Structural Engineering Commons^™

In-Plane Shear Lag Of Bolted Connections, Lip H. Teh, Benoit P. Gilbert

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

This paper points out that the shear lag factors embedded in the design equations specified in the North American, European and Australasian cold-formed steel structures codes for determining the net section tension capacity of bolted connections in flat steel sheets either yield “anomalous” results or become irrelevant when they exceed unity. The anomaly is demonstrated through laboratory tests and is explained using simple calculus. A proper mathematical expression for the in-plane shear lag factor, which does not suffer from the anomaly of the code equations and never implies shear lag factors greater than unity for any configuration, is presented and …

Top Arc Seam Weld Shear Strength And Stiffness For Sheet-To-Sheet Connections, R. Nunna, J. Martin, J. Mattingly, P. Bodwell, D. Boltz, K. Cullum, Roger A. Laboube

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

The North American Specification for the Design of Cold-Formed Steel Structural Members does not provide specific design guidance for sheet-to-sheet top arc seam welds in shear. A collaborative industry study has developed design guidance for both strength and stiffness of the connection to facilitate analytical evaluation of floor and roof diaphragm assemblies and wall assemblies. The test program was performed per AISI S905 and addressed material ductility, weld length, sheet thickness and the distribution of the force being transferred by the weld connection.

The Influence Of The Aspect Ratio On The Lateral Response Of The Sheathed Cold Formed Steel Walls, O. Iuorio, L. Fiorino, V. Macillo, M. T. Terracciano, R. Landolfo

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

The influence of the aspect ratio on the lateral response of cold formed steel walls is analyzed by three design methodologies. In particular the prediction provided by the AISI Lateral Design, that is at the moment the main document for the design of CFS buildings under horizontal loads, is compared with the results obtained by applying the principles of mechanics and with those provided by non-linear finite element models. This paper presents and discusses in terms of strength and stiffness the validity of the different design methodologies in case of non-conventional wall aspect ratios comparing the numerical results with available …

Seismic Computational Analysis Of Cfs-Nees Building, J. Leng, B. W. Schafer, S. G. Buonopane

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

The objective of this paper is to explore computational modeling of a coldformed steel framed building subjected to earthquake excitation. The selected two-story building will be subjected to full-scale motion on a shaking table in 2013 as part of the National Science Foundation funded Cold-Formed Steel – Network for Earthquake Engineering Simulation (CFS-NEES) project. The ledger-framed building employs load bearing cold-formed steel members throughout (wall, floors, and roofs) and employs OSB sheathed shear walls and an OSB sheathed diaphragm for the lateral force resisting system. Two- and three-dimensional analysis models capable of providing vibration, pushover, linear and nonlinear time history …

An Explicit, Dynamic Finite Element Model For The Local Failure Of Cold-Formed Trapezoidal Sheeting, Hèrm Hofmeyer

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

Trapezoidal sheeting, made of cold-formed, thin-walled steel, is widely used for the construction of cladding and roofs. At an interior support, the sheeting is subject to bending moments and a concentrated load, which leads to possible failure followed by two post-failure modes: the yield-arc and yield-eye modes. Until recently, it was not fully understood why a specific post-failure mode occurs and it was suggested that mode-jumping of the compressed sheeting flange may influence the mode occurring. This paper presents new research, in which both the compressed flange in isolation and the sheeting are modeled by using an explicit, dynamic finite …

Effects Of Cold-Formed Steel Framed Gypsum Partition Walls On The Seismic Response Of A Medical Facility, Ryan Davies, Rodrigo Retamales, Gilberto Mosqueda, Andre Filiatrault, Don Allen

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

The first experimental phase of the NEES Nonstructural Grand Challenge Project: “Simulation of the Seismic Performance of Nonstructural Systems” investigated the in-plane hysteretic behaviors of thirty-six full-scale cold-formed steel framed gypsum partition walls. Results of quasi-static reverse cyclic and dynamic testing on sixteen wall configurations including walls with commercial and institutional construction details and innovative connection techniques are first briefly reviewed. Thereafter, six tri-linear hysteretic models of partition walls with pinching behavior and strength and stiffness degradation are developed based on the experimental data for use in a finite element analysis platform. The partition wall models, represented by shear spring …

