Masonry Structural Design Competition for Civil Engineering and Architecture Students

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1 Masonry Structural Design Competition for Civil Engineering and Architecture Students Masonry Design at Clemson University In continuation of Clemson University s longstanding history with masonry research and design, the Glenn Department of Civil Engineering has put together a course offering students the ability to learn about masonry design and construction. This course will help further the awareness of masonry topics amongst students within the department, many of whom have chosen studies in the fields of structural engineering, construction planning and materials research. The class also offers those in related fields such as architecture and construction science a chance to venture outside their traditional curriculum in an effort to become well- rounded graduates more prepared for the working environment. Not only will these students learn about the historical tradition and relevance of masonry design and construction but they will be given chances to learn through hands- on demonstrations and activities outside the classroom in addition to lectures given by relevant industry professionals. The course is based on the principles laid out by the Masonry Society Joint Committee (MSJC) in its 2011 code. The students are introduced to the historical traditions of masonry throughout the world before being guided into modern design through coursework which involves examples and discussion from the point of view of the practicing design engineer. Work is assigned and students are expected to expand their knowledge of masonry throughout the course. The topics evolve through the introduction of materials and technical notes through simple unreinforced design to that of more advanced, reinforced shear and curtain wall design. Through the semester the students are given examples through Allowable Strength Design (ASD) as well as Load and Resistance Factor Design (LRFD) which together provide exposure to both common and future design practices. Finally, the students are given a chance to research individual topics and present a summary of their findings to the class. The final presentations provide both a wonderful opportunity for students to practice their speaking skills as well as a concluding discussion on more advanced topics within masonry such as acoustic considerations, thermal design, masonry accessories and detailing, sustainability, fire resistance and impact resiliency. Project Purpose and Description In an effort to supplement the topics discussed during lectures, during Spring 2013 semester, students were given the opportunity to participate in a competitive project in which they were tasked with designing, constructing and testing masonry walls. This semester- long project pushed students in all facets of what they learned in the course and charged them with not only the design but also the construction of an actual masonry project. Students were given the opportunity to compete for monetary prizes and plaques which signified the most outstanding masonry performances.

2 The task called for students to design a wall of required dimensions that would be tested for strength at the end of the semester. In addition to dimensions, students were allowed the use of a limited quantity of reinforcing bar and grout. They were also asked to design their walls such that 33% of the surface area was left open. Through the course of the semester students often made progress on the project through the completion of homework assignments which involved designing and analyzing their own masonry walls. Exposure to Masonry Practices In preparation for the masonry wall construction, the students were provided with hands- on experience and training working with masonry. The majority of the students had no prior experience in masonry construction. To provide exposure for the students, multiple out- of- class trips were organized that gave the class an opportunity to witness walls being constructed by trained masons. In addition, the students were given a chance to interact, ask questions and finally build small walls as practice. During the process, the class took away valuable information about the mixing and preparing of mortar, how best to apply it to the concrete masonry units and how to construct a wall properly with careful attention to each unit and course. These trips visited the TD Expo Center in Greenville, South Carolina for the Masonry Skills Competition and the Pickens County Career and Technology Center where masonry skills were demonstrated and taught (Figures 2 and 3). Figure 2: Masonry Skills Competition at the TD Expo Center hosted by Byard Stevens, Greenville, SC (above)

3 Figure 3: Masonry instructor Jeffery Stephens at the Pickens County Career & Technology Center, Liberty, SC (shown above) Wall Construction When the designs were finalized, a construction zone was selected on the grounds of the Clemson University Structures Laboratory. There, the students were supplied with tools and hardware to construct the designs they had submitted for approval. Concrete masonry units, the mortar and the grout were donated by local manufacturer Adams (formerly Cemex) and CCMA. The students were provided with 1 week in which to build their walls. Groups were encouraged to plan their construction to maximize variables like curing time. See figures 6 and 7 below. Figure 6: Construction began the afternoon of Wednesday, April 24 th (above).

