Final Capstone Project Reports- Master of Science in Structural Engineering Program

Bonnet, Jeffrey D. "Compression Chord Analysis Of A Cold-Formed Steel Joist Using Photoelasticity"

Nov. 2002, 76pp, includes references

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Abstract: Photoelastic analysis is an experimental tool which uses polarized light to determine stresses within a material. This project explores the validity and practicality of photoelastic analysis in structural engineering applications. This project was conceptualized from the destructive testing of the welded connection of a cold formed joist. In an attempt to utilize a less wasteful and potentially less expensive alternative, two non-destructive analysis tools are introduced -- finite element analysis (FEA) and photoelastic analysis. The results from FEA and photoelastic analysis of an epoxy coated steel joist are compared to results from destructive. It was found that both FEA and photoelastic analysis did accurately predict the critical failure region from destructive testing. Also, a model of the steel joist was made using a rapid prototyping (RP) technique called stereolithography. The RP model was then compared to the actual steel joist using photoelastic analysis. It was found that if the RP model was epoxy-coated, the stress gradients behaved quite similar to that of the steel joist. In an attempt to explain any inconsistencies in the results between the steel and RP joists, a simplified model is created. Independent tests were performed isolating three variables: material, scale, and orientation. Several unexpected characteristics were discovered in these tests, mostly due to the residual stresses inherent in the RP models. The findings show that photoelastic analysis has potential for becoming a valuable tool in structural engineering, especially for specimens with complex geometries. Perhaps the most important finding was that the accuracy of the photoelastic testing depends greatly on the amount of residual stresses, and if these stresses are minimized, the analysis is more likely to remain linear and thus more quantifiable. Several ideas are recommended to guide those in the future who wish to more qualitatively explore the photoelastic characteristics of RP models.

Charlton, Nathan A. "Development of D45 Reinforcing Wire in Concrete"

May 2009, 51pp, 4 references, figures, tables

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Abstract: Reinforced concrete is a standard practice of construction throughout the world today. Traditionally concrete is reinforced with hot rolled steel bays but an alternative to this is steel wire reinforcing which is produced from an extrusion process. The overall geometry of the wire reinforcing is different than that of rolled bars, and therefore the reinforced concrete members act differently when subjected to loading. In order to examine these differences and determine the adequacy of steel wire reinforcing in regard to development length, a series of large scale tests were conducted and evaluated using a linear elastic transformed section analysis. It was found that all D45 test specimens experienced a failure caused by pullout, and the current ACI design equations do not accurately predict the bond stress at failure of D45 reinforcing wire.

Christiansen, Mary "An Analysis of Concrete Performance: Increasing Gypsum Content"

May 2008, 61pp, 17 references, figures, tables

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Abstract: Construction and demolition debris account for over 12% of the material in our nation's landfills. Of that 12%, approximately one fifth is comprised of scrap gypsum wallboard. Gypsum wallboard is often sent to landfills because in many cases there is no strong end market for recycling it. The purpose of this project was to analyze the performance of concrete mixes when ground recycled gypsum wallboard is added in various amounts. Concrete is the most widely used construction material on Earth. Using gypsum as an additive in concrete could be an economical way to use a material that would most likely be thrown into the landfill. Multiple concrete mixes with varying gypsum contents (from 5 to 15% by weight) were tested for compressive strength over a period of ten weeks. Three of the concrete mixes reached the required strength of 4700 psi, though several mixes took longer than others to achieve the design strength. The batches that had more than 4% gypsum by weight added did not reach the required strength. Based on this research, it seems that for certain applications, such as backfill, foundation support, pavement base, conduit bedding, and architectural features or as fill for metal deck, a mix with a slightly increased gypsum content could produce acceptable concrete. Other properties, such as durability, shrinkage and expansion, and cracking need to be investigated further, but this experiment proves that design strength can be obtained if a long enough curing time is allowed.

DeLany, Heather "The Load-Deflection Behavior of Straight Deformed Bars in Concrete"

May 2009, 51pp, 7 references

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Abstract: This report covers the experiments and analysis conducted in the study of load-deflection behavior of straight deformed bars. The effects of clear cover, bonded length, and loading method on the stiffness of the load-deflection behavior were the primary focus.

Specimens that modeled the end of a beam in a knee joint were created and the reinforcement was loaded in tension, either monotonically or repetitively.

