Artykuły w czasopismach: „Portal frame experiment”

1

Li, Qi Cai, Zhen Shan Wang, Ming Zhou Su, Xue Chao Shao i Lin Shen. "Experiment on the Hysteretic Behaviors of Light-Weight Steel Portal Frame with Tapered Members". Advanced Materials Research 368-373 (październik 2011): 206–10. http://dx.doi.org/10.4028/www.scientific.net/amr.368-373.206.

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In order to study the seismic behavior of steel portal frame structures, Cyclic loading test on a 1:3-scaled model of single-story single-bay steel portal frame with tapered members has been carried out. Based on test results, hysteretic curve, skeleton curve, stiffness degradation and transverse displacement of the structure are obtained. Meanwhile, the seismic performances of the structure are analyzed from aspects of ductility, energy consumption, stiffness degradation, bearing capacity, etc. It is concluded that ductility and energy consumption capacity of this structure are poor; because of its light weight, the structure attracts little seismic load; when portal frame structure designed according to current Chinese design codes suffers from small seismic action, it has enough seismic bearing capacity.

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Mottershead, J. E., T. K. Tee, C. D. Foster i R. Stanway. "An Experiment to Identify the Structural Dynamics of a Portal Frame". Journal of Vibration and Acoustics 112, nr 1 (1.01.1990): 78–83. http://dx.doi.org/10.1115/1.2930102.

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This paper describes the application of sequential frequency domain techniques to the estimation of mass, stiffness, and damping parameters using measured frequency response functions from a portal frame rig. The theory of the method has been described in the authors’ previous publications. A portal frame is representative of many engineering structures. It is lightly damped and may be thought of as an element of several larger structures such as bridges, transmission towers, and the steel foundations of modern power generating plant. The results offered in this paper are thus of interest to a broad range of engineering problems where it is required to obtain mathematical models in terms of physical parameters.

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van de Lindt, John W., i R. Karthik Rechan. "Seismic Performance Comparison of a High-Content SDA Frame and Standard RC Frame". Advances in Civil Engineering 2011 (2011): 1–12. http://dx.doi.org/10.1155/2011/478475.

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This study presents the method and results of an experiment to study the seismic behavior of a concrete portal frame with fifty percent of its cement content replaced with a spray dryer ash (SDA). Based on multiple-shake-table tests, the high content SDA frame was found to perform as well as the standard concrete frame for two earthquakes exceeding design-level intensity earthquakes. Hence, from a purely seismic/structural standpoint, it may be possible to replace approximately fifty percent of cement in a concrete mix with SDA for the construction of structural members in high seismic zones. This would help significantly redirect spray dryer ash away from landfills, thus, providing a sustainable greener alternative to concrete that uses only Portland cement, or only a small percentage of SDA or fly ash.

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Wang, Zhen Shan, Ming Zhou Su, An Liang Song, Zhen Pang i Lin Shen. "Aseismic Test and Finite Element Analysis of Light-Weight Steel Portal Frame with Tapered Members". Advanced Materials Research 368-373 (październik 2011): 211–14. http://dx.doi.org/10.4028/www.scientific.net/amr.368-373.211.

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To study on the failure model, ductility, energy dissipation capacity, structural displacement, and stiffness of the portal frame structures on the effect of earthquake force, a pseudo-static experiment with a 1/3 scaled model has been completed. Based on the test result, though the ductility and the energy consumption capacity of the structure are poor, the requirement on aseismatic bearing capacity is satisfied, because the structure suffers the smaller seismic force as the deadweight of structure is light. Built up a finite element model according to the test specimen, then performed finite element analysis, the results showed that the finite element model can be used for seismic analysis of the portal frame.

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Su, Yi Sheng, Shu Fang Zheng, Qi Liang Li i Jin Yun Quan. "Experimental Study on the Static Performance of Joints in the Castellated Portal Frame of Light-Weight Steel". Applied Mechanics and Materials 166-169 (maj 2012): 563–68. http://dx.doi.org/10.4028/www.scientific.net/amm.166-169.563.

