EVALUATION OF 2-CELL RC BOX CULVERTS

• Main Author: Sharifi, Hossein
• Format: Others
• Published: UKnowledge 2018
• Subjects: Reinforced Concrete; Box Culvert; Finite Element Method; Live Loads; Dead Loads; Fill Height; Civil Engineering; Structural Engineering
• Online Access: https://uknowledge.uky.edu/ce_etds/66; https://uknowledge.uky.edu/cgi/viewcontent.cgi?article=1068&context=ce_etds

Reinforced Concrete Box Culverts (RCBCs) are an integral part of the national and international transportation infrastructure. The National Bridge Inventory Standards (NBIS) requires that all bridges, which include culverts with spans ≥ 20 ft. (6.1 m), be load rated for safe load carrying capacity in accordance with the AASHTO Manual for Bridge Evaluation (MBE). In Kentucky, the Transportation Cabinet manages more than 15,500 bridges, of which almost 1,400 are bridge size culverts. Of the 1241 bridge size RCBCs that were being evaluated in Kentucky between 2015 and 2018, 846 were 2-cell culverts (or 68%). The objective in this study is to evaluate 2-cell RCBCs using the finite element (FE) method and to propose dead load and live load demand equations that can be used to determine the capacity demand ratio (C/D) and the load rating. The results indicate that the maximum dead load forces (positive and negative moments, and shear) vary linearly with respect to an increase in fill height, while the variation is bi-linear for the maximum live load forces. The proposed equations are derived in terms of the clear span and fill height. The results also indicated that, for fill heights greater than 10 ft (3 m), the maximum live load positive bending moments are less than 10% of their dead load counterparts. The primary advantage of the proposed equations lies in their simple formulation when analyzing and designing 2-cell culverts, which in turn alleviates the need to conduct a detailed finite element analysis to determine the maximum forces in 2-cell RCBCs.