Of the twelve specimens tested, half of them had 2 d sub b of clear cover and half had 1 d sub b of clear cover. A third of the specimens had 16" of bonded length, one third had 12" of bonded length, and the other third had 8" of bonded length.

Major findings include an increase in the load-deflection behavior stiffness by a factor of 1.5 for bonded lengths of 12" and 16" and a negative result for the hypothesis that repetitive loading would decrease the stiffness of the load-deflection behavior.

Friedman, Adam D. " Axial, Shear and Moment Interaction of WT Connections"

May 2009, 157pp, 14 references, figures, bibliography

Appendix A: WT Connection Calculations
Appendix B: Test Frame and Set-Up Calculations
Appendix C: Shop Drawings
Appendix D: Test Data Output

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Abstract: Simple shear connections are commonly used in typical steel frame buildings. There are a number of shear connections including shear tabs, single angle, double angle, end plate, seated and tee connections. These connections are very economical, easy to fabricate, and provide adquate strength. The connections are used only for shear resistance, but it is commonly believed that they are capable of resisting an interaction of shear, axial, and moment.

The purpose of this thesis is to qualitatively and quantitatively measure the interaction of forces in WT connections. Results from testing explore how the connections perform in the event of a collapse of the center support in a steel frame building. The study considers robustness, redundancy and structural integrity of the connection. Test results are used to determine the level of flexural capacity of various WT connections. Results also show the presence of catenary action in the test assembly.

To properly study and analyze the connection performance, physical testing was performed on WT connections for 3, 4, and 5 bolt configurations. Data collected from the testing were used to calculate forces at the connection, including shear, axial, and moment. Further analysis confirmed failure modes and overall test assembly performance. Testing showed that WT shear connections have some level of flexural resistance. Catenary action was found to occur in the test assembly beyond the flexural resistance range of the connection. All of the tested WT connections had bolt shear rupture failures either during the flexural resistance period or in the catenary range. Finally, it was found that the connections provide a certain level of robustness, but would not be capable of supporting full design loads with the addition of unexpected moment and axial forces.

Gerloff, James R. "Cold-Formed Steel Slip-Track Connection"

Jan. 2004, 240pp, 16 references

Appendix A: Specimen Material Tests
Appendix B: MSOE Slip-Track Test Results
Appendix C: Summary of MSOE Slip-Track Test Results

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Abstract: The slip-track connection is one of the most commonly used connections when designing curtain wall systems. There is little guidance in the American Iron and Steel Institutes' (AISI) North American Specification for the Design of Cold-Formed Steel Structural Members (2001). This paper presents the nominal capacities for a slip-track connection as well as the effective distribution width of the track. Several methods of analysis were reviewed along with an example of each method. A parametric study of the slip-track connection was conducted as well as finite element modeling. A total of 108 test specimens were tested in different combinations with stud widths of 1 5/8" and 2 1/2". The specimens had a stud spacing of 16" and 24", a gap between the web of the track and the top of the stud of 1/2" and 1", and track thickness varying from 14, 16, to 18 gage. Seventy-two test specimens were tested in combinations with varying stud widths, stud spacing, and track thickness. Thirty-six test specimens were tested with alternate fastener spacing. These tests yielded higher failure loads, and for the sake of being conservative, only the tests with the fasteners located at the stud location are used in determining the nominal capacity. Finite element analysis was completed following the tests. A stud spacing of 24 inches was analyzed, with a stud flange of 1 5/8", a slip gap of 1/2", and track thickness of 18, 16, and 14 gages. Proposed design procedures based on the results of this project are provided.

Gough, Arlo Jay, Jr. "Headed Reinforcement Lap Splices In Concrete Masonry."

Nov. 2003, 69pp, 8 references

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Abstract: Headed reinforcing bars have been used in concrete construction in the past. Previous research has been conducted on the use of headed reinforcing bars as longitudinal bars in concrete applications. This experiment researches the use of splicing headed reinforcing bars in masonry construction. It is felt that a shorter splice length may be used to get the same capacity, or even more capacity, than code minimum splice length requirements for deformed bars. Tests were performed on nine specimens made with 8-inch units and three specimens made with 12-inch units to determine the effects of splice length and clear cover of headed reinforcement in masonry. Several limit states for headed reinforcement were reviewed and a few of them were analyzed. The limit states analyzed included: development, side blowout, and compression strut failure. A review of both variables (splice length and clear cover) for each limit state was provided. The limited number of specimens did not allow for additional variables to be tested. This experiment showed that splicing headed reinforcement in masonry warrants further review.

