• Steel and Composite Structures
• /
• v.48 no.6
• /
• pp.693-708
• /
• 2023

Composite beams, two materials joined together, have become more common in structural engineering over the past few decades because they have better mechanical and structural properties. The shear connectors between their layers exhibit some deformability with finite stiffness, resulting in interfacial shear slip, a phenomenon known as partial shear interaction. Such a partial shear interaction contributes significantly to the composite beams. To provide precise predictions of the geometric nonlinear behavior shown by two-layered composite beams with interfacial shear slips, a robust analytical model has been developed that incorporates the influence of significant displacements. The application of a higher-order beam theory to the two material layers results in a third-order adjustment of the longitudinal displacement within each layer along the depth of the beam. Deformable shear connectors are employed at the interface to represent the partial shear interaction by means of a sequence of shear connectors that are evenly distributed throughout the beam's length. The Von-Karman theory of large deflection incorporates geometric nonlinearity into the governing equations, which are then solved analytically using the Navier solution technique. Suggested model exhibits a notable level of agreement with published findings, and numerical outputs derived from finite element (FE) model. Large displacement substantially reduces deflection, interfacial shear slip, and stress values. Geometric nonlinearity has a significant impact on beams with larger span-to-depth ratio and a greater degree of shear connector deformability. Potentially, the analytical model can accurately predict the geometric nonlinear responses of composite beams. The model has a high degree of generality, which might aid in the numerical solution of composite beams with varying configurations and shear criteria.

• Journal of Korean Society of Steel Construction
• /
• v.29 no.5
• /
• pp.389-400
• /
• 2017

Based on U-shaped composite beam, the new form of AU-composite beam were developed to create economical and efficient components reducing the cost and shortening the length of construction work. Because the U-shaped sections are open and needs to be fixed by topping concrete securely. Therefore, it is required to maintain the U-shaped sections in a structure and to work in the safe condition through construction. It also requires accessories that resist the horizontal shear force for synthesis between the top and bottom of the U-shaped section. To reinforce these shortcomings, a shear connector has been developed with various purposes of steel plate anchors. In this study, the steel plate anchors were directly tested and the shear force was evaluated by the horizontal shear force. The experiment was divided into two types, depending on the applicable deck plates. As a result of the experiment, the continuous type specimens showed greater resistance in both strength and displacement than the ones of stud anchor specimen. In discontinuous type case, due to shear simulations and simple element analysis, the less increase the ratio of width to height and the more shear strength decreased. Thus, the shear strength equation of the stud anchor was modified to suggest the new shear strength based on the testing results.

• Journal of Korean Society of Steel Construction
• /
• v.24 no.4
• /
• pp.423-433
• /
• 2012

This paper summarizes full-scale gravity-load test results on CFT column-to-RC flat plate connections reinforced with shearhead. CFT construction has many structural and constructional advantages over conventional steel and RC column construction and is gaining wide acceptance. Meanwhile the use of RC flat plate system in the basement and residential floors of tall buildings is often mandatory to reduce story height and enable rapid construction in domestic practice. Combining CFT column and flat plate floor is expected to result in further rapid construction. However, the issues related to connecting CFT column to RC flat plate have not been fully addressed yet. Several promising connecting schemes by using steel shearhead were proposed and tested in this study. Test results showed that the proposed connection can exhibit the punching shear strength higher than RC flat plate counterparts. An empirical formula that can reasonably predicts the punching shear strength of the proposed connection was also proposed.

• Steel and Composite Structures
• /
• v.45 no.6
• /
• pp.797-818
• /
• 2022

Steel-precast ultra-high-performance concrete (UHPC) composite beams with demountable high-strength friction-grip bolt (HSFGB) shear connectors can be used for accelerated bridge construction (ABC) and achieve excellent structural performance, which is expected to be dismantled and recycled at the end of the service life. However, no investigation focuses on the demountability and reusability of such composite beams, as well as the installation difficulties during construction. To address this issue, this study conducted twelve push-out tests to investigate the effects of assembly condition, bolt grade, bolt-hole clearance, infilling grout and pretension on the crack pattern, failure mode, load-slip/uplift relationship, and the structural performance in terms of ultimate shear strength, friction resistance, shear stiffness and slip capacity. The experimental results demonstrated that the presented composite beams exhibited favorable demountability and reusability, in which no significant reduction in strength (less than 3%) and stiffness (less than 5%), but a slight improvement in ductility was observed for the reassembled specimens. Employing oversized preformed holes could ease the fabrication and installation process, yet led to a considerable degradation in both strength and stiffness. With filling the oversized holes with grout, an effective enhancement of the strength and stiffness can be achieved, while causing a difficulty in the demounting of shear connectors. On the basis of the experimental results, more accurate formulations, which considered the effect of bolt-hole clearance, were proposed to predict the shear strength as well as the load-slip relationship of HSFGBs in steel-precast UHPC composite beams.

