Eduardo Torroja Quotes

[E]xperimental investigation of stresses in a plane structure is of great interest and merit as applied to shells with single curvature (barrel shells, pipes) and to shells with double curvature (domes, etc.). In these structures similar states of stress are produced and can be determined at any point as acting in a plane tangential to the center layer of the shell.

In general, these phenomena are very easy to perceive and understand, but difficult to calculate. The danger of failure increases rapidly with decreasing depth or thickness of the structural member...

Stress phenomena are... not independent of scale, as was the case pertaining to simple external static equilibrium. ...with increasing dimensions of a structural element the volume and therefore the proper weight increases more rapidly than its cross-sectional areas...

Mathematics is merely a convenient tool by which the designer determines the physical proportions and details of a planned structure in order to transform his ideas... to the actuality of a finished structure.

[T]here are three different but interconnected conceptions to be considered in every structure, and in every structural element involved: equilibrium, resistance, and stability.

If you lean on a straight stick... [it] can resist your weight, despite its slenderness, as long as it remains straight; once it starts to bend, it will easily break. The danger of breaking increases with the deflection... [T]he danger of failure will diminish with the increased of the cross section, or if the same are of cross section should be maintained, by distributing the material in a hollow section.

Long before... our techniques of today, men could conceive and build structures adapted to the requirements of resistance... because he had observed... the branches of a tree bending under the weight of fruits and the tensioned cords of strings in which children have rocked from time immemorial...

The material in all elementary parts of a structure must have the properties of resistence to all internal forces produced by general loading conditions and by the action of any exterior force.

[E]very structure has a resistant function to fulfill... to ensure ...the static equilibrium of the structure for a long period of time.

The variety of exterior forms in concrete is limited only by the cost of forming; and its thickness is limited only by the size of aggregates, gravel, and sand.

One should become so familiar with the structure as to have the feeling of being, in full vitality and sentiment, part of it and of all its elements. ...it is necessary to achieve a sincere Einfühlung [empathy] of the process of resistence... through the deformation that is always essentially united with the process of stressing. ...[T]he comprehension of a structure requires intuitive knowledge of the ethology of its resistance and of its constituent materials.

The equilibrium... in order to become static—should be steady, permanent, lasting. ...This type of equilibrium... is... independent of any scale. A reduced model will show the same effects as the proper structure. Experiments on models are simple and... instrumental for understanding such structural problems.

Even children know that drafting rule is easier to bend flat than across the edges; and... they will not be much surprised if told that for the same width of the rule its resistance is proportional to the square of the thickness and the deflection is inversely proportional to the cube of the thickness. Nevertheless some modern designers seem to be unaware... since they require... beams of such slenderness that they resemble springboards...

Clay masonry, like concrete, is a "plastic" material that permits the pouring in situ of large monoliths of any shape or form, with certain limitations and by using special methods. Its economical possibilities when used in walls of popular housing, its excellent heat and sound insulation, as well as its aesthetic possibilities, should not be underestimated. Its resistance and durability can be substantially improved by using modern techniques and methods, for example, admixture of small amounts of Portland cement in accordance with granulometric investigation, petrographic composition, and rheological behaviour of all constituents.