• Steel and Composite Structures
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• v.39 no.4
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• pp.367-381
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• 2021

Reinforced concrete (RC) columns can be strengthened by direct fastening of steel plates around a column, forming composite actions. This method can increase both the total load bearing area and the concrete confinement stress. To predict the axial load resistance of strengthened RC columns, the equivalent passive confinement stress of the stirrups and the steel jacket should be accurately quantified, which requires the stress in the stirrups and shear force in the connections to be first obtained. In this paper, parameters, i.e., the stress ratio of the stirrups and shear force ratio of steel plate connectors are utilized to quantify the stress of the stirrups and shear force in the connections. A mechanical model for determining the stress ratio of the stirrups and shear force ratio of steel plate connectors is proposed and validated using the experimental results in a previous study. The model is found to be robust. Subsequently, a parametric study is conducted and the optimum stress ratios of the stirrups and the optimum shear force ratios of connectors are proposed for engineering designs.

• Structural Engineering and Mechanics
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• v.57 no.6
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• pp.1065-1084
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• 2016

The analysis and design of skeletal structures is greatly influenced by the behaviour of beam-to-column connections, where patented designs have led to a wide range of types with differing structural quantities. The behaviour of beam-to-column connections plays an important role in the analysis and design of framed structures. This paper presents an overview of the influence of connection behaviour on structural stability, in the in-plane (bending) mode of sway. A computer-based method is presented for geometrically nonlinear plane frames with semi-rigid connections accounting for shear deformations. The analytical procedure employs transcendental modified stability functions to model the effect of axial force on the stiffness of members. The member stiffness matrix were found. The critical load has been searched as a suitable load parameter for the loss of stability of the system. Several examples are presented to demonstrate the validity of the analysis procedure. The method is readily implemented on a computer using matrix structural analysis techniques and is applicable for the efficient nonlinear analysis of frameworks. Combined with a parametric column effective length study, connection and frame stiffness are used to propose a method for the analysis of semi-rigid frames where column effective lengths are greatly reduced and second order (deflection induced) bending moments in the column may be distributed via the connectors to the beams, leading to significant economies.

• Journal of the Korean Wood Science and Technology
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• v.30 no.3
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• pp.59-65
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• 2002

EYM (European Yield Model), which was adopted in NDS (National Design Specification for wood construction), has been used in Korea without any verification of the analysis of bolted wood connections. In the case of applying lumber from domestic small diameter logs, however, there are some problems with the direct application of EYM ; 1) relatively low dowel bearing strength and dimensional stability due to a large amount of immature wood, 2) effect of MC (moisture contents) on the dowel bearing strength of wood and the yield load of a bolted connection. To evaluate the strength properties of bolted connections with lumber from domestic small diameter logs, effect of MC on the dowel bearing strength of wood was investigated and double shear bolted connection tests were performed. As the MC of wood increased, the dowel bearing strength was linearly reduced, even under 19% MC, which showed that adjustment, not considered in NDS, was required. Double shear bolted connection tests indicated that effect of MC on yield load should be considered in order to determine design value.

• Structural Engineering and Mechanics
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• v.68 no.5
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• pp.591-601
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• 2018

Non-moment beam-to-column connections, which are usually referred to as simple or shear connections, are typically designed to carry only gravity loads in the form of vertical shears. Although in the analysis of structures these connections are usually assumed to be pinned, they may provide a small amount of rotational stiffness due to the typical connection details. This paper investigates the effects of this small rotational restraint of simple beam-to-column connections on the behavior and seismic response of steel braced non-moment resisting frames. Two types of commonly used simple connections with bolted angles, i.e., the Double Web angle Connection (DWC) and Unstiffened Seat angle Connection (USC) are considered for this purpose. In addition to the pinned condition - as a simplified representation of these connections - more accurate semi-rigid models are established and then applied to some frame models subjected to nonlinear pushover and nonlinear time history analyses. Although the use of bracing elements generally reduces the sensitivity of the global structural response to the behavior of connections, the obtained results indicate considerable effects on the local responses. Namely, our results show that consideration of the real behavior of connections is essential in designing the column elements where the pin-connection assumption significantly underestimates design of outer columns of upper stories.