Gross, Jason L. "Analysis of Wood Shear Walls with Alternating Spaces of Ventilation and Blocking"

June 2004, 85pp, includes references

Appendix A: Calculated Values for Fasteners and Sheathing
Appendix B: FEA Models

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Abstract:Shear walls have been used for many years as a lateral-force-resisting element for wood-member, light-framing construction. Ventilation requirements for attic roof spaces have been in place for just as long, but seldom has the topic of integrating the ventilation space with the connection between load carrying diaphragms with load resisting shear walls been addressed in the literature. The one reference found is the APA guide Introduction to Lateral Design, which mentions a technique to install blocking every other framing spece to accommodate venting in the spaces left open. It continues to explain that decreasing the nail spacing by half in the areas that remain, which results in twice as many nails in these spaces, can perform the same amount of shear transfer as a connection which has solid continuous sheathing. However, the guide does not mention any evidence to support the theory. This report describes similar design examples which have reduction values assigned for void spaces, analyzes the internal forces involved in placing vent spaces in different areas of the wall, lists the procedure and data from laboratory testing of shear wall specimens with and without vent spaces of two different capacities, and examines the difference between predicted and laboratory test results. The laboratory tests indicate there is not a reduction in strength due to the placement of void spaces in shear transfer connections, which proves the APA theory correct. A shear wall acts as a system of many parts, and for reasons not fully understood, the internal forces seem to distribute around openings to increase the overall performance of the wall. This report gives recommendations on future tests to validate the increase in strength that was observed.

Huber, Matthew L. "The Milwaukee School of Engineering's Photovoltaic System Project: Final Structural Report"

Aug. 2007, 124pp, 17 references

Appendix A: CC Roof Structure Plan
Appendix B: AISC 3rd Ed. Table 5-17
Appendix C: Copyright Approval Letters

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Abstract: The Milwaukee School of Engineering has recently been awarded the funding to install a 29 kWH photovoltaic (PV) system, supporting the nation's growing need for clean energy. For numerous reasons, MSOE has elected to install this system on the roof of the Student Campus Center (CC) building in downtown Milwaukee. Before proceeding with this project, a complete structural evaluation must be completed showing that the CC structure's capacity is adequate under new design codes. The objective of this project is to provide MSOE with a final structural report for the CC building, including a design for a solar panel mounting frame. Final recommendations, based upon the evaluation's findings, are necessary for MSOE to continue with their PV project. To complete this project, a firm understanding of the initial design intent is extremely important. After studying the CC structural plans, the new design codes, ASCE-7 and AISC's 3rd edition LRFD, were applied to determine the capacity of the current structure. It should be noted that the design codes have evolved significantly since the initial design in the 1940's. Using these design codes, a solar panel mounting frame was designed, increasing the roof demand even further. Through the structural evaluation, it was found that the CC structure had more than sufficient capacity to support current design codes. After designing the solar panel mounting frame, it was determined that the CC roof structure was able to support the frame as designed. However, the placement of these solar panel frames is restricted. MSOE may proceed with their PV project while following the strict recommendations of this report, and after receiving consent from a licensed Professional Engineer of the State of Wisconsin.

Jaeger, Jadon A. "Web Sidesway Buckling Of Crane Runway Beams"

Nov. 13, 2006, 67pp, 3 references

Appendix A: Web Sidesway Buckling Model Log File -- Simply Supported, No Stiffeners, Two Loads
Appendix B: Web Sidesway Buckling Model Log File -- Simply Supported, Stiffeners Included, Two Loads

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Abstract: Crane runway beams are a common fixture in warehouses and industrial facilities. Most crane trolleys apply two concentrated loads onto the runway beam. Few studies have been conducted investigating the web sidesway buckling capacity of beams subjected to two or more concentrated loads. The purpose of this report is to investigate the effects beam section, load spacing, transverse stiffeners, beam end fixity, and restraint type and location have on the web sidesway buckling capacity of crane runway beams. Finite element models employing shell elements were created in ANSYS to observe the deflected shape of the modeled beams and to determine the critical web sidesway buckling capacity. It was found that varying load spacing, the addition of transverse stiffeners, and the application of rotational restraints have only a marginal effect on a beam's web sidesway buckling capacity. Fixed ended beams have a significantly higher capacity than simply supported beams. An increase in beam section size increases the web sidesway buckling capacity with the flange width having the most effect.

