Academy Users Report / vol.19

Emeritus Professor Yoshikawa with
Disaster mitigation (Kurihara) Lab.,
Department of Urban and Civil Engineering, Faculty of Engineering, Tokyo City University

Research and Development on New Technologies and evaluation methods about Concrete, with Ensuring Safety of Structures
Unique Design Seminar Using UC-win/Section "Urban Design Drawing" Becoming a Popular Subject

Disaster mitigation Lab., Department of Urban and Civil Engineering, Faculty of Engineering, Tokyo City University
Location: Setagaya-ku, Tokyo
Research and development contents: concrete recycling, construction joints/adhesion, judging corrosion of reinforced bar inside and so on

"As you saw, students do not ask questions so much (during the class). This is because students teach each other. When there's something they just can't understand, they come to us including Teaching Assistant (TA) to ask questions."

This is a class of "Urban Design Drawing", which is a common course for the third-year students of the Department of Urban and Civil Engineering, Faculty of Engineering, Tokyo City University. In the bright classroom with functional layout located in the 2nd floor of Setagaya Campus No. 1 building, Associate Professor Norihiko Kurihara who teaches this course explained the flow of assignments and the points of a new assignment. He concluded by saying, "Let's get started", and all at once students made groups, starting to work on the assignment with different conditions from each other. Reviewing a series of conversation at the opening, he mentions a part of the unique educational approach to this course of study. In addition to using a package of software as its framework, this process of teaching each other should allow both of those who teaches and who are taught to understand design work more deeply, as he explains its advantage.

It was about 10 years ago that this style of class for seminar courses was devised. Professor Emeritus Hiromichi Yoshikawa (who was a professor at that time) and Associate Professor Kurihara were taking a leading role in finding an approach to learning seismic design calculation of reinforced concrete (RC) bridge piers efficiently. Originally, Prof. Yoshikawa was utilizing different kinds of software of FORUM8 including "UC-win/FRAME(3D)", a three-dimensional (3D) analysis program for space-framed structures for his study. With this as a start, they built up their original method of design practice seminar using "UC-win/Section" of FORUM8, an RC/SRC section calculation program for optional forms in consideration of biaxial bending jointly with FORUM8. Since then, the course has not only taken hold as a popular course but also been expanded by Associate Prof. Kurihara, who took over Prof. Yoshikawa's aim after his retirement.

Professor emeritus Hiromichi Yoshikawa,
Tokyo City University, giving advice to students in the seminar

 Paying Attention to Concrete as a material, Towards Mitigation of Disaster Damage

"Disaster Mitigation Laboratory" analyses resistance to earthquakes and risks of roads, bridges, railroads etc. aiming at mitigating disaster damage. In Department of Urban and Civil Engineering of the Univ., there are 3 labs having "disaster mitigation" in their names including "Kurihara Lab" (two others are "Yoshida Lab" and "Sekiya Lab" that is to start from the next fiscal year actually).

Among them, Kurihara Lab focuses on concrete as a material. The Lab works on various studies under the philosophy of "using concrete in its strong condition, for a long time, and safely", though concrete requires regular inspection and maintenance is essential while being superior in durability and economy.

Associate Professor Norihiko Kurihara,
Disaster mitigation (Kurihara) Lab.,
Department of Urban and Civil Engineering,
Faculty of Engineering, Tokyo City University
As his own study subjects that he has been focusing on in recent years, Prof. Kurihara mentions the following:
  • 1) concrete recycling
  • 2) construction joints/adhesion of concrete
  • 3) judging corrosion of reinforced bar inside RC
  • 4) RC reinforcement with urethane
For concrete recycling, for example, a technology for reusing waste concrete as aggregate by dissolving it with waste sulfuric acid is examined. He also pays attention to availability of urethane as reinforcing materials for concrete structures. Practical study is being proceeded to find out its reinforcing effect in cooperation with private companies.

In the Lab, there are one first year master's student and eight fourth-year undergraduates. The latter includes two female students.


 Innovation in Anticipation of Social Needs at the 90th Anniversary of the Founding

Tokyo City University was founded in 1929 as Musashi Senior Engineering School with 3 engineering departments of electricity, civil engineering, and architecture. Since then, after repeated renaming and expanding, the school was renamed Musashi Institute of Technology in 1949 under the Educational Reform Law, having Faculty of Engineering composed of 3 engineering Departments of Machinery, Electricity, and Construction, to make a new start. The school then kept on increasing faculties and reorganizing, establishing Graduate School of Engineering (doctoral and master's courses) and increasing majors step by step. In 1997, the Faculty of Environmental and Information Studies was established, and in 2007, the Faculty of Knowledge Engineering was established. In 2009 at the 80th anniversary of the founding, the school was renamed Tokyo City University, which is the current name. At the same time, the Faculties of Urban Life Studies and Human Life Sciences were established. In addition, in 2013, the Faculty of Environmental and Information Studies was reorganized into the Faculties of Environmental Studies and Informatics. In 2019, the University reaches the 90th anniversary of the founding.

