Base Plate로 보강된 기둥-기초 접합부의 뚫림전단강도 연구

김성겸,박종권,한상희,김병철,장일영 한국구조물진단유지관리공학회 2015 한국구조물진단유지관리공학회 논문집 Vol.19 No.2

In this paper, the RC column-based joint connection part carry out loading test by reinforced hollow or extended Base Plate in order to confirm that RC joint punching shear reinforcement effect of applying the Base Plate. Base Plate thickness, extension length, size, and type as the variable, Base Plate suitable for the stress distribution and shape and dimensions confirmed through experiment and then reinforcing effect was analyzed. Experimentally, vertical load transmitted to the Base Plate from column to foundation is effective to stress distribution and then, type of hollow reinforcement more efficient than a closed. Through experiment, improve performance and ductility due to reinforcement and relative to the thickness of the existing foundation reduced even showed better performance than the existing. The behavior of the reinforced specimens be able to induce from brittle to ductile. Experiment on loading to destroy performed the pattern of cracks, destruction aspect before and after reinforcement. 본 논문에서는 RC 기둥-기초 접합부분을 중공형 및 확장형 강재 Base Plate로 보강한 실험체에 대한 하중 재하 실험을 실시하여, 강재Base Plate가 부착된 RC 기둥-기초에서의 뚫림전단에 대한 보강효과를 정량화 하기 위한 구조해석 및 기초적 실험 연구를 수행하였다. 실험은 각 실험체별 부착된 Base Plate의 두께, 내민길이, 치수, 형식 등의 변수에 따라 수행하였으며 실험을 통하여 응력분산에 적합한 적정Base Plate의 모양 및 치수를 확인하였고, 보강효과에 대하여 분석하였다. 실험을 통해 Base Plate가 기초에 전해지는 수직하중의 응력분산에 효과적이었으며 폐쇄형보다 중공형 보강이 효율적인 것을 확인하였다. 보강을 통해 변위연성 능력의 향상으로 기존의 기초두께보다두께가 감소한 실험체에서도 기존보다 높은 성능을 나타냈다. 보강 후의 실험체로부터 구조물의 거동특성을 취성으로부터 연성으로 유도할 수 있었으며, 실험체를 파괴시까지 가력함으로써 파괴시 보강 전, 후에 대한 균열 및 파괴양상을 확인 하였다.

Exposed column-base plate strong-axis connections for small-size steel construction

Lim, Woo-Young,Lee, Dongkeun,You, Young-Chan Elsevier 2017 Journal of constructional steel research Vol.137 No.-

<P><B>Abstract</B></P> <P>Experimental study on exposed steel column-base plate connections subjected to both axial and lateral loadings is quite limited. Therefore, based on the intensive field investigation, nine specimens were tested to appraise the seismic performance of various column-base plate strong-axis connections of small-size steel structures in this study. The main parameters were the thickness of base plates, the embedment length of anchor bolts, and the presence of hook and rib plates. Flexural strength, deformation capacity, energy dissipation, and stiffness of the test specimens were investigated. Based on the test results, the hysteretic behaviour of exposed column-base plate strong-axis connections was significantly influenced by the base plate thickness as well as the number and embedment length of anchor bolts. However, the effect of rib plates on the flexural performance of column-base plate connections was negligible. The flexural stiffness of the specimens was approximately 15% of the flexural stiffness by the New Zealand Standard with the assumption that the supports were fixed. It was found that although column-base plate strong-axis connections were properly designed in accordance with design guides, the flexural performance of the connections could be unreliable without sufficient bond capacity between concrete and anchor bolts.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Cyclic behaviour of exposed column-base plate strong-axis connections of small-size steel structures has been studied. </LI> <LI> Location and number of anchor bolts are significantly important for reliable moment capacity of connections. </LI> <LI> Guidelines for plain anchor bolts are vital for small-size steel structures in the field. </LI> <LI> Thickness of base plates is an essential factor and thus appropriate thickness needs to be provided. </LI> </UL> </P>

Rotational behavior of exposed column bases with different base plate thickness

Yao Cui,Fengzhi Wang,Hao Li,Satoshi Yamada 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.32 No.4