Kempfert, Michael T. "Lateral Load Capacity of Steel Joist and Joist Girder Seats."

Nov. 2003, 92pp, 2 references, bibliography & appendices

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Abstract:Steel joist girders have been used for many years as an efficient system to resist gravity loads imposed on building roofs and floors. They may also be effectively used to resist lateral loads imposed on the building. In the past, extensive destructive testing has been completed to determine the allowable lateral loads that may be resisted by joist girders. Recently, the standard joist girder seat depth has been changed from 6-inch seats to either 5-inch for LH joists or 7 1/2-inch seats for joist girders. Therefore, the testing conducted in the past has become invalid. For this project, numerous destructive tests were performed to determine the lateral load capacities of the new joist girder seat depths. These capacities are then compared with the results obtained from finite element models of joist girder seats. It is found that the results from the finite element analysis closely match those found from the destructive testing. From the finite element analysis, the inflection point for the moment gradient of the joist girder seat is accurately found allowing the determination of the lateral load capacity. With the confidence gained in the accuracy of the finite element analysis, it is recommended that future destructive testing be limited, and that finite element analysis be used to determine lateral load capacities of joist girders with different configurations.

Lasecki, Susan L. Caluwe, PE "The Capacity of Headed Stud Anchors Installed in Corner Applications"

Nov. 2007, 101pp, 19 references

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Abstract: Decades of research and testing have been performed to determine the capacity of headed stud anchors in tension and shear loading. Additional studies have been made on the capacity of these anchors in combined loading. All of these studies have investigated headed stud anchors that have been installed normal to the face of the loaded concrete surface. The purpose of the investigation was to determine the capacity of headed stud anchors cast into concrete at an edge where the anchor is at a forty-five degree angle. This type of installation is commonly utilized in many cast-in-place, precast and tilt-up applications. Equations which represent the observed capacities will be developed and proposed for use in future design conditions. Four types of tests were performed to determine the capacities of the headed stud anchors. All of the headed stud test specimens consisted of 1/2" dia. x 4" long headed studs welded to a 3"x3"x5/16" steel angle at a forty-five degree angle. The first test type consisted of a single stud, the second type of test consisted of two studs spaced at 5" c/c, and the third test type consisted of two studs spaced at 9" c/c. The fourth test type was identical to the second test type except that confinement steel was added. The test specimens were each cast into an 8" thick slab with a center recess. Two slabs were cast; each with eight test specimens, four on each side of the center recess. A 3/8" thick steel plate was welded onto each of the steel angles. At the time of the test, a steel clevis was secured through the hole in this plate. A hydraulic ram was connected to a 3/4" dia. rod which was screwed into the clevis. The hydraulic ram was supported by a steel frame. One of the columns of the steel frame was located within the trough and the other was located to the outside of the projected failure area of the concrete around the headed stud. The hydraulic ram was used to then apply a vertical force on the test specimens. The maximum breakout strength was recorded and the failure areas were measured and documented. The observed concrete breakout failure surfaces were similar to those documented in tension tests of headed studs near a free edge of concrete. The failure cones closely represented the 35 degree failure cone used in current design standards. The capacity of the single stud test was almost precisely one half of the test values of the two studs spaced at 9" c/c. Studs spaced greater than twice the effective length of the stud have the capacity of a single stud multiplied by the total number of studs used. The ACI 318-05 and PCI Design Handbook - Sixth edition equations both provide an acceptable representation of the stud behavior, provided that the equations are applied properly. Proper application of these equations included correct determination of the effective embedment and the application of the eccentric load factor. New empirical equations were also derived from the actual test results which more closely represent the actual capacities of the connections. The use of these equations may be limited since the testing range was not broad enough to confirm their accuracy in conditions with longer or larger headed studs.

Lawson, David "Creep Characteristics of Post-Installed Epoxy-Based Anchors Subjected to Tensile Stresses"

May 2008, 79pp, 16 references

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Abstract: Industrial strength epoxies have become common use in construction for installing anchor rods into cured concrete. However, connections that rely upon the use of epoxy-based adhesives do not fare as well under tensile stresses as a cast-in-place or mechanical anchor connection. Such materials are prone to creep strains, which can eventually lead to failure in the connection if unchecked.

