Search

Basalt fiber (BF) is known for its high tensile strength, low elastic modulus, and environmental friendliness. To investigate the influence of basalt fiber reinforced concrete (BFRC) lamination heights on the beams' shear performance, four basalt fiber reinforced concrete and reinforced concrete (BFRC‐RC) beams featuring diverse laminated heights were fabricated and underwent bending tests. To further investigate the impact of stirrup and shear span ratios on the shear performance of BFRC‐RC beams, finite element models (FEMs) were established based on the experiments. The results indicated that four test beams experienced diagonal shear failure. Compared to RC beams, BFRC‐RC beams exhibited heightened ductility and stiffness. Additionally, as the BFRC laminated height rose, both cracking and peak loads increased. Compared to BFRC‐RC beams without stirrups, stirrups in those beams transitioned the diagonal shear failure to flexural failure. Stirrups in BFRC‐RC beams increased both the yield and peak loads, thereby enhancing their ductility. With a reduction in the shear span ratio, BFRC‐RC beams increased in both yield and peak loads, accompanied by a simultaneous decrease in yield and peak displacement. Finally, a model incorporating the influence of laminated height on BFRC‐RC beams' behavior was introduced to predict their bearing capacity. The theoretical values aligned well with the experimental results. [ABSTRACT FROM AUTHOR]

AbstractThe study on precast UHPC-NC composite beams investigated the effects of shear span ratio, stirrup reinforcement ratio, and NC strength on cracking shear force and diagonal crack width. Tests on eight UHPC-NC beams and one RC beam revealed that increasing the shear span ratio reduced the cracking shear force and widened diagonal cracks. U-shaped UHPC formwork enhanced cracking shear force and delayed crack development. While stirrup ratio had minimal impact on cracking force, it helped delay crack growth. A proposed model accurately estimated cracking shear force and maximum diagonal crack width, offering valuable insights for engineering applications. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Dalian University of Technology / Dalian Ligong Daxue Xuebao is the property of Journal of Dalian University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ultra-High-Performance Concrete (UHPC) is increasingly used in various engineering projects due to its exceptional mechanical properties. This work conducts a literature review of research on the shear performance of UHPC beams in recent decades, with a focus on summarizing the formulas for calculating shear capacity and the main factors influencing shear performance. Firstly, this work reviews the calculation methods for the shear capacity of UHPC beams in different countries, along with their respective advantages and limitations. Subsequently, it provides a detailed analysis of various factors influencing the shear performance of UHPC beams, including longitudinal and stirrup reinforcement, steel fiber content, aggregates, admixtures, the shear-span ratio, shear keys, bolts, shear-reinforcement techniques, and environmental impacts. Through horizontal comparisons, the performance of UHPC beams and ordinary concrete beams under similar experimental conditions is examined to reveal the optimal shear working conditions for UHPC beams. Additionally, it is found that UHPC performs exceptionally well in composite beams, being compatible with numerous materials and significantly enhancing the shear strength of these beams. Lastly, the paper proposes suggestions for maximizing the shear performance of UHPC beams within a safe and reliable operating range and outlines future research directions. [ABSTRACT FROM AUTHOR]

Copyright of Engineering Mechanics / Gongcheng Lixue is the property of Engineering Mechanics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Railway Construction Technology is the property of Railway Construction Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper investigated the influence of different shear span ratios, longitudinal (LR) and stirrup (SR) reinforcement ratios, and material types on the flexural and shear performance of reinforced ultra-high performance concrete (UHPC) beams. A series of bending tests with shear span ratios of 4.0, 1.5, and 1.0 were conducted. Results reveal that UHPC beams with a LR ratio of 2.53% exhibit 1.66, 2.00, and 1.45 times higher load capacity than that of the beams with a LR ratio of 1.34% at shear span ratios of 4.0, 1.5, and 1.0, respectively. A SR ratio of 1.40% can achieve 15% and 35% enhancement in load capacity of UHPC beams at shear span ratios of 1.5 and 1.0, respectively. The UHPC beams made with hybrid polyethylene and straight steel fibers have the highest load capacity compared to the beams with straight steel fibers and hooked steel fibers. The enhancement can achieve 8%, 5%, and 15% at shear span ratios of 4.0, 1.5, and 1.0, respectively. Furthermore, cross-section analysis, a novel truss-arch model, and strut-and-tie model were employed to theoretically calculate the load capacity of the UHPC beams with different failure modes. The relative errors of the cross-section analysis and truss-arch model are smaller than 9% and 25%. The findings of this work could provide guidelines for the structural design of UHPC beams under different loading conditions.