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In order to study the mechanical behavior of joints in the castellated portal frame of light-weight steel under static loads, a static loads experiment has been performed for these new joints in this paper. The experiment members include four castellated joints and one solid-web joint of original steel, considering three vary parameters which are connection form of joints, joint region with setting stiffener and the distance from the center of hole to joint region. Experiment shows: the stiffness of castellated joints is higher than the one of solid-web joint. The parameters have a great influence on the mechanical behavior of joints, except the connection form of joints.

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Nishiyama, M., H. Mugurama i F. Watanabe. "Hysteretic restoring force characteristics of unbounded prestressed concrete framed structure under earthquake load". Bulletin of the New Zealand Society for Earthquake Engineering 22, nr 2 (30.06.1989): 112–21. http://dx.doi.org/10.5459/bnzsee.22.2.112-121.

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An analytical method, by which hysteretic restoring force characteristics of unbonded prestressed concrete framed structure can be statically pursued on the basis of material properties, is presented. The bond-slip relationship between concrete and prestressing tendon is taken into account, and thus the method covers unbonded members and bonded members. For verifying the propriety of the analytical method, the experiment is carried out on a portal frame with an unbonded prestressed concrete beam of 4.2 m in length and reinforced concrete columns of 1 m in height. High intensity reversed cyclic lateral loading is applied. The experimental results show a good agreement with the analytical ones in terms of load-deflection relation and the fluctuation of the tendon stress at anchorage end.

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., M. Muthulakshmi, i M. Vinod Kumar . "Experimental Studies on Fibre Integrated Lightweight Concrete Frames Under Lateral Forces: A Review". Asian Journal of Engineering and Applied Technology 7, nr 1 (5.03.2018): 88–91. http://dx.doi.org/10.51983/ajeat-2018.7.1.874.

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Reinforced Concrete (RC) framed structure with masonry infill is the most common type of building in which, RC frames participate in resisting lateral forces. The poor performance of RC frame buildings under lateral forces is due to its heavy mass and rigid construction. Use of Lightweight concrete (LWC) is preferred since the dead load of concrete is enormous. A low density of the LWC, decreases the weight of the building thus reducing the effect of lateral forces. However, LWC having a lower modulus of elasticity, has a faster rate of crack development in RC members. So, fibres are employed as an additive to increase the energy absorption capacity and to control the crack development. Pumice is a natural material of volcanic origin, has low density, which makes it ideal for production of LWC. Based on these ideas, Pumice aggregate is used as a partial replacement of coarse aggregate to its volume with addition of steel fibres to the volume of concrete. This paper summarizes the collected literatures related to RC frames, LWC, Fibre Reinforced Concrete (FRC) and thereby attempts to predict the lateral load response of RC portal frame with the use of LWC and Steel fibres.

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Dheyaa Jaafar Witwit, Jaafar, i Nameer Abed Al-Ameer Alwash. "Experimental and Numerical Investigation for R/C Portal Frames Tested Under Uniform Load". International Journal of Engineering & Technology 7, nr 4.19 (27.11.2018): 763. http://dx.doi.org/10.14419/ijet.v7i4.19.27995.

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This paper presents an experimental and numerical investigations for three reinforced self-compacting concrete portal frames tested under uniform load. Control frame was tested without any types of strengthening, while second frame was strengthened with CFRP-sheet with dimensions (75 * 1000) mm at the bottom of beam and with dimensions (75 *700) mm at both joints, (350 mm) extending to the upper surface of the beam and (350 mm) on the outer face of the column. The last frame was cast in two pours tested without strengthening. The experimental tests showed that strengthened frame had stiffness more than control frame and its ultimate load was more than control frame by (19.45 %), while frame with two pours has an ultimate load less than a control frame with (11.26 %), however stiffness seem approximately to the control frame. Deflection for strengthened frame was less than control frame by (4.76%), on the other hand frame with two pours deflection was more than control frame by (4.55 %). A numerical finite element program ultimate load was more than experimental by about (4.28 %).

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Ozola, Lilita, i Janis Fabriciuss. "Numerical and Experimental Analysis of Timber Portal Frame with Semi-Rigid Knee Joints". IOP Conference Series: Materials Science and Engineering 1203, nr 3 (1.11.2021): 032008. http://dx.doi.org/10.1088/1757-899x/1203/3/032008.

