I have been giving lectures at various universities on "Creativity in Structural Engineering", and now, after the fifth time, I am beginning to get my act together. This subject has many implications on the practice of structural engineering, particularly on the way we encourage our employees.

I use the analogy of creativity in engineering to creativity in writing with which we all have a long experience. The analogy is set out in Table 1.

Each of the subjects is discussed in detail below:

I stress that these operations depend on our understanding of the functioning of the left and right hemispheres of the brain, but I postpone comments on the brain until later because it would pre-empt the entire discussion.

To create and to criticize are entirely different functions. A novice writer should not try to mix these operations. Create first, then criticize. I checked this point with a teacher of English in a university and he agreed that one must be very careful to stress the importance of the separation of these functions to beginning writers.

In engineering this function is often served by brainstorming. A group is assembled for this purpose and ideas are discussed. In our office this is called a "predesign conference". The problem is presented, and suggestions for the solution are made by any member of the group. Comments and evaluations are made, but ideas are not rejected outright even though preposterous. An apparently silly idea may have some merit, and this idea may beget another which may be much better. Eventually choices narrow down and the best ideas are selected for further study. Brainstorming is an exciting and invaluable technique for creativity and ought to be taught in school.

No writer can be successful without a vocabulary suited to his purpose. He must study words, their history, their real or hidden meanings, and their sounds. They must be able to recall the proper word for a particular meaning. Successful writers always seem to be great punsters.

In the same way, a structural engineer must to know and to recall instantly, the types and characteristics of many structural systems and structural elements. This takes a constant study of professional publications and literature from advertisers including Sweet's Catalogs. Also one must know how these systems and their elements work structurally, their faults and virtues, their costs and how to analyze and design them. There is usually a simple way to make a preliminary design to evaluate the principal structural components of a system or element. It is no good suggesting a system and them finding that you cannot design it.

As an experiment, I have made a list of some of the structures that should be in the vocabulary of a structural engineer. This is shown in Table 2. You can probably think of many more. How many of these structures do you know, understand and can begin to design?

PRATT TRUSS, warren truss, FINK TRUSS, parabolic arch, CIRCULAR ARCH, funicular arch, THREE HINGED ARCH, hingeless arch, TWO HINGED ARCH, rib stiffened arch, GIRDER STIFFENED ARCH, simple beam, CONTINUOUS BEAMS, haunched beams, ARTICULATED BEAMS, moment resisting frame, BRACED FRAME, hat stiffened frame, STEEL FRAME WITH CONCRETE SHEAR WALLS, steel frame with X bracing, STEEL TUBE FRAME, ruptured tube, TUBE-IN-TUBE, cable hung floors, STEEL STUB FLOOR SYSTEM, composite steel and concrete beams, CONCRETE ONE-WAY SLABS, flat plates, FLAT SLABS, waffle slabs, TWO-WAY SLABS WITH SHALLOW GIRDERS, one way slabs with shallow girders, ONE-WAY TAPERED SLABS, two-way tapered slabs, prestressed, CAST-IN-PLACE CONCRETE FLOORS, precast floor systems, PRETENSIONED PRECAST FLOORS SYSTEMS, twin tees, SINGLE TEES, precast cored slabs, CAST-IN-PLACE COLUMNS, precast columns, SPECIAL PATENTED CONCRETE FLOOR SYSTEMS, two-way postensioned floor slabs, ROOF PURLINS, Z roof purlins, SAG RODS, rod bracing, CRANE RUNWAY BEAMS, industrial trussed bents, BASE PLATE ASSEMBLIES FOR INDUSTRIAL BUILDINGS, timber joists, TIMBER BEAMS, laminated timber beams, LAMINATED TIMBER ARCHES, steel joists, LONG SPAN STEEL JOISTS, steel domes, LAMELLA ARCHES, lamella domes, FABRIC TENSION STRUCTURES, fabric air supported structures, FOLDED PLATES, barrel shells, hypars, DOMES OF REVOLUTION, intersection shells, FUNICULAR SHELLS, catenary shells, GROINED VAULTS, long barrel shells, SHORT BARREL SHELLS, saddle hypars, GABLED HYPARS, translation shells, PRESTRESSED BARREL SHELLS, space structures, FUNICULAR FRAMES, tied arch, SCHWEDLER DOME, cable nets, SQUARE FOOTINGS, rectangular footings, WALL FOOTINGS, combined footings, MASONRY WALLS, concrete walls, RETAINING WALLS, buttresses retaining walls, LONG COLUMNS, earthquake resistant steel frames, EARTHQUAKE RESISTANT CONCRETE FRAMES, silos, BUNKERS, staggered steel trusses, STAGGERED CONCRETE GIRDERS, masonry chimneys, REINFORCED CONCRETE CHIMNEYS, hyperbolic cooling towers, CIRCULAR TANKS, rectangular tanks, Underwater structures, TIMBER TRUSSED JOISTS, trussed rafters, STEEL PLATE GIRDERS, continuous highway steel plate girders, ORTHOTROPIC GIRDERS, steel box girders, CONCRETE BOX GIRDERS, raft foundations, LAMELLA GRID FLOORS, geodesic domes, SUSPENSION ROOFS, guyed towers, TRANSMISSION TOWERS, telephone poles, POWER POLES, culverts, INDUSTRIAL RIGID FRAMES, timber deck, SPANDREL BRACED ARCHES, suspension bridges, CABLE STAYED BRIDGES, concrete columns, STEEL COLUMNS, timber columns, SPACED TIMBER COLUMNS, pipes.

