Corrosion of conventional steel reinforcement is responsible for numerous structurally deficient bridges, which is a multi-billion-dollar challenge that creates a vicious cycle of maintenance, repair, and replacement of infrastructure. Repair of existing structures with fiber-reinforced polymer (FRP) has become widespread due to multiple advantages. Carbon FRP’s superior tensile strength and stiffness make it particularly effective in shear and flexural strengthening of reinforced concrete (RC) beams. This experimental study incorporates carbon fiber polymer composite bars and wraps to study and report on the flexural behavior of RC beams. By employing a combination of CFRP bar and wrap for strengthening RC beams, this study observed an approximate 95% improvement in flexural load capacity relative to control RC beams without strengthening. This substantial enhancement highlights the effectiveness of integrating CFRP in structural applications. Nevertheless, the key observation is the failure mode due to this combination providing significant insights into the changes facilitated by this combination approach.

This paper presents finite-element analyses and analytical models of innovative, small-scale, prototype deck panels examined under monotonic bending. The deck panels consisted of two glass fiber–reinforced polymer (GFRP) facesheets separated by webs formed from E-glass–woven fabric placed around trapezoidal-shaped, low-density, polyurethane foam segments. The proposed panel exhibited a higher structural performance in terms of flexural stiffness, strength, and shear stiffness than those of conventional sandwich panels. Analytical models were used to predict critical facesheet wrinkling in the sandwich panel. Furthermore, a three-dimensional model using simulation software was developed for analysis of the proposed panel system under monotonic four-point loading. The finite-element results in terms of strength, stiffness, and deflection were found to be in good agreement with those from the experimental results. A parametric study was also conducted to further evaluate the effects of the stiffness...

Polymer concrete (PC) is recognized for its lightweight nature, wear resistance, and rapid curing, making it well-suited for the repair of deteriorated infrastructure. This research critically addresses the challenge of enhancing overlay adhesion to compromised substrates by uniquely evaluating the role of pristine versus functionalized multi-walled carbon nanotubes (MWCNTs) in improving polymer concrete (PC) bond strength, particularly on concrete deteriorated by sulfate attack. PC mixtures containing varying concentrations of MWCNTs (0%, 0.25%, and 0.5% by weight) were prepared and tested for their mechanical properties, including compressive strength, modulus of rupture, and pull-off strength. Pull-off tests were conducted to assess the bond between PC overlays and Portland cement concrete (PCC) substrates. To examine the effects of substrate deterioration, PCC specimens were cured under two conditions: standard and sulfate-exposed environments. The results showed that neat polymer concrete (PC-Neat) achieved a high average pull-off strength of 2.82 MPa under normal conditions. Incorporating 0.25% pristine MWCNTs (PC-P25) significantly reduced the bond strength to 0.039 MPa. In contrast, improved performance was observed with functionalized MWCNTs. The addition of 0.5% COOH-functionalized MWCNTs (PC-FC50) yielded a pull-off strength of 2.22 MPa under normal conditions and 1.65 MPa in sulfate environments. Notably, under sulfate exposure, functionalized MWCNTs enhanced the bond strength by up to 15% compared to PC-Neat, highlighting their potential in aggressive environments. This distinct improvement in bond strength presents a significant finding, demonstrating a novel pathway for developing more resilient repair materials for infrastructure exposed to aggressive chemical environments.

Soil–steel composite bridges (SSCB) have become increasingly popular for short-span bridges as an alternative to concrete slab bridges mainly due to their low initial cost, rapid manufacture, simplified construction, and geometrical adaptability. SSCBs have a variety of applications and can be used over waterways or roadways. While conventional bridges tend to lose their load-carrying capacity due to degradation, SSCBs gain strength because of backfill soil consolidation. However, the load carrying capacity and integrity of such structures highly depends on the condition and load-carrying capacity of the steel arch element. A major drawback of SSCBs, especially those located on waterways or with poor drainage, is corrosion and subsequent loss of cross-sectional capacity. Unfortunately, the inspection of such bridges is not straightforward and any damage/collapse will be very costly to repair/replace. Fiber reinforced polymer (FRP) composites offer an attractive alternative to replace the steel in these types of bridges. FRP composites have significantly improved durability characteristics compared to steel, which will reduce maintenance costs and improve life-cycle costs (LLCs). This paper presents a new concept to use glass FRP as a construction material to construct soil–FRP composite bridges (SFCB). Various aspects of design and manufacturing are presented along with results and conclusions from a case study involving alternative bridge designs in steel and FRP composites.

One method of bridge construction consists of simply supported precast, prestressed concrete girders made continuous for live load through individual continuity joints connecting the two girder ends from adjacent spans. However, creep, shrinkage, and thermal effects can create large positive moments in the joints, leading to severe cracking and potential loss of moment transfer. A bridge in Fort Supply, Oklahoma, utilizing this type of connection was slated for joint replacement, and the Oklahoma DOT elected to use ultra-high-performance concrete (UHPC) for the replacement. To evaluate the effectiveness of the UHPC joint, a load test was conducted before and after joint replacement. The bridge was tested by systematically placing dump trucks filled with crushed stone at the midspan of each continuous span. Deflections were monitored for each test, and strains were monitored in two joints using strain gauges embedded in the UHPC joints during construction. While the measured deflections were small, the strain readings from the postrepair test showed that the UHPC joint was able to effectively provide continuity.

Aging infrastructure is increasingly costing taxpayers due to increased repair and replacement costs. Ultra-high performance concrete (UHPC) has recently been recognized as a viable material for both the repair of concrete and steel infrastructure as well as a replacement material for new structures due to its enhanced mechanical and durability properties. Such uses require a much better understanding of the multiaxial tensile properties of UHPC to utilize the material more efficiently. This study focused on developing a novel apparatus capable of subjecting specimens to tensile forces in each of the three principal directions simultaneously. Such an apparatus could collect data for a portion of the failure surface that currently only has a small dataset to establish trends. The “Looney Bin” was designed to test 50-mm cube specimens in triaxial tension, biaxial tension, tension-compression, and tension-tension-compression stress states. Once the apparatus and fixtures were designed and fabricated, trial tests were conducted on a non-proprietary UHPC without steel fibers to establish a test method for each of the stress states evaluated. Data were then collected for different stress states using the established procedures and plotted against previously published failure models for UHPC to verify that the collected data were reasonable.