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Abstract

Glass Fiber Reinforced Polymer (GFRP) composites have low permeability and high corrosion resistance. In recent years, as the use of GFRP in applications requiring high corrosion resistance has gradually expanded, its long-term performance in highly corrosive environments has caught public attention worldwide. Nevertheless, there is only limited theoretical research and accumulated test data on the corrosion resistance of GFRP. This paper analyses the long-term performance of GFRP in highly corrosive environments. Samples cut from pultruded GFRP profiles were exposed to alkaline, saline, and acidic solutions of different concentrations at 60°C. Additionally, the effects of acidic solutions at high temperature (90°C) were investigated. Flexural properties, changes in the flexural fracture mechanism, hardness, the rate of weight gain, changes in appearance, and scanning electron microscopy (SEM) images of fracture sections were analyzed over periods of 7, 15, 30 and 90days. Results indicate that flexural strength decreases with increased exposure time to both acidic and alkaline solutions. Under conditions of high concentration acidity and high temperature acidity, respectively, flexural strength decreases even more drastically. Additionally, it was found that saturated NaCl solution has little effect on GFRP.

Abstract

This study considers 4 experimental raw data and a survery of dataset. Stress-strain relationships of A1 and A2, R1 python file for distribution radar chart of Taguchi as a different variable data, and moment-curvature relationship of A1 were obtained. For the current study the fifth data of S1 was taken from a survey dataset of 500 responses. It is explained how the experimentally obtained raw data, code file of python and survery dataset are uploaded to the RDL platform.

Abstract

Earthquakes of magnitude Mw = 7.7 and Mw = 7.6 hit the city of Kahramanmaraş (Turkey) on 6 February 2023. These earthquakes caused serious damage in 11 provinces in Turkey resulting in over 50,000 deaths and huge economic losses with the collapse of thousands of buildings. Two consecutive devastating earthquakes have severely damaged the reinforced concrete building stock located in Malatya. There are many reasons reinforced concrete structures suffer damage under the influence of seismic loads. These reasons can be listed as material and section properties that do not comply with earthquake codes, workmanship defects, ground parameters that are not considered and design errors, as seen in field investigations after earthquakes in Turkey in the past. In this research, a field study was conducted on reinforced concrete buildings damaged after the earthquakes in Malatya province. The causes of structural damages in reinforced concrete buildings between 6–26 years of age were assessed in terms of design and material defects. The structural damages were mainly caused due to insufficient stirrups in structural members, short column, strong beam–weak column, failures of infill walls, soft story type collapse, poor concrete quality, and reinforcement corrosion. In addition to the field investigation, the spectrum relationships created using raw acceleration data obtained from DEMP (Disaster and Emergency Management Presidency) stations in Malatya province were compared with the design response spectra.

Abstract

This study aimed to investigate the precast reinforced concrete beam-to-column joints behaviors through the replaceable damper under cyclic loading. The precast concrete specimens have been embedded with steel reinforcement and specially shaped connectors. After the application of the replaceable damper under cyclic loading, the energy dissipation shaped very well and increased the bearing capacity of precast specimens. The precast concrete beam–to–column joints were designed and analyzed to compare with the traditional reinforced concrete (RC) specimen. The analysis result of the loading based on the controlled displacement method showed that the precast specimen model with a damper has more hysterical behavior than the traditional RC frame. Also, the specimen (PS-1) is passed the 2.7% chord rotation, which showed higher performance, than the traditional RC specimen. The efficiency of the PS-1 specimen with a special connection has been elaborated with the finite element method (FEM) and simulated by ABAQUS software.

Abstract

Mobile bridges are primarily to make span-crossing and form traffic path flexibly and rapidly. FRP (Fiber-reinforced polymer composite) is suitable for the construction of mobile bridge as its advantages of light-weight and high-strength. In this paper, the ANSYS optimization module is used to optimize the linear of the FRP bridge, in order to lose the weight of the bridge.

Abstract

Filament-wound fibre-reinforced polymer (FRP) tubes are an emerging FRP product employed in various FRP-concrete composite structures, such as concrete-filled FRP tubes (CFFTs). Due to the fibre orientations in the tube wall, the filament-wound FRP tube exhibits biaxial behaviour under simultaneous axial compression and hoop expansion, causing relaxation of the confining stress. Therefore, the conventional hoop tension test may result in overestimation of the confining stiffness. In this paper, the biaxial behaviour of FRP tubes is theoretically investigated using classical laminate theory in conjunction with an analysis-oriented model for FRP-confined concrete. The geometrical meaning of the biaxial tube behaviour is interpreted intuitively using the 3D geometrical approach previously proposed by the authors. For the convenience of analysis and design, this paper proposes a simplified approach to rectify the confining stiffness that considers both elastic and nonlinear biaxial effects. The predicted results show good agreement with the collected test data.

Abstract

The utilization of coral aggregate concrete (CAC) in marine construction has drawn the attention of engineers and researchers in recent years. Due to the high content of chloride in CAC induced by coral aggregates and sea water, reinforcing CAC with traditional material, i.e., steel, can cause serious corrosion-related durability problems. Replacing steel with corrosion-resistant fiber-reinforced polymer (FRP) has been considered a promising solution. This paper provides insight into the bond behavior between CAC and FRP bars. In total 30 pull-out tests were conducted. The investigated variables included the concrete matrix, FRP bar type, bar diameter, and thickness of concrete cover. Based on the test results, discussions on the bond failure modes, influencing factors of bond strength and bond stress-slip relationship were presented. For splitting failure mode and pullout failure mode, empirical bond stress-slip models were proposed respectively. Adopting the failure criterion of CAC proposed in a previous study, a mechanical model for bond strength under pullout failure mode was developed. Comparisons with test results validated that the proposed models provide reasonable predictions for the bond properties between GFRP bars and CAC.

