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Although Friberg's theoretical analysis is frequently used to analyse the dowel bar-concrete interaction in jointed plain concrete pavement (JPCP) system, the compressive stress concentration at top and bottom of the dowel slot cannot be explained with this theory. In this paper, two modifications including the elastic deformation of concrete support and the stress distribution factor considering the sinusoidal contact stress distribution are proposed to improve the Friberg's theoretical analysis. Modifications are then validated against elastic finite element analysis (FEA) results in terms of the contact stress distribution, the maximum compressive stress as well as the range of compression zone. To further investigate the maximum compressive stress at the joint surface, relevant parameters including the dowel bar diameter, the modulus of elasticity of concrete as well as the joint width are studied through elastic finite element analysis (FEA). Apart from proposing referenced moduli of dowel support, a close relationship between the modified modulus of dowel support and dowel bar diameter is also found and verified. Finally, differences between the Friberg's theoretical analysis and the modified method are summarised in a flow chart at the end of the paper. [ABSTRACT FROM AUTHOR]

During the past decade damage avoidance initiatives have attracted considerable attention among researchers and earthquake engineers. The paper proposes a Disc Spring Damage Avoidance Device which can practically be implemented in slotted beam connections. It comprises two distinct components for self-centering and energy dissipation. The components are tested under cyclic loading and the device performance in slotted concrete joints is validated using previous experimental and analytical results. Variation in system parameters is investigated using an improved analytical model. The results show that the device can mitigate the residual displacements down to zero while maintaining a reasonable level of energy dissipation. [ABSTRACT FROM AUTHOR]

Traffic loading is considered one of the main factors contributing to pavement deterioration. Large illegal loads in the form of vehicles traveling with axle loads above the permissible legal limits and/or overall overweight magnify the traffic impact on the performance of pavements. These overloads contribute to the deterioration of pavement sections which leads to substantial maintenance and repair costs. This paper illustrates an example of an approach to determine the effect of both normal and overweight loads on the performance of rigid pavements using the Long-Term Pavement Performance (LTPP) traffic data. The traffic load was evaluated by estimating the legal and illegal ESALs related to both fatigue and erosion damage by visual observation and by field-assessment of the degree of bonding based using the Falling Weight Deflectometer (FWD). The illustrated example utilized LTPP data from nine Jointed Plain Concrete (JPC) pavement sites with different traffic mixes. This study reveals that the damage in JPC pavements could be either (i) visible by the formation of transverse cracking as would be related to fatigue related ESALs or/and (ii) invisible by the reduction of the effective thickness as would be related to erosion ESALs. [ABSTRACT FROM AUTHOR]

In this study, a high-strength bolted prefabricated concrete beam-column junction is presented, and the prefabricated concrete beam-column joint parts are put through eight quasi-static tests. The axial compression ratio and the steel plate hoop thickness were used in extended parameter research using finite element software to completely examine the seismic performance of the construction. According to the findings, this node's ductility coefficient ranges from 2.57 to 3.69, which is bigger than 3. The specimen loses part of its bearing capacity and constantly loses ductility as the axial compression ratio rises. The failure displacement of the specimen decreases with an increasing axial compression ratio, but the yield displacement of the specimen is very slightly affected by the axial compression ratio. This node has an excellent energy dissipation capacity despite having a low viscous damping coefficient between 0.2 and 0.4, and when the axial pressure ratio rises, the capacity grows in response to the elevated pressure. Despite this, the energy consumption of the beam-column member is not significantly affected by the steel plate hoop thickness. Additionally, according to the variable-angle truss-arch model and taking into account the representation of the truss-arch model under different conditions, this paper presents the equation for the shear load capacity of diagonal sections of prestressed high-strength spiral hoop-restrained concrete beams under various conditions. [ABSTRACT FROM AUTHOR]