Exposed column base connections are used in low- to mid-rise steel moment resisting frames. This paper is to investigate the effect of the base plate thickness on the exposed column base connection strength, stiffness, and energy dissipation. Five specimens with different base plate thickness were numerically modelled using ABAQUS software. The numerical model is able to reproduce the key characteristics of the experimental response. Based on the numerical analysis, the critical base plate thickness to identify the base plate and anchor rod yield mechanism is proposed. For the connection with base plate yield mechanism, the resisting moment is carried by the flexural bending of the base plate. Yield lines in the base plate on the tension side and compression side are illustrated, respectively. This type of connection exhibits a relatively large energy dissipation. For the connection with anchor rod yield mechanism, the moment is resisted through a combination of bearing stresses of concrete foundation on the compression side and tensile forces in the anchor rods on the tension side. This type of connection exhibits self-centering behavior and shows higher initial stiffness and bending strength. In addition, the methods to predict the moment resistance of the connection with different yield mechanisms are presented. And the evaluated moment resistances agree well with the values obtained from the FEM model.

Flexural behavior of steel storage rack base-plate upright connections with concentric anchor bolts

Xianzhong Zhao,Zhaoqi Huang,Yue Wang,Ken S. Sivakumaran 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.33 No.3

Steel storage racks are slender structures whose overall behavior and the capacity depend largely on the flexural behavior of the base-plate to upright connections and on the behavior of beam-to-column connections. The base-plate upright connection assembly details, anchor bolt position in particular, associated with the high-rise steel storage racks differ from those of normal height steel storage racks. Since flexural behavior of high-rise rack base connection is hitherto unavailable, this investigation experimentally establishes the flexural behavior of base-plate upright connections of high-rise steel storage racks. This investigation used an enhanced test setup and considered nine groups of three identical tests to investigate the influence of factors such as axial load, base plate thickness, anchor bolt size, bracket length, and upright thickness. The test observations show that the base-plate assembly may significantly influence the overall behavior of such connections. A rigid plate analytical model and an elastic plate analytical model for the overall rotations stiffness of base-plate upright connections with concentric anchor bolts were constructed, and were found to give better predictions of the initial stiffness of such connections. Analytical model based parametric studies highlight and quantify the interplay of components and provide a means for efficient maximization of overall rotational stiffness of concentrically anchor bolted high-rise rack base-plate upright connections.

Base Plate로 보강된 기둥-기초 접합부의 뚫림전단강도 연구

김성겸,박종권,한상희,김병철,장일영 한국구조물진단유지관리공학회 2015 한국구조물진단유지관리공학회 논문집 Vol.19 No.2

In this paper, the RC column-based joint connection part carry out loading test by reinforced hollow or extended Base Plate in order to confirm that RC joint punching shear reinforcement effect of applying the Base Plate. Base Plate thickness, extension length, size, and type as the variable, Base Plate suitable for the stress distribution and shape and dimensions confirmed through experiment and then reinforcing effect was analyzed. Experimentally, vertical load transmitted to the Base Plate from column to foundation is effective to stress distribution and then, type of hollow reinforcement more efficient than a closed. Through experiment, improve performance and ductility due to reinforcement and relative to the thickness of the existing foundation reduced even showed better performance than the existing. The behavior of the reinforced specimens be able to induce from brittle to ductile. Experiment on loading to destroy performed the pattern of cracks, destruction aspect before and after reinforcement.

Topology optimization of steel plate shear walls in the moment frames

Mohammad Hadi Bagherinejad,Abbas Haghollahi 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.29 No.6

In this paper, topology optimization (TO) is applied to find a new configuration for the perforated steel plate shear wall (PSPSW) based on the maximization of reaction forces as the objective function. An infill steel plate is introduced based on an experimental model for TO. The TO is conducted using the sensitivity analysis, the method of moving asymptotes and SIMP method. TO is done using a nonlinear analysis (geometry and material) considering the buckling. The final area of the optimized plate is equal to 50% of the infill plate. Three plate thicknesses and three length-to-height ratios are defined and their effects are investigated in the TO. It indicates the plate thickness has no significant impact on the optimization results. The nonlinear behavior of optimized plates under cyclic loading is studied and the strength, energy and fracture tendency of them are investigated. Also, four steel plates including infill plate, a plate with a central circle and two types of the multi-circle plate are introduced with equal plate volume for comparing with the results of the optimized plate.

Variations of stress and deformation in the straightening process of turnout base plate

Hua Zhai,Yuanhao Wu,Xuepeng Liu,Qi Li,Yushan Wang 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.7

Straightening technology is an important method to manufacture a high-speed railway turnout base plate with positioning blocks after welding. According to the straightening experiment results, the differences in straightening deformation and stress distribution were investigated between the turnout base plate and the counterpart flat plate under different loading conditions. The residual deformation of the counterpart flat plate is much higher than that of the base plate because of the welded positioning blocks. A theoretical model was presented to predict the straightening deformation variation. Finite element simulations were performed to simulate stress variation in the straightening process of the base plate. The stress concentration and residual stress distribution of the base plate were visually observed. The stress concentration factor changes gradually with the interface angle deflection at the welding area of the positioning block. The variation of dynamic stress concentration factor can be calculated and provide a certain theoretical reference to predict the straightening parameters.

