beam structures:
Of particular importance are the supports, boundary conditions, and internal hinges and expansion joints, as these determine the degrees of freedom, equilibrium, and the degree of redundancy of the system. A as this may be an introduction to the physical significance and design implications of the term boundary conditions, close-ups of important support details and internal releases are included in many of the structures.
steel arches: from the old and new world: As arch construction is one of the oldest means of spanning rivers and forming the roofs of large buildings, it is appropriate that this set should start with illustrations of a number of historic arches, including Roman and Medieval. It was inevitable that the arch form should dominate the early history of building as without the availability of a material capable of taking significant tensile stresses, a predominantly compressive system was the only means of forming large spans -- hence early structural and architectural forms were primarily based on columns, arches, and domes.
columns and rigid frames:
Classical architecture has many examples of columns, from segmental stone columns to the buttresses and flying buttresses of cathedral construction. The stability of modern columns is very sensitive to boundary conditions, and a series of slides is devoted to close-ups of column supports. Stability can also be important in the design of modern tall buildings, and examples are given.
cable structures: Tension and suspension structures are a very important class of structure, particularly for long-span systems, and hence should be introduced early in a course of structural analysis. This must be done with caution on account of the nonlinear characteristics of many long-span tension and suspension structures. The one-to-one relationship between the arch and the tension structure is obvious in the case of the relatively stiff system where deflections do not significantly alter the distribution of internal forces (that is, systems which can be taken as linear). The use of cable and suspension systems in building construction is illustrated by long-span roofs, cable-net systems, and by a multi-story building with suspended floors.
domes and shells:
The dome is one of the oldest means of enclosing a large space, and from the Roman Pantheon and the Hagia Sophia in Istanbul to the domes of classical cathedral architecture, it is clearly a most important structural form.
Although precise analysis is complex, simplified analysis is not. The modern ribbed dome on a ringed beam is simply a radial arch structure and an extension of the structures considered. Also, the membrane analysis of hypar shells gives an understanding of their overall behavior, as does the simple beam theory of long barrel shells.
seismic examples:
The philosophy of earthquake design for structures other than essential facilities has been well established and proposed as follows:
a) To prevent non-structural damage in frequent minor ground shaking; b) To prevent structural damage and minimize non-structural damage in occasional moderate ground shaking; c) To avoid collapse or serious damage in rare major ground shaking. The implementation of this philosophy presents serious problems particularly in quantifying the different types of damage (structural and non-structural) and what constitutes frequent minor, occasional moderate, and rare major earthquake ground shaking.
truss structures:
Understanding the arrangement of members in a truss and their function is essential for a thorough understanding of truss systems. This is best accomplished by taking sections and using statics on free body diagrams. Many of the slides in this set are ideal for this purpose as their geometry is relatively simple even though the structures may be large. In many of the modern high-rise buildings, the shear bracing for wind or seismic forces is visible and shows clearly the importance of a continuous shear system from the point of origin of loading to the point of support. Large bridges tend to look more complex on account of the need for bracing compression members against buckling, but a careful study will reduce the complexity to the essentials of the framing geometry.
bridge construction: This set of slides shows the construction of eight different structures. They represent different forms of construction, in different materials, and of different spans. The earliest is the Forth Road Bridge near Edinburgh in Scotland, a major suspension bridge completed in 1964; and the most recent is the multi-span Dumbarton Bridge across San Francisco Bay, opened in 1981.
The Godden Collection (Structural Engineering Slide Library) is the product of 30 years of teaching structural analysis, structural design, and architectural engineering to undergraduate and graduate students in Europe and the United States. During this period the Dr. W.G. Godden has traveled extensively and has used color photography to bring to the classroom illustrations of structural engineering so that theory can be related directly to practice. The resulting slides are not always the standard type of book illustrations, but rather views taken from specific angles for the express purpose of illustrating particular facets of structural theory, response, or design. Over the years, this has developed into a large and comprehensive collection taken in many countries, covering all kinds of structural engineering, historic as well as modern.
In teaching courses on structural analysis, the author has found such a resource invaluable in supplementing the rigor of engineering analysis with applications to real life. Without such immediate illustration, engineering mathematics can be uninteresting, difficult to understand, and easily misapplied. In addition, it is often useful to start analysis with an actual structure rather than with a line diagram, to develop an expertise in structural idealization alongside the necessary competence in equation solving. As the advent of microcomputers makes the analysis of complex structures readily available to students early in their training, without necessarily developing an equivalent knowledge of structural geometry and response, careful illustration becomes increasingly important. Finally, it is found that in certain courses the use of case studies is an ideal means of both teaching and learning the whole process of structural engineering from the choice of geometry, to structural idealization, equation solving, and finally to design, construction, and structural behavior. Hence the Library has been developed with these three uses in mind, and having this resource available makes possible certain kinds of teaching that might otherwise be difficult.
Most structural systems are illustrated, and throughout the Library certain structures are singled out in each section for more extensive coverage using overall views, views from different angles, and close-ups of details such as boundary supports that have a significant influence on the method of analysis and on the resulting structural behavior.
The complete Slide Library can be found at http://nisee.berkeley.edu/godden/godden_intro.html. The selection shown here in the Godden Collection is a subset (focussing on steel structures only) of the original Slide Library and posted with permission of the author. The viewer should feel encouraged to visit the website, in particular because Dr. Godden uses an new image format (MrSID) which shows the slides in unparalleled brillance and resolution.
La Tour Eiffel: "A travers plusieurs rubriques abordant le sujet de façons différentes (évolution historique, lexique, images du siècle dernier, images de synthèses d'aujourd'hui ...), nous vous proposons donc de partir aux sources de cet incroyable monument et de découvrir les secrets de la structure de cette
Grande Dame."
(above: construction sequence - courtesy to Ralph M. Francis)