As a result of the advantages of the steel fiber reinforced concrete pavement structure, which includes high strength, high stiffness, and high stability, a large number of steel fiber concrete pavements will be used for highway construction in China. As a result, numerous cracks develop, which significantly reduces the life of the road; therefore, the study of the jointing problem is vital. As concrete research on the influence of the load transfer capacity and service life of prefabricated steel fiber reinforced concrete joints on the structural design and use function of the whole and pavement panels, the paper proposes two joint forms, tongue-and-groove and overlap. Using experiments and software, the stress and reflection of prefabricated road panels of the two joint forms are analyzed for different axial loads. The analysis reveals that the maximum tensile stress, shear stress, and deflection of the precast panels of both joint forms increase linearly as the axle load of the vehicle increases, while the service life decreases relatively. The load transfer capacity is independent of the axle load magnitude, and the load transfer capacity difference between the two types of joints is minimal and excellent. [ABSTRACT FROM AUTHOR]

This paper investigates the failure behavior of reinforced concrete beam - column joints (BCJs) strengthened with different schemes of carbon fiber reinforced polymer (CFRP) and the factors causing fracture. In the study, five reinforced concrete BCJ specimens having 1/1 geometric scale were tested under reversed-cyclic lateral loading. While one of them was used as a reference, the others were strengthened with CFRP. Damage development of the specimens was simultaneously monitored by the acoustic emission (AE) technique. Both the structural and AE data were combined to reveal the effects of CFRP strengthening schemes on the fracture pattern ana damage progress. Quantities, scales, levels, and locations of the damage show that the scale of the damage decreased with all strengthening procedures and that the strength and other mechanical properties improved. In addition, extending the strengthening material to the columns and beams contributed more to the structural behavior in terms of strength, energy dissipation capacity and rigidity as well as crack development. Although strengthening by wrapping only the beam and column extensions of the joint can give the desired performance in terms of load bearing capacity, it is not recommended owing to an increased risk of major shear cracks. [ABSTRACT FROM AUTHOR]

This paper aims to present a numerical nonlinear spring model able to simulate the cyclic behavior of the monolithic and the precast bolted reinforced concrete beam-column connections with the consideration of the concrete interface friction and the dowel action of reinforcing steel bars. The accuracy of this proposed model was verified by the comparison with some existing experimental test results. Generally, these comparisons showed good agreement and the model could simulate the cyclic performance of the tested specimens. Also, a study of the effect of increasing the area of shear reinforcement at the shear key zone was performed and discussed. [ABSTRACT FROM AUTHOR]

Whilst there has been research about reduced web section beams; RWS, their seismic behaviour when they are overlaid by slabs is not well understood. This study addresses this by assessing a high-definition finite element representation of non-seismically detailed RWS connections with slabs. The composite action is investigated, focusing on effects of the size and location of the web openings. These connections can reach a 4% interstorey drift, thus comprising special moment frames in accordance with AISC 341. Moreover, beam, column, and joint tearing were avoided entirely, and at the most, brittle failure of bolts in the end plate was observed. [ABSTRACT FROM AUTHOR]

Adhesive bonding is widely accepted as one of the most efficient and practical techniques for joining fiber-reinforced polymer (FRP) adherends. Additionally, configuration of such adherends with a core material into a sandwich composite produces structural elements with superior flexural stiffness and strength. While several studies have investigated the performance of bonded joints of FRP adherends, investigations into characterization of bonded joints in sandwich composites are limited. In this paper, the results from a comprehensive experimental investigation into the fracture toughness of adhesively bonded joints, with particular emphasis on the performance of adhesive joints between sandwich beams are presented. Experimental results showed no significant dependency between the adhesive fracture toughness and the adhesive layer thickness, while the analytical and finite element results indicated that the adhesive layer properties would influence the strain energy release rate and the ratio between modes I and II in mixed-mode. [ABSTRACT FROM AUTHOR]