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Abstract The problems related to development of rotational deformations of a knee joints and crack propagation in rafter elements of timber portal frames were discussed in this article. The rotational displacement, which develops between the rafter and column members due to the bending deformations of the bolts in the knee joint with a simultaneous embedment into the wood, increases the global deformations of the portal frame. Additionally, to axial force and bending moment the rafter elements are heavily loaded with shear force at the sections near knee joint especially. All effects together create very complicated complex of affecting factors. In the current study the design methodology of timber portal frames has been revised with the purpose to develop a more comprehensive set of design conditions for timber portal frames with dowel type fasteners in the knee joints. It is suggested to use the Hoffman failure criterion taking into account the difference of strength in tension and compression to manage the effects of plastic yielding combined with the crack development in wood assumed it as an orthotropic material. It has been proved by case studies of timber portal frames under service loads, as well as by tests and theoretical considerations. The set of design conditions must be supplement by additional clauses comprising Hoffman failure criterion regarding timber sections heavily loaded in shear and cross grain tension. Also, it is recommended that the design capacity of dowel type fastener should be decreased when shear force transferred by the bolt acts perpendicular to the grain direction inducing tension cross grain direction. Other measure may be application of some surface strengthening method.

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BAO, YUEQUAN, YONG XIA, HUI LI, YOU-LIN XU i PENG ZHANG. "DATA FUSION-BASED STRUCTURAL DAMAGE DETECTION UNDER VARYING TEMPERATURE CONDITIONS". International Journal of Structural Stability and Dynamics 12, nr 06 (grudzień 2012): 1250052. http://dx.doi.org/10.1142/s0219455412500526.

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A huge number of data can be obtained continuously from a number of sensors in long-term structural health monitoring (SHM). Different sets of data measured at different times may lead to inconsistent monitoring results. In addition, structural responses vary with the changing environmental conditions, particularly temperature. The variation in structural responses caused by temperature changes may mask the variation caused by structural damages. Integration and interpretation of various types of data are critical to the effective use of SHM systems for structural condition assessment and damage detection. A data fusion-based damage detection approach under varying temperature conditions is presented. The Bayesian-based damage detection technique, in which both temperature and structural parameters are the variables of the modal properties (frequencies and mode shapes), is developed. Accordingly, the probability density functions of the modal data are derived for damage detection. The damage detection results from each set of modal data and temperature data may be inconsistent because of uncertainties. The Dempster–Shafer (D–S) evidence theory is then employed to integrate the individual damage detection results from the different data sets at different times to obtain a consistent decision. An experiment on a two-story portal frame is conducted to demonstrate the effectiveness of the proposed method, with consideration on model uncertainty, measurement noise, and temperature effect. The damage detection results obtained by combining the damage basic probability assignments from each set of test data are more accurate than those obtained from each test data separately. Eliminating the temperature effect on the vibration properties can improve the damage detection accuracy. In particular, the proposed technique can detect even the slightest damage that is not detected by common damage detection methods in which the temperature effect is not eliminated.

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Khatiwada, S., N. Chouw i J. W. Butterworth. "Evaluation of numerical pounding models with experimental validation". Bulletin of the New Zealand Society for Earthquake Engineering 46, nr 3 (30.09.2013): 117–30. http://dx.doi.org/10.5459/bnzsee.46.3.117-130.

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Pounding damage in major earthquakes has been observed frequently in the form of aesthetic, minor or major structural cracks and collapse of buildings. These observations have attracted many numerical and experimental studies that led to analytical models for simulating seismic pounding. This study considers pounding between two steel portal frames without a seismic gap. The first frame has a constant natural period while the second frame has variable stiffness and mass values. Five different ground motions are applied to eight combinations of adjacent frames using a shake table. Numerical simulations for the same configurations are carried out with five pounding force models, viz. linear viscoelastic model, modified linear viscoelastic model, nonlinear viscoelastic model, Hertzdamp model and modified Hertzdamp model. The contact element stiffness and coefficient of restitution for numerical models are determined experimentally. The amplification of maximum displacement of the first frame predicted by the numerical simulations is compared with the shake table results. It was found that the Hertzdamp model always overestimated the responses while the other four models also frequently overestimated the amplifications. The predictions from the four models were not significantly different. Since the linear viscoelastic model requires substantially less computation, compared with the other models this model is more suitable for numerical modelling of pounding responses. However, more study is required to refine the numerical models before building pounding can be modelled with enough confidence.

