
Over the past decade, the NCSU research team has been successful in developing HMA models that can accurately capture various critical phenomena such as microcrack induced damage, strain rate - temperature interdependence, and viscoplastic flow that is critical for high temperature modeling; the resulting model is termed the viscoelastoplastic continuum damage (VEPCD) model. The primary objectives of this research are to (1) extend the VEPCD model to multiaxial state of stress; (2) develop a three-dimensional finite element program with the multiaxial VEPCD model; and (3) extend the principles used in the VEPCD modeling to the indirect tension mode.
Inverse Wave Propagation Algorithms. M.N. Guddati. Unsponsored. 09/2001 - current
Wave-based inversion is used in many fields of engineering including nondestructive evaluation, seismic imaging, seismology and medical imaging. In many cases, the extensive experimental data is processed by the inverse solution of the wave propagation problem to predict the underlying domain properties. These existing solution methods are either very approximate or extremely expensive. This project attempts to devise a method that will provide an efficient and accurate alternative to the existing data processing algorithms.
Modeling of Fractures in Layered Media. M.N. Guddati. Unsponsored. 09/01 - current
Proper understanding of fracture growth in layered media is of significant importance in various engineering problems of economic significance (cracking of laminated composites, hydraulic fracturing in the context of petroleum engineering and geophysics, to name a few applications). This project aims to develop an extremely efficient alternative to the existing numerical methods such as finite element and boundary element methods. An appealing feature of the resulting method is expected to be an approximate modeling procedure of slippage between un-bonded layers, a phenomenon that can have considerable effect on fracture growth.
NEESR-GC: Simulation of the Seismic Performance of Nonstructural Systems. A. Gupta and M. Margakis (University of Nevada, Reno); other participating institutions: SUNY-Buffalo, UC-San Diego, Cornell, GA-Tech, NC A&T, and UNC-Chapel Hill. (Project Managed by: CUREE). 2007 to 2012
Overall objective is to study the seismic performance of non-structural ceiling systems in buildings such as fire suppression piping, suspended ceiling fixtures, HVAC ducts, and partitions. NCSU's work is focused on computer modeling, optimization, and fragility evaluations for designing piping configuration needed to conduct experiments, Subtasks of this study focus on verification of theoretical formulations for seismic analysis of coupled building-piping systems as well as development of new formulations for improved verification with respect to the experimental results obtained by other participating organizations.
Load Combination Method and Analytical Methodology for IRWST and Other Dynamic Loads in Piping Analysis. A. Gupta. Korea Power Electric Company, KOPEC, South Korea. 2008
This project is aimed at providing technical knowledge on state-of-the-practice for combining various dynamic loads such as those due to Earthquake, Loss of Coolant Accident (LOCA), and Safety Relief Valves (SRV) in a nuclear power plant piping system analysis. This work has different aspects that relate to: (a) Providing background information on the currently specified load combination procedures in USNRC recommended and ASME recommended guidelines, (b) Theoretical basis for various recommendations, and (c) Train KOPEC engineers on incorporating appropriate load combination methods in an actual piping analysis and assist them with interpreting the results.
SST: Polymer Waveguide Sensors for Performance-Based Assessment and Health Monitoring of Civil Infrastructure Systems. Tasnim Hassan, M.J. Kowalsky, and K. Peters. National Science Foundation. 08/04 to 07/08
The goal of the project is to develop polymer sensors for health monitoring of civil infrastructure systems. Of specific interest is to develop a sensor that can measure strains in excess of 6% under high strain rates. Although the sensors to be developed can be utilized under a variety of load conditions and structural materials, this research program will focus on application of the sensors to concrete and steel structures subjected to earthquakes loads. The research will develop a data acquisition system that can be utilized in health monitoring and techniques for bonding the polymer sensors to concrete structures.
Finite Element Analysis and Microstructural Examination of Typhoon Bottom Tendon Connector for Investigating the Potential of Ratcheting Failure Mechanism. Tasnim Hassan and K.L. Murty. BHP Billiton (Americas), Inc. 07/07 to 02/08
The objective of the proposed research is to investigate if ratcheting failure mechanism causes the failure of Typhoon bottom connector during the hurricane Rita. Detailed finite element analysis of the bottom connector using advanced cyclic plasticity model and microstructural examinations on the recovered slivers of the bottom connectors will be conducted for detecting signs of ratcheting failure mechanisms.