Ultra-High-Performance Concrete (UHPC) is increasingly used in various engineering projects due to its exceptional mechanical properties. This work conducts a literature review of research on the shear performance of UHPC beams in recent decades, with a focus on summarizing the formulas for calculating shear capacity and the main factors influencing shear performance. Firstly, this work reviews the calculation methods for the shear capacity of UHPC beams in different countries, along with their respective advantages and limitations. Subsequently, it provides a detailed analysis of various factors influencing the shear performance of UHPC beams, including longitudinal and stirrup reinforcement, steel fiber content, aggregates, admixtures, the shear-span ratio, shear keys, bolts, shear-reinforcement techniques, and environmental impacts. Through horizontal comparisons, the performance of UHPC beams and ordinary concrete beams under similar experimental conditions is examined to reveal the optimal shear working conditions for UHPC beams. Additionally, it is found that UHPC performs exceptionally well in composite beams, being compatible with numerous materials and significantly enhancing the shear strength of these beams. Lastly, the paper proposes suggestions for maximizing the shear performance of UHPC beams within a safe and reliable operating range and outlines future research directions.

Bamboo scrimber beams are prone to brittle failure, and I-shaped steel beams are prone to buckling and out-of-plane instability. To address these issues, the failure process, failure mechanism, deformation and bearing capacity of composite beams made by combining I-shaped steel and bamboo scrimber plates with structural adhesive are studied, taking the shear span ratio (λ) as a variable. The failure modes of the composite beam are mainly bottom-up layer-by-layer tearing of the bamboo scrimber and slight out-of-plane deformation of the I-shaped steel in the late loading period. Meanwhile, the ultimate bearing capacity, load‒displacement curve, load–strain relationship and strain distribution of the mid-span section of the composite beams are obtained, indicating that the overall working performance of these beams is excellent and that the comprehensive effect of the components is remarkable. The shear capacity of the composite beam increases with decreasing shear span ratio. By referring to the existing calculation formula of the shear capacity and fitting the test results, we obtain a calculation model of the shear capacity of a composite beam. The average error between the theoretical values and the test values is 11%, indicating that the method can predict the shear capacity well. [ABSTRACT FROM AUTHOR]

An innovative type of precast braced concrete shear (PBCS) wall has been tested and verified to have comparable shear resistances relative to conventional cast-in-place reinforced concrete (RC) shear walls. The triangular or rectangular embedded expanded polystyrene (EPS) boards in PBCS wall panels can not only considerably reduce concrete use but also reduce the structural weight. To understand the functions of EPS boards in more depth, this paper investigates the effects of the thickness ratio of different shapes of EPS on the hysteretic behaviors of PBCS walls with various shear span ratios (SSRs). The finite element (FE) models of PBCS walls based on the multi-layer shell element are developed and verified to be sufficiently accurate in comparison with the experimental results. The analysis results indicate that the bearing capacity, lateral stiffness and ductility of PBCS walls show a downward trend with the increase in the thickness ratio of EPS boards. The rectangular EPS board has a more pronounced effect on weight reduction as well as concrete use reduction compared to the triangular EPS board under the same thickness ratio. The formulations regarding the bearing capacity are developed and show good agreement with the numerical results. The thickness ratio limit for PBCS walls to satisfy the ductility requirement is addressed. This investigation not only provides insight into the cyclic behavior of PBCS walls with varied thickness ratios but also demonstrates the potential applicability of PBCS walls in precast concrete (PC) structures for both thermal insulation and earthquake resistance purposes. [ABSTRACT FROM AUTHOR]

Concrete and steel are typical rate-dependent materials. Therefore, the dynamic behavior of reinforced concrete (RC) members is inevitably affected by the loading rate. To study the effect of the loading rate on the behavior of RC beam–column joints (BCJs), a dynamic test was carried out on RC BCJs. Cyclic loading with various loading rates was applied to the column end of RC BCJs to simulate horizontal earthquake excitation. The final crack morphology and the first principal stress contour plots of BCJs indicate that dynamic loading can promote the shear effect in the core region of RC BCJs. The lower the shear span ratio is, the higher the loading rate and the more obvious the effect. Experimental results show that the yield strength and ultimate strength of BCJs are approximately linear with the logarithm of the loading rate. There is no obvious effect of the loading rate on the yield, ultimate, and failure displacements of the BCJ, but the shear angle of the core region is approximately linear with the logarithm of the loading rate. In addition, the effects of the loading rate on the stiffness degradation, ductility, and energy dissipation capacity are studied. [ABSTRACT FROM AUTHOR]