4 Figure 7: Construction continued over the next several days before walls were left to cure (above). Expert Judges & Masonry Wall Review An assessment of the students masonry walls was carefully conducted with the help of a panel of expert reviewers. The judging took place on Monday, April 29 th, approximately one week after construction had begun and shortly before the testing procedures were initiated. During this review process a number of local officials were on- hand to evaluate the nine walls (Figures 8 and 9). This expert panel was comprised of representatives from Adams Products (supplier of masonry materials for this project), the Carolinas Concrete Masonry Association (CCMA), the Masonry Society (TMS), the Pickens County Career and Technology Center as well as Clemson University. Amongst these individuals were industry professionals with large amounts of experience in the design and construction of masonry. In addition, representatives from the Masonry Society and Clemson University brought a wealth of experience and knowledge involving masonry research, testing and university- level instruction. The results from the judging were combined with the results of the testing as well as the students predictions to tabulate and overall group score. The best three overall group scores were recognized with certificates and congratulations as well as prize money provided through the donations from the National Concrete Masonry Association s Education and Research Foundation. Monetary prizes in the amounts of $1,500, $1,000 and $500 were awarded to the first, second and third place groups, respectively in accordance with their overall project score. $1,000 prizes were also given to the groups whose wall had withstood the most force and to which group had more accurately predicted the strength of their wall.

5 Figure 8: A panel of expert reviewers was on- site to judge the walls before they were tested. Shown here are representatives from Clemson University, The Masonry Society, Adams Products and the Carolina s Concrete Masonry Association. Figure 9: The judges carefully reviewed each of the free- standing masonry walls. They noted and graded each group s wall according to the criteria of constructability, aesthetics and the functional use of masonry materials.

6 Testing at Clemson University Structures Lab Finally, the students were asked to diligently construct their walls at designated stations which had been determined such that the test frame could be safely relocated from station to station as the testing was completed. The station arrangement reflected the testing order and helped ensure that each wall would have roughly one week of curing time. Class instructor and project leader Dr. Atamturktur in addition to graduate assistant Gregory Roche and technical supervisor Danny Metz all made sure that at any point proper supervision and guidance was available on- site (See figures 10-14). Figure 10: Shown from one end, the test frame supported the top and bottom courses. A large piece of plywood was placed between the walls and the air bag. This protected the bag and ensured consistent pressure across the wall.

7 Figure 11: A side- view taken during test shows the wall flexing under severe lateral pressure. The beginnings of flexural failure can be seen in the middle portions of the wall were cracks in the mortar joints are forming. Figure 12: The test was considered complete when additional pressure in the air bag caused limited or no change in the walls deflection. Here, a failed wall remains in its final deflected shape.

8 Figure 13: Failure of the walls was not identical in each specimen. Here, multiple joints have failed and vertical cracks have moved through many of the 4- inch CMUs. Figure 14: The failure of each wall was carefully examined and noted after testing by all who were on- site. This included the group members, the testers, the judges, etc. Here, Clemson University emeritus faculty member and The Masonry Society President Dr. Russell Brown closely inspects a wall s failure.

9 Group Scoring The walls were evaluated according to a rubric with five primary areas of focus. These categories included the walls flexural capacity (35%), the groups ability to predict their walls strength (20%), the constructability of their design (15%), the aesthetics and workmanship displayed (15%) and the functional use of masonry materials (15%). The flexural testing was associated with the first grading category. Groups were ranked from first to last based on the strength of their wall. The group s calculations were associated with the second category in which they had to predict their walls capacity. Finally, the judge s reviews effected how groups scored in the final 3 categories of constructability, aesthetics and use of materials. Using this basic framework, it was a simple process to determine the best overall group scores. The top 3 were aware $1,500, $1,000 and $500 for their efforts. In addition, the best wall performance during test and the most accurate group prediction were individually awarded $1,000. All winning groups will be mailed certificates for their exemplary efforts.