Parameter Determination for Chaboche Model in ANSYS Finite Element Software Package for Two Materials. Tasnim Hassan. Honeywell International, Inc. 11/07 to 10/09
Honeywell Aerospace of the Honeywell International is attempting to develop design methodology for turbine or compressor disk that is successively taken to higher and higher strains in a spin test (through higher and higher rotational speeds) until the disk bursts. The ratcheting mechanism is involved in this progressive failure. However, the ratcheting mechanisms of the involved materials, PM Astroloy and forged Ti-6-4, are not known. In addition, the parameters of the Chaboche model which will be used in the finite element analysis for design development are not known. Through this project a set of experimental responses (experiments to be conducted by Honeywell Aerospace) and Chaboche model parameters for structural analysis will be developed.
Behavior of Shear Dominated Reinforced Lightweight Concrete Members under Seismic Conditions. M.J. Kowalsky. Expanded Shale, Clay, and Slate Institute. 01/04 to 12/07
The objective of the research described in this proposal is to develop a process by which the characteristic shear resistance under cyclic loading of various lightweight aggregates concretes can be assessed. The need for this research stems from the following reasons: (1) small dataset of past reversed cyclic shear critical tests, (2) relatively large scatter in experimental data that has been observed for monotonic shear critical tests, (3) lack of consensus among major worldwide concrete codes on lightweight concrete shear performance, and (4) potential economic impact if it is shown that existing shear strength reductions are overly conservative.
Design Criteria for Post and Beam Bents with Drilled Shafts and Other Structures. M.J. Kowalsky and M. Gabr. NC Department of Transportation. 07/05 to 08/07
The research described in this proposal aims to expand upon work currently underway for Pile-Bent bridge structures to all sub-structure systems employed by the NC Department of Transportation, including spread footings and columns supported on drilled shaft foundations. The research tasks encompass identifying issues specific to drilled shaft bent design and selection of a series of sample structures for analysis and design, as well as structural testing of bridge sub-structure to superstructure connections.
Seismic Performance of Spirally Welded Pipe Piles. M. Kowalsky and Tasnim Hassan. Skyline Steel Corporation. 04/07 to 07/09
Spirally welded pipe piles are manufactured in a manner that may result in various categories of welded joints any of which at or near the plastic hinge zone of a pile may determine its seismic performance. The location of the plastic hinge zone in the ground will depend on the stiffness of the soil, ground temperature, and pile diameter. This project will conduct experiments to determine the load-displacement responses under the AISC 341 load protocol, Appendix S, as well as to determine failure mechanisms for these three welds located at the plastic hinge of the pile.
Ductility of Welded Steel Column to Cap-Beam Connections. M. Kowalsky, Tasnim Hassan, and J.M. Nau. Alaska Department of Transportation. 08/07 to 07/09
This research will assess the ductility of a commonly used steel pipe-column to steel cap-beam connection used in Alaska for bridge and dock structures. The final goal is to develop recommendations for ductility capacity of the existing connection detail and for an alternative detail capable of sustaining the design ductility level while allowing for inspection. Recommendations will be provided for both current force-based design as provided in the 2004 AASHTO LRFD specifications (force reduction factors, ductility limits, displacement amplification factors) as well as for displacement-based design (target displacements and equivalent damping) as is being developed for future AASHTO bridge specifications.
Testing of Glulam to Steel Connection for RDU Terminal C Renovation and Expansion. R. Nunez, D. Johnston, and E. Sumner. Western-Archer Construction. Fall 2006 - Fall 2007
Test and evaluate the performance of glue-laminated girder to steel girder connections for the new terminal building at the Raleigh-Durham International Airport.