• Journal of Korean Society of Steel Construction
• /
• v.10 no.4 s.37
• /
• pp.759-767
• /
• 1998

Full-depth precast concrete deck bridge has shear pockets for shear connectors that give composite action with steel girder. Strength and shear stiffness of shear connection that is needed to design shear connectors in case that shear pockets are filled with nonshrink mortar are investigated. In case that simple span full-depth precast concrete deck bridge is designed by allowable stress design, distribution of shear connector is suggested and details of precast panel that is placed on the support are proposed. Appropriate distribution of shear connectors in strength design and fatigue design is investigated through parameter analyses using partial interaction theory. The effects of nonshrink mortar strength is studied using the results of experiments and analyses and adequate strength is proposed.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2005.03a
• /
• pp.179-184
• /
• 2005

Shear strength parameters obtained from filed survey are important factors in the analysis of slope stability. In this study, sensitivity analysis was performed to evaluate the effect of input parameters on the analysis of slope stability. The input parameters selected for sensitivity analysis were slope angle, cohesion, and friction angle. Monte-Carlo Simulation method was used for calculating input parameters and the factor of safety was computed by means of limit equilibrium method. A rock slope, which has failed in the field, was used for the sensitivity analysis in the analysis of slope stability. The result of analysis shows that the factor of safety of the rock slope was a little low. From partial correlation coefficient(PPC) of input parameters determined from the sensitivity analysis, slope stability was dependant on cohesion and slope angle. The effect of friction angle was lower than that of cohesion and slope angle on slope stability.

• Steel and Composite Structures
• /
• v.12 no.3
• /
• pp.261-273
• /
• 2012

This study proposes and examines a circular composite bridge pier for seismic resistance. The axial and flexural strengths of the proposed bridge pier are provided by the longitudinal reinforcing bars and the concrete, while the transverse reinforcements used in the conventional reinforced concrete pier are replaced by the steel tube. The shear strength of this composite pier relies on the steel tube and the concrete. This system is similar to the steel jacketing method which strengthens the existing reinforced concrete bridge piers. However, no transverse shear reinforcing bar is used in the proposed composite bridge pier. A series of experimental studies is conducted to investigate the seismic resistant characteristics of the proposed circular composite pier. The effects of the longitudinal reinforcing bars, the shear span-to-diameter ratio, and the thickness of the steel tube on the performance of strength, ductility, and energy dissipation of the proposed pier are discussed. The experimental results show that the strength of the proposed circular composite bridge pier can be predicted accurately by the similar method used in the reinforced concrete piers with minor modification. From these experimental studies, it is found that the proposed circular composite bridge pier not only simplifies the construction work greatly but also provides excellent ductility and energy dissipation capacity under seismic lateral force.

• Journal of the Korean Geotechnical Society
• /
• v.25 no.4
• /
• pp.105-112
• /
• 2009

In this study, a series of direct shear tests were performed to investigate the characteristics of friction angles for sands and interface friction angle between sands and construction materials with respect to different relative density of the Nak-dong River sands and shearing velocity. The result of the test shows that friction angles of sands are always higher than interface friction angle between sands and construction materials. As the shearing velocity get faster, the friction angles of sand became higher. With respect to the density of sand by reducing void ratio, friction angles increase linearly, and relevant equations were proposed to calculate the friction angle by changing void ratio and relative density of sand. The interface roughness of construction materials was also an important factor in interface friction angle.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2003.04a
• /
• pp.35-42
• /
• 2003

This paper provides the first known flexural vibration data for thick (Mindlin) rectangular plates having V-notches. The V-notch has bending moment and shear force singularities at its sharp corner due to the transverse vibratory bending motion. Based upon Mindlin plate theory, in which transverse shear deformation and rotary inertia effects are considered, the Ritz procedure is employed with a hybrid set of admissible functions assumed for the rotational and transverse vibratory displacements. This set includes: (1) a mathematically complete set of admissible algebraic-trigonometric polynomials which guarantee convergence to exact frequencies as sufficient terms are retained; and (2) an admissible set of Mindlin corner functions which account for the bending moment and shear force singularities at the sharp corner of the V-notch. Extensive convergence studies demonstrate the necessity of adding the Mindlin corner functions to achieve accurate frequencies for rectangular plates having sharp V-notches.

• Journal of Korean Society of Steel Construction
• /
• v.10 no.4 s.37
• /
• pp.721-730
• /
• 1998

In this paper, an experimental study have been many studies on the joints of steel structure, for it has great influences on the safety of structures. Research on block shear rupture of the joint receiving pure tension have been done in foreign countries, but not in Korea. This study focuses on the propriety of block shear design code, according to limited state design criteria of steel structures recently established in Korea, by an experiment on the joint of angle tension members. The methods of this study were to compare other study results on block shear rupture mode and ultimate capacity, and to evaluate the propriety of the criteria design code. The result is that tension yield shear ruptures and shear yield tension ruptures happened at the joint, and the experimental rupture load was 15% higher than the capacity entered in the criteria design code. We conclude that it is necessary to revaluate the block shear design code presented by many studies on the limited state design criteria of steel structures.