In this report, the creep characteristics of four commonly used adhesives for post-installed anchors were evaluated. The adhesives were used to install 3/8" diameter threaded rods into a concrete beam. The rods were then placed under a constant tensile load using a system of levers. Displacements in the anchors were measured daily over a period of eight weeks. Based on the data acquired and the shear stresses placed on the anchors, it was found that even when loaded within the manufacturer's approved allowable limits, the epoxies within the connections experienced creep. This raises concerns about using epoxy-based adhesives to design connections under a continuous tensile load.

Moorhead, William "Comparison of modeling in metal-plate-connected wood roof trusses"

Dec. 2008, 82pp, includes references, appendices, figures

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Abstract: Several editions of a national standard for metal-plate-connected wood truss design have been issued in the United States going back to 1960. However the current standard does not include language to precisely define how the heel joint region of a roof truss should be modeled in analysis to predict truss performance. The Canadian national standard for trusses does include provisions for the heel joint analog. This study compares results from trusses modeled under three different heel joint analogs, and includes the results from proprietary analysis and design software title. Certain truss types are reported to have much lower combined stresses in the first top chord panel adjacent to the heel joint when the Canadian provisions are used. Truss deflections are not appreciably affected by the various analogs compared. It is common that stresses in the first top chord panel adjacent to the heel joint are most influential in determining required chord grade, and the lower stress levels in the Canadian variations suggest that using the Canadian analog could provide designs with generally lower lumber grade requirements, and hence more economical trusses.

Nordling, Daniel W. "Interaction of bond and bearing for headed and hooked reinforcement"

Jan. 2009, 59pp, includes references, figures, tables

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Abstract: The interaction between bond and bearing for headed and hooked reinforcement in concrete is not well understood. Previous research has established the ultimate capacities of headed and hooked reinforcement in concrete. This project was conducted to better understand the interaction between bond and bearing between initial load application and ultimate capacity.

Tests were performed on a total of 16 specimens. Of these specimens, 5 were headed reinforcing bars, 5 were straight reinforcing bars, and 6 were hooked reinforcing bars. The reinforcing bars were ASTM A706, Grade 60, #7 bars. Concrete cover and bond length were the variables tested. Embedment depth remained constant for each specimen. Limit states of steel failure, breakout, pullout, side-face blowout, and splitting were analyzed to help determine the interaction between bond and bearing. Also, bonded length was used to analyze the bond strength over a partial development length.

Due to a limited number of test specimens, definite conclusions to the interaction between bond and bearing were not determined. However, the tests were used as verification for capacities found using ACI 318-02 code equations and proposed design equations from Thompson, Jirsa, and Breen for headed reinforcement. ACI 318-02 equations found a more conservative capacity for headed reinforcement than the proposed equations, but the tests indicated the proposed equations are more appropriate for capacity calculations. It was also found that the proposed equations cannot be applied to hooked reinforcement.

Patton, Jaime. "Effect of Splice Length of Headed Reinforcement Bars in Masonry Cells"

May 2004, 51pp, 4 references

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Abstract: The use of headed reinforcement is relatively new in masonry walls. Research is being conducted to determine if splice lengths can be reduced when heads are present. Previous research tested anchorage of headed bars in concrete and effects of splice length and clear cover in masonry. This project was conducted to further previous research by testing effects of headed reinforcement on splice length in masonry cells. Tests were performed with a total of 12 specimens. The specimens were constructed using ASTM C 90 dimensions of standard CMU block. There was a combination of 8-inch block cells and 12-inch block cells. Variables of splice length, development length, compressive strength and material confinement or clear cover were tested. Limit states of single blowout, compression strut or a combination of the two were developed and analyzed to determine the capacity of the specimens. Due to the limited number of test specimens, definite conclusions to the effect of headed reinforcement on lap splices in masonry cells could not be detrmined. Development length had no direct effect on the capacities, more cover led to higher capacity and longer splice length led to increased capacity. An equation was developed using previous research for in-plane and out-of-plane blowout failures. It was determined that the in-plane equation was the best fit for longer splice lengths. More research is needed to determine the effects of splice length on capacity for short splice lengths.