Modeling the Impact and Blast Performance of Fiber Reinforced Concrete. V.C. Matzen and Abhinav Gupta. Idaho National Laboratory. 2006 to 2009
This study is aimed at providing an experiment-based application for the blast/impact software investigation to be carried out at INL. An active research collaboration between INL and the Center for Nuclear Power Plant Structures, Equipment and Piping at NCSU is proposed. The collaboration will provide NCSU personnel an access to the advanced finite element software available at INL to model the structural performance of FRC. Simple experiments on FRC structural members will be conducted at NCSU for reconciliation of analytical and experimental results. The purpose would be to help in the development of new FRC material to withstand impact and blast loads.
I/UCRC Center, "Repair of Buildings and Bridges with Composites (RB2C). S. Rizkalla. National Science Foundation. 07/02 to 06/08
The NSF Industry/University Cooperative Research Center entitled "Repair of Buildings and Bridges with Composites" (RB2C), is located at the Constructed Facilities Laboratory, North Carolina State University (NCSU). The Center is working in collaboration with the Center located at the University of Missouri-Rolla (UMR). The Center at NCSU focuses on the needs of the construction industry in development of new and innovative structural components as well as strengthening/repair methods for existing structures using advanced composite materials.
NSF - I/UCRC - RB2C - Mistubishi Chemical FP America. S. Rizkalla. National Science Foundation. 07/02 to 06/08
The project investigates the use of high modulus carbon fiber polymer (CFRP) material for strengthening steel structures and bridges. The material in use now is in the form of sheets and strips bonded to the tension surface of steel structures. The first phase includes selection of the appropriate resin and bond characteristics of the material. The second phase is to test large-scale steel monopoles strengthening with different materials, configurations and subjected to static and fatigue loading conditions. The study will be continued to include the environmental effect on the strengthening system.
An Innovative Bridge Deck System. S. Rizkalla. NSF - I/UCRC - RB2C - Martin Marietta Composites. 07/02 to 06/08
The research includes development of an innovative system for highway bridge decks. The system is also suitable for manufacturing trailer walls using small thicknesses. The innovative concept consists of two layers of 2-D fiber pultruded sheets and styrofoam layers in between to provide the required thickness. At a later stage, bundled fibers are inserted in the third direction to increase the strength through-thickness properties of the panels. The system is a modified process for the Z-technology used for the aerospace industry. The test program consists of different tests to examine the material characteristics as well as the behavior of the panel.
Bond Behavior of SAS High Performance Steel. S. Rizkalla. SAS Stressteel, Inc. 04/04 to 07/07
To evaluate the bond characteristics of the SAS high tensile strength steel using end-block and splice beam test specimens according to the ICC specifications.
Debonding Failure in CFRP Strengthened Steel Structures. X. Zhao (Monash University), S. Rizkalla & R. Al-Mahaidi (Monash University). Australian Research Council. 01/05 to 12/07
The research will make a breakthrough in understanding the bond characteristics between CFRP and steel. It will enhance the capacity of Australian researchers to participate in a new cutting-edge research area, and help create a vibrant new industry for strengthening steel structures. The project will contribute to improved cost efficiency and safety of steel structures thereby contributing to the socio-economic well being of Australia and the USA including road, offshore, building and mining industries.
RC Beams Strengthened with Near Surface Mounted FRP. Jin-Guang Teng, S. Rizkalla & B. Taljsten (Sweden). Hong Kong National Research Council. 01/05 to 12/07
The project investigates the use of fiber reinforced polymer (FRP) material to strengthen reinforced concrete (RC) beams to increase their flexural and shear capacity. The project at Hong Kong will focus on installing these materials into the tension zones of the flexural members using the near surface mounted technique. The project complements the research in progress at North Carolina State University sponsored by the North Carolina Department of Transportation using 43-year old prestressed c-channels and AASHTO girders. The research findings will be greatly enhanced by the collaboration with the University of Technology, Sweden.
Evaluation of Bond Characteristics of MMFX Steel. S. Rizkalla. NSF - I/UCRC - RB2C - MMFX Technologies Corporation. 07/05 to 12/09.
