Civil and Environmental Engineering Commons^™

Detection And Elimination Of Rock Face Vegetation From Terrestrial Lidar Data Using The Virtual Articulating Conical Probe Algorithm, Kenneth John Boyko

Doctoral Dissertations

"A common use of terrestrial lidar is to conduct studies involving change detection of natural or engineered surfaces. Change detection involves many technical steps beyond the initial data acquisition: data structuring, registration, and elimination of data artifacts such as parallax errors, near-field obstructions, and vegetation. Of these, vegetation detection and elimination with terrestrial lidar scanning (TLS) presents a completely different set of issues when compared to vegetation elimination from aerial lidar scanning (ALS). With ALS, the ground footprint of the lidar laser beam is very large, and the data acquisition hardware supports multi-return waveforms. Also, the underlying surface topography is …

Development Of Lidar Assisted Terrestrial Radar Interferometry For Rock Deformation Monitoring, Ricardo Javier Romero Ramirez

Doctoral Dissertations

"Rock and soil slope movements cost millions of dollars annually. During the past few decades, engineers have relied on traditional methods to detect slope movements. These tools are valuable for small spatial areas but, may not be adequate or cost effective for large spatial areas. Remote sensing methods such as terrestrial laser scanning (TLS) and terrestrial radar interferometry (TRI) provide excellent spatial coverage, and with adequate post-data-processing software, sub-millimetric scale deformation sensitivity can be achieved.

This work will present a comparative experimental study between TLS and TRI. The comparative experimental study will allow us to achieve the two main objectives …

The Effects Of Silica On The Properties Of Vitreous Enamels, Signo Tadeu Dos Reis, Mike Koenigstein, Liang Fan, Genda Chen, Luka Pavic, Andrea Mogus-Milankovic

Materials Science and Engineering Faculty Research & Creative Works

Ground coat enamels for low carbon steel that contain silica as a mill addition have been developed to study the changes of their properties. Acid-resistant commercial enamel where silica addition was varied from 0 to 10.0 wt % was used for this investigation. The effects of the addition on the corrosion resistance, thermal properties, electrical properties, and mechanical adherence of the enamel to low carbon steel were studied. The corrosion resistance of the steel enameled coupons was tested using a salt spray (fog) apparatus for time periods reaching 168 h at room temperature. It was found that, although the density …

Field Implementation Of Rubberized Chip Seal, Ahmed Gheni, Alireza Pourhassan, Mohamed Elgawady, Yasser Darwish, William P. Schonberg

Civil, Architectural and Environmental Engineering Technical Reports

Chip seals have been widely used as a pavement maintenance surface treatment due to its competitive cost and construction time. Recently, the research team developed a rubberized chip seal where natural aggregate is replaced with crumb rubber obtained from recycled tires. During this study, a total of 108 laboratory specimens and a field chip seal section with different crumb rubber replacement ratios were investigated. Aggregate macrostructure, retention, and skid resistance were measured. The crumb rubber showed a remarkable performance in aggregate retention measured using the Vialit and Pennsylvania tests. The values of the mean texture depth of rubberized chip seal …

A Threshold To Utilize Guayule Resin As A New Binder In Flexible Pavement Industry, Ahmed Hemida, Magdy Abdelrahman

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This study denotes a threshold to utilize Guayule Resin as a new bio-based binder or asphalt cement (AC) proportion, both with/out crumb rubber modifier (CRM), regarding solutions for environment, cost, and sustainability aspects. Via this research, 15 designated binders will be presented, all of them were tested as unaged and RTFO, whereas eight binders proceeded with PAV. Superpave was utilized to study their physical properties. Viscosity was examined upon some guayule-based binders with/out CRM, getting 114cP (at 135℃) for BGR, increased to about 3 times with 10%CRM (by weight of liquid binder) and about 7-8 times with 20%CRM. Comparisons among …

Marine Boundary Layer Aerosol In The Eastern North Atlantic: Seasonal Variations And Key Controlling Processes, Guangjie Zheng, Yang Wang, For Full List Of Authors, See Publisher's Website.

