Process improvements in precast concrete construction using top-down parametric 3-D computer modeling

Design professionals worldwide have applied the technology of computer-aided design and drafting (CAD) on a broad scale, primarily to increase the efficiency of manual design and drafting methods and to promote standards, rather than to improve the process itself. Even with improvements in the technology, however, errors in design and drafting remain common. Taking the 2-D CAD technology further, the application of three-dimensional integrated parametric modeling of precast buildings at the assembly and piece levels may enable producers to greatly reduce design errors, resulting in significant improvements in project quality, cost, and schedule. An examination of a number of case studies of precast/prestressed concrete projects has revealed that the common causes of construction problems are design, detailing, and drafting errors, a lack of coordination between different disciplines, and inadequate management of changes. An analysis of the cases presented in this paper indicates that the application of 3-D top-down modeling and automated production of shop drawings holds the potential to eliminate most of the sources of error.