Shear Span-depth Ratio Research Articles

Shear Performance of RC Beams Strengthened with High-Performance Fibre-Reinforced Concrete (HPFRC) Under Static and Fatigue Loading.

This study experimentally assessed the shear performance of reinforced concrete (RC) beams strengthened with U-shaped High-Performance Fibre-Reinforced Concrete (HPFRC) under static and fatigue loading. Key parameters included HPFRC jacket thickness and beam shear span-depth (a/d) ratio. Five beams were tested under static loads to determine ultimate shear strengths, followed by fatigue tests on identical beams at 30-70% of ultimate shear strengths at 4 Hz. In static loading experiments, all the HPFRC jacketing proved effective, increasing the shear strength of RC beams by 95% to 130%. Although the strengthening system did not change the failure mode of the beams, the strengthened beams exhibited pseudo-ductile behaviour. As the a/d increased, the shear enhancement capability of the HPFRC jackets decreased. In fatigue loading experiments, all the HPFRC systems improved the fatigue life of RC beams. Specifically, in beams with an a/d ratio of 2.0, the fatigue life was extended from 75 cycles to a maximum of 951 cycles, while in beams with an a/d ratio of 3.5, it increased from 12,525 cycles to 48,786 cycles. In addition, a predictive model has been developed for the fatigue life of HPFRC/UHPFRC shear-strengthened beams, utilising the maximum fatigue load and the design's ultimate shear strength under static loading conditions.

Experimental study on the shear behaviors of inverted castellated T-steel reinforced UHPC (ICTSRU) beams with hollow section

To reduce the production costs of steel reinforced UHPC composite beams and fully utilize the material strength of steel, this paper introduced an innovative prefabricated composite beam comprising a reinforced ultra-high performance concrete beam and an internal castellated inverted T-steel, forming an inverted castellated T-steel reinforced UHPC (ICTSRU) composite beam. Investigating the shear behavior of ICTSRU beams is the primary objective of this research. Seven composite beams were loaded under simply supported four-point loading conditions, and the effects of key parameters such as the shear span-depth ratio, steel fiber volume fraction, and stirrup ratio were studied. The findings from the test indicated that the ICTSRU beams demonstrated superior deformation ability and significant residual shear strength after the peak load. The shear span-to-depth ratio significantly influenced the failure modes and carrying capacity of the ITSRU beams. As the span-to-depth ratio increased from 1.1 to 1.6 and 2.1, the failure mode developed from shear failure to flexural failure and the shear resistance decreased by 19 % and 48 %, respectively. Enhancing the steel fiber volume fraction and the stirrup ratio can mitigate the initiation and propagation of diagonal cracks, thereby augmenting the shear strength and ductility of ICTSRU beams. Following a comprehensive analysis of the experimental results, a predictive model for the shear strength of the ICTSRU beam is proposed. This model posits that the shear capacity of the ICTSRU beam comprises the shear resistance contributions from the UHPC matrix, stirrups, steel web, and steel fibers. A comparative analysis of the computed values and the test results showed that the proposed calculation method has a high accuracy in predicting the ultimate shear strength of ICTSRU beams.

Behavior and shear strength of prestressed steel reinforced concrete composite deep beam