Price, Andrew M. "Lateral Strength of Cold-Formed Steel Slip Track Connection"

Dec. 2006, 220pp, 4 references

Appendix A: Elastic Slope Data Plots
Appendix B: Original Data Plots

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Abstract: This project was based on the initial testing of the Cold Formed Steel Slip Track (CFS-ST) - to - Cold Formed Steel Stud connection and design procedure by James Gerloff. His analysis and conclusions allowed for this topic to be revisited by analyzing a new slip-track design. The variables used in determining the strength of the CFS-ST were design gap, e, thickness (gage) of material, and either the use of clips or no use of clips. All of these variables were standardized to analyze the effects that each variable had on the overall strength of the CFS-ST. Safety factors were also determined based on testing results and were compared with the original testing done by James Gerloff. The summary of results are determined for the nominal strength of the CFS-ST specimens.

Rescorla, Matthew R. "Partially restrained moment connections : classification of connections relative to stiffness, strength, and ductility"

July 2009, 85pp, tables, figures, appendices, 9 references

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Abstract: Integral to the design of all structures is connection design. Therefore, one must know the stiffness, strength, and ductility capacity, along with the moment-rotation characteristics of the connection that is being utilized. To that end, it was the author's intent to investigate two different types of connections in hopes of obtaining results that could be used to classify the connections as simple, partially restrained, or fully restrained. In addition, the connections' defining characteristics and the moment-rotation capacity of each connection were established.

The investigation was conducted using five test specimens. Three set-ups consisted of cold-formed c-channels bolted to vertical column tops and two set-ups consisted of wide flange members bolted to the face of a hollow structural section via a moment end-plate. Each specimen was placed and bolted into the testing apparatus such that the hydraulic ram could engage a beam cantilevered from the column approximately three feet. Loading was applied in a cyclical fashion; the load magnitude was recorded while linear differential variable transducer (LDTV) measured deflections near the joint.

It was established that both types of connection were within the "simple" range of two different connection classification schemes. The prevailing factors that contributed to the results are lack of enough bolts in conjunction with slightly oversized slots in the case of the c-channel tests and a very stiff beam compared to a relatively thin tube wall thickness for the moment end-plate connection.

The classification schemes chosen for this project are based on those found in the American Institute of Steel Construction (AISC) Steel Construction Manual and in publications by Bjorhovde et al., and Christopher and Bjorhovde.

Rinke, Brian J., P.E., S.E. "Reinforcing Steel Beams With Steel of Different Yield Stress for Flexure"

Aug. 2007, 116pp, 14 references, bibliography

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Abstract: Reinforcing steel members by welding on additional steel pieces has been a practice for as long as welding has been available. Structural engineers regularly investigate a variety of older buildings with steel framing that require reinforcing of the members. Information about combining the assumed lower yield steel of the original member with the higher yield steel of the new pieces seems to be difficult to find. Will the higher yield strength of the new steel offer any additional load carrying capacity to the system? To explore this condition, four steel beams were obtained and additional steel pieces were welded to them. These shapes were configured in a manner that is common to the industry for reinforcing steel that is currently in place in a building's structure. Each steel beam was placed in the test frame one at a time, supported at each end with half-round supports, and a hydraulic ram in the center of the test frame provided the force. The applied force was spread to two equal point loads, each eight inches off the centerline. Although the steel of the original beam and the reinforcing pieces had different yield strengths, only the material that was furthest away from the neutral axis of the beam had any influence on the load capacity of the system. In all of these shapes this was the top flange of the original beam. For configurations like those used, it is recommended to use the yield stress of the original beam when designing reinforced shapes. It was also observed that the deflections of the beams were greater than the calculated values, possibly caused by a slow and steady shift of the neutral axis of the systems throughout the course of each experiment, even before the beams began to yield. In addition, all of the beams had about the same load limit before the rotational stability was exceeded, regardless of the thickness of the flange or the web of the beam or how it was reinforced.

Robinson, Jonathan. "Analysis and design of masonry spanning 2-ways between in-wall pilasters"

May 2006, 183pp

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Abstract: Some of the most common buildings are one-story buildings and one of the most common construction methods for these one-story buildings is the use of load bearing masonry walls. A system used for this type of construction is one with pilasters that work by having unreinforced masonry spanning between them. In this project the focus was a pilaster system that included pilasters that did not project from the wall. Another specialty of this project was that the unreinforced masonry between the pilasters was allowed to span in two-directions. This specific system set the stage for a computer application to be created. This report goes through both reinforced and unreinforced masonry designs that were used to design this type of system. Along with this is an explanation of how the computer application was created. One special topic in this project is how the masonry pilaster system was affected by in-wall pilasters when thinking about the distribution of load for the unreinforced masonry spanning in two-directions.

