Digital Imaging and the Web in Teaching Structures: Part 3

Digital Imaging and the Web in Teaching Structures
Part 3

The Web

In addition to new opportunities for enhancing, annotating, and manipulating images, digital imaging also enables unprecedented avenues for image distribution and combination with text via the world wide web. The following discussion outlines possibilities for using the web in teaching, both as a medium for digital images and as a more general communication medium in teaching. These examples are far from a comprehensive list, they are rather the beginnings of exploration.

Web-based Image Archives

The power of the web as a medium for distributing photographs has been widely recognized, and high quality, well organized image archives are emerging. For structural engineering, the most important archive is the EqIIS collection at the Earthquake Engineering Research Center Library of U.C. Berkeley [EqIIS 1995]. This archive currently includes nearly 8,000 earthquake related images that can be freely duplicated and distributed. In addition to illustrating seismic phenomena, the images are useful for explaining basic structural phenomena. Images from these collection were used above in the examples from the Olive View Hospital and the Mexico City Earthquake. The images below, both from the EqIIS collection, graphically depict buckling and compression modes of failure in full-scale structures.

A buckled column, from the 1964 Alaska earthquake. This image is useful not only for illustrating buckling in general, but also the effects of support restraint. (original image from the EqIIS collection, the image shown has been cropped and enhanced)

A crushed reinforced concrete column. The broken horizontal ties are evidence of the outward pressure of the bursting concrete; the loss of the concrete then led to buckling of the longitudinal reinforcing (original image from the EqIIS collection, the image shown has been cropped and enhanced)

Another useful archive is the Visual Engineering Database at Virginia Tech University as part of the NSF sponsored SUCCEED coalition [SUCCEED 1995]. The image below from this archive shows the process of determining a stress-strain curve.

Testing a steel specimen, measuring applied force and change in length to collect data for stress-strain curves (original image from the SUCCEED Engineering Visual Database, the image shown has been enhanced)

Yet another source of images are home-grown web sites created by individuals with web access. Many such sites appeared after the Kobe and Northridge earthquakes. The image below shows an image taken from such a site.

An image from the Northridge earthquake, put on the web by David Kelmsley, a Los Angeles resident [Kelmsley 1995]. Note that all the stairways have pivoted upward; these stairways originally went to the second floor, and they still do; the first story parking level pancaked completely, bringing the second floor to ground level, pulling the stair with it.

Such sources are not generally reliable, but may yield useful images nonetheless.

After the Kobe earthquake, several Japanese news organizations put images on the web, however these images were copyrighted and thus required care in use and reproduction. The EqIIS and SUCCEED collections are particularly important, since their images can be freely reproduced for educational and research use.

Modelling and Image Analysis

In contrast to conventional slides, digital images can be made accessible outside of lecture via the web. This accessibility allows images to play a completely different pedagogic role in a course since they can provide a basis for assignments and study rather than serve only as an in-lecture supplement. The figure below shows a question where students are asked to draw a diagram of a computer analysis model based on a series of images of a simple truss structure.

Question: For the timber footbridge shown below sketch an analytic model of one of the supporting trusses. Clearly indicate nodes, elements, applied loads, boundary conditions, and end releases using notation outlined in lecture. Briefly explain your interpretation of boundary conditions and end releases.

An answer:

The nails provide little rotation restraint for the web members at the joints, particularly for the diagonal members which are fastened with a single nail, therefore the model should include rotational end releases for all web members.
The chord members are continuous at the joints, so do not use rotational releases at their ends.
The end supports seem to work by simple bearing, resisting lateral loads through friction only, therefore model both ends as rollers, restraining vertical motion only.
The deck framing exerts loads at the joints along the bottom chord.

This assignment seeks to go beyond simple slide identification, to interpreting the meaning of the slide content; it only begins to explore the possibilities with image-based assignments.

Collective Inductive Learning

One of the web's most common uses in teaching is distributing information to students: a technology substitution for handouts. It is also widely used as a resource for gathering information, supplementing the library. One of the greatest potentials for innovation in teaching with the web is collecting information from students, processing it, and reporting it back. This process creates a new kind of feedback mechanism that enables a class to participate in a collective effort, producing something larger than the sum of individual assignments.

Web-based forms and Common Gateway Interface (CGI) programming open these communication channels, so that students can fill out forms whose contents are collected, processed by the computer, and then presented for interpretation. The link below connects to a document that demonstrates the use of this technique for an assignment concerning the proportions of truss structures; students find an example of a truss, and report various aspects of its construction, scale, and proportions via the truss input form.

Truss Input Form

When all the observations are gathered, the data is processed as shown on the results page, linked below.

