• Title, Summary, Keyword: shear design

Search Result 2,784, Processing Time 0.049 seconds

Design Equation for Punching Shear Capacity of SFRC Slabs

  • Higashiyama, Hiroshi;Ota, Akari;Mizukoshi, Mutsumi
    • International Journal of Concrete Structures and Materials
    • /
    • v.5 no.1
    • /
    • pp.35-42
    • /
    • 2011
  • In this paper, a design equation for the punching shear capacity of steel fiber reinforced concrete (SFRC) slabs is proposed based on the Japan Society of Civil Engineers (JSCE) standard specifications. Addition of steel fibers into concrete improves mechanical behavior, ductility, and fatigue strength of concrete. Previous studies have demonstrated the effectiveness of fiber reinforcement in improving the shear behavior of reinforced concrete slabs. In this study, twelve SFRC slabs using hooked-ends type steel fibers are tested with varying fiber dosage, slab thickness, steel reinforcement ratio, and compressive strength. Furthermore, test data conducted by earlier researchers are involved to verify the proposed design equation. The proposed design equation addresses the fiber pull-out strength and the critical shear perimeter changed by the fiber factor. Consequently, it is confirmed that the proposed design equation can predict the punching shear capacity of SFRC slabs with an applicable accuracy.

Effect of plate properties on shear strength of bolt group in single plate connection

  • Ashakul, Aphinat;Khampa, Kriangkrai
    • Steel and Composite Structures
    • /
    • v.16 no.6
    • /
    • pp.611-637
    • /
    • 2014
  • A single plate shear connection, or shear tab, is a very popular shear connection due to its merit in ease of construction and material economy. However, problems in understanding the connection behavior, both in terms of strength and ductility, have been well-documented. Suggestions or design model for single plate connections in AISC Design Manual have been altered several times, with the latest edition settling down to giving designers pre-calculated design strength tables if the connection details agree with given configurations. Results from many full-scale tests and finite element models in the past suggest that shear strength of a bolt group in single plate shear connections might be affected by yield strength of plate material; therefore, this research was aimed to investigate and clarify effects of plate yield strength and thickness on shear strength of the bolt group in the connections, including the validity of using a plate thickness/bolt diameter ratio ($t_p/d_b$) in design, by using finite element models. More than 20 models have been created by using ABAQUS program with 19.0- and 22.2-mm A325N bolts and A36 and Gr.50 plates with various thicknesses. Results demonstrated that increase of plate thickness or plate yield strength, with the $t_p/d_b$ ratio remained intact, could significantly reduce shear strength of the bolt group in the connection as much as 15 percent. Results also confirmed that the $t_p/d_b$ ratio is a valid indicator to be used for guaranteeing strength sufficiency. Because the actual ratio recommended by AISC Design Manual is $t_p/d_b$ + 1.6 (mm) for connections with a number of bolts less than six and plate yield strength in construction is normally higher than the nominal value used in design, it is proposed that shear strength of a bolt group in single plate connections with a number of bolts equal or greater than seven be reduced by 15 percent and the $t_p/d_b$ ratio be limited to 0.500.

Direct design of partially prestressed concrete solid beams

  • Alnuaimi, A.S.
    • Structural Engineering and Mechanics
    • /
    • v.27 no.6
    • /
    • pp.741-771
    • /
    • 2007
  • Tests were conducted on two partially pre-stressed concrete solid beams subjected to combined loading of bending, shear and torsion. The beams were designed using the Direct Design Method which is based on the Lower Bound Theorem of the Theory of Plasticity. Both beams were of $300{\times}300mm$ cross-section and 3.8 m length. The two main variables studied were the ratio of the maximum shear stress due to the twisting moment, to the shear stress arising from the shear force, which was varied between 0.69 and 3.04, and the ratio of the maximum twisting moment to the maximum bending moment which was varied between 0.26 and 1.19. The required reinforcement from the Direct Design Method was compared with requirements from the ACI and the BSI codes. It was found that, in the case of bending dominance, the required longitudinal reinforcements from all methods were close to each other while the BSI required much larger transverse reinforcement. In the case of torsion dominance, the BSI method required much larger longitudinal and transverse reinforcement than the both the ACI and the DDM methods. The difference in the transverse reinforcement is more pronounce. Experimental investigation showed good agreement between design and experimental failure loads of the beams designed using the Direct Design Method. Both beams failed within an acceptable range of the design loads and underwent ductile behaviour up to failure. The results indicate that the Direct Design Method can be successfully used to design partially prestressed concrete solid beams which cater for the combined effect of bending, shear and torsion loads.