Characterizaiton Of Cold-Formed Steel Shear Wall Behavior Under Cyclic Loading For The Cfs-Nees Building, P. Liu, K. D. Peterman, C. Yu, B. W. Schafer

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

The objective of this paper is to provide a full hysteretic characterization of OSB sheathed cold-formed steel (CFS) shear walls designed for use in the National Science Foundation funded Network for Earthquake Engineering Simulation (NEES) project: CFS-NEES (www.ce.jhu.edu/cfsnees). The shear walls were designed for a two-story ledger-framed building (i.e., the CFS-NEES building) that will undergo full-scale shake table testing at the University of Buffalo NEES site. Shear walls in real construction, such as the CFS-NEES building, have details that differ from the shear walls tested and provided for strength prediction in standards such as AISI-S213-07. Differences include: (a) ledger (rim …

Design Capacity Determination Assisted By Testing Based On Lrfd Method, Y. Q. Li, L. P. Wang, Z. Y. Shen

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

In some special circumstances of structural design, adequate calculation models are not available in current specifications or they cannot be used directly for new materials or structural configurations. In these cases, tests of the prototype units may be accepted as an alternative to calculation. If this alternative procedure is adopted, corresponding requirements and evaluation of test results should apply. In this paper, a complete procedure of determining the design capacity of the test specimens based on statistical analysis and Load and resistance factor design (LRFD) method was presented: characteristic value of experimental resistance was obtained from the minimum value of …

Critical Elastic Shear Buckling Stress Hand Solution For C- And Z-Sections Including Cross-Section Connectivity, Kevin Aswegan, Cristopher D. Moen

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

This paper presents an approximate solution for the critical elastic buckling stress of cold-formed steel C- and Z-section members including cross-section connectivity. The elastic buckling solution is developed to support the extension of the Direct Strength Method to the shear ultimate limit state, where the cross sectional critical elastic shear buckling stress (load) is employed to predict shear capacity. The shear buckling stress and buckled half-wavelength are calculated with a classical energy solution for a thin plate with edges rotationally restrained. Rotational stiffness expressions in the AISI S100-07 specification, originally derived for distortional buckling of C- and Z-sections, are used …

Load Distribution In Floor To Wall Connections, D. M. Fox, D. R. Knill, R. M. Schuster

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

Presented in this paper is a cold formed steel load distribution system developed by iSPAN Systems LP that enables the installation of floor joists without the need to align them with the supporting wall studs. The floor joists are supported by a shear connection attached to a cold formed steel perimeter distribution member. In addition to the load distribution aspect, the system results in a simplified lateral design approach. An experimental verification study was carried out to establish the load distribution capability of the system, resulting in a simplified procedure to determine the connection requirements and load transfer characteristics to …

Improved Protocols For Automated Wheelpath Crack Detection In Pavements, Daniel Patrick Byram

Graduate Theses and Dissertations

Roadway pavement distress evaluations are vital to understanding the mechanics of pavement stability, determining the distribution of rehabilitation costs, and knowing the appropriate rehabilitation strategies. Advancements in technology over the past two decades have changed the way these surveys have been performed by means of automated data collection and interpretation. More and more state agencies have invested in automated road analyzing vehicles that are able to collect high resolution images of the pavement. Fewer have adopted automated data processing software with the ability to interpret road distresses due to the common discrepancies in distress classification algorithms.

