This paper presents on-site inspection techniques to examine a damaged prestressed concrete girder bridge. The bridge is 18.3 m [60 ft.] and consists of double-tee beams (DT3000 x 700 ) with a 50 mm [2 in.] topping concrete. To simulate the effect of deterioration for the girder, the leg member is intentionally damaged by cutting 2 prestressing strands. A load test is conducted to evaluate the flexural behavior of the bridge before and after the damage. A site inspection is conducted after 10 months of the load test. The inspection techniques used for this study includes the visual inspection, pull-off test, ultrasonic test, rebound hammer test, core test, and surveying. The bridge exhibits significant cracks and spalling of the concrete in the deck and the legs. Corrosion of the reinforcing steels is observed. The pull-off test shows that the bond strength between the flange of the girder and the topping concrete is adequate. The ultrasonic test exhibits some internal defects of the leg member, including an increased transmission time of the ultrasound. The in-situ concrete strength measured is reasonably close to the specified 28 day concrete strength, based on the rebound hammer test and the core test, with an average error of 2.1%. Permanent downward deflections are not observed, whereas a maximum camber of approximately 35 mm [1.4 in.] is measured by surveying. The inspection techniques reported in this study are reliable and recommended to examine concrete bridge elements.

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.

During the last decade, the Swedish Road Administration (SRA) has transferred resources from corrective to preventive bridge maintenance. Presently, 10 to 15 percent of the budget is devoted to preventive maintenance whereas corrective maintenance, repair, and reconstruction comprise the remaining 85 to 90 percent. This reallocation has resulted in considerable efficiency gains but further savings are likely to be large. Preventive maintenance aims at measures to maintain the function of the bridge structure. Frequent measures include water washing, cleaning, vegetation removal, crack repair, material refill, and stretching of bridge railings. SRA has defined a series of technical requirements to harmonize the preventive bridge maintenance. Several technical requirements state that a structural element or element part “should be 95 percent clean”. SRA has also developed methods to verify that the technical requirements are fulfilled. However, the scientific basis for the relationship between the technical requirements and the function of the bridge structure is unknown or weak. The verification methods are not always unquestionable. The paper contains a critical review of the technical demands for preventive bridge maintenance in Sweden. Do they adequately promote durability and long-lasting service life? Are the prescribed requirement levels appropriate? Could the technical requirements be replaced by other and better requirements? How do they look like in an international comparison? There is a general belief that performance-specified contracts would be more cost-effective than other contract types. Do the Swedish demands facilitate or obstruct performance-specified contracts for bridge maintenance? The questions are discussed in the paper that also contains a summary of a Swedish pilot study conducted at the Swedish Cement and Concrete Research Institute.

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.

This paper presents a field application on the use of Fiber Reinforced Polymers (FRP) to repair a corrosion-damaged reinforced concrete (RC) girder. Concrete surface rehabilitation and Carbon FRP (CFRP) repair was undertaken on a 9.75 m (32 ft) long section of the 22.86 m (75 ft) long girder at the south span of the Scheifele Bridge, in the Regional Municipality of Waterloo, Ontario. Four different repair schemes were utilized along the length of the girder. The different steps of the rehabilitation work are described including surface preparation, application of the CFRP sheets, and installation of sensors as part of the structural health monitoring system. The sensors comprised of electrical strain gauges, corrosion probes and fiber optic sensors placed at critical locations along the bridge girder. Visual inspection and analysis of the data gathered over the last four years showed that the FRP repair system was able to halt the existing corrosion activity and protect the structural integrity, thus prolonging the bridge service life.