Numerical simulation of Y-type perfobond rib shear connectors using finite element analysis

  • Kim, Kun-Soo;Han, Oneil;Gombosuren, Munkhtulga;Kim, Sang-Hyo
    • Steel and Composite Structures
    • /
    • v.31 no.1
    • /
    • pp.53-67
    • /
    • 2019
  • This study presents finite element analysis (FEA) on a Y-type perfobond rib shear connection using Abaqus software. The performance of a shear connection is evaluated by conducting a push-out test. However, in practice, it is inefficient to verify the performance by conducting a push-out test with regard to all design variables pertaining to a shear connector. To overcome this problem, FEA is conducted on various shear connectors to accurately estimate the shear strength of the Y-type perfobond rib shear connection. Previous push-out test results for 14 typical push-out test specimens and those obtained through FEA are compared to analyze the shear behavior including consideration of the design variables. The results show that the developed finite element model successfully reflects the effects of changes in the design variables. In addition, using the developed FEA model, the shear resistance of a stubby Y-type perfobond rib shear connector is evaluated based on the concrete strength and transverse rebar size variables. Then, the existing shear resistance formula is upgraded based on the FEA results.

Reinforced concrete corbels strengthened with carbon fiber reinforced plastics

  • Lu, Wen-Yao;Yu, Hsin-Wan;Chen, Chun-Liang;Yang, Tzong-Hwan;Lin, Yu-Sin
    • Computers and Concrete
    • /
    • v.10 no.3
    • /
    • pp.259-276
    • /
    • 2012
  • A total of nine reinforced concrete corbels were tested, in this study. Six were externally strengthened with carbon fiber reinforced plastics (CFRP), in the horizontal direction. The cross-sectional area of CFRP and the shear span-to-effective depth ratios are the parameters considered, in this study. Test results indicate that the higher the cross-sectional area of CFRP, the higher is the shear strength of the corbels, and the lower the shear span-to-effective depth ratios, the higher is the shear strength of corbels. The shear strength predicted by the design provisions in section 11.8 of the ACI Code, the strut-and-tie model in Appendix A of the ACI Code, and the softened strut-and-tie (SST) model were compared with the test results. The comparisons show that both the strut-and-tie model in Appendix A of the ACI Code, and the SST model can accurately predict the shear strength of reinforced concrete corbels, strengthened with CFRP.

Shear behavior of Large-Diameter Concrete Filled Tube (CFT)

  • Jung, Eun-bi;Lee, Seo-Haeng;Yoo, Jung-Han;Roeder, Charles;Lehman, Dawn
    • International journal of steel structures
    • /
    • v.17 no.4
    • /
    • pp.1653-1667
    • /
    • 2017
  • Circular concrete filled tube (CFT) is composite structure to fill concrete in steel tube as formwork. By combining advantage of steel tube and concrete, CFT has more superior deformation capacity and strength than reinforced concrete and steel structure, since bond stress between steel tube and concrete has influence on prevention of local buckling and increase in strength of concrete. For such a reason, CFT has been applied to as columns in buildings, and pile and drilled shaft foundations. CFT drilled shaft is designed to large diameter due to large local shear strength by seismic load, liquefaction and lateral spreading of soil layer. However, it brings uneconomical design by the conservative shear equation of current design provision. Until today, shear studies of circular CFT to improve shear equation have been rarely conducted and they are limited to small scale test. In this research, the numerical and experimental results are compared to current shear design equations, with the ultimate goal to serve as an initial analytical study that aids in planning further experimental and analytical research on shear resistance and behavior of circular CFT, which leads to improved shear design equations.