Results of Assignment

This assignment illustrates the use of the web in inductive learning. Conclusions are drawn not from general principles but from specific cases, by induction rather than deduction. Induction is rarely used as a formal method in technical education, but is extremely important, since the specific cases provide a context for the theory and its exceptions. The expertise of seasoned designers arises not only from their command of theory but also--perhaps more so--from the depth of their experience; they have many points on their mental scatter plots. The objective of this assignment, as well as the extensive use of images, is to teach students to learn from informed observation.

Collective Review

Architectural education has long recognized the benefits of collective review of student work; it is one of the fundamental principles of the jury review process. The public display and discussion of work is an important opportunity for students to learn both from critics and from each other in analyzing different approaches to a problem. The jury allows the instructor to categorize the various approaches and point out lessons that students can learn from one another.

The web offers opportunities for collective review of student work in a non-studio setting by digitizing samples of student work and compiling it into a web site that organizes the material, and interprets the overriding themes that emerge from the collective body of work. The link below is connected to a page reviewing the results of a structural model project where students built small structural models that were loaded to failure. There were 38 projects that were tested in small groups during four separate section meetings and one general meeting. Using a digital camera to document testing in each section and compiling the images with interpretation and commentary in a web document, it is possible to document the overall project and allow the entire class to benefit from its own collective effort.

Model Testing Project

Collective review can also be used in a simpler way for more conventional coursework such as quizzes. The link below is connected to a set of notes concerning a conventional quiz. The notes include examples excerpted from student tests, along with contrasting approaches to correct solutions, critical commentary, and explanations of common mistakes. Although each quiz is a strictly individual effort, the collective review allows the members of the class to learn from the work of others. This approach also emphasizes that there is typically more than one way to solve a problem, even for narrow problems having a single correct answer.

Quiz notes.

Conclusions

Digital imaging and the web offer a variety of new opportunities for teaching in general, and for teaching architectural structures in particular. Photographs have a long tradition as a tool in architectural education for linking theory to reality, digital imaging creates new opportunities for strengthening that role. Image annotation is a particularly important technique for emphasizing the metaphor that relates a real structure to a rigorous theoretical model.

By making images available outside of lecture, the web further enhances the opportunities to integrate powerful visual materials into a technical course. The web also offers important opportunities for establishing new kinds of feedback loops that engage a course in a collective effort; this is particularly useful for inductive learning, an important mode of learning that typically receives little attention in technical education.

The development of this course has taught many lessons and provides a model for developing a whole structures curriculum, which is the next step in the process. Many of the techniques are also applicable to broader areas of design. As for assessing the effectiveness of these techniques, time will tell; the first offering of the course is in progress at the time of this writing.

The preface to the course web site includes the following quote:

Speaking frankly and speaking the truth are two different things entirely. Honesty is to truth as prow is to stern. Honesty appears first and truth appears last. The interval between varies in direct proportion to the size of the ship. With anything of size, truth takes a long time coming.

from A Wild Sheep Chase, by Haruki Murakami
translated by Alfred Birnbaum

The methods presented here seek to speak frankly and visually about structures and design, they represent a significant departure from traditional methods of teaching structures, taking an approach that is both inductive and deductive, rigorous and visual. The truth concerning the impact of these methods in the design studio and beyond will take a long time coming. That experiment is in progress.

Acknowledgements

Many people have contributed to this project. I am deeply grateful for the support of the Lilly Endowment Teaching Fellowship Program and the University of Virginia's Teaching + Technology Initiative under the guidance of Barbara Nolan, Jude Reagan, and Polley McClure. The other fellows in those programs have been a major source of inspiration and ideas. Special thanks to Christie Stephenson, and Duncan Kincaid for their ideas about digital imaging. I owe a big debt to Bill Godden of U.C. Berkeley, who granted permission to use images from his magnificent slide collection; his insight, organization, and photographic skill provide a model to anyone interested in using photographs in technical teaching. Marva Barnett and Randy Pausch gave invaluable advice concerning teaching and pedagogy. Ken Schwartz provided constant mentorship and support throughout.

Bibliography

[Black 1994] G. Black, S. Duff, "A Model for Teaching Structures: Finite Element Analysis in Architectural Education," Journal of Architectural Education, 48/1, Sept. 1994. pp. 38-55.

[Condit 1982]C. Condit American Building 2nd edition, University of Chicago Press, 1982.

[EqIIS 1995] EqIIS--Earthquake Image Information System, EERC Library, http://nisee.ce.berkeley.edu/eqiis.html

[Kelmsley 1995] Los Angeles Earthquake, 1994 The URL for the summary is http://maillist.civil.ubc.ca:80/gallery/la_quake_94 The URL for the image shown is http://maillist.civil.ubc.ca:80/gallery/la_quake_94/TownHse1.jpg

[SUCCEED 1995] SUCCEED Engineering Visual Database, Virginia Tech University, 1995 http://succeed.edtech.vt.edu/default.html

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