A writer must have absolute command of grammar and style. This requires study, development, constant evaluation and refinement.

An engineer must know the whole spectrum of theory and practice and constantly study and use his knowledge. How else can he properly evaluate and use a new structural system or element. Theory is not the end but the means to structural engineering. The real thrill comes from developing structures and seeing them built in the field. You can only do this when you know both theory and practice.

These are the tools of each trade, and you had better master all of them or you will be handicapped in this modern age. You must gain control over each one of these tools in sucession and each greatly increases the production and the quality of the result.

The key to the computer is the programmable calculator and every young engineer should be able to use one. Just the operation of adding feet and inches on a calculator will save an inordinate amount of time. It has been my experience that even though recent graduates have been exposed to computer, they really have little feel for them. The exception is the engineer with his own personal computer. Mastery of the computer is an absolute must for the creative structural engineer. Computers tend to be overused and are a means and not an end. There should be computing equipment available for every level of structural engineering.

A writer will never be known unless he is able to sell his manuscripts to a publisher; so also the engineer must be a salesmen to get creative structures designed and built. This applies not only to principals selling a system to an architect or to an owner, but also to a junior engineer selling the design of a structural element to his boss. The structural engineer must convince his client that his structure is the optimum solution with the lowest cost and greatest aesthetic value. He must understand the architect and how to please him. At the same time he must have confidence in his own judgement. These are skills that must be studied, cultivated and developed.

SUMMARY

The ideas discussed above, embrace the whole spectrum of structural engineering. I hope that in my lectures, the students will get an insight into the meaning and purpose of structural engineering. At least it gives them food for thought.

CREATIVITY AND THE BRAIN

In my lecture, I postpone my discussion of this subject until the last because the implications are so far reaching that they would obscure the message that I have tried to give above.

My breakthrough in understanding on how I create, came from a book by Betty Edwards called "Drawing on the Right Side of the Brain", published by Houghton Mifflin Co., Boston. We have, actually, three brains, the first is the original primitive brain developed when we were salamanders. The others are the right and left hemispheres and the connecting cables.

These hemispheres have entirely different programs for information processing, and these are listed in Table 3 . The left side is used for analysis, counting, marking time, step-by-step procedures, verbalization, rational statements based on logic, and is sequential, critical, and objective. The right hemisphere is intuitive, subjective, relational, holistic, time-free, analog, non-rational, spacial, and is used for synthesis.

The right side is the creative side of the brain, and it solves problems in a flash of insight. It governs our visualization of forms and stresses in space. one' of the keys to the development of the use of the right side comes through drawing and that is why, if we get stuck, we revert to making sketches.

The brain may use either the right or left side in combination, and we do not know when it shifts sides. In some individuals the left side may dominate and in others the right. Some brilliant individuals have complete control of both sides. Development of the right side is especially important to the structural engineer.

Engineering education has tended to stress the development of the left hemispheres to the detriment of the right. Unfortunately, drawing has almost been eliminated from the engineering curriculum. Examination passers are strong left siders so teachers tend to favor these types and so neglect the creative students. This is a real inditement of our engineering education.

What implications does this aspect of creativity and training of employees have for the practicing structural engineer? I have incorporated my thoughts into the following recommendations:

1. Make your young engineers learn to sketch and to draw even though you use drafters for most of your drawings.
   
   
2. Encourage brainstorming for both structural systems and details whenever possible.
   
   
3. Encourage young engineers to increase their technical knowledge by reading and studying technical publications including architectural magazines. Buy subscriptions if necessary.
   
   
4. Encourage them to learn when and how to create, when and how to criticize, and how to use these tools in their work. They will make better structural engineers.
   
   

Milo S. Ketchum