Shear Strength Equation Research Articles

Improved Design Shear Method for the Bolted Cold-Formed Steel Clip-Angle Connector

In this paper, the ultimate shear capacity of the 3-bolt cold-formed steel clip-angle between the cold-formed steel (CFS) beam and column is evaluated through 54 laboratory tests. A series of experiments were conducted by varying (1) thickness, and (2) aspect ratio (L/D) of clip-angles for different depths (D) and widths (A). The experimental program consists of three phases of tests: (1) Phase-I: direct shear load tests on clip-angle attached to a CFS column through 4.6-grade bolts; (2) Phase-II: CFS column replaced with a hot-rolled steel (HRS) column, since the CFS column experienced bearing failure in Phase-I; and (3) Phase-III: 10.9-grade bolts used instead of 4.6, as the 4.6-grade bolts subjected to bolt shear failure in Phase-II. Failure modes observed in the test specimens are (1) shear local buckling of clip-angle; (2) column bearing failure; (3) bolt shear failure; and (4) tear failure in clip-angle. Design shear equations from the literature, for the bolted clip-angle, were found to be inefficient for the high-grade steel (fy=375 MPa to 550 MPa), and conservative for the commonly available low-grade steel (fy=275 MPa). Hence a new shear strength equation is suggested for the clip-angle from the collated data of the present study and past research work. A comparative study between 2-bolt and 3-bolt clip-angle configurations was conducted to evaluate the increase in shear strength. Reliability studies were conducted, and corresponding resistance and safety factors were suggested for the design shear strength calculation corresponding to load and resistance factor design (LRFD), limit state design (LSD), and allowable strength design (ASD) methods.

CatBoost–Bayesian Hybrid Model Adaptively Coupled with Modified Theoretical Equations for Estimating the Undrained Shear Strength of Clay

The undrained shear strength of clay is an important index for the calculation of the bearing capacity of the foundation soil, the calculation of the soil pressure of the foundation pit, and the analysis of the slope stability. Therefore, the purpose of this paper is to conduct a comprehensive study of the combined use of machine learning with clay theoretical equations to estimate it. Under the Bayesian framework, the CatBoost algorithm (CatBoost–Bayesian) based on Bayesian optimization algorithm was developed to obtain the feature importance level of soil parameters affecting the undrained shear strength of clay, so as to adaptively couple the theoretical equation of undrained shear strength of K0 consolidated clay, which was derived from the modified Cambridge model. Then, the theoretical equation of undrained shear strength of the isotropically consolidated clay was established from the critical state of the clay parameters. Finally, it was illustrated and verified using the experimental samples of Finnish clay. The results indicate that the theoretical equation established by the overconsolidation ratio and effective overburden pressure parameters can well estimate the undrained shear strength of isotropically consolidated clays, and the parameter uncertainty can be considered explicitly and rigorously.

Modified Equation of Shear Strength with Respect to Saturation

Unsaturated soil shear strength is a significant topic in geotechnical engineering. The measurement of unsaturated soil properties such as shear strength and matric suction could be costly, hard, time-consuming, and often impractical to obtain. The purpose of this research is to propose a new shear strength model for unsaturated soil and to predict the shear strength by using the degree of saturation directly because the water saturation is easy to obtain. More specifically, this study focused on Bishop’s shear strength theory and van Genuchten’s soil–water characteristic curve to describe the effect of saturation on shear strength. The new shear strength model was expressed as a function of saturation degree, residual degree of saturation, effective shear strength indices, net normal stress, and five parameters. The performance of the presented model in this paper was verified by fitting it to data obtained by laboratory tests on silty sand including the triaxial shear test and soil–water characteristic curve test. From these two laboratory tests, we obtained the variation in the matric suction and shear strength with the degree of saturation under various dry densities. This proposed model was also validated against the shear strength results of the clayed-silty sand and Ankara clay recorded in the literature. Comparing the result of the shear strength under the variation of one parameter, this model was much more sensitive regarding parameter m, which was related to the material characteristic. The comparison between the predicted values and experimental points was particularly fine and showed the ability of this model to be applied to a wide range of soils.

