Sustainability of Concrete Infrastructures

Sustainability of modern civil engineering structures is the broad objective of the present paper. Infrastructures should be designed and built to be used satisfactorily over longer life spans without collapse or deterioration requiring major repair. Progress in materials, analysis, and design makes it possible to achieve a life span for concrete infrastructures of 100-125 years. An appropriate life span can be a contractual requirement for all civil engineering infrastructures. For these objectives, provisions for lasting satisfactory serviceability are increasingly adopted in codes. Only deficient serviceability or strength, developing gradually over a number of years, is discussed. Lessons to be learned from collapse, excessive deflection and cracking of bridges, and intolerable sagging of slab floor are discussed. The paper presents limited means to control long-term deflection and cracking of bridges, including slab bridges and flat-plate floors; other recommendations that enhance sustainability of future infrastructures are put forward.