Development and Delivery of a Concrete Masonry Design and Construction Course

Transcription

1 Development and Delivery of a Concrete Masonry Design and Construction Course FINAL REPORT May 21, 2014 Dr. Thomas Nicholas, P.E. Dr. Tara L. Cavalline, P.E. Page 1 of 10

2 Introduction Previously, the Department of Engineering Technology and Construction Management at the University of North Carolina at Charlotte (UNC Charlotte) has not offered a course in masonry design or construction. With Charlotte, North Carolina being one of the largest metropolitan centers in the south, there was a need to provide an educational foundation to graduating seniors and graduate students on concrete masonry design and construction. The funded proposal has provided support in the development and offering of a course entitled Masonry Design and Construction at UNC Charlotte. This course was offered during the Spring 2014 semester as a senior elective course to UNC Charlotte s Civil Engineering Technology and Construction Management students, as well as to graduate students in the UNC Charlotte s Masters in Construction Management and Facility Management program. The course was designed/developed to address masonry design and construction in both the classroom and laboratory. Course Modules A primary objective of this project was to develop a modular course that could be easily implemented at other institutions. Furthermore, the course had to be structured to provide an even distribution of design and construction while catering to both senior level students and graduate students. In order to achieve the level of instruction for both constituents and provide a modular course, the instructors have developed an innovative approach to the classroom, termed course modules. Course modules are based on the eleven course objectives (listed in Table 1) that were covered in the class The undergraduate students were required to complete each course module at the appropriate instructional level (undergraduate or graduate, with appropriately scoped accompanying exams) for successful completion of the course. The graduate students had to complete the course modules; however, they were asked to perform additional work for successful completion of the course. The significance of course modules is that each module is objective specific and objectives can be added or taken away to customize specific course or university requirements. Furthermore, one or two modules can be used in a training environment providing flexible use of the material. Table 1 Learning Objectives: 1.) Demonstrate understanding of basic masonry materials and their history. 2.) Demonstrate understanding of basic masonry construction practices. 3.) Demonstrate understanding of mortar properties and joint properties. 4.) Demonstrate understanding of basic masonry inspection practices. 5.) Demonstrate understanding of where, when, and why to use a masonry structure. 6.) Analyze and design unreinforced concrete masonry structures using code requirements. 7.) Understand how to calculate the compressive behavior of concrete masonry. Page 2 of 10

3 8.) Understand how to calculate the flexural strength of concrete masonry for each design element. 9.) Analyze and design reinforced concrete masonry beams using code forces. 10.) Analyze and design reinforced concrete masonry walls and columns using code forces. 11.) Analyze and design reinforced concrete masonry walls and shear walls. Course Delivery The course was delivered to 20 students (15 undergraduate and five graduate students), and was deemed by both instructors and students as a success. In all, six course modules were developed to cover the eleven learning objectives listed in Table 1. The Course Module list is as follows: 1. Course Module 1 a. Demonstrate understanding of basic masonry materials and their history. b. Demonstrate understanding of basic masonry construction practices. 2. Course Module 2 a. Demonstrate understanding of mortar properties and joint properties. b. Demonstrate understanding of basic masonry inspection practices. c. Demonstrate understanding of where, when, and why to use a masonry structure. 3. Course Module 3 a. Analyze and design unreinforced concrete masonry structures using code forces. b. Understand how to calculate the compressive behavior of concrete masonry. 4. Course Module 4 a. Understand how to calculate the flexural strength of concrete masonry for each design element. b. Analyze and design reinforced concrete masonry beams using code forces. 5. Course Module 5 a. Analyze and design reinforced concrete masonry walls and columns. 6. Course Module 6 a. Analyze and design unreinforced and reinforced concrete shear walls. The objective of the lecture portion of the course was to introduce students to design of masonry walls, beams, columns, and foundations, and to familiarize students with applicable codes and standards. The class performed very well in the lecture portion of the course with many earning high marks in the analysis and design of masonry systems. Most students recommended that we continue to offer the class for future students. All 20 students successfully completed the class with exam averages of 84% for the first exam, 81% for the second exam and 78% on the final exam. The final grade average in the class was an 84%. While the lecture received high marks, the students had the most praise for the course management style (Course Modules) and the laboratory. The class provided very positive feedback on the mixed lecture and lab style course which in academia would resemble a just-in-time course delivery format. In order to aid in the students understanding of masonry systems and design, a site visit to a local construction Page 3 of 10

4 project was scheduled that utilized both CMU and clay masonry building systems, illustrated in Figure 1. The commercial building was designed to be a multi-unit complex for student housing. Due to the multiple buildings located on the site at different stages of construction, the students were provided with a unique experience in visualizing the building process. Figure 1. Masonry Course Construction Site Visit The objectives of the laboratory portion of the course was to introduce students to laboratory tests used in quality assurance and control of masonry construction and to provide students with the opportunity to learn masonry construction techniques by constructing large-scale mock-ups in a laboratory setting. By far, the students responded most favorably to the lab component of the course. Every student was engaged during lab and eager to participate as illustrated by Figure 2. The lab average for the class was 86% and the final project report average was a 90%. The following labs were performed during the spring semester: 1. Introduction to Masonry Materials (1 Laboratory) 2. Aggregate Characterization for Masonry Mortar and Grout (2 laboratories) 3. Masonry Mortar (2 laboratories, Figure 2) 4. Masonry Grout (2 laboratories) 5. Masonry Prism Test (2 laboratories) 6. Masonry Construction Demonstration and Training (1 Laboratory, Figures 6 and 7) 7. Full Scale Masonry Wall and Construction (4 laboratories, Figure 3) Page 4 of 10

