41. The firm contributed a lot to the introduction of Prestressed Concrete Structures in Egypt. 42. Slabs in prestressed concrete are usually produced in lengths of up to 200 meters. 43. Superstructure of the viaduct consists of prestressed prefabricated girders executed as freely supported beams. 44. A prestressed box beam or girders bridge was built in Dorrance Township in 1988. 45. A prestressed box beam bridge was built over the creek in 1963 in Laflin. 46. He did not invent prestressed concrete, but he did develop it for practical use. 47. It is a prestressed concrete bridge of 584 m, which rest on 8 columns. 48. These girders were prestressed by post-tensioning four wire cables embedded in the concrete. 49. Built in 1964, a prestressed box beam carries Bryn Mawr Avenue over Ithan Creek. 50. A prestressed box beam or girders bridge carrying Pennsylvania Route 239 was built in 2004.
