Construction Research Congress 2009 contains 152 peer-reviewed papers presented at the conference held in Seattle, Washington, April 5-7, 2009. Sixteen countries were represented: Australia, Brazil, Canada, China, Colombia, Hong Kong, India, Israel, Korea, Japan, Saudi Arabia, Singapore, South Africa, Thailand, Turkey, and the United Kingdom. The papers are organized into general state-of-knowledge research areas in construction engineering and management. Topics discussed include: project control, general Operations issues, procurement and contracting, organizational leadership and management, advances in project planning, design, and construction, sustainable construction and facilities, project risks and safety, project planning and control, project/process integration and improvement, lean construction, quantitative methods and models, infrastructure management and disaster mitigation, underground construction, construction simulation, education, and research methods. This proceedings is invaluable to construction engineers and researchers, contractors, and others involved in the field of construction.