Copyright of Engineering Mechanics / Gongcheng Lixue is the property of Engineering Mechanics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

As a transfer member at the discontinuous place of vertical load, the deep beam has a complex stress mechanism and many influencing factors, such as compressive strength of concrete, shear span ratio, and reinforcement ratio. At the same time, the stress analysis principle of traditional shallow beams is no longer applicable to the design and calculation of deep-beam structure. The main purpose of this paper was to use the strut-and-tie model to analyze its stress mechanism, and to verify the applicability of the model. Nine high-strength concrete deep-beam specimens with longitudinal reinforcement with an anchor plate of the same size were tested by two-point concentrated loading method. The effects of shear span ratio (0.3, 0.6, and 0.9), longitudinal reinforcement ratio (0.67%, 1.05%, and 1.25%), horizontal reinforcement ratio (0.33%, 0.45%, and 0.50%), and stirrup reinforcement ratio (0.25%, 0.33%, and 0.50%) on the failure mode, deflection curve, characteristic load, crack width, steel bar, and concrete strain of the specimens were analyzed. The results showed that the failure mode of deep-beam specimens was diagonal compression failure. The normal section cracking load was about 15 to 20% of the ultimate load, and the inclined section cracking load was about 30~40% of the ultimate load. The shear span ratio increased from 0.3 to 0.9, and the bearing capacity decreased by 32.9%. When the longitudinal reinforcement ratio increased from 0.67% to 1.25%, the ultimate load increased by 42.6%. The shear span ratio and longitudinal reinforcement ratio have a significant effect on the bearing capacity of the high-strength concrete deep beams with longitudinal reinforcement with an anchor plate. The shear capacity of nine high-strength concrete deep-beam specimens with longitudinal reinforcement with an anchor plate was calculated by national standards, and the results were compared with the calculation results of the Tan–Tang model, the Tan–Cheng model, SSTM, and SSSTM. The analysis showed that the softened strut-and-tie model takes into account the softening effect of compressive concrete, and is a more accurate mechanical model, which can be applied to predict the shear capacity of high-strength concrete deep-beam members with longitudinal reinforcement with an anchor plate. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Railway Science & Engineering is the property of Journal of Railway Science & Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Railway Science & Engineering is the property of Journal of Railway Science & Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

According to the shear capacity test results of six steel-fiber-reinforced high-strength concrete (SFHSC) corbels with welded-anchorage longitudinal reinforcement under concentrated load, the effects of shear span ratio and steel fiber volume fraction on the failure mode, cracking load and ultimate load of corbel specimens were analyzed. On the basis of experimental research, the shear transfer mechanism of corbel structure was discussed. Then, a modified softened strut-and-tie model (MSSTM), composed of the diagonal and horizontal mechanisms, was proposed, for steel-fiber-reinforced high-strength concrete corbels. The contributions of concrete, steel fiber and horizontal stirrups to the shear bearing capacity of the corbels were clarified. A calculation method for the shear bearing capacity of steel-fiber-reinforced high-strength concrete corbels was established and was simplified on this basis. The calculation results of the model were compared with the test values and calculation results of the GB50010-2010 code, the ACI318-19 code, the EN 1992-1-1 code and the CSA A23.3-19 code. The results showed that the concrete corbel with small shear span ratio mainly has two typical failure modes: shear failure and diagonal compression failure. With the increase in shear span ratio, the shear capacity of corbels decreases. Steel fiber can improve the ductility of a reinforced concrete corbel, but has little effect on the failure mode of the diagonal section. The calculated values of the national codes were lower than the experimental values, and the results were conservative. The theoretical calculation values of the shear capacity calculation model of the corbels were close to the experimental results. In addition, the model has a clear mechanical concept considering the tensile properties of steel-fiber-reinforced high-strength concrete and the influence of horizontal stirrups, which can reasonably reflect the shear transfer mechanism of corbels. [ABSTRACT FROM AUTHOR]