In order to optimise the utilisation of material properties, simplify the construction process and enhance the industrialisation of steel reinforced concrete beams, an innovative prestressed steel reinforced concrete composite beams(PSRCC) was proposed, which was achieved by integrating prestressing technology and prefabricated technology to steel reinforced concrete structure. To investigate the shear PSRCC deep beams, a static load test was conducted on 7 PSRCC deep beams. The study investigated the effects of parameters such as shear span-depth ratio, prestressed tendons degree, form, height and application sequence on the failure mode, crack pattern, load-displacement behavior, strain response and damage evolution. A model was established to predict the shear strength of PSRCC deep beams, considering the steel-concrete interaction, using the von Mises yield criterion and the SST model, which assessed the contributions of composite strut, prestressed tendons and shear steel web for shear strength. The test results showed that the prefabricated and cast-in-situ concrete components maintained good integrity, and PSRCC deep beams eventually experienced typical diagonal compression failure. Applying prestressing and reducing the shear span-depth ratio under identical conditions would reduce the deformation capacity of PSRCC deep beams. When the shear span-depth ratio was reduced from 1.0 to 0.5, the cracking load and peak load of the specimens increased by 17.31 % and 16.53 % respectively. Increasing the prestress level from 0 to 0.3 and 0.6 increased the cracking load of the specimens by 1.41 and 2.36 times, respectively, but the peak load of the specimens increased by only 3.37 % and 8.17 %. The cracking load of the parabolic tendon specimen increased by 2.18 for the comparison specimen but was 8.33 % lower than that of the linear tendon specimen with the same degree of prestressing. Comparison of the two prestressing sequences showed that the cracking load of the specimen with tensioning prestressed tendons after pouring the entire beam section increased by 29.84 %, but the peak load increased by only 3.11 %. As the height of the prestres tendons increased, the cracking and peak loads of the specimen reduced by 5.84 % and 5.71 % respectively. Consequently, the shear strength of PSRCC deep beams was significantly influenced by the shear span-depth ratio and minimally affected by prestress-related parameters. The proposed model accurately predicted the shear strength of PSRCC deep beams compared to existing codes, offering valuable guidance for design.

Experimental Investigation on Shear Behavior of Non-Stirrup UHPC Beams under Larger Shear Span–Depth Ratios

Due to the extraordinary mechanical properties of ultra-high-performance concrete (UHPC), the shear stirrups in UHPC beams could potentially be eliminated. This study aimed to determine the effect of beam height and steel fiber volume content on the shear behavior of non-stirrup UHPC beams under a larger shear span–depth ratio (up to 2.8). Eight beams were designed and fabricated including six non-stirrup UHPC beams and two comparing stirrup-reinforced normal concrete (NC) beams. The experimental results demonstrated that the steel fiber volume content could be a crucial factor affecting the ductility, cracking strength, and shear capacity of non-stirrup UHPC beams and altering their failure modes. Additionally, the height of the beam had a considerable effect on its shear resistance. French standard formulae were more accurate for the UHPC beams with larger shear span–depth ratios, PCI-2021 formulae greatly overestimated the shear capacity of UHPC beams with larger shear span–depth ratios, and Xu’s formulae were more accurate for the steel fiber-reinforced UHPC beams with larger shear span–depth ratios. In summary, French standard formulae were the most suitable formulae for predicting the shear capacity of UHPC beams in this paper.

Punching Shear Strength of Isolated Concrete Column Footings with Low Shear Span-Depth Ratios

Punching Shear Strength of Isolated Concrete Column Footings with Low Shear Span-Depth Ratios

Rehabilitation of reinforced concrete deep beams by near-surface-mounted steel reinforcement

Abstract This article describes an experimental investigation of the behavior of reinforced concrete deep beams repaired by near-surface-mounted (NSM) steel bars. The first beam was loaded under a two-point load up to failure, and the other six deep beams were loaded to 0.4 and 0.75 of ultimate load. Then, they were repaired by NSM steel bars. The bar orientation and angle were the main variables in these beams. The primary goal of this study is to determine whether it is possible to restore the reinforced concrete deep beam with shear reinforcement to its full load-carrying capacity by NSM steel bars as the method of repair. All deep beams were tested with a shear span-depth ratio of 0.8. The test findings showed that the NSM steel repair bars were very effective in restoring the loaded deep beams’ full capacity. Moreover, NSM steel bars enhanced the original deep beams’ strength capacity from 4.16 to 19.44%. The ultimate load, mechanisms of failure, load–crack width distribution, and load–deflection profile are tracked as results.