3D anisotropy in shear failure of a typical shale

It is inadequate to study the shear failure anisotropy of shale in only 2D space. Aiming at a 3D analysis, a series of direct shear tests was conducted on Longmaxi shale with three typical bedding orientations: arrester, divider and short-transverse orientations. During testing, acoustic emission (AE) and digital image correlation (DIC) techniques were simultaneously employed to monitor failure development, after testing, X-ray computed tomography (CT) scanning was adopted to acquire and reconstruct the fractures inside typical ruptured samples for more detailed analysis. The results indicated that the shear strength parameters exhibited 3D anisotropies and those of the arrester sample did not have equivalent shear strength parameters to the shale matrix. The maximum (minimum) shear strength and cohesion were obtained with the divider (short-transverse) orientation, and the internal friction angle reached its maximum (minimum) with the divider (arrester) orientation. Combining the AE, DIC and CT techniques, four characteristic stress levels that can capture the progressive shear failure process of shale rocks were identified, and the onset and accelerated development of shear damage-induced dilation were observed at the crack initiation and coalesce stress thresholds, respectively. During the crack coalescence stage, the dominated microcracking mechanism transferred from tensile-mode to shear-mode. For the arrester and divider orientations, more tensile-mode AE events were generated due to the microcracking along the vertical beddings. Compared with the divider samples, a more complex fracture network with a larger fracture area and volume was obtained in the arrester samples, whose strengths were smaller.

Experimental and numerical investigations of block shear failure in gusset plates welded to double angle members

Double angle braces are used extensively in structures to resist lateral loads such as wind, earthquake, and blast loads. A possible failure mode in the gusset plate when all-around weld is used for the angles is the block shear failure. To date, only limited test data on welded gusset plates failing in this mode have been reported in the literature, and all of them only considered concentrically loaded gusset plates. This paper investigates the block shear failure in welded gusset plates experimentally and numerically when connected to double angle members with possible in-plane load eccentricity effects. The test results, including failure loads, fracture sequences, and load-displacement responses are reported in detail. Results showed that tensile fracture was initiated adjacent to the angle heel weld and then propagated along the tension plane. Due to existing in-plane load eccentricity, shear planes did not rupture simultaneously and the shear plane adjacent to the heel weld failed earlier. Following the testing, a numerical investigation using nonlinear finite element analyses with ductile damage capability was performed on the tested specimens. Subsequently, a parametric study was carried out to generate further numerical data over a wide range of gusset and angle dimensions, welding configurations, and connection lengths. Accordingly, the existing design equations for block shear strength as given by AISC specification were evaluated. It was shown that AISC provides excessively conservative and scattered failure loads because of ignoring stress triaxiality and using shear yield instead of shear rupture in its strength equations. In addition, equations specified for welded gusset plates by previous studies were considered and shown to be unsafe for general use. To address these shortcomings, an improved block shear strength equation is proposed in this paper and shown to predict the gusset strength in block shear with improved accuracy.

Model trees and stepwise regressions for accurate in-plane shear strength predictions of partially grouted masonry walls

The behaviour of partially grouted (PG) masonry shear walls is complex due to masonry's anisotropic nature and the nonlinear interactions among its constituents. Currently available code- and research-based shear strength equations provide highly variable results when predicting the in-plane shear strength of PG masonry walls. It is crucial to develop a greater understanding in this area, as sudden shear failures of masonry walls can lead to catastrophic losses of human life and property. This study presents the development of several new in-plane shear strength models for PG masonry walls using stepwise regression and model trees with data compiled from 292 experimentally tested walls. The models are found to significantly outperform existing code- and research-based shear strength equations. It was found that, of the variables studied, the most significant ones are the axial load, wall geometry, compressive strength of mortar, and area of interior vertical reinforcement.

SHEAR STRENGTH OF HIGH STRENGTH STEEL FIBER REINFORCED CONCRETE COLUMNS

At present, the highest high-rise RC building in Japan is over 200 meters high. All columns from the first to the 13th floor of the building are applied high strength steel fiber reinforced concrete columns （HSFRC）to control damage under huge earthquake loading. The high strength steel fiber reinforced concrete columns are contain 1.0% steel fiber by volume. It is the first time to apply much steel fiber for high strength concrete columns. Nevertheless, there is no established design equation for high-strength SFRC columns. Therefore, authors have conducted an experimental study of HSFRC columns since 2020. A total of 15 specimens were conducted. In this research, 13 specimens’ experimental data are used. The shear strength equation based on truss arch theory with the volume ratio of steel fibers as a variable factor is proposed as a design equation for high-strength steel fiber reinforced concrete columns.