In addition to automated …

Laboratory Performance Of Highway Bridge Girder Anchorages Under Simulated Hurricane-Induced Wave Loading, Jora Lehrman, Christopher Higgins, Daniel Cox

TREC Final Reports

Many bridges along the Gulf Coast of the United States were damaged by recent hurricanes, and many more are susceptible to similar damage. This research examines the structural performance of common connection details used to anchor prestressed concrete girders to the substructure. Full-scale specimens were fabricated and tested under static and dynamic cyclic load histories. Dynamic load histories were developed from previously conducted hydraulic tests of a 1/5 scale model of a highway bridge under hurricane wave loads. The load effects considered included the pseudo-statically applied vertical uplift force, horizontal force, combined horizontal and vertical forces, and dynamically applied combined …

Development Of System Reliability Models For Railway Bridges, Anna Maria Rakoczy

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Performance of the railway transportation network depends on the reliability of railway bridges, which can be affected by various forms of deterioration and extreme environmental conditions. More than half of the railway bridges in US were built before 1950 and many show signs of distress. There is a need for efficient methods to evaluate the safety reserve in the railway bridges by identification of the most sensitive parts of the bridge.

An accurate estimation of remaining fatigue life of a structural component is very important in prioritizing bridge rehabilitation and replacement. However, existing procedures to evaluate the fatigue behavior of …

Concrete Surface With Nano-Particle Additives For Improved Wearing Resistance To Increase Truck Traffic, Genda Chen, Dongming Yan, Chenglin Wu, Zhibin Lin, Nicholas Leventis, Shruti Mahadik-Khanolkar

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This study focused on the use of nanotechnology in concrete to improve the wearing resistance of concrete. The nano materials used were polymer cross-linked aerogels, carbon nanotubes, and nano-SiO₂, nano-CaCO₃, and nano-Al₂O₃ particles. As an indirect measurement of the concrete wearing resistance, the tensile and compressive properties and the permeability of concrete were evaluated for various mix designs. The optimal amount of nano material additives were determined following the American Society of Testing Methods (ASTM) standard test methodologies. The test results from the materials were compared for their mechanical behaviors. This type of …

Initial Study And Verification Of A Distributed Fiber Optic Corrosion Monitoring System For Transportation Structures, Hai Xiao, Genda Chen, Zhan Gao, Ying Huang, Fujian Tang

Electrical and Computer Engineering Faculty Research & Creative Works

For this study, a novel optical fiber sensing system was developed and tested for the monitoring of corrosion in transportation systems. The optical fiber sensing system consists of a reference long period fiber gratings (LPFG) sensor for corrosive environmental monitoring and a LPFG sensor coated with a thin film of nano iron and silica particles for steel corrosion monitoring. The environmental effects (such as pH and temperature) are compensated by the use of the reference LPFG sensor. The sensor design, simulation, and experimental validation were performed in this study to investigate the feasibility of the proposed sensing system for corrosion …

Conference Proceedings, Blake Tullis, Robert Jansson

International Junior Researcher and Engineer Workshop on Hydraulic Structures

No abstract provided.

Effects Of Alternate Cementitious Materials On Compressive Strength And Environmental Impacts Of Cement Mix Designs., Mitchell R. Bush

Materials Engineering

Specific proportions of Portland cement, fly ash, and blast furnace slag cement mixtures where chosen by a ternary phase diagram to be investigated. By experimental testing and company data history fly ash was limited to not exceed 30% and contribution of Portland cement must be over 50%. Ten chosen mix designs were batched by following ASTM C305-94 and cured for twenty-eight and forty-two days, the extended cure length allows the reaction of pozzolanic material with calcium hydroxide to complete. Compressive strength testing at forty-two days yielded low strength for mix designs with 20% or less Portland cement compared to our …

Throwing Frame For Athletes With Dissabilities, Andrew Higgins, Stefan Owechko, Gabriel (Gabe) Terrasas, Kevin Crisfield