Shear performance of partially encased composite beams with high-strength steel and UHPC

Various countries across the globe have implemented strategic policies that encourage the development and use of high-performance materials in engineering structures. This study focused on the shear performance of partially encased composite beams with high-strength steel and UHPC (PEHC beams). Seven PEHC beams under simply supported three-point loading conditions were tested to investigate the effect of main parameters such as the shear span-depth ratio, thickness of steel web, types of steel web, and types of stirrups on shear failure modes, crack patterns, load-deflection behavior, and the response of strains. Two failure modes were observed in PEHC beams, involving diagonal compression failure and shear compression failure. As the shear span-depth ratio decreased from 2.0 to 1.5 and 1.0, the shear strength increased significantly by 13.3% and 70.8%, respectively. Test results demonstrated that the increase in the thickness of steel web and the use of steel solid web positively affect the shear strength of PEHC beams, whereas the impact of normal-strength stirrups types proved insignificant. Finally, a theoretical method was proposed to predict the shear strength of PEHC beams by considering the coworking of four mechanisms: the composite truss, the steel web, the stirrups, and the steel fibres. Then the method was validated by the good agreement between the predicted and tested shear strength results, highlighting its applicability in providing accuracy.

Experimental investigation on shear behavior of full-scale glued laminated bamboo beams under three-point loading test and using digital image correlation technique

Applying bamboo in construction is expected to reduce carbon footprint and promote environmental protection. Very limited information is available in the literature about the shear behavior of glued laminated bamboo (glubam, i.e., a type of engineered bamboo) beams. To this end, this paper presents an experimental investigation of shear behavior for full-scale glubam beams using three-point loading test. Fourteen specimens were tested, considering the effect of shear span-depth ratio (a/d) and beam depth on the shear response of glubam beams. Digital Image Correlation (DIC) technique was conducted to measure the strain fields on two specimens with different shear span-depth ratios. The test results show that the glubam beams with a/d= 1.0 occurred local compressive damage at the loading region and the mixed local compression-flexure damage; and beams with a/d= 2.0 exhibited flexure-dominated damage together with a minor local compressive settlement at the loading region. Specifically, increasing the shear span-depth ratio reduces the load capacity but improves the ductility and minimizes the global damage in the glubam beam. Larger shear area of the beam has a smaller shear stress, which demonstates the scale effect on the shear behavior of the glubam beam. DIC technique is feasible for monitoring the shear behavior of glubam beams with a small shear span-depth ratio. Meanwhile, this technique can also be employed for the beams with a relatively large shear span-depth ratio to monitor the shear behavior at a relatively small deformation.

Behaviour of reinforced concrete corbels strengthened by FRP composites and steel bars: a critical review

In reinforced concrete (RC) structures, corbels that extend from the faces of reinforced concrete columns are commonly employed to support primary beams and girders. Frequently, the use of corbels is limited to cantilevers with a shear span-depth ratio that is often less than 2. Because of this relatively low ratio, corbel strength is normally dominated by shear, which is comparable to deep beams. However, owing to some reasons (e.g., design and/or construction faults, modification of facility use, deterioration, and aging), strengthening of existing corbels is becoming of prime importance. The aim of the present paper is to conduct a critical review of commonly proposed techniques that have been implemented to strengthen RC corbels. These techniques comprised near surface mounted (NSM) steel bars, NSM fibre reinforced polymer (FRP) bars, and FRP sheets. The latter strategy included carbon (CFRP) and glass (GFRP) sheets. Hybrid strengthening (combining FRP sheets and FRP/steel bars) was also highlighted in this paper. The strengthened (upgraded) RC corbels were evaluated considering several parameters, including shear span to depth ratio (a/d), quantity and configuration of reinforcement, FRP type, and levels of damage in the tested specimens.

