This paper presents an experimental investigation into the bond behavior between basalt FRP (BFRP) sheet and concrete substrate under coupled effects of freeze-thaw cycling and sustained load. Specially designed double-lap shear specimens were exposed to up to 200 freeze-thaw cycles with sustained load. After exposure, the specimens were tested to failure. Digital Image Correlation (DIC) test method was applied to capture the full-field strain in the study. Nonlinear constitutive law of FRP-concrete interface was determined based on full-field deformation and strain analysis. Test results show that freeze-thaw cycling leads to significant decreases in load carrying capacity, ultimate slip, shear strength and increases in effective stress transfer length of FRP-concrete interface. Additional damage is generated when the load condition is taken into account during freeze-thaw cycling test. Moreover, apparent changes in failure mode were found with the increasing number of freeze-thaw cycles.

This paper investigates the design of fiber reinforced polymer (FRP) reinforced concrete based on ACI 440.1R serviceability requirements related to deflection control of one-way slabs and rectangular beams, and uses this information as the basis for evaluating the minimum member thickness requirements needed to satisfy ACI 318 deflection limits. Serviceability is shown to govern design in most cases, as flexural members designed for deflection control are usually stronger than required. Slabs satisfying deflection requirements have a service load that ranges from 20 to 30% of the nominal member capacity, while service loads for beams range from 35 to 45% of the member capacity. Recommended minimum member thickness values for slabs are too conservative and require revision, while those for beams appear reasonable. A practical approach for design of FRP reinforced concrete members is proposed based on selection of member thicknesses needed to satisfy deflection and strength criteria.

The flexural strength and deflection of high-strength concrete beams reinforced with multiple layers of reinforcement and combinations of different reinforcement types (steel, GFRP, and CFRP bars) were evaluated experimentally and analytically. Three beam specimens, reinforced with a single type of reinforcement, and three other specimens, reinforced with a combination of different types of reinforcement, were constructed and tested. An investigation was performed on the influence of hybrid reinforcing with multiple layers of steel or FRP flexural reinforcements on load-carrying capacity, post cracking stiffness, cracking pattern, and ductility. The low post cracking stiffness, high deflection, deep crack propagation, large crack width, and low ductility of FRP bar-reinforced beams were controlled and improved by hybrid reinforcing with steel bars. The test results were compared with the cracking and ultimate moment predictions of ACI Code, and with the service deflection predictions of ACI 440.1R-06 and Bischoff. In addition, alternative service deflection prediction models for hybrid reinforced concrete beams with multiple layers of steel or FRP bars were proposed based on the effective moment of inertia approach of ACI 440.1R-06 and Bischoff.

A pedestrian bridge in Albstadt, Germany showed immense corrosion damages of the steel reinforcement. The damages were so immense that the bridge had to be torn down due to a lack of load-bearing capacity and, therefore, replaced by a new bridge. The architectural design follows a slender construction principle, thus, by using the new composite material textile reinforced concrete (TRC) a slender concrete superstructure is achieved. By using non-corrosive textiles, concrete covers can be reduced to a minimum of only some millimetres and cross-sections are minimized. The paper describes the design, structural analysis, load-bearing behavior and production processes of a 97 m (3819 in.) long TRC pedestrian bridge. The whole construction is subdivided into six prefabricated parts, each offering a maximum length of L=17.20 m (677 in.) and a maximum span of Ls=15.05 m (593 in.). The cross-section, which is a T-beam, has a height of only H=0.435 m (17 in.) resulting in a slender bridge construction with a slenderness ratio of H:Ls = 1:35.

Debonding of fibre-reinforced polymer (FRP) composites externally bonded to reinforced concrete (RC) structural members can severely limit the effectiveness of the FRP strengthening. Anchorage of the FRP with anchors made from fibre sheets (i.e FRP anchors) is an effective means to increase its usable strain (and strength). This paper in turn reports the results of tests on one-way spanning RC slabs strengthened in flexure with FRP composites and anchored with FRP anchors. The tests reveal the strategic use of different types and positions of FRP anchors to increase the strength and deflection capacity of the strengthened slabs by up to 30 % and 110 %, respectively, above that of the unanchored but strengthened control slab. FRP anchors of greater strength placed closer to the peak bending moment region were found to be most beneficial in addition to closer spaced anchors of lesser fibre content in the low bending moment region.