Mechanical Engineering

Team Zeus’ senior project was to design, build and test a working throwing frame system for Bridge II Sports, a nonprofit organization in North Carolina. The throwing frame is used to allow athletes and individuals with disabilities to throw shot-put, discus, and javelin using a frame to sit against. Team Zeus was specifically tasked to build a frame that is lighter weight and more transportable than products that are currently on the market. This frame also is adjustable to accommodate a wide range of athlete weights, sizes, and abilities. The final result is a 35lb aluminum frame with two different …

Performance-Based Analysis Of A Reinforced Concrete Shear Wall Building, Garrett Richard Hagen

Master's Theses

PERFORMANCE-BASED ANALYSIS OF A REINFORCED CONCRETE SHEAR WALL BUILDING

Garrett Richard Hagen

In this thesis, a special reinforced concrete shear wall building was designed per ASCE 7-05, and then the performance was investigated using the four analysis procedures outlined in ASCE 41-06. The proposed building was planned as a 6-story office building in San Francisco, CA. The structural system consisted of a two-way flat plate and reinforced concrete columns for gravity loads and slender structural walls for seismic loads. The mathematical building models utilized recommendations from ASCE 41-06 and first-principle mechanics. Moment-curvature analysis and fiber cross-section elements were used in …

Seismic Hazard Assessment Of Oregon Highway Truck Routes, Peter Dusicka, Selamawit Tesfayesus Mehary

TREC Final Reports

This research project developed a seismic risk assessment model along the major truck routes in Oregon. The study had adopted federally developed software tools called Risk for Earthquake Damage to Roadway Systems (REDARS2) and HAZUS-MH. The model was the first time REDARS2 has been adopted and used in research outside of the original development team, presenting a number of unique challenges. The development of the model was a complex, intensive process that required a significant research effort, manipulation and adjustment of data. Furthermore, limitations of the software tools themselves had been identified that prevented the inclusion of important aspects such …

Structural Health Monitoring Of A Bridge Structure Using Wireless Sensor Network, Cheekian Teng

Masters Theses

Bridge Structural Health Monitoring (SHM) has rapidly become one of the main interests in civil engineering field. Inexpensive and efficient SHM method utilizing Wireless Sensor Network (WSN) is helping to facilitate the selection of the bridges that require maintenance. The changes to structural properties (i.e. stiffness) caused by damage (i.e. corrosion) will change the structural responses (i.e. acceleration responses) to ambient motions. Modal analysis algorithms applied to the vibration responses acquired through WSN provide the modal properties (i.e. natural frequency, modal shape and damping ratio) that will change with the changes in stiffness indicating possible existence of damage. Three output-only …

Short Term Monitoring Of Suspender Cables On An In-Service Highway Bridge, Gannon Stromquist-Levoir

Master's Theses

No abstract provided.

Sensors For Integrated Monitoring And Mitigation Of Scour, Genda Chen, David Pommerenke, Zhi Zhou, Ying Huang

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Systems and methods for detecting scour. Some embodiments provide systems which include a sensor and a signal generator with a combined density equal to or greater than that of water. Optionally, the sensor can be a magnet, magnetic resonator, or accelerometer. In some embodiments, the sensor is adapted to be placed in regions potentially subject to scour and to sense a scour-related condition. The signal generator generates a wireless signal conveying data regarding the as-sensed scour-related. In some embodiments the sensor is the signal generator while a receiver of the wireless signal can include an antenna, a magnetometer, or an …

Computer-Aided Engineering Tools For Structural Health Monitoring Under Operational Conditions, Priscilla O. Mensah-Bonsu

Master's Theses

This thesis presents two different applications of computer-aided non-destructive approaches for structures monitored under operational conditions. The first part of the thesis is the development of a graphical user interface (GUI) software for real-time autonomous assessment of structural health condition based on the signature vibration properties of the structure under study. The program, called ConImote2, operates on the wireless sensor network platform called imote2. ConImote2 is created in the Matlab platform for accessibility and to enable extension of its capabilities by the user. The primary goal of creating the program is to overcome the issue of data inundation from SHM …

Developing A Family Of Curves For The Hec-18 Scour Equation, Timothy Calappi, Carol J. Miller, Donald Carpenter, Travis Dahl

