The San Nicolas Church in Gandia (Spain) or how Eduardo Torroja devised a new, innovative and sustainable structural system for long-span roofs

This paper analyzes the structural behavior and the context of the roof designed by the Spanish engineer Eduardo Torroja for the San Nicolas Church in Gandia (Spain). The roof is an unknown, unique, elegant and sustainable thin-walled structural system made of two deep concrete beams spanning 29 m. The structure was possible because of Torroja’s exceptional conceptual design, which used prestressing in a new way to counterbalance the biaxial bending and torsion problems caused by using deep beams with an open asymmetric cross section in long-span structures. per explains in detail the conceptual design of the roof as well as the results of a complete finite element modeling of the structure carried out by the authors, which provides a better understanding of this unknown masterpiece of Structural Art. The paper describes its original way of overcoming the major drawbacks of using open cross-section beams in long-span structural systems and points out the capabilities of simplified analysis methods to develop conceptual designs for complex structures. The authors believe the study provides inspiration for future designs and will help to give value and preserve a masterpiece of concrete construction.