5 Figure 2. Compressive Strength Testing of Mortar Cubes - ASTM C109 Since both graduate students and undergraduate students were enrolled in this course, a unique pedagogical opportunity existed. For each laboratory exercise, the students were broken into groups led by a graduate student. This allowed for all undergraduate students to work with and be mentored by high-performing, more experienced students during both the in-class procedures and in development of laboratory reports. This also provided an opportunity for graduate students to serve as team leaders, using project management skills to lead the work effort of the group. Overall, this format aided in enhancement of the overall quality of work performed and submitted in the laboratory portion of this course. Semester Project The Masonry Design and Construction students were tasked to perform the following to construct the masonry wall illustrated by Figure 3: For the semester project, we will be using two materials for mortar: LWA and Sand. In the interest of time, the laboratory testing will be divided amongst the following two groups: Mortar Mixture CMU Fine Aggregate Group Members Sand LWA Lightweight, Standard 8x16 Lightweight, Standard 8x16 Normal weight natural sand Light weight aggregate Student Student Page 5 of 10

6 Assignment: The goal of this exercise is to successfully construct and test to failure, a 24 x 72 CMU hollow wall. The parameters of your design will be f m = 1000 psi, lightweight block and a mortar test strength similar to type S. Objectives: 1. Calculate the design capacity of the wall in the same manner as performed in Course Module 3. Make sure to calculate the code values and a value that does not include safety factors. 2. Construct the wall, making sure to construct three prisms to serve as companion specimens for determination of the true f m. 3. Graduate students only: a. Design wall instrumentation - Hardware b. Provide instructor with instrumentation needs list for ordering c. Design wall instrumentation Software d. Perform trial test using Instron for load and deflection e. Instrument wall 4. Full scale test of wall to failure Figure 3. Test Specimen Dimensions and Detail (Student Final Report) As most of the students (and instructors) were unfamiliar with constructing masonry walls, UNC Charlotte partnered with CCMA and Gates construction to provide a Masonry Construction Demonstration and Training day. The Master Masons, shown in Figure 4, donated their time and skill to train the class on the proper way to construct a CMU wall. The Masons discussed troweling techniques, leveling, inspection practices and construction tolerances while building a mock-up wall for the class. An emphasis was placed on quality assurance and control considerations utilized in practice. Once the demonstration was complete, the students built a Page 6 of 10

7 mock up wall resembling the wall they would build for the semester project as shown in Figure 5. Figure 4. Master Masons from Gates Construction - Masonry Construction Demonstration and Training The class was divided into two teams each consisting of graduate and undergraduate students for the semester project. As previously stated, team one constructed a lightweight system utilizing lightweight unreinforced wall system and team two constructed a normal weight unreinforced wall system shown in Figure 6 (right picture). Team one s wall (Wall Test #1), experienced a localized crushing failure at the load application location that produced a maximum load of 21,489 lbs (Figure 7) which was well short of the predicted value of 51,300 lbs. It should that the wall capacity of Wall #1would have been greater than recorded; however, due to safety concerns after the crushing failure the test was aborted. Team two s wall (Wall Test #2) (Figure 6), produced a maximum load of 59,141 lbs which represents a 13% increase over the theoretical value determined to be 51,374 lbs (Figure 8). Page 7 of 10

8 Figure 5. Students Learning to Construct CMU Wall - Masonry Construction Demonstration and Training Page 8 of 10

9 Figure 6. Before Failure (Left) and After Failure (Right) of Full Scale Wall Test #2. Figure 7. Load-Displacement vs. Time for Wall Test #1 Page 9 of 10

10 Conclusions Figure 8. Load-Displacement vs. Time for Wall Test #2 In closing, the course was a success for the students, instructors and the Department. Student reviews for the course quantitatively was a 4.83 out of 5 for both overall, I learned a lot in this course and overall course evaluation. Qualitatively, the students had the following statements: I wish I had more classes like this. The lecture/lab format worked very well. Dr. Nicholas and Dr. Cavalline are great teachers, I really enjoyed this course and Masonry! This was a fast paced course, loved the lecture/lab format. We should have more classes like this. Masonry should be a required course here, I m going to recommend it to everyone. While the preceding statements only represent some of the student comments, all student comments were very positive and similar to the comments provided. The course is planned to be placed on the rotating elective course offering in the department with hopes from the instructor of a permanent place in the curriculum. Attachments As part of the final report submission, digital copies of each Course Module that contains: 1. PowerPoint Lecture 2. Required Reading 3. Homework Assignment 4. Laboratory Procedure Page 10 of 10