Acoustic Emission (AE) is a non-destructive Structural Health Monitoring (SHM) technique used to detect the presence and movement of defects in reinforced concrete structures. Various AE based techniques help to identify the occurrence of damage, but there is a need to develop a mechanism for the evaluation of damage index based on AE parameters. This study investigates the ability of AE energy parameters to detect damage to a reinforced concrete (RC) beam-column joint (BCJ). An experimental study has been conducted to test BCJ under cyclic load, and damage progression has been monitored using AE parameters. The results showed a significant increase in energy dissipated and AE energy when a BCJ is reinforced with ductile detailing. Further, a relationship has been developed between energy dissipated and AE energy to determine the damage index. A novel damage index based on AE energy has been developed for reinforced concrete beam-column joints. [ABSTRACT FROM AUTHOR]

A rapid and reliable method to detect the activation of contraction joint cracks is needed to assess the effectiveness of sawcut depth and timing on new concrete pavements and for forensic investigation. A one-sided ultrasonic measurement technique is presented that detects the existence of a contraction joint crack, which is not visible from the concrete slab surface. A multi-sensor ultrasonic array device is used to generate and receive ultrasonic shear waves (S-wave) across the inspected joint. The acquired time-domain signals are used to calculate a newly defined feature, called normalised transmission energy (NTE), across the joint. A laboratory experiment investigated the proposed technique on three 500 × 500 × 150 mm3 concrete specimens with 38 mm notch depth, the first without a propagated crack, the second with a narrow width crack, and the third specimen with a full-depth open crack. The laboratory results demonstrate that the NTE technique can identify the existence or not of a crack beneath the notch. Finally, the NTE technique coupled with a 2D decision boundary equation was field validated on 152 concrete pavement contraction joints with various slab thickness (e.g. 102 to 152 mm) and notch depths (less than 38 mm) from multiple projects in Illinois and Iowa (USA). [ABSTRACT FROM AUTHOR]

The moment frames that consisted of prefabricated concrete beams and columns, which were linked by the unbonded post-tensioning, have been proposed for multi-story buildings. However, their lower structural strength and stiffness limited the applicability of their systems in the earthquake-prone areas. Curved steel braces were proposed in this study to improve the structural performance of the post-tensioned precast reinforced concrete (RC) beam-column joints, along with four joint specimens consisting of braces with different cross section height and eccentricity were tested under the reversed cyclic loads while the parametric analysis was also carried out using the finite element analysis (FEA) model. Also, the failure mode, strength, stiffness, and energy dissipation were analyzed. Based on the results, the whole joints have a stable mechanical behavior with an inter-story displacement angle of 5%, concrete crushing at the end of the beam, and a bending yield of curved braces form the failure mode. The curved steel braces could provide good strength, stiffness, and energy dissipation for the precast joints and these features of the joints could gradually increase with the expansion of the brace section height and the reduction of the brace eccentricity. The equivalent viscous damping coefficient at 4% inter-story displacement angle ranged from 0.12 to 0.2, which was two to three times higher than the general post-tensioned precast RC joints. When the eccentricity of the curved steel brace was less than 0.3, the joint strength was greatly impacted by the eccentricity and changed a bit when it was greater than 0.3. The results showed the practical feasibility of the post-tensioned frames with curved steel braces. [ABSTRACT FROM AUTHOR]

The choice between continuously reinforced concrete pavement(CRCP) and jointed concrete pavement(JCP) for different concrete pavement applications has long been controversial. Research on these two types of pavement has been conducted continuously for decades, but existing studies have mostly focused on life cycle costs (LCCs) with numerous assumptions or have predicted life expectancy by using short-term performance results. In this study, comparing CRCP and JCP based on real performance data and actual maintenance and rehabilitation (M&R) cost data collected over 30 years from the Jungbu Expressway in Korea. To assess performance, the service life and pavement conditions of each pavement type were compared. To assess the cost, construction cost and M&R cost data collected over 30 years were compared. In terms of performance, CRCP was superior to JCP based on the 31-year service life of CRCP and the 28-year service life of JCP. In terms of pavement conditions, CRCP was also superior to JCP based on the Highway Pavement Condition Index (HPCI) and International Roughness Index (IRI). Furthermore, in terms of cost, although the construction cost of CRCP was slightly higher than that of JCP, the total cost of CRCP, including the M&R cost, was 8.5% less than that of JCP. [ABSTRACT FROM AUTHOR]