Proposed shear capacity equation for ultra-high performance fiber reinforced concrete beam containing coarse aggregate

This paper proposes a shear capacity equation for ultra-high performance fiber reinforced concrete beam containing coarse aggregate (UHPFRC-CA) and without coarse aggregate (UHPFRC) that captures all UHPFRC’s direct and indirect shear influencing factors. Six beam samples (each sample containing two beam specimens) were tested for shear strength under four point loading configuration using shear span-depth ratio (a/d), percentage volume of steel fiber (Vf), shape of steel fiber and stirrup spacing (s) as shear design parameters to obtain their ultimate shear strength (Vu). The obtained Vu was subjected to Analysis of Variance (ANOVA) to assess the significance of adding a coarse aggregate factor (dca) to the proposed equation. The proposed equation was validated by comparing its Vu with this study’s experimental Vu, other researchers’ Vu and Vu estimated using existing shear equations. ANOVA results showed that dca is significant in the Vu of UHPFRC-CA beams. Findings also revealed that the proposed equation does not only predict the Vu of UHPFRC-CA beams with a very high degree of accuracy but also gives better estimates of the Vu of UHPFRC-CA and UHPFRC beams when compared with the existing shear equations considered in this study. Further findings showed that the proposed equation reflects the effect of changes in Vf, a/d, s, ρ, shape of steel fiber and maximum size of coarse aggregate better than the existing shear equations for UHPFRC beams. Therefore, the proposed equation can be safely use for the shear design of UHPFRC-CA beam whose compressive strength ranges from 150 N/mm2 to 170 N/mm2.

Verification of Truss-Arch model unified for RC beams with stirrups using shear database

A shear strength analysis model called “Truss-Arch Model Unified (TAMU)” was proposed for shear-critical reinforced concrete (RC) beams with transverse reinforcement. The TAMU has its roots in the Compatibility Strut-and-Tie Model (C-STM) which is a computational modeling approach for the overall force–deformation analysis of deep beams. The TAMU simplified the C-STM so that a limited analysis can be executed by hand methods of analysis to predict the maximum load-carrying capacity of RC deep beams. While the tensile stress of concrete is generally taken into account to evaluate the shear strength of RC beams, the TAMU limit analysis focuses on the strength reduction of the principal diagonal concrete arch due to the transverse principal tensile strain. In the present study, a shear database is assembled from previous works reported in the literature to further substantiate the validity of the TAMU approach. The shear database consists of tested RC beams with shear reinforcement whose shear span-depth ratios (a/d) are between 0.5 and 4.5. Comparative TAMU analysis results show satisfactory agreement with the ultimate strengths observed in 460 RC beam tests regardless of D- and B-regions, demonstrating the method’s ability to predict the maximum load-carrying capacity for shear-critical beams. Additionally, the TAMU approach shows better accuracy and consistency against the database compared to AASHTO sectional shear design methods. The probability of reasonable prediction of the TAMU method is 92% in d-regions and 78% in B-regions, respectively, which is significantly higher than those of AASHTO sectional shear design methods, especially in d-regions. Thus, the TAMU method may be a viable improvement as an alternative strength analysis method for shear-critical RC beams with transverse reinforcement.

Response of high-strength concrete beams with corrugated discrete steel fibers to small shear span-depth ratios

The behavior of high-strength, fiber-reinforced concrete (HSFRC) beams under concentrated loads was affected by many different aspects, such as the type of fibers used and the volume percent of the fibers; nevertheless, the behavior was primarily affected by modifying the shear span-to-depth ratio (a/d). In this experimental investigation, the influence of a/d ratios (ranging from 1.5 to 2.2) is investigated on the response of twelve high-strength fiber-reinforced concrete (HSFRC) beams containing varying amounts of discontinuous steel fiber (vf) in the concrete mixture. The purpose of this study was to analyze the manner of failures of the tested beams and to identify a limiting a/d for effective beam depth. Shear failure was observed in high-strength concrete (HSRC) beams with a vf of 0% at a/d ratios as high as 2.2, according to the findings of the study. Altering either the a/d ratios or the vf had an effect on the way in which the HSFRC beams responded to the stimulus. Some of the HSFRC beams that were put through the shear–flexure test failed. In addition, the findings demonstrated that, as the a/d ratio increased up to 2.2, the beams with a vf of 0.5% and 0.75% broke in pure flexure with multi-cracking. This indicates that the a/d ratio has a substantial impact on the various failure behaviors of HSFRC beams.

