Methods of Construction of Drilled Shafts and Critical Errors in Design and Construction

摘要

A review of methods of construction for drilled shafts and common critical errors made in design and construction are presented. The general topics are issues related to designing for ease of constructability, reinforced concrete design, designing for axial loading, designing for lateral loading, and construction specifications. Issues discussed for designing for constructability include understanding of the construction processes by the design engineer, proper sizing of the foundation, compatibility of concrete mix design and reinforcing steel detailing, and plans and specifications of good quality. Subjects discussed for designing for axial loading are the information required to complete a complete design and utilization of bearing graphs to identify economic foundation dimensions. Areas discussed for designing for lateral loading include a suggested design strategy for lateral loading, a discussion of the effects of eccentricity due to permissible variation in shaft location. Issues discussed for reinforced concrete design are how number of longitudinal bars affect moment capacity in different directions of loading, use of cracked section analyses to evaluate nonlinear bending stiffness, and when shear capacity might control the section design. Additional topics discussed are use of inadequate data from geotechnical soil investigations, performance of design computations by individuals without proper training and education, poor quality inspection, and lack of comprehensive reviews of final designs.