International Concrete Abstracts Portal

This paper reports on the use of externally bonded fiber reinforced polymers (FRP) laminates and Near Surface Mounted FRP bars for the flexural strengthening of a concrete bridge. The bridge selected for this project is a three-span simply supported reinforced concrete slab with no transverse steel reinforcement, load posted and located on Martin Spring Outer Road in Phelps County, MO. The original construction combined with the presence of very rigid parapets caused the formation of a wide longitudinal crack which resulted in the slab to behave as two separate elements. In order to clarify the behavior of the structure, load tests were performed and a finite element method (FEM) analysis undertaken. The FRP strengthening was designed to avoid further cracking and such that the transverse flexural capacity be higher than the cracking moment. Both FRP techniques were easily implemented and showed satisfactory performance.

Since its inception in 1995, the ISIS Canada research network has developed design procedures and innovative techniques for the rehabilitation and repair of existing concrete structures using fiber reinforced polymer (FRP) materials. In co-operation with various industrial partners, ISIS Canada has conducted many field application projects, successfully transferring ISIS technology into practice in the field. This paper provides a review of four recent field applications in Western Canada, utilizing externally bonded FRP for the repair and strengthening of bridges. The projects include flexural strengthening of a bridge deck under lateral bending, shear strengthening of I-shaped AASHTO girders for two bridges, and the repair and strengthening of concrete corbels supporting a single girder pedestrian bridge. Some construction costs and the time required to complete each project are presented, as well as practical details specific to each application.

This paper presents eight field applications of an innovative composite pile in marine environments. The pile consists of a concrete-filled circular fiber-reinforced polymer (FRP) tube. No internal reinforcement was necessary in this system since the FRP tube acted as reinforcement in the axial and hoop directions, in addition to its function as a permanent formwork for the concrete. The field applications utilized the innovative piles in a variety of configurations including fender piles, dauphins, supports for marine structures and for bridge pier protection. In these applications, the pile is subjected to a variety of loading conditions including different levels of bending and axial compression loads. Prior to using the new piles in field installations, a large experimental program was initiated to examine the structural performance of the piles in bending, under axial loads and under combined bending and axial loads. The test results were used to verify analytical models, which were then used to develop simple design charts to be used by the designers. This paper describes the different field applications of the composite pile, a summary of the experimental program including test results, and the design charts.

Innovative pile foundations consisting of concrete-filled circular fibrereinforced polymer (FRP) tubes (CFFT) have increasingly been used for a variety of applications, mainly in marine environments. This paper presents a different application of CFFT in two bridges in the State of Virginia, the Route 40 and Route 351 bridges. Some of the piles in these bridges consisted of CFFT, which were projected above the ground level to function as piers for support of the superstructures of the bridges. The paper presents the results of full-scale field test programs carried out at the two bridge sites, before construction of the bridges, in order to compare the structural and geotechnical performance of the new CFFT composite piles to conventional prestressed concrete piles. Details of the construction and connection between the CFFT composite pile and RC cap beam are also presented. The Route 40 Bridge has been in service since 2000 and to date, no indications of unsatisfactory performance have been reported. The new Route 351 Bridge is expected to be finished and open for traffic in May 2003.

A new connector system and a new method for the construction of partially precast concrete sandwich panels are described. The new connectors are constructed using glass fiber reinforced polymer and are used to tie two precast concrete layers together through a layer of rigid extruded polystyrene insulation. In contrast to existing connector systems that incorporate steel lattice girders, the new system effectively eliminates thermal bridges and undesirable forced compatibility strains in the concrete layers. In addition to providing energy savings for the building owner, the new system and method can provide cost savings for the wall fabricator.