At present, Tokyo City University is composed of 6 Faculties of Engineering, Knowledge Engineering, Environmental Studies, Informatics, Urban Life Studies, and Human Life Sciences; and Graduate Schools of Integrative Science and Engineering, Engineering (name is changed to "Graduate School of Integrative Science and Engineering" for the students who enroll in and after 2018 fiscal year), and Environmental and Information Studies. The number of students of both undergraduate and graduate students is about 7,500 in total, while the number of full-time faculties is 286 (both figures are as of May 2018). 3 campuses in Setagaya, Yokohama, and Todoroki are situated as the base for education and studies.

The Faculty of Engineering consists of 8 Departments of Mechanical Engineering, Mechanical Systems Engineering, Medical Engineering, Chemistry and Energy Engineering, Nuclear Safety Engineering, Architecture, Urban and Civil Engineering, and Electrical and Electronic Engineering (scheduled to be renamed Electrical, Electronic Communication Engineering). It is located in Setagaya Campus.

Department of Urban and Civil Engineering, which responds to a wide range of social demands about cities and targeting engineering for improving urban quality beyond the category of conventional civil engineering, holds more than 400 students. Not only "Disaster Mitigation Lab" including "Kurihara Lab" but also Laboratories of Planning Management, Water Park Environment, Geotechnical Environmental Engineering, and Structural Safety, each of which contains subdivided laboratories.

 Deliberate Mechanism of "Urban Design Drawing" and Flow of Class

"I had been teaching in the university for 29 years, and this class is one of my masterpieces."

In order for students to learn practical design, it is essential for them to do actual work at the same time. When doing so, it is also important that the contents of a student's work is entirely different from those of other students. However, if the degree of freedom is too high, the class may diffuse too much. Therefore, basically it is necessary to follow professional design procedure. In this sense, the method of "Urban design drawing" mentioned at the beginning is truly a solution that take account of, and satisfy all of these elements, says Professor Emeritus Yoshikawa.

About 10 years ago, he and Associate Prof. Kurihara and others played a leading role in examining whether they could develop an educational method to allow students to learn seismic design calculation of RC bridge piers efficiently and in a short time using a software package on the market for such part that is hard to work on by manual calculation. In that process, they paid attention to "UC-win/Section" as a software package to use, partly because software packages of FORUM8 had been introduced for research before. Using this, a system was built up in such a way that design practice seminars, which also serve as an opportunity to learn how to use a tool for practical calculation, are given twice a week (200 min.) contained in classes for 14 weeks. TA for assisting the teaching faculty was also provided.

UC-win/Section used in the seminar

Currently, nearly 50 students of the Department of Urban and Civil Engineering, which is almost half of third-year students (nearly 90) are taking the design seminar for the second semester of the third-year of the Dept., "Urban design drawing/seismic design of RC piers", which almost follows this framework. In this seminar, students are given 3 assignments in stages for which they are required to submit a report (calculation sheet) for each one:
  • Assignment 1: Section analysis of the bridge base
    Assignment 2: Seismic design of RC piers (part 1)
    Assignment 3: Seismic design of RC piers (part 2)
In coping with a series of practical assignments, students are supposed to do seismic design conforming to Specifications For Highway Bridges for single column RC piers.

In specific, Assistant Prof. Kurihara prepares 60 to 70 different sets of design conditions in advance at each time. For Assignment 1, in order to confirm resistance to earthquakes of the pier base based on the set conditions, each of the students make a section analysis and calculate M-φ relationship and bending yield strength. At that time, each of the students is given different figures, size, design conditions etc. Since they have influence on the following assignments, it is so mechanized that one student has to cope with his or her own assignment and make calculation without relying on another student.

For Assignment 2, a student makes seismic design calculation based on the section the student determined by him- or herself in Assignment 1, using the simple excel sheet created originally for the allowable stress method, and UC-win/Section for the horizontal capacity method.

"To tell the truth, in Assignment 2, the initial settings are given so that the judgment of resistance to earthquakes will be 'OUT'".

