Modelling and classification of tubular joint rigidity and its effect on the global response of CHS lattice girders

Wang, Wei,Chen, Yiyi Techno-Press 2005 Structural Engineering and Mechanics, An Int'l Jou Vol.21 No.6

In engineering practice, tubular connections are usually assumed pinned or rigid. Recent research showed that tubular joints may exhibit non-rigid behavior under axial or bending loads. This paper is concerned with establishing a new classification for tubular joints and investigating the effect of joint rigidity on the global behavior of CHS (Circular Hollow Section) lattice girders. Parametric formulae for predicting tubular joint rigidities are proposed, which are based on the finite element analyses through systematic variation of the main geometric parameters. Comparison with test results proves the reliability of these formulae. By considering the deformation patterns of respective parts of Vierendeel lattice girders, the boundary between rigid and semirigid tubular connections is built in terms of joint bending rigidity. In order to include characteristics of joint rigidity in the global structural analysis, a type of semirigid element which can effectively reflect the interaction of two braces in K joints is introduced and validated. The numerical example of a Warren lattice girder with different joint models shows the great effect of tubular joint rigidities on the internal forces, deformation and secondary stresses.

Effect of Joint Type on Rigid Airfield Pavement Behavior

오한진,김성민,정원석,이용현,조영교 대한토목학회 2014 KSCE Journal of Civil Engineering Vol.18 No.5

The effects of dowel and key joints in the rigid airfield pavements on the stress distribution in the concrete slab and on the LoadTransfer Efficiency (LTE) at joints were investigated in this study. Numerical analysis models including dowel and key joints of therigid airfield pavements were developed to analyze behaviors under environmental and aircraft gear loads. The analysis resultsshowed that under gear loads both the dowel and key joint pavement slabs had very similar stress distributions when the joint gap didnot exist, but the key joint pavement slab had larger stresses than dowel joint one when the joint gap existed and the loads wereapplied near the joint. The LTEs at joints were excellent at both pavement slabs without a joint gap, but the LTE decreasedsignificantly in the key joint pavement as the joint gap became larger. Under environmental loads, the stresses at both the dowel andkey joint pavement slabs were almost the same and those increased slightly when there was a joint gap. When the rigid airfieldpavement had only the dowel joints along both the longitudinal and transverse joints, there was no stress concentration in the slabsand the stresses were smaller and the LTEs were higher than the pavement that had the dowel joints along one direction and the keyjoints along the other direction, which was the current airfield pavement joint design in Korea.

Study on the Infl uence of Connection Confi guration on Composite Joints

Shan Gao,Lanhui Guo 한국강구조학회 2018 International Journal of Steel Structures Vol.18 No.3

Steel–concrete composite joints possess higher bearing capacity, initial stiff ness and redundancy than bare steel joints. The confi guration of beam-column connection would infl uence the behavior of composite joints, such as rigidity, rotation capacity and so on. In this paper, the test of two fully welded rigid composite joints and two fl ush endplate semi-rigid composite joints was introduced. The loading conditions in the tests involved sagging moment and hogging moment. The mechanical behavior of composite joints under bending moment was studied in detail, especially on the infl uence of connection confi guration. The test results indicated that the experimental phenomena and failure mode of fully welded composite joint and fl ush endplate composite joint under hogging moment were similar to each other. The buckling of bottom fl ange of steel beam determined the behavior of composite joint under hogging moment, such as initial stiff ness and bending strength. It indicated that using fl ush endplate connection instead of fully welded connection in composite joints had little infl uence on the behavior of the joint under service loads if the failure mode of joints is governed by the same component. Four models for moment-rotation relation of composite joints are compared with experimental results. Based on the comparison, a new combination model of power function expression and linear expression is developed. With proper optimum shape parameter and descending stiff ness, the new model could present the moment-rotation relation of composite joints, regardless of connection confi guration or loading condition.