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The response of marine low cloud systems to changes in aerosol concentration represents one of the largest uncertainties in climate simulations. Major contributions to this uncertainty are derived from poor understanding of aerosol under natural conditions and the perturbation by anthropogenic emissions. The eastern North Atlantic (ENA) is a region of persistent but diverse marine boundary layer (MBL) clouds, whose albedo and precipitation are highly susceptible to perturbations in aerosol properties. In this study, we examine MBL aerosol properties, trace gas mixing ratios, and meteorological parameters measured at the Atmospheric Radiation Measurement Climate Research Facility's ENA site on Graciosa Island, …

Assessment Of Small-Scale Anisotropy In Stably Stratified Turbulent Flows Using Direct Numerical Simulations, Amrapalli Garanaik, Subhas Karan Venayagamoorthy

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In this study, the validity of the widely used Kolmogorov hypothesis of local isotropy of dissipative scales in stably stratified turbulent flows is investigated using high-resolution direct numerical simulations. Departure from isotropy is investigated for the first time in terms of the turbulent Froude number defined as Fr = ϵ/(NEk), where N is the buoyancy frequency, Ek is the turbulent kinetic energy, and ϵ is the rate of dissipation of turbulent kinetic energy. It is shown that for both ϵ and the rate of scalar (density) dissipation, ϵρ, the small-scale statistics are nearly isotropic in the weakly stratified turbulent regime …

Biaxial Bending Of Cold-Formed Steel Storage Rack Uprights – Part I: Parametric Studies And Response, Nima Talebian, Benoit P. Gilbert, Cao Hung Pham, Romain Chariere, Hassan Karampour

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

This paper first introduces an advanced finite element model to determine the biaxial bending capacity of cold-formed steel storage rack upright sections. The model is found to accurately predict published experimental results with an average predicted to experimental capacity ratio of 1.02. Second, the validated model is used to run parametric studies and analyse the biaxial response of slender, semi-compact and compact unperforated storage rack upright cross-sections. Analyses are run for local and distortional buckling failure modes only. Ten and four different cross-sectional shapes are analysed for local and distortional buckling, respectively, and nine biaxial bending configurations are considered per …

Sidelap And Structural Fastener Tests For Steel Deck Diaphragms, Y. Shi, S. Torabian, Benjamin W. Schafer, W. S. Easterling, M. R. Eatherton

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

Steel deck diaphragm systems, which are commonly used for roof construction in steel-framed buildings, consist of many parts such as corrugated steel deck sheets, sidelap fasteners between adjacent sheets, structural fasteners from the sheets to the supporting beams or joists, chord elements, and collectors. Load-deformation behavior of a steel deck diaphragm system is typically dominated by sidelap and structural fastener limit states. To understand and accurately model the behavior of steel deck diaphragm systems, it is therefore necessary to characterize the behavior of the individual fasteners. The effect of local geometry and detailing at these fasteners such as how the …

The 2017 Aisi Cold-Formed Steel Design Manual, Joshua Buckholt, Helen Chen

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

The 2017 edition of AISI D100, the Cold-Formed Steel Design Manual (Manual) has been published. Updates to the Manual include: alignment with AISI S100-16, the North-American Specification for the Design of Cold-Formed Steel Structural Members (NA Specification); several new and varied design examples; additional discussions related to the design of cold-formed steel structures and components; and expanded bibliographies of relevant resources. The database of examples illustrating the Direct Strength Method (DSM) and new provisions in the NA Specification has been expanded. Also published with the Manual are the North-American Specification and its Commentary.

Distortional Buckling Of Cold-Formed Steel Flanges Under Stress Gradient, Robert S. Glauz

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

The strength of cold-formed steel beams with stiffened flanges may be controlled by distortional buckling. Buckling stress prediction methods have been developed for flanges under uniform compression. However, channel sections are commonly used where bending occurs about the minor axis with flanges under stress gradient, such that the edges are in compression and the flanges may experience distortional buckling. Current design specifications do not explicitly address this failure mode, which could lead to unsafe designs. This paper presents and verifies an analytical approach for distortional buckling stress prediction for flanges under stress gradient. The approach is consistent with the design …

Tensile Strength And Serviceability Of Cold-Formed Steel Clip Angles, Wenying Zhang, Zhishan Yan, Mahsa Mahdavian, Mohamad Yousof, Cheng Yu

