Title:
Design Example of Bridge Pier Cap Beam Considering Torsional Effect
Author(s):
Yang Yang, Ruili He, and Lesley Sneed
Publication:
Symposium Paper
Volume:
344
Issue:
Appears on pages(s):
131-148
Keywords:
bridge pier cap, flexure, shear, torsion, reinforcement design, AASHTO LRFD BDS, ACI 318
DOI:
10.14359/51728294
Date:
10/1/2020
Abstract:
A bridge pier cap beam supporting girders of two unequal spans was designed per AASTHTO LRFD
Bridge Design Specifications (AASHTO LRFD BDS-17) and the ACI 318 Building Code Requirements for
Structural Concrete (ACI 318-19) with consideration of torsional effect. Envelopes of bending moment, shear, and
torsional moment are given in the problem statement as the result of a comprehensive structural analysis on the
bridge. Flexural design is presented firstly based on the bending moment envelope to determine the required area of
longitudinal reinforcement. Then shear and torsion design is presented to determine the required area of transverse
reinforcement and additional longitudinal reinforcement. Based on the design calculations, the arrangement of
reinforcement is illustrated in a cross-section view for the cap beam. Comparison between the two approaches is
also included in terms of the equations used and areas of shear and torsion reinforcement determined.