Computational and experimental study of structural fuses optimized to resist buckling

The concept of structural fuses, i.e., replaceable hysteretic dampers that limit the forces that can be transferred to the surrounding structure, has been used in research and practice to improve the seismic performance of structural systems. A recent study used topology optimization to develop new structural fuse shapes that discourage buckling and promote stable yielding of shear-acting structural fuses. The objective of the current study is to further validate and develop the optimized shapes to allow the design and application of these optimized structural fuse shapes in practice. First, the pixelated optimized topology was interpreted as a collection of geometric shapes, parameterized to make it accessible for design, and plastic mechanism analysis was used to develop a generalized equation for shear strength. An experimental study was conducted on three specimens that were 711 mm by 762 mm by 25 mm thick, to evaluate strength, stiffness and hysteretic behavior. Finite element models were then validated against the experimental results, and used to conduct a computational parametric study to evaluate the effect of varying key design parameters on strength, stiffness, out-of-plane buckling, effective plastic strain, and energy dissipation. The experimental study showed that one of the optimized geometries possessed a good balance between buckling resistance and fracture resistance reaching approximately 11% shear angle without either. Design guidance is provided for this topology including a parameterized method for reproducing the shape, design equations, and recommendations for proportioning.

Punching Shear Behavior of Fibrous High Strength Concrete Slabs Reinforced with BFRP Bars

Abstract This study offers test findings from research work conducted to investigate the punching shear behavior of fibrous high strength concrete flat slabs reinforced with Basalt fiber-reinforced polymer (BFRP) bars. Eleven two-way concrete slabs were tested until they failed under central concentrated force. BFRP bars were employed to reinforce ten of the eleven slabs for flexural reinforcement, while steel bars were used to reinforce one slab for comparison. Each slab measured 1000 × 1000 × 70 mm with a 60 × 60 mm steel column at the center of the slab. The flexural-reinforcement type, flexural-reinforcement ratio, and steel fibers content were the test parameters. According to the test findings, raising the BFRP reinforcement ratio improved the slabs’ punching shear capability and load-deflection response. In comparison to slabs with a lower reinforcing ratio, these slabs also showed fewer, narrower cracks. Steel fibers were added, which improved the failure mode from brittle, unexpected failure to ductile failure. The experimental findings are compared to a shear strength equation offered by several concrete design codes, including ACI 440.1R-15, CAN/CSA S806-12, and JSCE.

Effect of connection transverse reinforcement on the behavior of GFRP-RC T-connections: Numerical investigation

This study numerically investigates the cyclic behavior of glass fiber-reinforced polymer (GFRP) reinforced concrete exterior beam-column (T-BC) connections (GFRP-RC T-BC connections) with varying amounts of transverse reinforcement (TR) in the connection panel. The amount of TR required to provide adequate confinement and shear strength to the GFRP-RC T-BC connections has not yet been fully understood. The primary objective of this study was to evaluate the effects of TR configuration and amount of TR on the load-drift ratio response, strain distributions and shear strength of the GFRP-RC T-BC connections. The numerical investigation was conducted using the numerical models developed in ATENA software and validated against the test results of four T-BC connections (one steel-RC and three GFRP-RC). The TR ratio and TR configurations (2 leg, 3 leg, and 4 leg horizontal stirrups) in the connection panel were the main parameters of the numerical study. Results of the numerical study indicated that increasing the TR ratio in the connection panel to 0.72% significantly enhanced the peak load, stiffness and drift ratio capacity of the GFRP-RC T-BC connection. Four leg TR configuration showed significantly better performance of the GFRP-RC T-BC connections due to the higher confinement factor than the other TR configurations. A shear strength equation was proposed for the GFRP-RC T-BC connections, which represents a linear relationship between shear strength and the TR ratio up to 0.60%, followed by stable shear strength of 0.85fc′ for a TR ratio up to 1.30%.

Effects of Strain-Softening and Strain-Rate Dependence on the Anchor Dragging Simulation of Clay through Large Deformation Finite Element Analysis

Large-deformation finite element (LDFE) analysis with the coupled Eulerian–Lagrangian (CEL) technique for large-deformation soil functions without twisting or distorting the mesh. However, the model does not consider the strain-softening and strain-rate dependence of clay-based soils. The undrained shear strength of clay is sensitive to the strain rate. In addition, the strain-softening effect of soil strength reduction accompanied by large-scale shear deformation should be considered. In this study, anchor dragging simulations were performed for large-deformation analysis considering strain-softening and strain-rate dependence. Furthermore, a shear strength equation expressing the strain-softening and strain-rate dependence of the Tresca constitutive model was developed based on VUMAT, an ABAQUS/Explicit subroutine. The equation was designed so that it could be linked to the LDFE/CEL model. The model was verified by performing comparative analysis with the Mohr–Coulomb (M–C) perfect-plasticity model. The newly constructed Tresca base strain-softening and strain-rate-dependence VUMAT algorithm in the LDFE/CEL model analysis confirmed the effects of strain-softening and strain-rate dependence. The proposed model enabled a highly realistic simulation of the actual phenomenon than the M–C model. Finally, a parametric study on strain-softening and strain-rate dependence was conducted, and the behavior of clay due to the anchor drag phenomenon was revealed.