A three-dimensional model of steel-bamboo composite box beam was established using ABAQUS finite element software to study the shear behavior of steel-bamboo composite box beam, focusing on the anisotropy and yield criterion of bamboo glulam and the elasticity of steel. And this model used a bilinear cohesion model to simulate the steel-bamboo interface slip and compare with the experimental results to analyze the influence of each variable parameter on the shear performance of steel-bamboo composite box beam. The study showed that the load-displacement curves obtained from the finite element simulation and the test were in good agreement, and the damage characteristics were similar, which proved the reliability and effectiveness of the finite element model of the steel-bamboo composite box beam and the bilinear cohesion model. On the basis of this model, the parameters of shear span ratio, bamboo plywood and cold-formed thin-wall steel thickness were analyzed. It is expected to provide a reference basis for the finite element simulation of steel-bamboo composite structures. [ABSTRACT FROM AUTHOR]

The seismic performances of 28 geometrically similar concrete shear walls reinforced with basalt fiber-reinforced polymer (BFRP) bars were simulated using a mesoscale modeling approach. In the modeling, concrete heterogeneities were explicitly described, and the interaction between BFRP bars and surrounding concretes was also considered. The influences of shear depth, shear span ratio and vertical reinforcement ratio on the failure of shear walls were investigated. The simulation results indicated that with the increase of shear depth, the failure modes were basically the similar, while the nominal shear strength decreased significantly, namely, the presence of size effect was demonstrated. The shear wall would exhibit different failure modes as the shear span ratio varies. Moreover, it was found that the vertical BFRP bar presented an ignorable influence on the failure mode, while the increase of vertical reinforcement ratio would obviously improve the shear strength of BFRP-RC shear wall. Finally, the present simulated shear strengths were compared with some available size effect laws and some codes. [ABSTRACT FROM AUTHOR]

An innovative type of precast braced concrete shear (PBCS) wall has been tested and verified to have comparable shear resistances relative to conventional cast-in-place reinforced concrete (RC) shear walls. The triangular or rectangular embedded expanded polystyrene (EPS) boards in PBCS wall panels can not only considerably reduce concrete use but also reduce the structural weight. To understand the functions of EPS boards in more depth, this paper investigates the effects of the thickness ratio of different shapes of EPS on the hysteretic behaviors of PBCS walls with various shear span ratios (SSRs). The finite element (FE) models of PBCS walls based on the multi-layer shell element are developed and verified to be sufficiently accurate in comparison with the experimental results. The analysis results indicate that the bearing capacity, lateral stiffness and ductility of PBCS walls show a downward trend with the increase in the thickness ratio of EPS boards. The rectangular EPS board has a more pronounced effect on weight reduction as well as concrete use reduction compared to the triangular EPS board under the same thickness ratio. The formulations regarding the bearing capacity are developed and show good agreement with the numerical results. The thickness ratio limit for PBCS walls to satisfy the ductility requirement is addressed. This investigation not only provides insight into the cyclic behavior of PBCS walls with varied thickness ratios but also demonstrates the potential applicability of PBCS walls in precast concrete (PC) structures for both thermal insulation and earthquake resistance purposes.

To investigate the shear capacity and failure mechanism of RC beams after fire exposure, fourteen full-scale beams without stirrups were tested at ambient temperature and after fire exposure. Three parameters, including the loading ratio, shear span-to-depth ratio and longitudinal reinforcement ratio, were considered in static load tests. The deterioration mechanism of the shear bearing capacity at the diagonal section of RC beams without stirrups after fire exposure was experimentally, numerically and theoretically revealed, and a calculation formula for the shear capacity of post-fire beams without stirrups was proposed. The results show that the shear capacity and stiffness of the specimens decreased after fire exposure, and the shear strength loss of the beams increased with fire exposure time. The shear capacity and stiffness of fire-damaged specimens decreased as the shear span ratio λ increased, and the shear strength loss of the beams decreased with λ. Compared with the theoretical calculation and experimental results of beams without stirrups, the average of the absolute errors was 10.48%. Therefore, this formula can better calculate the residual shear capacity of beam without stirrups after fire exposure. [ABSTRACT FROM AUTHOR]