소규모 철골조 노출형 주각부의 반복가력 실험

임우영,유영찬,유미나 한국구조물진단유지관리공학회 2017 한국구조물진단유지관리공학회 논문집 Vol.21 No.2

Cyclic loading tests for a total of nine test specimens were performed to evaluate the seismic performance of the exposed steel column-base plate connections. From the tests, flexural strength, deformation capacity, energy dissipation, and initial stiffness were investigated. The primary test parameters were the thickness of base-plate, embedment length of anchor bolt, the presence of hook, and rib plates. Test results showed that flexural behavior of column base-plate connection was substantially affected by the base-plate thickness, embedment length and the number of anchor bolts. On the other hand, the effect of rib plates on the increase of the flexural performance was not observed. The initial stiffness of the test specimens was about 15% of the flexural stiffness obtained by assuming that the support is fixed. As a result, even if the exposed column base-plate is designed in accordance with current design recommendations, in case that bond strength between concrete and the anchor bolts is not sufficient, the base-plate connection showed an unaccceptable load-displacement behavior.

An Edge-based Smoothed Three-node Mindlin Plate Element (ES-MIN3) for Static and Free Vibration Analyses of Plates

T. Nguyen-Thoi,T. Bui-Xuan,P. Phung-Van,S. Nguyen-Hoang,H. Nguyen-Xuan 대한토목학회 2014 KSCE JOURNAL OF CIVIL ENGINEERING Vol.18 No.4

The edge-based strain smoothing technique is combined with the three-node Mindlin plate element (MIN3) to give a so-called theedge-based smoothed three-node Mindlin plate element (ES-MIN3) for static and free vibration analyses of plates. In the formulationof the ES-MIN3, the MIN3 together with a shear stabilized technique is used to compute the strains and to avoid the shear locking. Then the strain smoothing technique on the smoothing domains associated with edges of elements is used to smooth the strains on theadjacent elements. This strain smoothing technique can provide proper softening effect, which will effectively relieve the stiffbehavior of the MIN3 and thus improve significantly the accuracy of solutions. The numerical examples demonstrated that the ESMIN3is free of shear locking, passes the patch test and shows three superior properties such as: (1) be a strong competitor to othersexisting plate elements in the static analysis; (2) can give high accurate solutions in free vibration analysis; (3) can provide accuratelythe values of high frequencies of plates by using only coarse meshes.

Performance assessment of mass-based yield prediction for Chinese cabbage yield monitoring applications

( Ashrafuzzaman Gulandaz ),( Sazzadul Kabir ),( Nasim Reza ),( Mohammad Ali ),( Shaha Nur Kabir ),( Sun-ok Chung ) 한국농업기계학회 2023 한국농업기계학회 학술발표논문집 Vol.28 No.1

Yield monitoring is a crucial tool for the effective management of agricultural production and accurate measurement of crop yield prediction. The objective of this study was to assess the effectiveness of an impact-based load cell for predicting the mass-based yield of Chinese cabbage for yield monitoring. Specifically, the study aimed to identify the optimal configuration for the load cell setup to ensure accurate yield prediction. The experiments were conducted using two different load cell configurations, including the number and placement of load cells. Two layouts of impact plates were tested; one with two load cells, 150 mm apart, and the other with a single load cell, mounted center on the supporting impact plate. Both of the layouts used an acrylic plate and a 10mm thick polyurethane cushion as supporting impact plate to avoid damage to the load cells and cabbages. The performance of the load cell setup was evaluated by comparing the predicted mass with the actual mass of the cabbage samples. The effects of three variables- conveyor speed, falling height, and impact plate angle on cabbage mass were also considered. Three different conditions were tested, including static condition, vibration, and with vibration and inclination. The single load cell configuration provided the most accurate prediction of mass-based yield, with the maximum R2 value of 0.92, the minimum RMSE of 205g, and an error less than 5% for all experimental variables compared to the double load cell configuration. Based on the findings, it can be concluded that the load cell configuration with a single load cell is reliable and effective tool for predicting mass-based yield monitoring. This configuration can also be extended for other crops with similar characteristics.