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

This paper reports the recent research findings of cold-formed steel clip angles in tension. The relevant experimental program and the proposed design methods are presented. The test program involved two phases of testing: Phase I of program focused on the pull-over strength of screw connections on the anchored leg of the clip angles, and Phase II of program concentrated on the tensile strength of the anchored leg of the clip angles within the service deflection limit. Design methods for predicting the pull-over strength as well as tensile strength within the serviceability deformation limit are proposed based on the test results …

Strength Of Cold-Formed Steel Clip Angle In Combined Bending And Shear Loading, Cheng Yu, Zhishan Yan, Wenying Zhang

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

Thin-walled cold-formed steel (CFS) clip angles have been commonly used for connecting CFS framing members or attaching CFS members to the major building structure. The implementation of clip angles involves consideration of ultimate strength for combined bending moments and shear forces. Therefore, a test program of CFS clip angle was recently conducted to investigate the behavior and strength of cold-formed steel clip angle subjected to combined bending moments and shear forces at different boundary conditions. The research included connection tests on clip angle. The testing method was adopted from the AISI S914 Test Standard for Joist Connectors Attached to Clod-Formed …

Critical Design Criteria For Standard, Truncated, And Parallel Chords Cold-Formed Steel Trusses, Maelle Van Thienen, Johannes Dimyadi, James B. P. Lim, G. Charles Clifton

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

The design of cold-formed steel trusses can be a very complicated and long repetitive process involving up to 28 load combinations added to serviceability checks depending on the design standards being used. This process is particularly tedious if a near optimal solution is required. Additionally, the risk of introducing human errors is usually quite high as it is a process often done by hand. FRAMECAD Structure is a niche software solution born from the desire to provide a complete solution for constructing with cold-formed steel by a company selling roll-forming machines. FRAMECAD Structure specialises on automating the calculations and design …

Cold-Formed Ferritic Stainless Steel Tubular Sections Under End-One-Flange Loading Condition, Hai-Ting Li, Benjamin Young

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

This paper presents experimental and numerical investigations of cold-formed ferritic stainless steel tubular sections under End-One-Flange (EOF) loading condition. A series of web crippling tests was conducted on cold-formed square and rectangular hollow sections of ferritic stainless steel grade EN 1.4003. The web crippling test results were used for the verification of the finite element (FE) model. Upon verification, a parametric study was performed thereafter. The codified web crippling design provisions in American, Australian/New Zealand and European standards for stainless steel structures were assessed. Improved web crippling design rules are proposed for cold-formed ferritic stainless steel tubular sections under EOF …

Optimum Slot Weld Width For Cold-Formed Steel, Emilee A. Martin, Fredrick R. Rutz

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

Slot welds can be used for connections in cold-formed steel (CFS) structures. However, structural engineers will find AISI S100, “North American Specification for the Design of Cold-Formed Steel Structural Members” (AISI 2016) - which can be used for guidance in calculating structural capacity of many welds types - silent on this specific application.

Research at the University of Colorado Denver has been directed toward determination of the strength of slot welds in sheet steel. A comprehensive series of tests were performed to determine structural capacity and ductility of various slot weld widths using a metal inert gas (MIG) welding process. …

Using Generalized Beam Theory To Assess The Behavior Of Curved Thin-Walled Members, Nuno Peres, Rodrigo Goncalves, Dinar Camotim

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

In this work, the first-order behavior of naturally curved thin-walled bars with circular axis, without pre-twist, is assessed with the help of the Generalized Beam Theory (GBT) formulation previously developed by the authors. With respect to the previous work, which dealt with simple cross-sections, the present paper presents a method to obtain the deformation modes for arbitrary flat-walled cross-sections. Despite the complexity involved in this generalization, the standard GBT kinematic assumptions are kept, since they are essential to (i) subdivide the modes in a meaningful way and (ii) reduce the number of DOFs necessary to obtain accurate solutions. It is …

Proposal To Improve The Dsm Design Of Cold-Formed Steel Angle Columns: Need, Background, Quality Assessment And Illustration, Pedro Borges Dinis, Dinar Camotim