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Kim, Minjae, i Eunjong Yu. "Experimental Study on Lateral-Load-Resisting Capacity of Masonry-Infilled Reinforced Concrete Frames". Applied Sciences 11, nr 21 (25.10.2021): 9950. http://dx.doi.org/10.3390/app11219950.

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In this study, an experimental program was performed on masonry-infilled frame specimens with varied construction precision and masonry thickness. A total of five portal frame specimens, which consist of four masonry-infilled frames and a bare frame, were tested, and the results were analyzed to investigate the effects of construction precision and interaction between the masonry infill and the frame. The test results indicated that the gap in the masonry infill decreased strength by 75% to 80% and stiffness by 55% to 70%. A comparison between the measured and predicted peak strength using the current code shows that the code equations underestimate the strength by up to 70%. This is due to the fact that the contribution of friction in shear resistance of the masonry wall is actually ignored in the current code since no adequate method for estimating the normal force is provided. In addition, reflecting the observation that the failure mode of the columns changed to shear failure when thick masonry walls were used, a mechanical model that can explain the shear failure and enables the estimation of maximum strength was proposed. The maximum strengths of the specimens calculated using the proposed model were in good agreement with the experimental results.

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Kwon, Y. B., H. S. Chung i G. D. Kim. "Experiments of Cold-Formed Steel Connections and Portal Frames". Journal of Structural Engineering 132, nr 4 (kwiecień 2006): 600–607. http://dx.doi.org/10.1061/(asce)0733-9445(2006)132:4(600).

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Chen, Yuhui, Xiaoyao Zheng, Xintang Wang i Zhanliang Wang. "Experimental Study of Bearing Capacity of Steel Frame with Portal Steel Plate Shear Wall Member". Journal of Physics: Conference Series 2468, nr 1 (1.04.2023): 012075. http://dx.doi.org/10.1088/1742-6596/2468/1/012075.

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Abstract The steel frame with portal steel plate shear wall unit presented here is a new steel structure by assembling the portal steel plate shear wall into the steel frame through bolt connection. For study of shear resistance and bearing capacity of the structure, it is necessary to conduct experimental research. Three frame specimens are made here, and two geometric shapes and the case of setting stiffeners and not setting stiffeners are considered respectively. The concentrated lateral load is applied in the test and displacements and strain were measured. The results show that the setting of the shear wall element has an obvious effect on improving the lateral stiffness of the steel frame, and the failure also shows obvious plastic deformation characteristics. It is also seen that the connection has no evident failure or deformation, which means the connection construction is effective.

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Zhang, Xi, Kim J. R. Rasmussen i Hao Zhang. "Experimental investigation of locally and distortionally buckled portal frames". Journal of Constructional Steel Research 122 (lipiec 2016): 571–83. http://dx.doi.org/10.1016/j.jcsr.2016.04.017.

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Gu, Zhihao, Yang Chen, Taiping Yao, Shouhong Ding, Jilin Li i Lizhuang Ma. "Delving into the Local: Dynamic Inconsistency Learning for DeepFake Video Detection". Proceedings of the AAAI Conference on Artificial Intelligence 36, nr 1 (28.06.2022): 744–52. http://dx.doi.org/10.1609/aaai.v36i1.19955.

