This paper presents a unique approach to examine the performance of constructed concrete bridges in cold regions, based on a combined statistical analysis and geographic information system (GIS) method. A total of 3,013 bridges and 1,126 bridge decks selected from the State of North Dakota (one of the coldest regions in the United States) are analyzed. Detailed technical information of the examined bridges is obtained from the National Bridge Inventory (NBI) database constructed between 2006 and 2007. A statistical analysis is conducted to identify the critical sources of bridge deterioration in cold regions, in particular concrete bridges, using the ordinary least-square multiple regression method. The performance of concrete bridges under cold weather is in general satisfactory, while the deck slabs are the critical structural members and may require regular maintenance and repair. The contribution of the year-built and the presence of water are the most critical factors to the bridge deterioration. A case study is presented based on a 29-span bridge consisting of cast-in-place deck slabs supported by prestressed concrete and steel plate girders. Detailed inspection results are reported and adequate maintenance methods are discussed.

The paper deals with a rehabilitation case study on a pre-stressed concrete (PC) bridge (named “Torrente Casale”), located in the south of Italy (on the Salerno-Reggio Calabria highway). The bridge, built in the ’70s, was enlarged in 2001 in order to satisfy the new traffic demand. A seismic assessment of the bridge resulted necessary in order to verify its capacity to sustain both gravity and seismic loads. Both destructive and non-destructive tests have been performed in order to evaluate concrete and steel reinforcement mechanical properties. A theoretical analysis was performed, showing that the bridge piers existing cross section and internal reinforcement were not adequate to satisfy the seismic actions. Thus, two rehabilitation systems were investigated: a) an innovative technique based on the combined use of Fibre Reinforced Polymer laminates (FRP) and Steel Reinforced Polymer spikes (SRP), b) a traditional rehabilitation technique (i.e. RC jacketing). The design assumptions and calculations for the rehabilitation as well as the comparison between the effectiveness of the two investigated strategies are presented and discussed in the paper. The main construction phases of the strengthening technique, executed by following the first outlined strategy are also presented and illustrated.

Recently, the non-corrodible fibre reinforced polymer (FRP) reinforcing bars, especially glass FRP bars, have been increasingly used in concrete bridge deck slabs. Although corrosion of steel reinforcement in a major cause of a bridge deterioration, almost every bridge component requires some kind of repair/rehabilitation due to various kinds of damage or changed circumstances such as freeze-thaw and wet-dry damage, accidental (vehicle) damage, excessive cracking, poor design details, poor quality construction, inadequate maintenance, changes in level of service, etc. Therefore, there have been concerns regarding the feasibility and economics of repairing concrete elements reinforced with FRP materials. This paper presents an experimental study on the rehabilitation of concrete bridge deck slabs reinforced with GFRP internal reinforcement. The main objectives of this study are to (1) determine the most suitable concrete demolition method causing minimal or no damage to GFRP bars used as main reinforcement in concrete slabs; (2) evaluate the most effective repair technique by verifying the flexural strength and load-transfer efficiency of concrete slabs after repair. To fulfil these objectives, 16 full-scale concrete slabs (1500×2250×200 mm) totally reinforced with GFRP bars were constructed and tested in the laboratory. The test parameters include concrete demolition technique, type of GFRP bars, concrete compressive strength, number of reinforcement layers, thickness of concrete cover, and repair technique. It is concluded that GFRP-reinforced deck slabs can be easily and effectively repaired.

This CD-ROM contains twelve papers that were presented at sessions sponsored by ACI Committee 345 at the ACI Spring 2010 Convention in Chicago, IL. The papers contain information relating to the current technology for concrete bridge repair and maintenance. The papers discussed case studies of damage and corresponding repair, state-of-the-art repair technologies, evaluation and inspection techniques, and maintenance of existing concrete bridges. Note: The individual papers are also available. Please click on the following link to view the papers available, or call 248.848.3800 to order. SP-277

The Texas Department of Transportation (TxDOT) maintains over 33,000 on-system bridges. A considerable number of these bridges are damaged each year by extreme events or structural deterioration and must be repaired rapidly. Externally bonded carbon fiber reinforced polymer (CFRP) composites provide TxDOT with a viable technique for repairing many damaged concrete bridges. CFRP has been used extensively as structural reinforcement for its exceptional engineering properties, simplicity, flexibility, and rapid placement. TxDOT began using CFRP in 1999 and has repaired more than 30 impact-damaged concrete bridges, resulting in considerable time and money savings. This paper summarizes TxDOT’s experience repairing concrete bridges damaged by impact, fire, corrosion, and alkali-silica reaction (ASR), focusing on damage assessment, determination of reparability, and procedures essential for effectiveness. TxDOT engineers have made a conscious effort to utilize CFRP materials to repair impact-damaged beams. CFRP has been used to supplement prestressed strands to restore flexural capacity, laterally ‘harden’ bottom flanges against damage from re-impacts, and enhance the ductility, shear strength, and integrity of concrete bridge beams. For repeatedly impact damaged beams, CFRP has been used as ‘sacrificial’ reinforcement to protect the primary reinforcement, the prestressed strands, and to increase survivability, thus preserving the structure. Recommendations regarding the effectiveness of such CFRP repairs are presented.