Shear strength degradation mechanism dependent on size increase in RC slender beams by using 3D Rigid-Body-Spring-Method

This study aims to clarify the mechanism of the size effect on the shear behavior for reinforced concrete (RC) slender beams. Three Dimensional Rigid-Body-Spring-Method (3D RBSM), a basic analytical tool applied in this paper, was first demonstrated to be capable of reproducing the shear behavior of large scaled RC slender beams without and with stirrup. Furthermore, the size effect on the shear behavior of three groups of geometrically similar RC slender beams with shear span-depth ratio a/d of 3.51 classified by different levels of stirrup ratio were quantitatively evaluated, and the mechanism of size effect was explained by investigating on beam and arch actions and localized information such as compressive stress in concrete and crack pattern. The analytical results indicated that the RC beams without stirrup showed evident size effect on the shear strength while the arrangement of stirrups along shear span inhibited the size effect to a great extent. More importantly, it was revealed that the size effect on the shear strength of beams without stirrup was dominant by the size dependence of arch action which resulted from the overall decrease in the level of nominal compressive resultant with increasing effective depth. On the other side, for the beams with stirrup, it was clarified that although the size effect on arch action still existed, it was caused by the change in the slope of arm length for arch action, which was induced by the transformation of diagonal crack pattern with increasing effective depth. However, this transformation of diagonal crack pattern contributed to the increase in nominal beam action. As a result, the decrease in nominal arch action was offset by the increase in nominal beam action in terms of combined size effect.

Mechanism of shear strengthening for RC beam by drilling web openings based on experiment and 3D RBSM analysis

In practice, web openings are usually drilled in reinforced concrete (RC) beams to accommodate pipes and cable installations. But introducing web openings always causes shear degradation of RC beams. This study aims to establish a rational position design of multiple small web openings, which can improve the shear behavior of RC beams, by controlling the path of critical diagonal crack. Three-point bending tests on four RC beams without and with web openings (shear span depth ratio: 2.59 and 3.56) were firstly carried out to evaluate the strengthening effect attributed to the proposed placement of web openings. Besides, the Three Dimensional Rigid-Body-Spring Method (3D RBSM), a discrete numerical methodology, was applied to simulate the test process, and the strengthening effect due to the placement of web openings was parametrically investigated. Finally, the decoupling of shear components (beam and arch actions) was conducted to comprehensively understand the shear strengthening mechanism due to drilling web openings, by using RBSM-based methodology. The test and numerical results confirmed that the proposed position design of web openings could evidently improve the shear strength and deformation ability of RC beams, because the multiple web openings could increase the angle of critical diagonal crack, by predetermining it propagation path. Moreover, it was clarified that the strengthening mechanism of shear behavior owing to web opening setting was dependent on the more dramatic development of arch action with the increasing angle of critical diagonal crack. The present paper provided a rational design to solve the problem of shear degradation caused by small web openings in the field of concrete member design, and proved a possibility to strengthen the shear behavior of existing concrete beams by drilling web openings.

Influence of Different Dapped-End Reinforcement Configurations on Structural Behavior of RC Dapped-End Beam