Based on the development and distribution of cracks, we explored the shear performance of concrete beams without web reinforcement under different shear span ratios and longitudinal reinforcement ratios. Nine groups of concrete beams without web reinforcement with shear-span ratios of 1.5, 2, 2.5 and longitudinal reinforcement ratios of 1.28%, 1.62%, and 1.99% were used for four-point loading shear tests. The cracks on the surface of the test beam were analyzed by applying fractal geometry theory, and the box counting method was used to calculate the fractal dimension of the cracks on the surface of the beam under the effect of the graded load and the ultimate load. The relationship among the fractal dimension of the beam surface, the ultimate load, the graded load and the span was discussed. The results show that the shear-span ratio is inversely proportional to the ultimate load and cracking load, while the longitudinal reinforcement ratio is directly proportional to the ultimate load and exhibit a small influence on the cracking load. Concrete beams without web reinforcement have obvious fractal characteristics under the effect of graded loading or ultimate load. The fractal dimension under the effect of graded load is 0.964–1.449, and the fractal dimension under the effect of ultimate load is around 1.33. The graded load, mid-span deflection and fractal dimension show a good logarithmic relationship. The change curve of graded load and fractal dimension is affected by the shear-span ratio and the beam longitudinal reinforcement ratio. The intermediate deflection is less affected by the shear-span ratio. Under the effect of the longitudinal reinforcement ratio, the curvature of the curve shows a trend of first increasing and then decreasing, but the relationship between the ultimate load and the fractal dimension has certain differences. The ultimate load first increases and then decreases with the increase of the shear span ratio, and the difference is greater with the increase of the longitudinal reinforcement ratio.

It is generally believed that the shear span ratio is one of critical factors governing the shear failure of reinforced concrete beams. For a certain shear span scenario, the shear transfer mechanism is often attributed to one of the two typical categories: 'beam-action' for slender beams with a large shear span ratio, and 'arch-action' in deep beams with a small shear span ratio. However, in the medium shear span ratio range, neither the beam action nor the arch action dominates. In this study, an alternative model based on the notion of discontinuous fields is established under the framework of limit analysis. A shear strength formula for medium shear spans is derived subsequently by solving a combined action of the smeared-arch subfield and the vertical stirrups linking the fan subfield. After that, the least shear strength is obtained via the kinematic analysis of these discontinuous fields. To examine the proposed model, an experimental study is conducted through two T-beam specimens with artificially preset cracks and two benchmark specimens. In comparison with existing approaches and test results collected from this study and other twenty-two specimens in the literature, the proposed discontinues field model has a fairly good agreement in the shear strength predictions. A further discussion on the advantages and limitations of the simplified discontinuous field model also demonstrates that it provides a better transition of the shear strength verifications between slender beams and deep beams. • A discontinuous field model is proposed to address the shear design of RC beams with medium shear span. • A new shear strength formula is derived by combining static and kinematic analysis. • The inclined angle of equivalent critical crack is taken as the stationary value. • Artificially preset cracks in shear tests are used to examine the discontinuous fields. [ABSTRACT FROM AUTHOR]

The seismic performance of prefabricated hollow circular piers with socket and slot connection was evaluated through model tests and numerical simulations. The quasi-static tests with cyclic lateral load and constant axial load were conducted on three large pier specimens. The piers of these three specimens were cast by polyvinyl alcohol (PVA) fiber concrete, and the piers were connected to the cover beams by slotted connections and to the bearing platform by socketed connections. The seismic performance of the specimens was investigated in terms of failure modes, hysteresis curves, skeleton curves, stiffness degradation, energy dissipation, and residual deformation. The test results showed that, within a certain range, increasing the axial compression ratio is able to enhance the shear bearing capacity of prefabricated hollow piers and increase the cumulative energy dissipation, but it is not beneficial to the ductility. In addition, the increase in the shear span ratio significantly reduces the shear bearing capacity of piers and increases the residual deformation of the specimen, but the ductility is significantly improved. In addition, the numerical model of the prefabricated hollow pier was established by ABAQUS. The result of the numerical simulation was consistent and similar to the experimental result in terms of damage modes and load–displacement curves. Finally, the parametric analysis of the prefabricated hollow piers was carried out on the basis of the numerical model. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Several size-effect laws (SELs) have been proposed and verified for concrete-like quasi-brittle materials. However, there is no SEL that can quantitatively describe the influence of related factors on size effect in carbon fiber–reinforced polymer (CFRP)-strengthened lightweight aggregate concrete (LWC) components without stirrups, for example, the shear failure of beams. The main purpose of the present study is to develop a novel SEL for the evaluation of shear strength of CFRP-strengthened LWC and normal-weight concrete (NWC) beams. A 3D mesoscale simulation method is employed to explore the structural behavior of both LWC and NWC beams wrapped with CFRP sheets, in which both the concrete heterogeneities and the steel/concrete interactions are considered. Based on the modeling approach, the influences of shear span ratio and CFRP ratio on the shear failure behavior and the size effect on shear strength are studied. Also, the shear contribution by CFRP on the LWC beams having different shear span ratios under different structural sizes (i.e., beam-depth) is examined. Finally, a novel size effect law that can quantitatively describe the influence of shear span ratio and CFRP ratio on shear strength of CFRP-strengthened LWC beam is developed, and it is verified with the available test data and simulation results. [ABSTRACT FROM AUTHOR]