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

This paper presents a proposal for the codification of an efficient design approach, based on the Direct Strength Method (DSM), for cold-formed steel equal-leg angle columns with short-to-intermediate lengths, i.e., those buckling in flexural-torsional modes. Initially, the available experimental failure load data, comprising fixed-ended and pin-ended (“cylindrical hinges”) columns with several geometries (cross-section dimensions and lengths) and tested by various researchers, are collected and used to show that the currently codified DSM design provisions are not able to handle adequately short-to- intermediate angle columns and that a specific DSM-based design approach is needed to estimate the failure loads of such …

Comparison Of Experimental And Numerical Results For Flexural Capacity Of Light-Gage Steel Roof Deck, Christopher H. Raebel, Dawid Gwodzdz

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

The objective of this paper is to present a comparison between experimental results to each of two numerical analyses of cold formed steel roof deck in flexure. Prior numerical studies using the Direct Strength Method (DSM) and the Equivalent Width Method (EWM) have shown discrepancies between results obtained by the two methods. The goal of this research initiative was to compare results from each of the two numerical analysis methods to experimental results in an effort to determine which numerical method is most appropriate for analyzing steel deck in flexure.

Twenty-four physical tests were conducted using four different deck gages …

The Design And Development Of Lightweight Composite Panels For Rigid Wall Structures, Jeremy J. Artman, Cheng Yu

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

The paper presents a research effort aimed at developing a stronger, lighter, and more economic shelter for both military and civilian use. Reported herein are the research results on developing solid wall panels using cold-formed steel corrugated sheathing and members, as well as polyurethane spray foam for insulation. This research includes calculating uniform load density, determining the overall strength of the panel, and investigating the flexural strength of the roof panels. Research incorporated different connection methods, with varied stud spacing, to determine the safest design for the new mobile facilities. Previous research has shown that cold-formed steel corrugated sheathing performs …

Experimental Study On Uplift Capacity Of Purlins Considering Restraints From Standing Seam Roof Systems, Wei Luan, Yuanqi Li

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

A total of 32 specimens of single-span purlin roof assemblies considering uplift wind load were tested to investigate the structural behavior of cold-formed steel purlins with one flange fastened to standing seam roofs. Failure modes and failure loads of purlins with different parameters were obtained. Full finite element models, incorporate purlins, clips and standing seam roof panels, were developed, and the analysis results were consistent to a high degree with the test results. Using the same element type and material model, the rotational restraint of test roof systems and corresponding influence factors were investigated by finite element models. Finally, using …

A Finite Element Study Of Corrugated Steel Deck Subjected To Concentrated Loads, Vitaliy V. Degtyarev

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

An extensive parametric study was initiated to get a better understanding of steel deck behavior under concentrated loads and to develop design recommendations for a wide range of deck profiles. This paper presents first results from the study related to 1.5-in. deep roof decks of types B and F. The study was performed on non-linear finite element models of deck validated against available test data. Deck gage, span length, span condition, concentrated load locations along and across the deck span were varied in the study. The observed deck behavior under concentrated loads, as well as the effects of the studied …

Web Bearing Capacity Of Cold-Formed Ferritic Stainless Steel Unlipped Channels With Web Perforations Under The End-Two-Flange (Etf) Loading, Amir M. Yousefi, James B. P. Lim, G. Charles Clifton

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

Laboratory and numerical evaluations on the web bearing capacity of unlipped cold-formed ferritic stainless steel channels are described in this paper. The channels considered have circular perforations in the web and are loaded under the end-two-flange (ETF) load case. A total of 387 results comprising 27 laboratory and 360 numerical results are presented. A nonlinear quasi-static finite element (FE) model was developed for the numerical investigation. An extensive parametric study is described to determine web bearing capacity reduction factors for different sizes of circular web perforations and cross-section dimensions; the circular web perforations are either centred or offset to the …

Web Crippling Behavior Of Cold-Formed Ferritic Stainless Steel Unlipped Channels Under Interior-One-Flange And End-One-Flange Loadings, Amir M. Yousefi, James B. P. Lim, G. Charles Clifton

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

The web crippling strength of cold-formed ferritic stainless steel unlipped channels subject to interior-one-flange and end-one-flange loading is considered in this paper. A total of 144 results are presented, comprising 36 laboratory and 108 numerical results. These results cover the cases of both flanges restrained and unrestrained to the load and reaction plates. Unlike other work in the literature, the numerical analysis in this paper uses nonlinear quasi-static finite element analysis with an implicit integration scheme, which has advantages over static and quasi-static with an explicit integration scheme analyses, particularly for post buckling predictions of unlipped channels subject to web …