Severe damage or collapse of reinforced concrete dapped-end beams (RC-DEBs) may occur during the service life. The collapse of the Concorde overpass structure in Laval, Quebec, Canada, in 2006 revealed the causes of collapse, i.e., insufficient shear strength (no stirrups), misplacement of hanger reinforcement, etc. In addition, the inspection report of RC half-joint bridges in England until 2018 expressed that damages or failures of half-joint structures can be attributed to the poor condition of structures or non-compliant reinforcement detailing. These conditions exhibited how important it is to understand the proper detailing of dapped-end reinforcement. To date, some studies have performed investigations on the effect of inadequate dapped-end reinforcement on the structural behavior of DEBs. However, the results of the research to date were not yet complete enough to disclose the role of each group of dapped-end reinforcement in resisting the working load. Therefore, this study was carried out to investigate the main role of each group of dapped-end reinforcement separately on the structural performance of RC-DEBs. Eight large-scaled RC-DEBs (with sizes of 1800 mm length, 120 mm width and 250 mm height) were prepared, cast and cured. All DEB specimens were tested under the three-point loading up to failure. To localize the effect of shear failure, the shear span-depth ratio (av⁄d) of 1.43 was set. Test results exhibited that arrangement of a specific group of dapped-end reinforcement separately affects the structural performance of DEBs significantly. The diagonal reinforcement (DR) group was found to be more effective than the vertical hanger reinforcement (HR) group. The failure load capacity of the DR group (DEB-18) achieved 0.29 times that of the control beam (DEB-3). Meantime, the nib flexure reinforcement (NFR) group demonstrated the most important role in the structural performance of DEBs compared to other dapped-end reinforcement groups. The failure load capacity of the NFR group (DEB-39) reached 0.62 times that of the control beam, while rupture deflection of the NFR group also exhibited the highest value than other groups, i.e., 0.62 times that of the control beam. In addition, analysis results of rosette strain gages (RSGs) data indicated that regions near to re-entrant corner and its vicinity experienced the highest stress concentration factor (SCF) compared to other places of the beams. These regions were more susceptible to experiencing the first crack, progressive crack, damage or failure first than other regions of DEBs. The greater the value of SCF, the greater the probability of collapse occurring in the related structural elements, which is also followed by a lower failure load capacity. DEB-1 (without dapped-end reinforcement) has the highest SCF (205.68), and the lowest failure load capacity (12.58 kN), whilst DEB-3 (with the complete dapped-end reinforcement) has the lowest SCF (79.62), but the highest failure load capacity (105.26 kN). Obviously, DEB-3 can withstand the working load properly. Its adequate dapped-end reinforcement is able to accommodate and distribute the high stress flows in the dapped-end region properly, which causes the SCF value to decrease.

Shear Strength of Ultra-High-Performance Concrete Beams with Small Shear Span-Depth Ratios

Shear Strength of Ultra-High-Performance Concrete Beams with Small Shear Span-Depth Ratios

Reinforced Concrete Corbels Shear Test: The Triangular-Truss Method Evaluation

In this paper, five reinforced concrete double-corbel specimens with the same designed bearing capacity are produced according to the triangular-truss method (TTM) in GB 50010-2010. Corbels with different dimensions and reinforcement configurations are obtained by separately varying the concrete compressive strength and shear span. The differences in the mechanical performance and load-bearing capacity of the corbels are compared to evaluate the accuracy and rationality of the TTM under specific variables. Then, the accuracy in predicting the load-bearing capacity of GB 50010-2010, ACI 318-19, EC 2, CSA A23.3-04, the softened strut-and-tie method, and the Russo strut-and-tie method is compared. The results show that the safety factor (ratio of the actual bearing capacity to the designed bearing capacity) of the TTM is increased from 1.419 to 1.718 when the concrete strength is improved from 20.8 MPa to 65.3 MPa; the safety factor of the TTM is increased from 1.414 to 1.859 when the shear span–depth ratio is increased from 0.25 to 0.67. Compared to GB 50010-2010, ACI 318-19, and EC 2, the predictions of CSA A23.3-04 for corbels are closer to the test values. The safety level of codes GB 50010-2010, ACI 318-19, and EC 2 is essentially the same; both the SSTM and the Russo STM are accurate in the predictions.