Civil and Environmental Engineering Faculty Research Publications

Accurate pier scour predictions are essential to the safe and efficient design of bridge crossings. Current practice uses empirical formulas largely derived from laboratory experiments to predict local scour depth around single-bridge piers. The resulting formulas are hindered by insufficient consideration of scaling effects and hydrodynamic forces. When applied to full-scale designs, these formula deficiencies lead to excessive over prediction of scour depths and increased construction costs. In an effort to improve the predictive capabilities of the HEC-18 scour model, this work uses field-scale data and nonlinear regression to develop a family of equations optimized for various non-cohesive soil conditions. …

Slope Stability Monitoring Using Remote Sensing Techniques, Omar Alberto Conte Robles

Graduate Theses and Dissertations

During the past six years the Arkansas State Highway and Transportation Department (AHTD) has spent over nine million dollars repairing slope failures that have occurred in the state of Arkansas. Specifically, higher than average precipitation in 2004 and 2008 led to large quantities of slides, all of which were repaired. Two highways, within the state of Arkansas, with known historical movements along or across the highways are being monitored using traditional surveying techniques and advanced remote sensing techniques. These slides, both of which are located in fill slopes. One a 500-foot long slide located north of Chester, Arkansas, within the …

Computer Modeling Of The Influence Of Structure Plan Areas On Tornado Forces, Nashmi Hassan M Alrasheedi

Graduate Theses and Dissertations

The study of the conventional Straight Line (SL) wind flow dominates research into wind loads on structures. Most structure design takes into account only research into SL flow. Few researchers have studied tornado forces on buildings and attempted to distinguish between tornadic wind loads and SL flow loads. Using a computer simulation, this research addresses and distinguishes between the tornadic forces and SL forces on structures. In the numerical simulation, tornado forces and SL forces will be compared on large structure plan areas and on thin structure plan areas. Additionally this research investigates how the increase in the vortex strength …

Safety Investigation And Guidance For Retrofitting Existing Approach Guardrail Transitions, Eric R. Jowza

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Throughout the United States, various approach guardrail transition systems are routinely implemented by State Highway Departments to connect standard strong-post, W-beam guardrail systems to the blunt end of concrete bridge rails and roadside median barriers. When installed correctly, approach guardrail transitions shield the hazardous exposed ends of rigid parapets as well as significantly reduce the propensity for wheel snag and vehicle pocketing throughout the transition region. Unfortunately, approach guardrail transitions that are installed in the field may not always resemble that of the as-tested configuration, thus reducing the desired lateral stiffness and strength of the transition system. A recent survey …

Transversely Post-Tensioned Box-Beam System For Precast Parking Structures, Jenna Hansen

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Parking structures are essential to any growing commercial district, yet little thought is given to their longevity and appearance. This is particularly the case with precast parking structures. Typical issues include poor joint performance and the impact of stemmed members on interior building aesthetics. Research provided in this report proposes an alternate design that improves long term joint performance and optimizes the perspective spacing between deck members. These benefits (along with the others) are incorporated to reflect the benefits of parking structures designed using cast-in-place concrete and structural steel with concrete decking. Other benefits include: flexible column spacing, reduced / …

Efficient Precast/Prestressed Floor System For Building Construction, Eliya E. A. Henin

Department of Construction Engineering and Management: Dissertations, Theses, and Student Research

Precast floor systems provide a rapidly constructed solution to multi-story buildings that is economical, high quality, fire-resistant, and with excellent deflection and vibration characteristics. Conventional precast concrete floor system cannot compete with cast-in-place post tensioning flat slab floor systems when high span-to-depth ratio and flat soffit are required. This is due to the significant depth of standard precast beams, and use of column corbels and beam ledges. This research presents the development of a new precast concrete floor system that eliminates the limitations of conventional precast floor system and provides a competitive precast alternative to cast-in-place flat slab floor systems. …