Tests of reinforced concrete deep beams

  • Lu, Wen-Yao;Hsiao, Hsin-Tai;Chen, Chun-Liang;Huang, Shu-Min;Lin, Ming-Che
    • Computers and Concrete
    • /
    • v.15 no.3
    • /
    • pp.357-372
    • /
    • 2015
  • This study reports the test results of twelve reinforced concrete deep beams. The deep beams were tested with loads applied through and supported by columns. The main variables studied were the shear span-to-depth ratios, and the horizontal and vertical stirrups. The shear strengths can be effectively enhanced for deep beams reinforced with both horizontal and vertical stirrups. The test results indicate the shear strengths of deep beams increase with the decrease of the shear span-to-depth ratios. The normalized shear strengths of the deep beams did not increase proportionally with an increase in effective depth. An analytical method for predicting the shear strengths of deep beams is proposed in this study. The shear strengths predicted by the proposed method and the strut-and-tie model of the ACI Code are compared with available test results. The comparison shows the proposed method can predict the shear strengths of reinforced concrete deep beams more accurately than the strut-and-tie model of the ACI Code.

Evaluation of Average Shear-wave Velocity Estimation Methods of Multi-layered Strata Considering Site Period (지반주기를 고려한 다층지반의 평균전단파속도 추정 방법 평가)

  • Kim, Dong-Kwan
    • Journal of the Earthquake Engineering Society of Korea
    • /
    • v.23 no.3
    • /
    • pp.191-199
    • /
    • 2019
  • To calculate proper seismic design load and seismic design category, the exact site class for construction site is required. At present, the average shear-wave velocity for multi-layer soil deposits is calculated by the sum of shear-wave velocities without considering of vertical relationship of the strata. In this study, the transfer function for the multi-layered soil deposits was reviewed on the basis of the wave propagation theory. Also, the transfer function was accurately verified by the finite element model and the eigenvalue analysis. Three methods for site period estimation were evaluated. The sum of shear-wave velocities underestimated the average shear-wave velocities of 526 strata with large deviations. The equation of Mexican code overestimated the average shear-wave velocities. The equation of Japanese code well estimated the average shear-wave velocities with small deviation.

Seismic design of connections between steel outrigger beams and reinforced concrete walls

  • Deason, Jeremy T.;Tunc, Gokhan;Shahrooz, Bahram M.
    • Steel and Composite Structures
    • /
    • v.1 no.3
    • /
    • pp.329-340
    • /
    • 2001
  • Cyclic response of "shear" connections between steel outrigger beams and reinforced concrete core walls is presented in this paper. The connections investigated in this paper consisted of a shear tab welded onto a plate that was connected to the core walls through multiple headed studs. The experimental data from six specimens point to a capacity larger than the design value. However, the mode of failure was through pullout of the embedded plate, or fracture of the weld between the studs and plate. Such brittle modes of failure need to be avoided through proper design. A capacity design method based on dissipating the input energy through yielding and fracture of the shear tab was developed. This approach requires a good understanding of the expected capacity of headed studs under combined gravity shear and cyclic axial load (tension and compression). A model was developed and verified against test results from six specimens. A specimen designed based on the proposed design methodology performed very well, and the connection did not fail until shear tab fractured after extensive yielding. The proposed design method is recommended for design of outrigger beam-wall connections.

Design of composite plate girders under shear loading

  • Shanmugam, N.E.;Baskar, K.
    • Steel and Composite Structures
    • /
    • v.6 no.1
    • /
    • pp.1-14
    • /
    • 2006
  • Experiments have been carried out on six composite and two plain steel plate girders under shear loading to understand the elastic and inelastic behaviour of such girders. The failure mechanism assumed and used to develop design equations is normally based on the failure patterns observed in the experiments. Therefore, different types of cracks and failure patterns observed in the experiments are reviewed briefly first. Based on the observed failure patterns, a design method to predict the ultimate shear capacity of composite plate girders is proposed in this paper. The values of ultimate shear capacity obtained using the proposed design method are compared with the corresponding experimental values and it is found that the proposed method is able to predict the shear capacity accurately.