• Journal of the Korea Concrete Institute
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• v.18 no.1 s.91
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• pp.135-145
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• 2006

In high multistory reinforced concrete buildings, coupled shear walls can provide an efficient structural system to resist horizontal force due to wind and seismic effects. Coupled shear walls are usually built over the whole height of the building and re laid out either as a series of walls coupled by beams and/or slabs or a central core structure with openings to accommodate doors, elevators walls, windows and corridors. A number of recent studies have focused on examining the seismic response of concrete, steel, and composite coupling beams. However, since no specific equations are available for computing the bearing strength of steel coupling beam-wall connections, it is necessary to develop such strength equations. There were carried out analytical and experimental studies to develop the strength equations of steel coupling beam-connections. Experiments were conducted to determine the factors influencing the bearing strength of the steel coupling beam-wall connection. The results of the proposed equations were in good agreement with both test results and other test data from the literature. Finally, this paper provides background for design guidelines that include a design model to calculate the bearing strength of steel coupling beam-wall connections.

• Structural Engineering and Mechanics
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• v.54 no.1
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• pp.149-168
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• 2015

In the bolted connections, bolt placements are generally described and are generally made in the direction of design effects and in the perpendicular direction to design effects. In these both directions, the reliability of the distance of bolts to the edges of connection plate and the distance of bolts to each other is investigated for high strength steel connections built up with high strength bolts in this study. For this purpose, simple SL (bearing type shear connection) and SLP (bearing type shear connection for body-fit bolts) type steel connections with St 52 grade steel plates with 8 different thicknesses and with 8.8D grade high strength bolts (HV) were constituted and analyzed under H (Dead Loads+Live Loads+Snow Loads+Roof Loads) and HZ (H Loads+Wind Loads+Earthquake Loads) loadings. Geometric properties, material properties and design actions were taken as random variables. Monte Carlo Simulation method was used to compute failure risk and the first order second moment method was used to determine the reliability indexes of those different distances describing the placement of bolts. Results obtained from computations have been presented in graphics and in a Table. Then, they were compared with some values proposed by some structural codes. Finally, new equations were constituted for minimum and maximum values of distances describing bolt placement by regression analyses performed on those results.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.04a
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• pp.283-289
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• 2000

The panel shear and bearing strengths determining the seismic resistance of reinforced concrete column-to-steel beam connections are predicted by various methods for four previously tested exterior beam-column joints. The analytical approach to model the joint deformation is also examined. Several analyses incorporating the deformations of panel shear and bearing in the joint are demonstrated using a analyses incorporating the deformations of panel shear and bearing in the joint are demonstrated using a fairly simple connection model in the commercial packages such as Drain2dx and IDARC. The strength prediction results indicated that the ASCE method with the modifcation of the comprssion strut contribution is th most accurate. It is also considered that the analytical model presented including the joint deformation can be used for the overall analysis

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.154-157
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• 2006

An experimental study was conducted to study the behavior of slab-column connections under lateral load. Test variables include gravity shear ratio$(V_g/V_o=0.3,\;0.5)$ and flexural reinforcement ratio of slab(p=0.01, 0.015). Strength and ductility of tested specimens were evaluated in accordance with gravity shear ratios and slab reinforcement ratios. Shear stresses of Code's equation at the critical section were also compared with experimental results.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.530-533
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• 2006

This thesis investigates the behavior of precast wall systems with a new vertical connection which are proportioned by the displacement based design. The proposed precast wall systems are supposed to provide additional spaces and seismic strengthening in remodeling existing residential buildings. For a fast remodeling constructions using PC walls require an efficient, economic fabrication method. A C-type vertical connections for PC wall systems is proposed for transfer of bending moment between walls in the vertical direction while a shear key in the center of wall is prepared to transfer shear forces by bearing. The proposed vertical connection allows us easy fabrication because of different direction of slots at the edges of wall. The dimension of C-type connection components are determined by engineering models and a series of test.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.8 s.227
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• pp.1174-1182
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• 2004

Recently, Self Piercing Rivet(SPR) has been spotlighted in the automotive industry as a substitutive resort of spot welding and has also been watched by the designer as lightening a car body due to their superior assembly processes. Fatigue behavior of SPR joint needs to be investigated experimentally and numerically to predict its structural stiffness and fatigue life. Testing of lap-shear specimens with various material combinations is performed to obtain the joining strength and the fatigue life of SPR connections. The simulation of SPR lap-shear specimens is also conducted to obtain the structural stiffness of SPR connections under different material combinations. A Finite element model of the SPR lap-shear specimen is developed using a FEMFAT SPR pre-processor. The fatigue lift of SPR specimen is predicted using a FEMFAT 4.4e based on the liner finite element analysis.