Matching Items (5)
Description
The computation of the fundamental mode in structural moment frames provides valuable insight into the physical response of the frame to dynamic or time-varying loads. In standard practice, it is not necessary to solve for all n mode shapes in a structural system; it is therefore practical to limit the system to some determined number of r significant mode shapes. Current building codes, such as the American Society of Civil Engineers (ASCE), require certain class of structures to obtain 90% effective mass participation as a way to estimate the accuracy of a solution for base shear motion. A parametric study was performed from the collected data obtained by the analysis of a large number of framed structures. The purpose of this study was the development of rules for the required number of r significant modes to meet the ASCE code requirements. The study was based on the implementation of an algorithm and a computer program developed in the past. The algorithm is based on Householders Transformations, QR Factorization, and Inverse Iteration and it extracts a requested s (s<< n) number of predominate mode shapes and periods. Only the first r (r < s) of these modes are accurate. To verify the accuracy of the algorithm a variety of building frames have been analyzed using the commercially available structural software (RISA 3D) as a benchmark. The salient features of the algorithm are presented briefly in this study.
ContributorsGrantham, Jonathan (Author) / Fafitis, Apostolos (Thesis advisor) / Attard, Thomas (Committee member) / Houston, Sandra (Committee member) / Hjelmstad, Keith (Committee member) / Arizona State University (Publisher)
Created2014
Description
The main objective of this study is to investigate the behaviour and applications of strain hardening cement composites (SHCC). Application of SHCC for use in slabs of common configurations was studied and design procedures are prepared by employing yield line theory and integrating it with simplified tri-linear model developed in Arizona State University by Dr. Barzin Mobasher and Dr. Chote Soranakom. Intrinsic material property of moment-curvature response for SHCC was used to derive the relationship between applied load and deflection in a two-step process involving the limit state analysis and kinematically admissible displacements. For application of SHCC in structures such as shear walls, tensile and shear properties are necessary for design. Lot of research has already been done to study the tensile properties and therefore shear property study was undertaken to prepare a design guide. Shear response of textile reinforced concrete was investigated based on picture frame shear test method. The effects of orientation, volume of cement paste per layer, planar cross-section and volume fraction of textiles were investigated. Pultrusion was used for the production of textile reinforced concrete. It is an automated set-up with low equipment cost which provides uniform production and smooth final surface of the TRC. A 3-D optical non-contacting deformation measurement technique of digital image correlation (DIC) was used to conduct the image analysis on the shear samples by means of tracking the displacement field through comparison between the reference image and deformed images. DIC successfully obtained full-field strain distribution, displacement and strain versus time responses, demonstrated the bonding mechanism from perspective of strain field, and gave a relation between shear angle and shear strain.
ContributorsAswani, Karan (Author) / Mobasher, Barzin (Thesis advisor) / Dharmarajan, Subramaniam (Committee member) / Neithalath, Narayanan (Committee member) / Arizona State University (Publisher)
Created2014
Description
The Barrett creative project in residential structural design serves as the culmination of my most meaningful undergraduate experiences and interests. I previously interned for D.R. Horton, a home builder, and spent a significant amount of time on the development sites and in the engineering management office. This experience sparked a curiosity in the design of wood frames for homes and the residential industry as a whole. Since then, I have also had the opportunity to intern for Felten Group, an architecture, engineering, and forensics firm specializing in residential work. A residential roof structure is designed following the American Society of Civil Engineer's Minimum Design Loads for Buildings and Other Structures design code, in addition to the National Design Standards for Wood Construction manual. Although the sub discipline of wooden structural design can often be disregarded as the simplest type of analysis, I believe that it is a key component of an education in structural engineering. Like all aspects of civil engineering, the design of a house is composed of many interconnected systems, which include the balance of structural integrity and cost, functionality and aesthetics, and light and space. For my creative project, I took these ideas into account when designing both the floor plan and roof structure of the house using Revit and RISA, respectively. Well-rounded engineers are not only technically competent, but they also understand the social dimensions of a problem and how all the systems work together. The project focuses on creating a cohesive representation of a structure as a whole and how the individual frames, trusses, and beams interact with one another using RISA, a structural analysis program. With RISA's 3D interface, I have a better understanding of how more complex structures behave, which I have not gained from my 2D perspective in classes. RISA is used to calculate support reactions and the deflections of the trusses, which are checked against the bearing capacities of the supports and deflection design criteria to ensure a safe design. Concepts such as tributary area, truss connections, and the behavior of girder systems are also explored through the process.
