• Steel and Composite Structures
• /
• v.32 no.1
• /
• pp.59-66
• /
• 2019

Hollow steel-reinforced concrete-filled GFRP tubular member is a new kind of composite members. Firstly set the mold in the GFRP tube (non-bearing component), then set the longitudinal reinforcements with stirrups (steel reinforcement cage) between the GFRP tube and the mold, and filled the concrete between them. Through the axial compression test of the hollow steel-reinforced concrete-filled GFRP tubular member, the working mechanism and failure modes of composite members were obtained. Based on the experiment, when the load reached the ranges of $55-70%P_u$ ($P_u-ultimate$ load), white cracks appeared on the surface of the GFRP tubes of specimens. At that time, the confinement effects of the GFRP tubes on core concrete were obvious. Keep loading, the ranges of white cracks were expanding, and the confinement effects increased proportionally. In addition, the damages of specimens, which were accompanied with great noise, were marked by fiber breaking and resin cracking on the surface of GFRP tubes, also accompanied with concrete crushing. The bearing capacity of the axially compressed components increased with the increase of reinforcement ratio, and decreased with the increase of hollow ratio. When the reinforcement ratio was increased from 0 to 4.30%, the bearing capacity was increased by about 23%. When the diameter of hollow part was decreased from 55mm to 0, the bearing capacity was increased by about 32%.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2001.04a
• /
• pp.181-188
• /
• 2001

Due to many advantage of advanced composite material, research on the composite compression member is initiated. In this paper structural characteristics of concrete filled glass fiber reinforced composite tubular member is studied. Through 4-point flexural test with various level of axial force, the performance of composite compression member was analyzed. Also numerical method to find P-M diagram of composite compression member was developed. It is demonstrated that result of numerical method agree well with experimental results.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2002.04a
• /
• pp.61-68
• /
• 2002

Tubular members have been applied in a wide range of frame structures including offshore structures. For the efficient load flow in tubular-member structures, the joints of tubular members are usually reinforced using internal ring stiffener for the steel tubular joint having a large diameter. The objective of this paper is to numerically assess the behavior of X-joints with an internal ring stiffener, and to evaluate the reinforcement effect of a ring stiffener, and to establish the strength formulae. Nonlinear finite element analysis is used to compute the static strength of axially loaded tubular joints. From the numerical results, internal ring stiffener is found to be efficient in improving static strength of tubular X-joints. Maximum strength ratios are calculated as 1.5~3.5, and the effective dimensions of ring stiffener are found. Regression analyses are performed considering practical size of ring stiffener and strength estimation formulae are proposed.

• Steel and Composite Structures
• /
• v.17 no.3
• /
• pp.253-269
• /
• 2014

Among the various alternatives to make a steel tubular member connection, making a slotted and gusset plate welded connection is one of the most frequently preferred alternatives. This type of connection is essentially an end connection that is made by slotting the tube longitudinally, inserting the gusset plate and then placing longitudinal fillet welds at the tube-to-plate interface. In this paper an experimental study on the behaviour of such connections in stainless steel is presented. 24 specimens were tested under concentrically applied axial tensile forces for varying tube-to-gusset plate weld lengths. Both circular and box section members were considered in the test program. Load-deformation curves were obtained and comparisons were made in terms of strength and ductility. The results obtained from the study were then critically examined and compared with currently available design guidance for slotted gusset plate welded tubular end connections. It is noted that no specific rules exist in international specifications on structural stainless steel which cover the design of such connections. Therefore, the results of this study are compared with the existing design rules for carbon steel.

• Steel and Composite Structures
• /
• v.6 no.2
• /
• pp.103-122
• /
• 2006

The capacity of tubular truss chords subjected to concentrated reaction forces in the vicinity of the open end (i.e., the bearing region) is not directly treated by existing design specifications; although capacity equations are promulgated for related tubular joint configurations. The lack of direct treatment of bearing capacity in existing design specifications seems to represent an unsatisfactory situation given the fact that connections very often control the design of long-span tubular structures comprised of members with slender cross-sections. The case of the simple-span overhead highway sign truss is studied, in which the bearing reaction is applied near the chord end. The present research is aimed at assessing the validity of adapting existing specifications' capacity equations from related cases so as to be applicable in determining design capacity in tubular truss bearing regions. These modified capacity equations are subsequently used in comparisons with full-scale experimental results obtained from testing carried out at the University of Pittsburgh.

• Ocean Systems Engineering
• /
• v.13 no.2
• /
• pp.97-121
• /
• 2023

Through-the-thickness stress distribution in a tubular member has a profound effect on the fatigue behavior of tubular joints commonly found in steel offshore structures. This stress distribution can be characterized by the degree of bending (DoB). Although multi-planar joints are an intrinsic feature of offshore tubular structures and the multi-planarity usually has a considerable effect on the DoB values at the brace-to-chord intersection, few investigations have been reported on the DoB in multi-planar joints due to the complexity of the problem and high cost involved. In the present research, data extracted from the stress analysis of 243 finite element (FE) models, verified based on available parametric equations, was used to study the effects of geometrical parameters on the DoB values in two-planar tubular DYT-joints. Parametric FE study was followed by a set of nonlinear regression analyses to develop six new DoB parametric equations for the fatigue analysis and design of axially loaded two-planar DYT-joints.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1999.10a
• /
• pp.571-574
• /
• 1999

Due to many advantages of advanced composite material, research on the composite compression member is initiated. In this paper structural characteristics of concrete filled glass fiber reinforced composite tubular member si studied. Experimental results shows that strength and ductility of composite compression member is considerably increased due to concrete confinement action of composite surface. Thus it can be anticipated that increased strength of concrete will be incorporated in the design of composite compression member.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 1995.10a
• /
• pp.234-241
• /
• 1995

Offshore structures are exposed to higher probability of collision with ship because of their limited mobility. In general, the consequence of the collision is reported to be relatively small and it is desirable to consider minor collisions in the design stage. It is important to have a comprehensive understanding of the dynamic responses of a tubular, their main member, under collision to design offshore structure against possible accidents. It is needed to estimate the probable extent of damage of a tubular, depth of dent, affected by the time history of impact load in ender to design a tubular strong enough for collision. In this paper, dynamic behaviors of a tubular due to the lateral impact are investigated through the numerical simulations with hydrocode DYNA3D, a three dimensional elasto-plastic large deformation impact contact problem analyzing program.

• Journal of Korean Society of Steel Construction
• /
• v.13 no.2
• /
• pp.133-141
• /
• 2001

A tubular member holding an axially through-gusset connection is often used to transmit axial compression in a steel truss structures. The elastic buckling loads of the member is affected by the stiffness ratio($\beta$) and the length ratio(G) because of two elements with different properties. In current code, however, the strength is evaluated with an effective length factor k=0.9 without considering the above effect. Therefore this study analyzed a theoretical mechanism based on the elasticity theory and performed a finite element analysis to investigate the influence parameters on the elastic buckling strength of axially loaded member.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 1999.11a
• /
• pp.183-188
• /
• 1999

Due to many advantages of advanced composite materials, research on the application of composites to the construction industry is initiated. In this paper, fabrication methods efficient for infrastructures and application examples of each method are discussed. It also presents the structural characteristics of concrete filled glass fiber reinforced composite tubular member. Experimental results shows that strength and ductility of composite compression member is considerably increased due to concrete confinement action of composite surface.