Schmitz, Robert P. "Fabric-Formed Concrete Panel Design"

Oct. 25, 2004, 80pp, 19 references

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Abstract: Concrete wall panels have traditionally been cast using a rigid formwork. Straight-forward methods of analysis and design are available for the traditionally cast concrete wall or floor panel. This is not so for the panel cast in a flexible fabric formwork. The purpose of this report is to develop a design procedure that allows one to design a fabric cast concrete panel. A four-step procedure for analytically modeling the fabric formwork is developed in order to determine the final shape of the concrete wall panel. The structural analysis program ADINA was employed to analyze the complexities of a flexible fabric formwork and the concrete panel cast in it. Analytical modeling and design techniques are developed in this report that will allow the design community another way to express themselves through the use of flexible fabric formwork.

Schultz, Joshua Adam "Design of Fully Tempered Monolithic Structural Glass with Point Supports Based on Ultimate Stresses and Stress Distributions"

May 2008, 79pp, 20 references, figures, tables

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Abstract: This paper investigates stresses in a typical application of fully tempered glass as a point supported structural balustrade. Loadings are defined by building codes, but literature on strength or other limit states for tempered glass in this application is limited. The paper compares finite element analysis, equations from plate theory, and test results. The goal of the paper is to establish an accurate and efficient method of design that uses a manual calculation to select a preliminary design thickness and employs the calibrated finite element method for the final design. The experimental results serve as a baseline against which the finite element models are compared in order to determine accuracy.

Experimental strain data is gathered from six fully tempered, monolithic glass balusters loaded to both service and ultimate conditions. Strain and deflections are measured and used to select the finite element model which most accurately idealizes the test results.The effect of element type, integration schemes and boundary conditions on finite element analysis results and computational processing time are compared, leading to the conclusion that for this application the model with solid linear elements and "pinned" boundary conditions provide the best results. Consideration of plate theory, including the effects of stress concentrations, results in an equation for field stresses and adjustment factors for stresses in glass and around holes. The resulting calculation provides maximum stresses based on plate thickness which compares favorably with the linear finite element results.

Experimental, finite element and manual results all show that the stresses at a 200 lb load are approximately 8,000 psi and about 24,000 psi at failure. These test results calibrate the finite element and plate theory predictions and suggest a design procedure.

Thompson, Scott L. "Axial, Shear and Moment Interaction of Single Plate "Shear Tab" Connections"

May 2009, 182pp, 23 references, figures, tables

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Abstract: The construction and engineering fields have long used simple shear connections such as single plates, single angles, and t-sections as supports for framing members in steel framed structures due to their relative simplicity and cost effectiveness of fabrication and erection. Historically these connections have been thought to support vertical shear loads exculsively; however, knowledge of their ability to support axial forces and moments has been speculated but seldom verified.

The purpose of this research is to provide observations and numerical verification of the single plate "Shear Tab" connection's ability to support the combination of shear, axial, and moment forces as a result of a simulated column failure. This research presents a historical background of the single plate connection's development along with providing insight into the connection's ability to utilize catenary action as an inherent secondary load transfer mechanism.

Nine full scale tests simulating an interior column failure have been conducted for various depths of single plate connections. Shear, axial, and moment forces, as well as beam end rotation values have been derived from experimentally measured strain and deflection data to provide numerical evidence of the various observed connection rupture failures. A preliminary bolt force analysis technique has been developed to provide an understanding of the connection's behavior prior to failure as well as to provide comparisons between the observed failure mechanisms and those expected using the current steel specification.

This research has shown the single plate connection has a low level ability to transform from a shear and flexural response to catenary tension. The experimental data suggest the shear tab connection alone could not support its intended design level shear load in the event of a catastrophic loss of a supporting column.

Whittinghill, Chad J. "Partial Fixity in Steel Single Plate Connections to HSS Tube Columns"

April 2009, 129pp, 10 references, appendices, tables, figures

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Abstract: When analyzing a structure, beam to column connections are classified as simple, fully restrained, or partially restrained. The type of end connection used in the analysis greatly affects the design of the beam and the column. Previous research has suggested that single shear plate connections, which are commonly designed as simple connections, may be stiffer than originally assumed. The scope of the previous research was limited to examine the accuracy of modeling single plate connections of beams to HSS tube columns as simple connections. The results of this research are used to demonstrate how modeling single plate connections as partially restrained, rather than simple, can lead to a more accurate analysis and possible cost savings.