Structural Behavior of Construction Joints in a Composite Rigid-Frame Bridge

조상현,최정호,이희영,정원석 한국콘크리트학회 2024 International Journal of Concrete Structures and M Vol.18 No.1

Composite rigid-frame bridges with steel girders have excellent structural performance, but behavioral inconsistency appears at the connection between the steel girder and concrete pier. In addition, composite rigid-frame bridges are challenging to construct owing to the need to connect different materials at the pier. Therefore, this study developed and demonstrated a composite rigid-frame bridge with a construction joint and anchors. The structural performance and composite behavior of the proposed construction joint were investigated by evaluating a direct connection between the girder and concrete prior to casting (Joint A), a plain construction joint (Joint B), and a construction joint with anchors (Joint C). Joints B and C exhibited 16.5% and 46.5% higher ultimate capacities, respectively, than did Joint A. Finite element analysis of Joint C was conducted, and its results were verified against the experimental results. Further, parameter analysis was performed to determine the effects of the steel girder strength and anchor diameter. The results indicated that the proposed construction joint with anchors exhibited excellent structural performance and composite behavior.

Structural Behavior of Beam-Column Joints Consisting of Composite Structures

Lee, Seung-Jo,Park, Jung-Min,Kim, Wha-Jung Korea Concrete Institute 2002 KCI concrete journal Vol.14 No.3

This study proposes a joint model consisting of different types of members as a new structural system, and then investigates the resulting structural behavior. The joint model consists of a concrete-filled steel tube column (CFT) together with a steel reinforced concrete at the end plus reinforced concrete beam at the center. For comparison, two other joint models were designed, that are, a CPT with a reinforced concrete beam, and a CFT with a steel reinforced concrete at the end plus steel concrete beam at the center, then their joint capacity and rigidity, energy absorption capacity, etc., were all investigated. From the results, the CFT column with a steel reinforced concrete at the end plus steel concrete beam at the center was outstanding in terms of its capacity and rigidity. The results of this analysis demonstrate that an adequate connection type and reinforcement method with different materials of increasing the rigidity, thereby producing a capacity improvement along with protection from pre-fractures.

The Influence of Fixation Rigidity on Intervertebral Joints - An Experimental Comparison between a Rigid and a Flexible System

Kim, Won-Joong,Lee, Sang-Ho,Shin, Song-Woo,Rivard, Charles H.,Coillard, Christine,Rhalmi, Souad The Korean Neurosurgical Society 2005 Journal of Korean neurosurgical society Vol.37 No.5

Objective: Spinal instrumentation without fusion often fails due to biological failure of intervertebral joints (spontaneous fusion, degeneration, etc). The purpose of this study is to investigate the influence of fixation rigidity on viability of intervertebral joints. Methods: Twenty pigs in growing period were subjected to posterior segmental fixation. Twelve were fixed with a rigid fixation system(RF) while eight were fixed with a flexible unconstrained implant(FF). At the time of the surgery, a scoliosis was created to monitor fixation adequacy. The pigs were subjected to periodic radiological examinations and 12pigs (six in RF, six in FF) were euthanized at 12-18months postoperatively for analysis. Results: The initial scoliotic curve was reduced from $31{\pm}5^{\circ}$ to $27{\pm}8^{\circ}$ in RF group (p=0.37) and from $19{\pm}4^{\circ}$ to $17{\pm}5^{\circ}$ in FF group (p=0.21). Although severe disc degeneration and spontaneous fusion of facet joints were observed in RF group, disc heights of FF group were well maintained without major signs of degeneration. Conclusion: The viability of the intervertebral joints depends on motion spinal fixation. Systems allowing intervertebral micromotion may preserve the viability of intervertebral discs and the facet joint articular cartilages while maintaining a reasonably stable fixation.

Component method model for predicting the moment resistance, stiffness and rotation capacity of minor axis composite seat and web site plate joints

Aleksander Kozlowski 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.20 No.3

Codes EN 1993 and EN 1994 require to take into account actual joint characteristics in the global analysis. In order to implement the semi-rigid connection effects in frame design, knowledge of joint rotation characteristics (<i>M</i>-<i>φ</i>relationship), or at least three basic joint properties, namely the moment resistance <i>M_R</i>, the rotational stiffness <i>S_j</i> and rotation capacity, is required. To avoid expensive experimental tests many methods for predicting joint parameters were developed. The paper presents a comprehensive analytical model that has been developed for predicting the moment resistance <i>M_R</i>, initial stiffness <i>S_j.ini</i> and rotation capacity of the minor axis, composite, semi-rigid joint. This model is based on so-called component method included in EN 1993 and EN 1994. Comparison with experimental test results shows that a quite good agreement was achieved. A computer program POWZ containing proposed procedure were created. Based on the numerical simulation made with the use of this program and applying regression analysis, simplified equations for main joint properties were also developed.

