Rectangular Footing Dimensions to Develop the Plastic Moment Capacity of RC Bridge Columns

Abstract

This technical note presents charts that allow bridge engineers to quickly estimate the minimum footing dimensions, as controlled by the nominal (or ultimate) bearing capacity of the supporting soil, to develop the biaxial plastic moment capacity of corresponding columns. The design aids are applicable to rectangular, circular, and oval reinforced concrete (RC) columns with cross-sectional dimensions of up to 2.44 m (8 ft), longitudinal reinforcement ratios from 1 to 2%, transverse reinforcement ratios from .4 to 1.2%, concrete compressive strengths (fc′) from 28 (4) to 42 MPa (6 ksi), and axial load levels between .5 and .2fc′Ag.