Experimental And Analytical Studies Of Cold-Formed Steel Sections With Edge-Stiffened Circular Holes Subjected To Web Crippling, Asraf Uzzaman, James B. P. Lim, David Nash, Amir M. Yousefi, Benjamin Young

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

Cold-formed steel sections are often used as wall studs or floor joists and such sections often include web holes for ease of installation of services. The holes are normally punched or bored and are unstiffened; when the holes are near to points of concentrated load, web crippling can be the critical design consideration. Recently, a new generation of cold-formed steel channel sections with edge-stiffened circular holes has been developed. The web holes are stiffened through a continuous edge stiffener/lip around the perimeter of the hole. In this paper, a combination of experimental investigations and non-linear finite element analyses are used …

Parametric Studies And Design Recommendations Of Cold-Formed Steel Sections With Edge-Stiffened Circular Holes Subjected To Web Crippling, Asraf Uzzaman, James B. P. Lim, David Nash, Amir M. Yousefi, Benjamin Young

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

A parametric study of cold-formed steel sections with edge-stiffened circular holes subjected to web crippling under one-flange loading condition was undertaken using finite element analysis. The effect of different hole sizes, edge-stiffener length and distances of the web holes to the near edge of the bearing plate on the web crippling strengths of channel sections were investigated. The web crippling strengths are influenced by various geometry parameters: the ratio of the hole depth to the flat portion of the web, a/h, the location of the hole as defined by the distance of the hole from the edge of the …

A Preliminary Study On Stainless Steel Hollow Flange Beams Featuring Lateral-Distortional Buckling, Shuang Niu, Zhidong Zhang, Feng Fan

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

To explore the potential of using stainless steel structurally, extensive research has been carried out to study the structural behavior of stainless steel member as associated with the nonlinear stress-strain relationship. Hollow flange sections feature improved structural efficiency and a unique issue of web distortion. Steel hollow flange sections have been studied and commercially distributed (e.g. the very first HFB section and lately LSB section). As a proactive study, this paper investigates stainless steel hollow flange beams of double-symmetric section with numerical modeling and parametric analysis. The validity of the idealized FE model was verified with existing study on steel …

On The Effect Of Web Stiffening Of Cold-Formed Steel Thin-Walled Lipped Sigma Sections In Compression Members, Rashideddin Cheraghi, Hamidreza Mohammadzadeh

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

Cold-formed steel cross sections are high strength thin-walled profiles which are highly prone to local and distortional instabilities. Stiffening techniques are utilized in the industry as a solution to enhance local and distortional buckling strengths. The sigma section is that channel section which its web pushed inward for the stiffening reason. In this research, the effect of side sway of the web (dx) on the buckling behavior of lipped sigma sections is investigated. The results demonstrate that stiffening inclined components of the web in lipped sigma sections for dx up to 0.5512”(14 mm) act as a stiffener and change the …

Bracing Design For Torsional Bucking Of Cold-Formed Steel Wall Stud Columns, C. D. Moen

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

A method is presented for calculating the required brace stiffness and strength to limit torsional buckling deformation in cold-formed steel wall stud columns. The bracing (bridging) design method utilizes recent insight from classical stability solutions that define twist of singly and doubly-symmetric columns with an initial twist imperfection as a function of column compressive load. A wall stud design example is provided.

Behavior Of Beam To Column Cold-Formed Section Connections Subjected To Bending Moments, Maged T. Hanna, Mohamed M. El-Saadawy, Ghada M. El-Mahdy, Ehab H. A. H. Aly

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

Cold formed sections are often used in the construction of mid-rise buildings due to their high strength weight ratios, and fast erection. In these buildings, the connections between joists and studs are mainly simple connections. However, application of these sections can be extended to moderate span frames where connections between members are subjected to bending moments. Strength and stability of such frames depends to large extent on the behaviour of the connections between their members. Over the last twenty years, several researchers undertake tests on cold formed section connections subjected to bending moments. Major of them classify the connections as …