Connections were made between a W24x76 beam and HSS tube columns of varying size and thickness. A horizontal force and beam deflection were measured simultaneously throughout a predetermined load cycle. Each tube column section was tested using three separate bolt configurations. From this data, a rotational stiffness was determined for each trial connection. The rotational stiffness values were then used in sample problems to compare true moment and deflection behavior with the assumed behavior.

The test connections all displayed moment-rotation behaviors that were well within the AISC recommendations for designing as simple shear connections. However, each connection was able to transfer moment to the column. While this moment transfer may be insignificant in many designs, understanding the true connection behavior may be valuable for beams with minor end moment demands.

Willis, David Charles, P.E. "Embedment of cast-in-place anchors in concrete : minimum embedment depth"

October 2009, 104pp, 13 references, appendices, tables, figures, nomenclature

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Abstract: Anchor bolts have been a major building component for a long time. However, design of anchor bolts has only recently been introduced into building codes. ACI 318-02, Appendix D, presents the first building code requirements (for non-nuclear facilities) for anchoring to concrete. Anchor design is controlled by the lowest value of the applicable failure modes. For an anchor in tension, these include the steel strength of the anchor, the concrete breakout strength, the pullout strength, and the concrete side-face blowout strength. Splitting failure of the concrete must also be considered in design.

When the anchors fail as a result of the concrete, a sudden brittle failure is experienced. It has long been considered good engineering practice to design for ductility where possible. A ductile failure associated with the anchor steel does not produce a sudden rupture. This report explores the failure modes associated with a single anchor in tension in an effort to produce a recommendation for a minimum embedment depth of an anchor in concrete to assure the steel failure modes govern. Eighteen anchors made from 3/4" threaded rods were embedded in concrete as varying embedment depths. Some of the embedded anchors included a nut at the embedment depth, while the rest were embedded as plane threaded rod. A tensile load was applied to the anchors until failure.

The results of the anchor tests narrowed the range in which the embedment depth is sufficient to fully develop the steel strength of the anchor. Tests also showed that for short embedment lengths, the headed and non-headed threaded rods failed at similar loads. Although threaded rod appears to be closely related to deformed bar, the development and interaction with concrete proves to be much closer to plane steel bars. Analysis suggests that bond strength between the concrete and the anchor play a critical role in the ultimate strength of the anchor.

Establishing a minimum embedment depth for a steel anchor would allow for engineers to provide quick and economical anchor design with added confidence. A steel controlling failure mode design would incorporate the ductile elastic properties of steel into all anchor designs. With additional testing and analysis, an established relationship between the anchor type, anchor size, and concrete strength could be developed to establish a minimum embedment depth for anchors in concrete.

Zimdahl, Jamie L. "The Behavior of Headed Reinforcement in Concrete Members with an Applied Tensile Load"

May 2009, 67pp, 6 references

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Abstract: As the exploration for additional uses of headed deformed bars continues, it becomes more necessary to determine the behavior of reinforcement. Currently, little information is available on a method to predict the behavior or capacity of headed reinforcement. This project will focus on determining if it is possible to analyze the individual behavior of a straight bar and a bar head, and then combine them to find the relationship of a headed bar with bonded length. Twelve beam-end specimens, consisting of a pair of matching specimens for each of the six different variable combinations, were tested to find the effects of bonded length and clear cover. Headed bars with 0" bonded length were tested, and the results were superimposed onto the results of straight bars of certain bonded lengths. The results of the superposition were compared to the test results of headed bars with matching bonded lengths. Test results showed that a percentage of the stiffness of the headed bar with 0" bonded length is combined with a percentage of the stiffness for a straight bar of a certain bonded length to make up the stiffness of a headed bar with bonded length. After testing a variety of percentage combinations, the combination that accurately models the behavior of headed reinforcement could not be identified for certain. It was determined that the assumption that linear superposition of the stiffness of a headed bar of 0" bonded length and a straight bar with bonded length is not accurate. A more accurate behavior could be found by documenting and graphing the independent behavior of the head and the bond length at each stage of loading. With the completion of further testing focused on the effects of clear cover and bonded length, the behavior of headed reinforcement could better be understood.

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