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The rapid development of facial manipulation techniques has aroused public concerns in recent years. Existing deepfake video detection approaches attempt to capture the discrim- inative features between real and fake faces based on tem- poral modelling. However, these works impose supervisions on sparsely sampled video frames but overlook the local mo- tions among adjacent frames, which instead encode rich in- consistency information that can serve as an efficient indica- tor for DeepFake video detection. To mitigate this issue, we delves into the local motion and propose a novel sampling unit named snippet which contains a few successive videos frames for local temporal inconsistency learning. Moreover, we elaborately design an Intra-Snippet Inconsistency Module (Intra-SIM) and an Inter-Snippet Interaction Module (Inter- SIM) to establish a dynamic inconsistency modelling frame- work. Specifically, the Intra-SIM applies bi-directional tem- poral difference operations and a learnable convolution ker- nel to mine the short-term motions within each snippet. The Inter-SIM is then devised to promote the cross-snippet infor- mation interaction to form global representations. The Intra- SIM and Inter-SIM work in an alternate manner and can be plugged into existing 2D CNNs. Our method outperforms the state of the art competitors on four popular benchmark dataset, i.e., FaceForensics++, Celeb-DF, DFDC and Wild- Deepfake. Besides, extensive experiments and visualizations are also presented to further illustrate its effectiveness.

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ZHU, SONGYE, WEN-YU HE i WEI-XIN REN. "ADAPTIVE-SCALE DAMAGE DETECTION FOR FRAME STRUCTURES USING BEAM-TYPE WAVELET FINITE ELEMENT: EXPERIMENTAL VALIDATION". Journal of Earthquake and Tsunami 07, nr 03 (wrzesień 2013): 1350024. http://dx.doi.org/10.1142/s1793431113500243.

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The superior human vision system provides ingenious insight into an ideal damage detection strategy in which structural modeling scales are not only spatially varying but also dynamically changed according to actual needs. This paper experimentally examines the efficacy of a multi-scale damage detection method based on wavelet finite element model (WFEM). The beam-type wavelet finite element in this study utilizes the second-generation cubic Hermite multi-wavelets as interpolation functions. The dynamic testing results of a one-bay steel portal frame with multiple damages are employed in the experimental validation. Through a multi-stage updating of the WFEM, the multiple damages in the steel portal frame are detected in a progressive manner: the suspected region is first identified using a low-scale structural model, and the more accurate location and severity of the damage can be identified using a multi-scale model with local refinement. As the multi-scale WFEM considerably facilitates the adaptive change of modeling scales, the proposed multi-scale damage detection method can efficiently locate and quantify damage with minimal computation effort and a limited number of updating parameters and sensors, compared with conventional finite element methods.

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Rinchen, Rinchen, i Kim J. R. Rasmussen. "Experiments on Long-Span Cold-Formed Steel Single C-Section Portal Frames". Journal of Structural Engineering 146, nr 1 (styczeń 2020): 04019187. http://dx.doi.org/10.1061/(asce)st.1943-541x.0002487.

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Asgarian, B., A. A. Aghakouchak i R. G. Bea. "Nonlinear Analysis of Jacket-Type Offshore Platforms Using Fiber Elements". Journal of Offshore Mechanics and Arctic Engineering 128, nr 3 (12.01.2006): 224–32. http://dx.doi.org/10.1115/1.2185678.

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A nonlinear fiber element for analysis of jacket type offshore structures is formulated and implemented in the nonlinear program DRAIN-3DX. This element can be used for modeling the nonlinear behavior of both strut and portal members. The element predicts buckling load and post buckling behavior of strut members accurately. It also produces fairly accurate results for yield load and post yield behavior of portal members. This element is verified using the experimental data for individual strut and portal members subjected to cyclic displacements. The element is then used to predict nonlinear behavior of two tested X-braced jackets made of tubular members under cyclic lateral displacement. The results are in good agreement with experiments and the results of other analytical models in terms of frame hysteretic behavior, energy dissipation, buckling load, load-deformation curve, strength and stiffness degradation.

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Blum, H. B., i K. J. R. Rasmussen. "Experimental investigation of long-span cold-formed steel double channel portal frames". Journal of Constructional Steel Research 155 (kwiecień 2019): 316–30. http://dx.doi.org/10.1016/j.jcsr.2018.11.020.

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Chu, Yun Peng, Yong Yao i De Bin Li. "Seismic Behavior Study on Improving Beam-Column Connections in Portal Frames". Advanced Materials Research 368-373 (październik 2011): 881–84. http://dx.doi.org/10.4028/www.scientific.net/amr.368-373.881.