Improving the shear design of steel-bar reinforced ultra high performance fibre reinforced concrete beams using mesoscale modelling

Understanding the failure mechanisms of steel-bar reinforced ultra high performance fibre reinforced concrete (UHPFRC) beams is crucial to improving their design but challenging because of the contrast between beam size and fibre size. We develop a 2D mesoscale finite element model with the fibres explicitly resolved to bridge this gap by simulating the damaging and fracturing processes of the beams. To make fibre distribution in the model mechanically representative, we propose a method to project the fibres from 3D to 2D. The continuum damaged plasticity model is used as the constitutive law for the UHPC matrix, and the zero-thickness cohesive elements with softening constitutive law are used to model the nonlinear bond-slip behaviour of the fibre- and bar-matrix interfaces. The models are validated against experimental data obtained from 3 and 4-point loading tests by comparing the simulated and measured fracturing processes, crack patterns and the load-displacement curves. The validated models are then used to analyse the sensitivity of the shear strength of the beams to fibre content, shear span-to-depth ratio, as well as shear and longitudinal reinforcement ratios in the beam, from which a shear strength equation is proposed to improve the design of reinforced UHPFRC beams. The improvement of the new equation over the AFGC equation is demonstrated against experimental data measured from 32 beams with various material properties.

Performance of Strengthened, Reinforced Concrete Shear Walls with Opening

Shear walls are one of the primary lateral resisting structural elements. Due to architectural and technical needs, openings in the structural wall are almost inevitable. Discontinuity regions and a reduction in wall stiffness result from these openings. The use of fiber-reinforced-polymer (FRP) systems is a sustainable construction solution for strengthening these areas and is a viable method to restore their integrity and serviceability. This paper presents an experimental and analytical study on the behavior of reinforced concrete (RC) shear walls with openings of various sizes and positions strengthened using glass-fiber-reinforced-polymer (GFRP) sheets. Ten RC shear walls were cast and tested; initially without strengthening; and then retested with a layer of bi-directional GFRP sheet added around the opening. The finite-element (FE) program ANSYS was used for modeling since using FE contributes to sustainability. The results showed that for un-strengthened walls with a 6.25% opening and strengthened walls with an 11.11% opening, the rate of stiffness degradation was reasonably low. As the opening size was enlarged, the strength and stiffness values were drastically reduced; and the shear walls with an opening at the mid-height position also have smaller load capacities compared to the bottom and top opening positions. In addition, the ability of the GFRP sheets to control stress redistribution and crack propagation improved the overall performance of the walls. The FE and experimental results match well. Furthermore, the ACI and ECP calculations revealed a good prediction of lateral load capacity without considering the opening position, whereas the other proposed models were inaccurate. Finally, the author proposed a reduction factor (β) to the shear strength equation provided by ECP-203-2020 depending on openings sizes and locations; and suggests that FRP sheets be used around openings to assure the appropriate performance and avoid unexpected failure.

Impact of Dicranopteris linearis roots on the shear strength of different soil layers in collapsing wall of Benggang