The high-strength steel commercially known as Micro-composite Multi-structural formable (MMFX) steel could lead to potential savings through the use of lower reinforcement ratios due to it's higher strength. The proposed research will investigate the bond behavior of MMFX steel to concrete. The first phase of the proposed research program will include the parameters believed to significantly affect the bond strength: concrete compressive strength, bar size, concrete clear cover, and confinement level. Three universities are participating in this study, namely, University of Texas at Austin, The University of Kansas, and North Carolina State University. Each university will test twenty-two full-scale splice beams for the first phase of the program.
Development of Rational Design Methodology for Precast, Prestressed Concrete Spandrel Beams. S. Rizkalla & P. Zia. NSF - I/UCRC - RB2C - Precast/Prestressed Concrete Institute. 07/06 to 06/09
The goal of the proposed research is to develop appropriate design procedures and to simplify the detailing requirements for precast, L-shaped spandrel beams. The research includes an extensive experimental program designed to test prototype precast L shaped spandrel beams and an analytical phase based on non-linear finite element techniques.
Behavior of Concrete Sandwich Panels Reinforced with CFRP Grid. S. Rizkalla. AltusGroup. 08/06 to 07/07
The objective of the study is to determine the behavior of prestressed concrete sandwich panels under the effect of gravity and simulated wind loading conditions. The panels are reinforced transversely by a new innovative carbon fiber reinforced polymer to achieve composite action under the combined gravity and wind load. The research consists of an experimental program which included testing of six full-scale sandwich panels varying from 20 to 40 feet. All panels will be tested under fatigue and monotonic loading conditions to failure.
Characteristics of Glass Fiber Reinforced Polymer Material. S. Rizkalla. Martin Marietta Composites. 08/06 to 07/07
The main objective of the project is to evaluate the structural performance of 3-D FRP sandwich panels. The panels consist of GFRP laminates and foam core where the top and bottom skin GFRP layers are connected together with through thickness fibers. The experimental program focuses on the overall flexural behavior under various loading conditions. The variables are number of GFRP piles, core configurations, density of the through-thickness fibers and the direction of the embedded through-thickness fibers.
Structural Behavior of Grancrete Material. S. Rizkalla. NSF - I/UCRC - RB2C - Grancrete Corporation . 01/07 to 06/08
The proposed research program is designed to examine a new type of concrete as material for construction of buildings, bridges and special infrastructural applications. The initial phase of the evaluation includes tests to determine the basic material characteristics of Grancrete including compressive strength, elastic modulus, tensile strength, creep, shrinkage, and toughness of materials. The second phase will include examining the behavior of Grancrete mixed with small aggregate to enhance the overall behavior as construction materials. Based on the findings, the research will be extended to include the behavior of Grancrete reinforced with steel reinforcements and fiber reinforced polymer materials. The research plan will be examined every six months with the industrial members to finalize the research needed to optimize the use of these materials as construction material.
Developing a Telematics Platform for Bridge Monitoring and Health Prognositcs. S. Rizkalla. National Science Foundation (Supplement to RB2C Center). 07/07 to 06/09
The approach proposed in this TIE project integrates the extensive research on physics of bridge damages and instrumentation of bridge monitoring system, conducted at the RB2C Center, with the feature-based smart prognostic agent, namely the Watchdog Agent® developed by the IMS Center, to accurately quantify and predict bridge deterioration. The major merit of this work will be the initiation of a combined physics-statistics-based prognostics approach, which expands and integrates the theories and tools developed in RB2C and IMS. The developed methodology will bring about innovation to predict bridge deterioration and provide a general framework for prognostic bridge health management for next-generation intelligent transportation maintenance systems.
Basalt Fiber Reinforced Cementitious Matrix Composites for Infrastructure Repair. S. Rizkalla. National Science Foundation (Supplement to RB2C Center). 07/07 to 06/09
The project focuses on the strengthening and upgrade of existing reinforced concrete (RC) structures using a new class of composites made of basalt fibers embedded in a cement-based matrix (BFRC). Basalt fibers are manufactured in a single-stage process by melting naturally occurring basalt rock. The BFRC confining system represents a promising solution to overcome limitations of current fiber-reinforced-polymer (FRP) systems that make use of carbon or glass fibers impregnated with an epoxy resin. The research will first study the mechanical and durability performance of commercial grade basalt fibers and then of the system obtained by combining them with the cementitious matrix.
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