Reinforced concrete (RC) bridge piers of highway viaducts are exposed to the vehicular impact hazard with impact location usually close to the ground (i.e., bottom of the pier), thus resulting in dominant shear damage. Different simplified approaches for the assessment of RC bridge pier performance under impact loads are generally based on equivalent static models. One crucial element for these approaches is the determination of the static shear performances and residual axial capacity. Because of limited experimental results available under these conditions, six half-scale rectangular RC columns with different volumetric reinforcement ratios and axial compressive loads were tested under near-ground lateral loads with monotonic static conditions. Test results indicate a clear major diagonal crack at the bottom of RC columns with an inclination angle of approximately 30° below the point of application of the lateral load, and it eventually slips along the crack surface under axial loads followed by failure (i.e., loss of residual axial capacity). The increase in the volumetric reinforcement ratio significantly improves the shear deformation capacity and shear crack resistance with a slight increase in the shear capacity. The increase in the axial load can also slightly increase the shear capacity of the columns but is accompanied by a reduction in shear deformation capacity. Additionally, prediction performances of three commonly used shear capacity models for the case of RC columns under near-ground lateral loads are investigated. Finally, based on the test results, an existing residual axial capacity model is modified to improve its prediction performance. [ABSTRACT FROM AUTHOR]

To investigate the shear capacity and failure mechanism of RC beams after fire exposure, fourteen full-scale beams without stirrups were tested at ambient temperature and after fire exposure. Three parameters, including the loading ratio, shear span-to-depth ratio and longitudinal reinforcement ratio, were considered in static load tests. The deterioration mechanism of the shear bearing capacity at the diagonal section of RC beams without stirrups after fire exposure was experimentally, numerically and theoretically revealed, and a calculation formula for the shear capacity of post-fire beams without stirrups was proposed. The results show that the shear capacity and stiffness of the specimens decreased after fire exposure, and the shear strength loss of the beams increased with fire exposure time. The shear capacity and stiffness of fire-damaged specimens decreased as the shear span ratio λ increased, and the shear strength loss of the beams decreased with λ. Compared with the theoretical calculation and experimental results of beams without stirrups, the average of the absolute errors was 10.48%. Therefore, this formula can better calculate the residual shear capacity of beam without stirrups after fire exposure.

The seismic performance of prefabricated hollow circular piers with socket and slot connection was evaluated through model tests and numerical simulations. The quasi-static tests with cyclic lateral load and constant axial load were conducted on three large pier specimens. The piers of these three specimens were cast by polyvinyl alcohol (PVA) fiber concrete, and the piers were connected to the cover beams by slotted connections and to the bearing platform by socketed connections. The seismic performance of the specimens was investigated in terms of failure modes, hysteresis curves, skeleton curves, stiffness degradation, energy dissipation, and residual deformation. The test results showed that, within a certain range, increasing the axial compression ratio is able to enhance the shear bearing capacity of prefabricated hollow piers and increase the cumulative energy dissipation, but it is not beneficial to the ductility. In addition, the increase in the shear span ratio significantly reduces the shear bearing capacity of piers and increases the residual deformation of the specimen, but the ductility is significantly improved. In addition, the numerical model of the prefabricated hollow pier was established by ABAQUS. The result of the numerical simulation was consistent and similar to the experimental result in terms of damage modes and load–displacement curves. Finally, the parametric analysis of the prefabricated hollow piers was carried out on the basis of the numerical model.