Abstract‘Benggang’ is a local term for a widespread type of severgully erosion with steep collapsing walls in granitic, low, hilly areas of southern China, and its development and expansion are closely related to the shear strength of the collapsing wall. Plant roots play an important role in improving soil shear strength. However, the shear strength of root‐soil complexes in different layers of collapsing walls remains obscure. We selected Dicranopteris linearis fern roots and adopted the direct shear method to evaluate the effect of root weight density (RWD) (0–1.25 g 100 cm−3) on the shear properties of the lateritic, sandy and detritus layers. The results showed that roots could enhance soil shear strength, and the maximum increase in the lateritic layer was 11.53%, higher than that in the sandy (5.84%) and detritus layers (3.17%). As the root content increased, the cohesion of the sandy and detritus layers increased and then decreased, and their maximum increase in cohesion and the fitting optimal RWD were lower than those of the lateritic layer. The internal friction angle was not affected by roots. When the root content was constant, the shear strength and cohesion of the lateritic layer were significantly higher than those of the sandy and detritus layers, while their internal friction angle was significantly lower than that of the latter two layers. The average increment of soil cohesion calculated by the Wu‐Waldron model (WWM) was 10.52 kPa, which was 0.30, 3.75 and 19.38 times the measured average values of the lateritic, sandy and detritus layers, respectively. The correction coefficient k′ was 0.02–1.18, and the in the lateritic layer was the highest (0.82), followed by that in the sandy and detritus layers. By combining the modified WWM with Coulomb's formula, new shear strength equations for root‐soil complexes of D. linearis were established. The predicted shear strength compared well with the measured shear strength (R2 > 0.90, NSE >0.90). Overall, the roots only had a significant reinforcement effect on the lateritic layer, and they could still not change the mechanical properties of the collapsing wall, which were more stable in the upper layers and weaker in the bottom. Therefore, other measures should be taken in the bottom layers to improve the stability of Benggangs.Highlights Effect of D. linearis roots on the shear strength of collapsing walls in Benggang was studied. Roots could improve collapsing‐wall soil shear strength, mainly reflected in the cohesion. The roots enhancement effect in lateritic layer was better than that of sandy and detritus layers. New shear strength equations of root‐soil complexes were established based on the Wu‐Waldron model.

Effect of Water Content on Strength of Alluvial Silt in The Lower Yellow River

In order to study the strength characteristics of alluvial silt in the lower Yellow River Channel at Luokou, Jinan, by varying the moisture content five times, direct shear tests were conducted and soil–water characteristics curves were obtained to explore the relationships between moisture content and matric suction as well as the bishop coefficient and shear strength. The soil–water characteristics curve test shows that the water retention curve of silt samples in the lower Yellow River can be fitted by the VG (Van Genuchten) model with the appropriate fitting coefficients. The direct shear test reveals that the relationship between shear stress and shear displacement alters from the shear softening type to the hardening type with the increase in moisture content and normal stress. The cohesion has a nonlinear inverse relationship with moisture content while a small variation is reported in the internal friction angle. Finally, a simple shear strength equation for silt in the lower Yellow River is proposed in relation to moisture content, to define the relationship between the effective stress parameter and the matric suction for future engineering purposes.

Micromechanical-Based Shear Strength Equation Considering the Stress-State Effect for Unsaturated Soils

Unsaturated soil shear strength is a crucial and useful parameter for predicting geostructure stability, soil erosion, seasonal variation, and land management. Unsaturated shear strength measurement, however, is frequently costly, complex, and time-consuming. The main objective of this paper is to present a new generalized equation for the shear strength estimation of unsaturated soils. The proposed equation is derived from a micromechanical equilibrium condition considering the interaction of air, water, and solid phases. The particle contact area effect is taken into account in the proposed model, even though it is thought to be negligible in existing equations. In comparison with existing equations, the proposed one has the benefit of being able to capture the nonlinear influence of saturation degree and matric suction on unsaturated shear strength. The proposed equation is compared with several other existing equations as well as experimental data for four different soil types to verify its validity. The findings indicate that the proposed equation has a potential application in estimating unsaturated soil shear strength and that it outperforms existing equations. The stress state also has a substantial impact on the shear strength properties of unsaturated soils, which was extended to include in the proposed equation. The results reveal that the proposed equation is capable of accurately predicting the variation of the soil–water characteristic curve and unsaturated soil shear strength as a function of the stress state.

Shear mechanism and design of small-scale tubular flange corrugated web girders

This paper explores numerically the shear behaviour and web strength of a new type of corrugated web girders (CWGs) consisting of an upper tubular flange, a corrugated web and a lower flat plate flange. The current finite element (FE) models, simulate by ABAQUS software, are validated using the results of three new small-scale experimentally tested girders that have been recently published by the authors. Three main points are studied in this paper, namely the propagation of the plastic shear hinges (PSHs), the effect of the corrugation wavelength and the development of a new elastic design model for the girders. First, the girders are simulated to unveil their shear failure mechanism, focusing on the propagation of the plastic shear hinges (PSHs) that characterise the shear failure of conventional flat-webbed girders. Through comparisons between the tubular flange CWG and the corresponding CWG with flat plate flanges (called hereafter as the conventional CWG), it is found that PSHs occur in the lower flange of former girder at the ultimate load whatever the type of the shear buckling is, while the later does not show PSHs for cases failing by local or interactive buckling. The effect of the wavelength of the corrugation of the tubular flange CWG is secondly analysed and the results show that as the corrugation wavelength decreases, the shear capacity increases with the local shear buckling or interactive shear buckling, but this rule is not suitable for the global shear buckling mode. Finally the shear ratio of the tube to that of the entire cross-section is derived and the shear strength equation of the tubular flange CWG is provided and verified through comparisons with test results.

