Architect and engineer . n this greatbridge, the massive looking piers, thebreadth of arches, may suggest a lavishuse of materials out of keeping with de-pression-stricken purses. Rather, however,do they offer examples of how depressionis to be met and circumvented. The entirestructure is cellular, hollow. The material isdisposed efficiently, and although some sec-tions are thin, there is ample strength inthe mutual support the component partsgive one another and the whole. The sof-fit slabs of the arches are six inches thick;the outer faces of the pier shafts are fif-teen inches thick, but th
Architect and engineer . n this greatbridge, the massive looking piers, thebreadth of arches, may suggest a lavishuse of materials out of keeping with de-pression-stricken purses. Rather, however,do they offer examples of how depressionis to be met and circumvented. The entirestructure is cellular, hollow. The material isdisposed efficiently, and although some sec-tions are thin, there is ample strength inthe mutual support the component partsgive one another and the whole. The sof-fit slabs of the arches are six inches thick;the outer faces of the pier shafts are fif-teen inches thick, but the three remainingsides of each shaft are only six inchesthick. At the corners where these six inchsides intersect, are interior column sectionsthree feet two inches square, integral withthe walls. A six inch by six inch rabbet isformed in the outer corner of these diaphragms six inches thick stiffenthe arches, while interior horizontal dia- THE ARCHITECT AND ENGINEER ^ 35 ? AUGUST. NINETEEN THIRTV-FIVE. SOUTH VIEW OF CABRILLO BRIDGE. BALBOA PARK. SAN DIEGO phragms eight inches thick and about fif-teen feet on centers, stiffen and strengthenthe pier shafts. When one thinks of whatwould have resuUed had the same quantityof material been conventionally disposed insolid sections conventionally braced, therecan be only a feeling of profound gratitudeover this avoidance of what might havebeen. A joint is formed at the crown of eacharch. The arch webs are keyed for trans-mitting shear—otherwise the separation iscomplete. Consequently the structure re-solves into a series of piers carrying sym-metrical arched cantilevers. So far as deadloads are concerned, each pier is loadedsymmetrically. Unbalanced live loadingcan occur, but combined with the deadloads is relatively unimportant. The bridge was completed in 1914. Atthat time there was nothing but a coveringof low brush on the slopes and floor of thevalley. The beautiful trees which now sur-round it have all grown an
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