ContributorsVitz, Kahla Jordan (Author) / Ward, Kristen (Thesis director) / Morgan, John (Committee member) / Civil, Environmental and Sustainable Engineering Programs (Contributor) / Division of Educational Leadership and Innovation (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
In the structural engineering industry, the design of structures typically follows a prescriptive approach in which engineers conform to a series of code requirements that stipulate the design process. Prescriptive design is tested, reliable, and understood by practically every structural engineer in the industry; however, in recent history a new method of design has started to gain traction among certain groups of engineers. Performance-based design is a reversal of the prescriptive approach in that it allows engineers to set performance goals and work to prove that their proposed designs meet the criteria they have established. To many, it is an opportunity for growth in the structural design industry. Currently, performance-based design is most commonly utilized in regions where seismic activity plays an important role in the design process. Due to its flexible nature, performance-based design has proven extremely useful when applied to unique structures such as high-rises, stadiums, and other community-centric designs. With a focus placed on performance objectives and not on current code prescriptions, engineers utilizing performance-based design are more adept to implement new materials, design processes, and construction methods, and can more efficiently design their structures to exist on a specific area of land. Despite these many cited benefits, performance-based design is still considered an uncommon practice in the broad view of structural design. In order to ensure that structural engineers have the proper tools to practice performance-based design in instances where they see fit, a coordinated effort will be required of the engineers themselves, the firms of which they are employed, the professional societies to which they belong, and the educators who are preparing their next generation. Performance-based design holds with it the opportunity to elevate the role of the structural engineer to which they are informed members of the community, where the structures they create not only perform according to design prescriptions, but also perform according to the needs of the owners, engineers, and society.
ContributorsMaurer, Cole (Author) / Hjelmstad, Keith (Thesis advisor) / Chatziefstratiou, Efthalia (Committee member) / Dusenberry, Donald (Committee member) / Arizona State University (Publisher)
Created2021
Description
As structural engineers in practice continue to improve their methods and advance their analysis and design techniques through the use of new technology, how should structural engineering education programs evolve as well to match the increasing complexity of the industry? This thesis serves to analyze the many differing opinions and techniques on modernizing structural engineering education programs through a literature review on the content put out by active structural engineering education reform committees, articles and publications by well-known educators and practitioners, and a series of interviews conducted with key individuals specifically for this project. According to the opinions analyzed in this paper, structural engineering education should be a 5-year program that ends with a master’s degree, so that students obtain enough necessary knowledge to begin their positions as structural engineers. Firms would rather continue the education of new-hires themselves after this time than to wait and pay more for students to finish longer graduate-type programs. Computer programs should be implemented further into education programs, and would be most productive not as a replacement to hand-calculation methods, but as a supplement. Students should be tasked with writing codes, so that they are required to implement these calculations into computer programs themselves, and use classical methods to verify their answers. In this way, engineering programs will be creating critical thinkers who can adapt to any new structural analysis and design programs, and not just be training students on current programs that will become obsolete with time. It is the responsibility of educators to educate current staff on how to implement these coding methods seamlessly into education as a supplement to hand calculation methods. Students will be able to learn what is behind commercial coding software, develop their hand-calculation skills through code verification, and focus more on the ever-important modeling and interpretation phases of problem solving. Practitioners will have the responsibility of not expecting students to graduate with knowledge of specific software programs, but instead recruiting students who showcase critical thinking skills and understand the backbone of these programs. They will continue the education of recent graduates themselves, providing them with real-world experience that they cannot receive in school while training them to use company-specific analysis and design software.
ContributorsMaurer, Cole Chaon (Author) / Hjelmstad, Keith (Thesis director) / Chatziefstratiou, Efthalia (Committee member) / Civil, Environmental and Sustainable Eng Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2020-05