Shear Performance of Concrete Beams with a Maximum Size of Recycled Concrete Aggregate

The use of concrete mixes with recycled materials has gained traction in research communities. However, the major drawback of the recycled concrete aggregate (RCA) has been the contribution of the cement paste mortar attached to the surface. The quantity of surface-attached mortar on the virgin aggregate dominates and defines the shear performance of concrete beams. Concrete shear failure is usually abrupt and catastrophic, especially in concrete beams without shear reinforcement. The effectiveness of the maximum size of RCA for the performance of untreated and treated with pozzolanic cement and rice husk ash (RHA) slurry was investigated. A total of sixteen (16) beams containing RCA of four (4) maximum sizes, 10, 14, 20, and 25 mm, were prepared and tested after 28 days. The beams were loaded in shear using shear span-depth ratios of 1.25 and 2.50. The results showed that the shear strength of the beams increases as the aggregate size increases to a maximum size of 20 mm, beyond which the shear strength reduces. It was attributed to the attached mortar, which increased as the size of the aggregate increased, creating a weak zone for shear failure in the concrete. In addition, RCA pretreatment using slurry-containing cement and RHA strengthened the attached mortar on the aggregate surface. It resulted in a dense and more compact aggregate that slightly improved the shear strength by about 2.2% for beams containing 20 mm RCA size. The ultimate shear strength of the experimental work in the study was predicted using eight (8) selected models from the literature. Models that account for the aggregate size and shear span to depth ratio resulted in shear strength ratios of 1.29, 0.91, 1.08, and 1.20 for Bažant and Becq-Giraudon, 2002, Zsutty, 1968, Xu et al., 2012, and Gastebled and May, 2001, which are almost similar outcomes to the experimental results.

Vertical shear capacity of steel-concrete composite deck slabs with steel ribs

The design of steel-concrete composite (SCC) deck slabs is likely governed by the vertical shear under small shear span-depth ratios. This paper aims to propose the calculation method of the vertical shear capacity of the SCC deck slab (Vu). Firstly, Vu is computed as the summation of the contributions of concrete layer (Vc,u) and steel members (Vs,u). Vc,u is treated as the product of the shear capacity of an equivalent reinforced concrete member without web reinforcement and a coefficient that reflects the effects of steel ribs. The formula of Vs,u is developed based on the force equilibrium conditions between the concrete layer and steel members and the section analysis considering the steel-concrete slips. Later, an iterative calculation method is proposed and verified against experiments and finite element (FE) models established via validated simulation techniques. Lastly, an extensive parametric analysis is implemented using the iterative method, from which a simplified calculation method was proposed and proved. Results indicate the iterative method is able to capture the effects of material and geometric parameters, shear span-effective depth ratio, and the degree of steel-concrete interaction. The increases in the heights of concrete layer and steel rib, as well as the rib thickness, can effectively enlarge Vu, while the influences of the steel plate’s thickness and the steel-concrete slips are relatively minor. The iterative method produces accurate predictions with a mean error of 1% and a coefficient of variation of 0.05. The simplified method is more engineer-friendly and yields the average FE/test-predicted ratio being 1.11 as well as the percentage of safe predictions being 95%.

Experimental Study on Shear Behavior of Precast High-Strength Concrete Segmental Beams with External Tendons and Dry Joints

Precast high-strength concrete segmental beams with external tendons and dry joints (ED-PHCSBs) have become a potential alternative for achieving accelerated bridge construction due to their lighter self-weight and easier installation. In order to investigate the shear behavior of ED-PHCSBs, eight precast concrete segmental specimens were fabricated and tested to failure. For comparison purposes, one externally prestressed high-strength concrete monolithic beam was also investigated. The primary parameters, including concrete strength, shear span-depth ratio, stirrup ratio, joint number, and joint location, were adopted. Test results indicated that increasing the concrete strength or stirrup ratio can effectively improve the shear capacity of the ED-PHCSBs. The shear span-depth ratio was inversely proportional to shear strength for all specimens. The results also revealed that the joint number had a marginal effect on the defections and stresses of the external tendons of ED-PHCSBs. AASHTO 2017 and Chinese code 2018 can conservatively estimate the shear strength of ED-PHCSBs. Considering the actual failure modes of the precast beams, a calculation method based on a modified strut-and-tie model was proposed. The average and standard deviation of the ratios of the test results to the predicted value of the proposed method were 0.98 and 0.08, respectively. It indicated that the proposed formula was more accurate.