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

As a common engineering timber member used in the construction of timber bridges, a glulam T-beam has good mechanical properties. However, the low shear strength and various natural defects of timber cause the glulam T-beam to be prone to shear failure under load, and its shear performance is affected by web width and shear span ratio. To reveal the influences of web width and shear span ratio on the shear performance of glulam T-beams, five groups (10 in total) of glulam T-beam components and one group (2 in total) of glulam rectangular beam components were designed and manufactured with Larix gmelinii as a raw material. The deflection, strain, and ultimate bearing capacity of each component were measured using the mid-span concentrated force loading method. The failure mode of the component was observed, and its failure mechanism was discussed. The strain, deflection, and ultimate bearing capacity of each component were compared and analyzed. The calculation formula of the shear bearing capacity of a plywood T-beam was proposed. Results show that the failure mode of glued timber T-beam is shear failure along the grain. Compared with a rectangular beam, the ultimate bearing capacity of a glulam T-beam is increased by 71.36% on average, and the bending stiffness is increased by 131.28% on average. The shear capacity and bending rigidity of the glulam T-beam increase with the increase in web width and decrease with the increase in shear span ratio. The formula presented in this paper is reasonable and reliable, and the theoretical calculation value agrees well with the test value. This study can provide a reference for the engineering application and design of glulam T-beams. [ABSTRACT FROM AUTHOR]

To expand the application of wood as a building material, a new type of I-shaped wood-steel beam that consisted of laminated veneer lumber and cold-formed thin-walled steel was considered in this paper. The shear performance of nine wood-steel composite beams was tested to evaluate the effects of shear span ratio, web thickness, and flange thickness. Then, the failure pattern and failure mechanism of the composite beams were analyzed. The main affecting factors of shear capacities were also discussed. Furthermore, the calculation formula for bearing capacities of composite beams was established and the calculation results were compared with the experimental results. The experimental results showed that the combined effect of composite beams was excellent. The shear capacity was mainly affected by shear span ratio and web thickness. The calculation formula of the shear capacity was established based on the shear flow theory and the specification for structural steel buildings. The formula was derived from the micro-segment balance method and the reciprocal theorem of shear stress. The calculation results according to the formula were in good agreement with the experimental values. [ABSTRACT FROM AUTHOR]

The mechanical properties of concrete and steel are seriously degraded under high temperature, so that reinforced concrete (RC) members after fire may not be able to satisfy the prescribed performance. In this study, 27 full-scale RC beams were carried out shear tests to investigate the shear behaviour after fire. A total of 20 beams were subjected to fire on three sides in accordance with ISO 834 standard fire curve, and the remaining 7 beams (which were not subjected to fire) were employed as a reference. The influences of fire time, stirrup ratio, shear span ratio, longitudinal reinforcement ratio, and preloading (40% loading level) were considered. The experimental results indicated that the shear failure mode of the RC specimens after fire exposure was similar to that of the reference specimens. Both the residual shear load bearing capacity and stiffness of the RC beams decreased after being subjected to fire. The loss of shear bearing capacity increased with the heating time. In addition, the ultimate load bearing capacity of specimens with stirrups subjected to the same fire exposure time decreased with an increasing shear span ratio. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Henan University of Science & Technology, Natural Science is the property of Editorial Office of Journal of Henan University of Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Engineering Mechanics / Gongcheng Lixue is the property of Engineering Mechanics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Different from the traditional concrete mixing procedure, the innovative post-filling coarse aggregate concrete (PFCC) reduces the cost of pumping concrete by increasing the coarse aggregate content and reducing the usage of cement. Previous studies have shown that PFCC enhances the compressive strength, elastic modulus, and flexural strength of concrete. In this paper, the shear behavior of 13 post-filling coarse aggregate concrete beams and 3 control beams was tested to determine the relationships between the shear performance of the beam and the post-filling coarse aggregate ratio, concrete strength grade, shear span ratio and stirrup reinforcement ratio. The results showed that the ultimate shear capacity of beam specimen increases first and then decreases with the increase in post-filling coarse aggregate ratio, reaching the maximum at 15% post-filling ratio. The results also indicated that the ultimate shear capacity of the beam increases with the increase in concrete strength grade and stirrup ratio. However, experimental results exhibited that the ultimate shear capacity decreases as the shear span ratio increases. This study provides a reference for the application of post-filling coarse aggregate concrete in engineering practice.

Copyright of Journal of Shanghai University / Shanghai Daxue Xuebao is the property of Journal of Shanghai University (Natural Sciences) Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Engineering Mechanics / Gongcheng Lixue is the property of Engineering Mechanics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper attempts to disclose the shear behavior of reinforced concrete (RC) beams designed by compressive force path (CFP) method. For this purpose, three beams were designed by the CFP method and another three by GB 50010-2010. For each type of beams, the three beams were prepared with different shear span ratios, respectively 2.0, 1.5 and 1.0. Then, a monotonic loading test was performed on all the beams. To identify the effect of shear span ratio on shear behavior, the author compared the CFP beams with GB beams in terms of ultimate load, failure process and failure mode. In addition, the loaddeflection curve and load-strain curves of concrete, reinforcement and stirrups were analyzed in details. The results show that the shear capacity of RC beams is mainly affected by the stress transmitted along the CFP; Compared with the GB method, the CFP method, despite using fewer number of stirrups, effectively guaranteed the shear capacity of the beams with any of the three shear span ratios, and did not significantly change the ultimate load; the amount of stirrups saved by the CFP is negatively correlated with the shear span ratio of the beam. To sum up, the CFP method was proved as a feasible and rational way to design RC beams. [ABSTRACT FROM AUTHOR]

