much stronger than it otherwise would be. This type of concrete can be used to build structures that are lighter, more graceful, and in a much greater variety of shapes than standard concrete. Komendant was Professor of Architecture at the University of Pennsylvania from 1959 to 1974 and visiting professor at the Pratt Institute in the late 1970s. Collaboration with Louis Kahn In 1956 Komendant met architect Louis Kahn, who was soon to become one of the most honored architects of his time, and began a contentious but highly productive collaboration that lasted until Kahn's death 18 years later.<ref name=18-years>{{cite book |title=18 years with architect Louis I. Kahn |last=Komendant |first= August |year=1975 |isbn=0-913690-06-6 |pages=192}}</ref> Kahn was five years older than Komendant and, like him, had been born in Estonia. Kahn had decided in the early 1950s that he would no longer use the relatively lightweight steel structures that were typical of modern architecture. He had come to the conclusion that only structures made of reinforced concrete would allow him to achieve his goal of creating structures that would simultaneously provide support, shape spaces and furnish integral sculptural embellishment. This approach required the collaboration of a structural engineer who understood Kahn's architectural philosophy, one who could grasp the effect Kahn wanted to produce with a proposed design and suggest a suitable alternative if it was not practical from an engineering standpoint. Komendant, who was already known for his expertise with pre-stressed concrete, proved to be a creative thinker and a productive collaborator. Kahn described him as "'one of the rare engineers qualified to guide the architect to develop meaningful form". According to Robert McCarter, one of Kahn's biographers, "Komendant would serve as Kahn's primary consultant on the majority of his commissions for the rest of his career". The first project they worked on together, the Richards Medical Research Laboratories, was a breakthrough project for Kahn, his first to receive widespread recognition. Two other buildings they worked on together, the Salk Institute for Biological Studies and the Kimbell Art Museum, received the prestigious Twenty-five Year Award, which is given by the American Institute of Architects to only one building per year. Although each of them knew they achieved particularly outstanding results when they worked together, they did not always find it easy to do so. Komendant could work with exceptional speed while Kahn was notoriously slow, to Komendant's great frustration. Komendant felt