Study on safety and stability of high altitude dump under severe drying-wetting alternation.

This study aimed to reveal the impact of the severe drying-wetting process on the safety and stability of high-altitude dumps. Numerical calculations were conducted for the open mining dump of limestone mines for cement in high-altitude mining areas. The distribution law equation of the matric suction and the shear strength equation were imported for unsaturated soil based on the unsaturated-saturated seepage theory. Therefore, the evolution characteristics of the unsaturated-saturated seepage field and the stability of the dump were studied under severe drying-wetting. The results indicated the following rules: As the intensity of the wetting-drying alternation increased, the surface soil on the dump changed from an unsaturated to a saturated state, the matric suction continued to decrease until it reached zero, the shear strength decreased, and the unsaturated area shrank. The dump slipped under the influence of the drying-wetting alternation, the sliding area was the dump itself, and developed to the deep layer as the intensity of the drying-wetting alternation strengthened. The cumulative settlement value of the dump increased with time and eventually stabilized, and the maximum accumulative settlement value calculated by simulation was in good agreement with the actual monitoring value. The safety factor decreased as the intensity of the drying-wetting alternation increased.

Machine Learning-Based Model for Predicting the Shear Strength of Slender Reinforced Concrete Beams without Stirrups

The influence of concrete mix properties on the shear strength of slender structured concrete beams without stirrups (SRCB-WS) is a widespread point of contention. Over the past six decades, the shear strength of SRCB-WS has been studied extensively in both experimental and theoretical contexts. The most recent version of the ACI 318-19 building code requirements updated the shear strength equation for SRCB-WS by factoring in the macroeconomic factors and the contribution of the longitudinal steel structural ratio. However, the updated equation still does not consider the effect of the shear span ratio (a/d) and the yield stress of longitudinal steel rebars (Fy). Therefore, this study investigates the importance of the most significant potential variables on the shear strength of SRCB-WS to help develop a gene expression-based model to estimate the shear strength of SRCB-WS. A database of 784 specimens was used from the literature for training and testing the proposed gene expression algorithm for forecasting the shear strength of SRCB-WS. The collected datasets are comprehensive, wherein all considered concrete properties were considered over the previous 68 years. The performance of the suggested algorithm versus the ACI 318-19 equation was statistically evaluated using various measures, such as root mean square error, mean absolute error, mean absolute percentage error, and the coefficient of determination. The evaluation results revealed the superior performance of the proposed model over the current ACI 318-19 equation. In addition, the proposed model is more comprehensive and considers additional variables, including the effect of the shear span ratio and the yield stress of longitudinal steel rebars. The developed model reflects the power of employing gene expression algorithms to design reinforced concrete elements with high accuracy.

A novel shear strength model for partially encased composite (PEC) beams based on strain compatibility

Steel and concrete composite beam has been widely applied in large-span or heavily-loaded structures; however, the large shear force at the beam supports may cause web crippling or local damage. To address this problem, partially encased composite (PEC) beams, in which steel web is encased in concrete or reinforced concrete, are proposed to enhance the load-carrying capacity, anti-crippling, and anti-fire performances. In engineering practice, the vertical shear usually governs the final failure at intermediate supports; hence, accurate shear strength prediction is essential for PEC beams in practical design. Although some existing test results and shear equations exist for shear-critical PEC beams, the shear mechanism is still unclear because two shear force transferring mechanisms are coupled by the structural steel and web concrete. Therefore, it is essential to explore the contributions of the different mechanisms and how they work together as a composite structure. In this paper, the shear strength equations in current design codes and the shear strength models proposed by other researchers were reviewed and evaluated using a database consisted of the existing test results of 27 large-scale PEC beams. After identifying the shortcomings of these equations and models, this paper proposed a novel shear strength model, in which the shear contributions of the structural steel and web concrete were determined by von Mises yielding law and composite truss analogy, and the interaction between these two parts was evaluated by the strain compatibility. Finally, a comparison with the database was reported to verify the applicability of the proposed model. The results indicated that the proposed model could predict the shear strength of PEC beams with sufficient accuracy, and the strain compatibility could reasonably decouple the shear contributions of different anti-shear mechanisms.