The mechanical behavior of fabricated partially encased composite (PEC) beams was investigated by testing 12 specimens under unidirectional cyclic loads. The main test variables were the shear span ratio, concrete thickness and screw arbors etc. The researching results show that: with the increase of shear span ratio, the failure mode of the specimens changes from shear failure to bending failure. In the later stage of loading, some specimens show asymmetric concrete damage on both sides of the web, which leads to additional torsion on the specimens besides bending and shearing. The screw arbors not only enhance the confining effect of steel on concrete and prevent the local buckling of compressed steel flange, but also play the role of shear connection and ensure the composite action between steel and concrete. The concrete thickness has a great influence on the bearing capacity of specimens with a small shear span ratio, but has only a small effect on specimens with a large shear span ratio as its effect on the flexural capacity of normal section is limited. According to the superposition principle, a formula for calculating the shear capacity of fabricated PEC beams was proposed. On the basis of plane section assumption, a method for calculating the bending capacity of fabricated PEC beams was developed. A three-line model was proposed to reflect the normalized relationship between Vm and Mm. [ABSTRACT FROM AUTHOR]

To investigate the shear capacity of solid-web H-shaped steel reinforced concrete (HSRC) columns under combined torque, seven HSRC columns were tested using axial compression ratio (n), torsion bend ratio (γ), and shear span ratio (λ) as test parameters. The stress process and failure mode of the HSRC column were observed and recorded. The load-displacement (P - ∆) hysteresis curve and skeleton curve of each specimen were analyzed. The influence of three parameters on the shear capacity of the HSRC column was discussed. And revealed the shear mechanism under different failure modes of the HSRC column. The calculation formula of the shear capacity of the HSRC column was derived. The results show that the failure modes of HSRC columns under different parameters could be classified as bending-torsion-bending failure, torsion-bending failure, and torsion-shear-bond failure. The addition of H-shaped steel can effectively inhibit the development of the inclined crack and improve the shear capacity of the specimen. The P - ∆ hysteresis curve of the specimen is full spindle. Increasing the axial compression ratio will increase the shear capacity of the specimen, but increasing the torsion bend ratio and shear span ratio will decrease. Finally, based on the calculation theory of normal section and inclined section bearing capacity, the calculation formulas of shear bearing capacity of HSRC columns under two kinds of composite torque are proposed for different shear span ratios. The calculation results are in good agreement with the experimental values. • The quasi-static load test of reinforced concrete column under combined action of composite torque is carried out. • The P - ∆ curve and skeleton curve of HSRC columns are analyzed, and the shear mechanism of HSRC columns is revealed. • The formulas for calculating the shear capacity of HSRC columns under two kinds of composite torque are proposed. [ABSTRACT FROM AUTHOR]

The mechanical properties of concrete and steel degrade after exposure to fire, thus the fire-damaged reinforced concrete (RC) members may not be able to satisfy the prescribed performance. Therefore, it is of great significance to identify the degree of fire damage for RC members or even the entire RC structure. For RC beams, comprehensive studies have been conducted on the residual flexural capacity after fire, but those related to the post-fire shear properties are barely found in the literature. In this paper, the shear tests of twenty-five beams––including frame beams and cantilevers––were carried out to investigate the difference in their shear behaviors before and after fire exposure. The parameters controlling shear capacity, such as shear span ratio, the concrete slab (i.e. the flange of the beam), and the stirrup spacing, were investigated. The experimental results indicated that both the shear capacity and the stiffness of the RC beams degraded after fire. The diagonal cracks of frame beams with fewer stirrups concentrated seriously, and their crack width increased considerably. Based on the test results, a simplified evaluation process was developed to evaluate the shear capacity of RC beams after fire, and the proposed formula was proven to be able to predict the residual shear capacity of fire-damaged RC beams with sufficient accuracy. [ABSTRACT FROM AUTHOR]