Transverse Design of Adjacent Precast Prestressed Concrete Box Girder Bridges

Transverse post-tensioning design and detailing of precast, prestressed concrete adjacent-box-girder bridges

“…Manual 21 method was developed by El-Remaily et al 6 and is reported in section 8.9 of the manual. In this method, the post-tensioning force required to achieve adequate stiffness in the transverse direction to keep differential deflection within the acceptable limit (0.02 in.…”

“…4 and Table 1, assuming mild skew angles (that is, less than 15 deg), average span lengths, and AASHTO HS-25 truck loading with impact. 6 New charts need to be developed to accommodate the cases of highly skewed bridges with different span lengths and using the AASHTO LRFD specifications truck and lane loads in addition to dynamic load allowance. 20…”

“…This is based on the assumption that both shear and flexure forces must be transversely transferred at the joints between adjacent members to control both translational and rotational deformations. 6 In Japan, adjacent box girders are designed using sections and design criteria similar to those used in the United States. However, longitudinal joints are detailed differently and transverse post-tensioning is significantly higher.…”

“…Using the Japanese practice, longitudinal cracking and concrete deterioration has rarely been reported. El-Remaily et al 6 give details of the posttensioning arrangement and joint dimensions used.…”

Adjacent box girders without internal diaphragms or post-tensioned joints

“…The Precast Prestressed Concrete Bridge Design Manual 3 presents charts for determining the required post-tensioning force to achieve adequate stiffness in the transverse direction for adjacent box girders. El-Remaily et al 4 developed these charts assuming that post-tensioned transverse diaphragms are the primary mechanism for the distribution of wheel loads across the bridge and the differential deflection limit between adjacent boxes is 0.02 in. (0.5 mm).…”