수직 하중에 따른 목재 짜맞춤 접합부의 강성도 평가

박천영,김광철,이전제 한국가구학회 2012 한국가구학회지 Vol.23 No.3

Recently, interest in wooden construction have been growing by increasing needs and demands for eco-friendly and traditional wooden building(Hanok). Especially, Hanok has the technical development in manufacturing the mortise-tenon joint without fasteners(precut), so it could be called to modernization, industrialization and popularization. But the structural design and analysis of the structure were not regulated and had the difficulty to consider the variation of wooden member and to conduct the difficulty in the structural analysis and the design of the joint. In this study, the stiffness ratio of wooden mortise and tenon joint was evaluated according to the vertical loading, lintel and loading speed. The joint was distinguished in semi-rigid joint regardless of their factors. The stiffness ratio was 0.40 in vertical loading, 0.50 without vertical loading and 0.44 in horizontal loading with high speed. This study would be utilized to the structural analysis and design with structural analysis and design program.

절점 강성을 고려한 공간 구조물의 비선형 불안정 거동에 관한 연구

손수덕,김승덕,황경주,강문명 한국공간구조학회 2003 한국공간구조학회지 Vol.3 No.1

The structural system that discreterized from continuous shells is frequently used to make a large space structures. As well these structures show the unstable phenomena when a load level over the limit load, and snap-through and bifurcation are most well known of it. For the collapse mechanism, rise-span ratio, element stiffness and load mode are main factor, which it give an effect to unstable behavior. In our real situation, most structures have semi-rigid joint that has middle characteristic between pin and rigid joint. So the knowledge of semi-rigid joint is very important problem of stable large space structure. And the instability phenemena of framed space structures show a strong non-linearity and very sensitive behavior according to the joint rigidity For this reason In this study, we are investigating to unstable problem of framed structure with semi-rigidity and to grasp the nonlinear instability behavior that make the fundamental collapse mechanism of the large space frame structures with semi-rigid joint, by proposed the numerical analysis method. Using the incremental stiffness matrix in chapter 2, we study instability of space structures.

Research on Whole‑Process Tensile Behavior of Headed Studs in Steel–Concrete Composite Structures

Liang?Dong Zhuang,Hong?Bing Chen,Yuan Ma,Ran Ding 한국콘크리트학회 2021 International Journal of Concrete Structures and M Vol.15 No.4

The headed studs have been widely applied in steel–concrete composite structures as shear connectors. However, the tensile performance of headed studs is also key to the structural performance in many cases such as the semi-rigid composite joints including steel beam–concrete wall joint and steel column–base joint. Therefore, this study presents experimental and analytical study on the whole-process tensile behavior of headed studs. Tests on a total of 33 pullout specimens are first conducted. The tensile capacity and load–deformation behavior of the anchorage concrete, which dominates the structural performance of headed studs, are thoroughly analyzed. In addition, test data in the literature are collected for quantitatively evaluating the influence of embedment depth, bearing area, boundary conditions, and concrete strength on the tensile behavior of the anchorage concrete. On the basis of the influence evaluation, an analytical model represented by a piecewise function is proposed to describe the whole-process load–deformation behavior of the anchorage concrete and validated through the comparison between the predicted curves and all collected experimental results. Then the proposed model is applied to simulate the rotational behavior of the typical semi-rigid joint anchored by headed studs, which takes the contribution of the anchorage concrete into consideration, and is verified by experimental results. The research findings indicate that tensile behavior of anchorage concrete is crucial to the structural performance of semi-rigid joints, even for headed studs with large embedment depth and bearing area.