摘要: |
Precast/prestressed concrete girders are widely used in bridge construction in Nebraska. Occasionally, girders are subjected to damage due to different reasons, such as accidental collision of over-height vehicle/equipment, incidental damage during abutment/deck replacement, malfunctioning of supports/joints, and/or corrosion of reinforcing steel/strands.
The current Nebraska Department of Transportation (NDOT) Bridge Office Policies and Procedures (BOPP) document provides limited information regarding the assessment and repair procedures for damaged precast/prestressed concrete girders. Specifically, general standard notes provide for concrete rehabilitation and repair in Section 2.3.4. On the other hand, several other transportation agencies in USA and Canada have developed repair manuals/special provisions for the repair of damaged concrete components with a particular focus of girders.
In addition, several studies sponsored by National Cooperative Highway Research Program (NCHRP) and State Departments of Transportation (DOTs) evaluated the effectiveness of different repair and retrofit techniques, such as carbon-fiber reinforced polymers (CFRP), ultra-high performance concrete (UHPC), external post-tensioning, and strand splicing. These techniques continuously evolve and new ones are developed.
The main project objective is to develop a comprehensive repair manual for NDOT precast/prestressed concrete girders subjected to various types of damage as well as provide repair alternatives and a methodology for selecting concrete girder repair that enables NDOT and contractor to make timely and cost-effective repair decisions. |