The article presents the results of a research study that was conducted at the American University of Beirut (AUB) on the effect of transverse reinforcement crossing the critical hooked bars region of normal strength concrete (NSC) beam-column joints on the bond strength and ductility of the mode of failure of the hooked bars. Nine full-scale beam-column joint specimens were tested. The specimen simulated the rigid connection of a cantilever vertical beam to a base column. The load was applied near the tip of the beam while the column was fixed to the strong floor. The tensile beam bars were anchored in the column using hooked-bar anchorages. In previous research, confinement to the joint was provided either by carbon fiber reinforced polymer (CFRP) sheets externally confining the joint or steel fibers incorporated in the concrete mix. Results revealed that the transverse reinforcement crossing the hooked bars region was effective in increasing the anchorage capacity and the ductility of the load-deflection history of the specimens. Correlation of the effects of the three different confinement modes is presented. [ABSTRACT FROM AUTHOR]

The Ministry of Transportation of Ontario in Canada recently undertook a pilot study of using precast concrete inlay panels to rehabilitate high-volume asphalt highway pavements. Three different versions of this rehabilitation strategy were designed and constructed. The pilot study was constructed on a high-volume highway in Ontario in 2016 and subjected to service conditions. One of the performance measures being tracked for the project is Load-Transfer Efficiency (LTEδ), measured via Falling Weight Deflectometer (FWD) testing. Two FWD evaluations were performed on the pavement section: immediately following construction, and after one year of service. The LTEδ performances of the different design strategies are summarised and analysed, using least significant difference statistical analysis. Similarly, the potential for sub-panel voids is measured using zero-load back-calculation. Because of the limitations of LTEδ in measuring joint performance, a relative displacement measure (RD75) is developed and its use is outlined and recommended as a meaningful measure of joint performance based on FWD test results. [ABSTRACT FROM AUTHOR]

Analytical investigations were carried out on high-strength concrete beam–column joints reinforced with high-strength steel rebars. The bond performance of test specimens was evaluated and compared with building code provisions. An analytical approach was obtained to study the influence of various patterns of column axial loading on the failure mechanism of beam–column joint subassemblies. In addition, a finite-element study was conducted to investigate the seismic behavior of reinforced concrete beam–column joints designed with high-strength materials. A novel recommendation for the joint depth to beam bar diameter ratio and the comparison between the proposed equations and those suggested by codes was presented. [ABSTRACT FROM AUTHOR]

Seismic performance assessment is carried out for reinforced concrete structure built in low-strength concrete lacking confining ties in beam-column joint. Shake-table tests were performed on 1/3rd scaled two-story frame using design-spectrum-compatible accelerogram, scaled to various target levels. The frame is observed with beam longitudinal bar slip and pullout. Joints with no confining ties experienced extensive damage, observed with cover/core concrete spalling. The frame could resist 70% of the design ground motion to remain within the code-specified drift limit. The code requirement for minimum column depth will not avoid joint damageability in case of low-strength concrete and joints lacking confining ties. [ABSTRACT FROM AUTHOR]

This work presents a finite-element method (FEM) analysis of the behaviour of continuous segmental concrete bridges with external prestressing and dry joints, focusing on the response under combined shear and flexure, at the service limit state (SLS) and at the ultimate limit state (ULS). A previously validated FEM model has been applied to simulate the structural behaviour of continuous bridges until failure. A geometrically non-linear analysis has been performed, where the particular behaviour of the dry joints, the concrete plasticity and the slipping of the prestressing tendons at the deviators have been considered. Results of the analysis have been compared with the available data of the modelling of simply supported bridges, and the different behaviour introduced by the support redundancy has been pointed out. Analysis proves that the SLS can govern the design of the prestressing force, whereas in simply supported bridges, it is the ULS that always governs the design. Concrete and steel remain essentially linear under ultimate loads, which implies that there is an extra safety factor against failure. Before failure, when support and mid-span joints are opened, moment redistribution has occurred and an arch springing from the bearings is formed within the concrete, which equilibrates the external loads. [ABSTRACT FROM AUTHOR]