Abstract

A semi-analytical procedure is presented for predicting the complete flexural response of partially interacting steel–concrete composite beams up to failure. The governing equation of the Euler–Bernoulli beam theory is solved wherein concrete, steel and the shear connectors joining the concrete slab to the steel beam are assumed to have nonlinear stress-deformation relationships. The adopted constitutive relationship for the connectors allows for partial or full composite action. The solution is applicable to beams and one-way slabs subjected to concentrated or uniform load and/or their combination. The governing equation is numerically solved by satisfying the equilibrium and compatibility requirements along the member. For the reinforced concrete part of the composite beam, a nonlinear moment–curvature relationship is developed that accounts for concrete nonlinearity in compression and for cracking and tension-stiffening in tension as well as for steel reinforcement nonlinearity. The steel profile is assumed to have a bilinear elasto–plastic strain-hardening moment–curvature relationship. Comparison of the proposed model results with the corresponding experimental load–deflection curves and interfacial shear–slip curves of several beams tested by others shows good agreement. The relative simplicity, efficiency and easy application of the present solution make it possible to accurately predict the failure load, interfacial slip and full nonlinear response of partially interacting composite beams.

Abstract

This study develops empirical models for the prediction of the bond strength of uncorroded and corroded reinforcement bars. The effects of hooked reinforcement on the bar’s development length when covered fully and partially are examined. An accelerated corrosion method is used to corrode the reinforcement bars embedded in concrete specimens. Pull-out tests are performed to investigate the ultimate bond strength of the concrete specimens. The effects of two different geometries of reinforcement bars are discussed by considering two different concrete strength levels and concrete cover depths. It is found that partly covered hooked reinforcement bars increase the radial stress on the concrete surface and reduce the bond strength. Increases in the bond strength due to the increased roughness of the steel bar caused by the confined corrosion products are less for hooked bars. The results reveal that the developed models show good relationships with the experimentally computed test results.

Abstract

To perform accurate seismic analyses of corroded reinforced concrete (RC) buildings, it is necessary to predict the bond-slip relationships to modify the moment-curvature relationships. In this study, empirical models were developed to predict the bond strength of corroded RC columns. Twenty-five RC columns were tested under combined cyclic lateral displacement excursions for three concrete strength levels—specifically, 9, 27, and 37 MPa (1305, 3915, and 5365 psi, respectively)—at two axial load ratios of 0.20 and 0.40 and at four corrosion levels. An accelerated corrosion method was applied to corrode the reinforcing bars embedded in the RC columns. The actual corrosion levels were determined by breaking the concrete and extracting all the longitudinal and transverse reinforcing bars from the RC columns. Three empirical models were developed. The first model was used to predict the development length of the corroded reinforcing bars. The second and third models were used to predict the bond strength and slip in the reinforcing bars as a function of the corrosion levels. The results indicated that previous models that predict the bond strength of corroded RC members were limited because of the theoretically considered development length of the noncorroded reinforcing bars.

Abstract

For the past few decades, there has been an increase in awareness regarding the safety of highway bridges from blast loads. Since abutments/Retaining walls (RWs) are portions of bridges, investigating abutments/RW or RW behaviour under blast loads is important. As there have not been any studies investigating the dynamic response of retaining walls due to blast loading, an experimental study was conducted to examine the influence of blast loads on the dynamic behaviour of reinforced concrete retaining wall (RCRW) with sand as a backfill material. A shock tube was used to generate blast loads on the soil-RW model. The influence of the relative density, backfill saturation, blast load intensity, and traffic load equivalent surcharge on the blast behaviour of RCRW with sand backfill was studied. The results showed that the modes of wall movement were affected by the backfill relative density, blast load intensities, and degree of saturation. Under the same load conditions, an increase in the wall movement was noticed in loose backfill, and a translation response mode was evident in this condition. A relationship between wall relative movements and mobilized earth pressure coefficients was determined. The mobilized passive resistance of the RW backfill induced by blast load was used to determine the force–displacement relationship. Acceleration time histories for RW/backfill were found for all conditions. The findings of this research will help to properly evaluate and design bridges’ abutment and to develop resilient transportation infrastructure systems.

Abstract

Although most of the earthquake codes and engineers do not consider the effect of infilled walls on seismic performance levels of reinforced concrete buildings, infilled walls have remarkable effects during earthquakes. They mainly effect the initial stiffness and thus roof drift ratios of buildings. The aim of the present study was to examine the effect of scaled infilled wall frames on seismic performance levels of reinforced concrete buildings. An experimental study was performed to compare the different designed infilled wall systems. Three frames were tested under lateral loading by considering the impact of bond-slip relationships for different scenarios as frames without infilled walls, frames with infilled walls having anchor bars and frames with infilled walls not having anchor bars. Failure patterns for each frame was presented. The contribution of slippage of reinforcement bars to the total lateral displacement for three frames were evaluated as an indirect bond-slip relationship. It is believed that obtained results in this study would provide a guideline for the reinforced concrete buildings in seismic prone area.