That is, each student should not only make judgment based on calculation by each one but also judge why the check result is "OUT". For example, through trial and error in the process, students may recognize something that is hard to learn only by the lecture, e.g. importance or effectiveness of main reinforcement or horizontal restraining reinforcement. Furthermore, in the following Assignment 3, students are required to change bar arrangement so that it meets the design criteria (obtains "OK"), make seismic design calculation again, and prepare the final report, according to Associate Prof. Kurihara.

Drawing of urban design / RC pier seismic design: Utilization of package software

■Foundation's section
Section: Multiple rebars + side rebars
Load: Axis force + bending moment (impossible to calculate manually)
Section analysis by UC-win/Section (purchased 9 sets)
■For calculation of M-φ relation, Mu, φy, φu: UC-win/Section
■For calculation of Mu and φu: Manual calculation
Consider section as single rebar structure and calculate. Compare with UC-win/Section
■Allowable stress equation (Level I earthquake motion)
Prepare Excel spreadsheets that can calculate the stress on concrete and rebar.
■Equation for Ultimate Lateral Strength during an earthquake (Level II earthquake motion)
Click to enlarge the image. Click to enlarge the image.
Drawing of urban design / RC pier Seismic Design: Result/Impression/Assignment
  1. All 60 students are given different design condition. => Everyone has to make calculation sheets on his/her own.
  2. Although experiencing the hard and troublesome manual calculation is important, students can also get a lot from utilizing and learning with commercial tools for practical calculation.
    Students got used to the software instantly and sat happily in front of PC.
  3. Students used PC software.
    By using technical words such as lateral strain reinforcement, shear rebar, and curvature that students saw for the first time, they quickly learned the engineering meaning of those words.
  4. Students who acquired skills faster than others taught students who needed to catch up.
  5. Section characteristics and stress that are difficult to be computed manually can be calculated quickly by using the package software.
  6. Students were given the initial design condition that would make the judgment of resistance to earthquakes turn out to be "OUT", and hence the check result will also be "OUT".
    Students had to change design or execute reinforcement calculation. By doing so they managed to understand the core of the seismic design calculation.
  7. Students were given the design condition that would make the judgment of resistance to earthquakes turn out to be "OUT", and hence the check result will also be "OUT".
    Through trial and error, students found the importance and effectiveness of main rebar/lateral restrain reinforcement. This can never be acquired by listening lectures. Students can understand what seismic design is all about through trial and error approach that they can take in tutorials.

 Expanding Availability of Software both in Terms of Education and Research

"A good software program can be used also for engineering education," says Prof. Emeritus Yoshikawa.

Prof. emeritus Yoshikawa has been experiencing the design seminar for 10 years. Through appropriate use of software on the market as well as actual design calculation sheet, the students learn the process of practical designing, and those who master the skill quickly support other students. He says that he has been actually feeling the effectiveness of these attempts by seeing such scenes.

On the other hand, in "Urban Design Drawing" of the second semester this fiscal year, Mr. Keisuke Hashimoto, master's first year, the Division of Architecture and Civil Engineering, Graduate School of Integrative Science Engineering, and Mr. Takuya Yoshida, fourth-year undergraduate of the Department of Urban Engineering, Faculty of Engineering, both of whom belong to Kurihara Lab., take charge of TA (teaching assistant). They support Associate Prof. Kurihara, and instruct the students directly about how to use UC-win/Section or equations as needed. From this point of view, they mentioned their impression about easiness and visibility of making structural analysis with the software.

Associate Prof. Kurihara says that so far high weight has been attached on studies regarding the area of material of concrete, and that in recent years, the range of studies are becoming larger to include the area of its structure.

"The property of concrete changes a little from when it is in the condition of the material to when it is executed into RC structures. We would also like to incorporate examination of what this difference is like into our study (in the future). This requires verification using software programs like this. We plan to prepare different devices."

Emeritus Professor Hiromichi Yoshikawa creates and uses a dynamic model "vibration response learning machine" as part of practical lesson. Recently, he manages a post type archive introducing civil engineering facilities and continuously dispatches information via SNS for the purpose of recognizing the correct meaning of social infrastructure and succeeding it to the next generation.
His ultimate goal is "to publish images of infrastructure facilities built 100 years ago for the next 100 years."
Click to enlarge the image.

●Visit Civil Engineering Structures
The post type archive now contains 800 facilities.

●Discover Doboku
He transmits information to his 6500
followers a couple of times a week.

Click to enlarge the image.
Professor emeritus Hiromichi Yoshikawa,
Tokyo City University
(Written by Takashi Ikeno)
(Up&Coming '19 New Year issue)