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The beam-column joints of steel solid-web portal frame has high stress concentration, which cause brittle fracture of plate under reciprocating load. Low reciprocating load test and finite element analysis for three kinds of joints, Discussing the ultimate bearing capacity, hysteretic performance and fracture mechanic properties, Which the results shows that: the bearing capacity of improved joint has grater increased than the joint with endplate keep upright; when load to limit state, the flange plate of joint with endplate keep upright has strong fracture performance, this point has been proved during the experiments; According to the numerical distribution of cracks factor, can qualitative identify dangerous position of component, as a basis of fracture fortification for structure.

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Barszcz, A. M. "Validation of Csd Advanced Analysis of Braced Frame Responses Using Subframe Experimental Investigations". Archives of Civil Engineering 64, nr 2 (31.12.2018): 111–46. http://dx.doi.org/10.2478/ace-2018-0020.

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AbstractThis paper deals with a Continuous Stiffness Degradation (CSD) version of advanced analysis of braced steel framing. It is based on the gradual stiffness degradation concept of frame and truss members. A novelty of the approach presented herein is related to the introduction of the bracing member response in the whole range of its behaviour in tension and compression, including the post-limit range. The validation of the proposed advanced analysis is performed for braced framework with rolled angle section braces. The validation of the brace force-deformation model has been presented in the author’s earlier publication. The basis for the presented CSD advanced analysis is briefly summarized and its difference with regard to the Refined Plastic Hinge (RPH) version of advanced analysis is emphasized. Experimental investigations dealing with tests on portal braced sub-frame specimens are referred to briefly. Results of the experimental investigations are presented in the form of a frame global response and they are used for the validation of the developed computational model.

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Balthazar, José Manoel, Reyolando Manoel Lopes Rabelo da Fonseca Brasil i F. J. Garzeri. "On Non-Ideal Simple Portal Frame Structural Model: Experimental Results under a Non-Ideal Excitation". Applied Mechanics and Materials 1-2 (wrzesień 2004): 51–58. http://dx.doi.org/10.4028/www.scientific.net/amm.1-2.51.

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We present measurements of the non-linear oscillations of a portal frame foundation for a non-ideal motor. We consider a three-time redundant structure with two columns, clamped in their bases and a horizontal beam. An electrical unbalanced motor is mounted at mid span of the beam. Two non-linear phenomena are studied: a) mode saturation and energy transfer between modes; b)interaction between high amplitude motions of the structure and the rotation regime of a real limited power motor. The dynamic characteristics of the structure were chosen to have one-to-two internal resonance between the anti-symmetrical mode (sway motions) and the first symmetrical mode natural frequencies. As the excitation frequency reaches near resonance conditions with the 2nd natural frequency, the amplitude of this mode grows up to a certain level and then it saturates. The surplus energy pumped into the system is transferred to the sway mode, which experiences a sudden increase in its amplitude. Energy is transformed from low amplitude high frequency motion into high amplitude low frequency motion. Such a transformation is potentially dangerous. We consider the fact that real motors, such as the one used in this study, have limited power output. In this case, this energy source is said to be non-ideal, in contrast to the ideal source whose amplitude and frequency are independent of the motion of the structure. Our experimental research detected the Sommerfeld Effect: as the motor accelerates to reach near resonant conditions, a considerable part of its output energy is consumed to generate large amplitude motions of the structure and not to increase its own angular speed. For certain parameters of the system, the motor can get stuck at resonance not having enough power to reach higher rotation regimes. If some more power is available, jump phenomena may occur from near resonance to considerably higher motor speed regimes, no stable motions being possible between these two.

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Jůza, Jan, Michal Jandera i Tomáš Křemen. "Experimental investigation on the square and rectangular hollow section stainless steel portal frames". Thin-Walled Structures 189 (sierpień 2023): 110897. http://dx.doi.org/10.1016/j.tws.2023.110897.

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Gulejova, Barbora Bruant. "IPPOG Global Cosmic Rays Portal: Making Cosmic Rays Studies available to schools worldwide". Journal of Physics: Conference Series 2156, nr 1 (1.12.2021): 012161. http://dx.doi.org/10.1088/1742-6596/2156/1/012161.

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Abstract The International Particle Physics Group (IPPOG) is a global network active in informal education and outreach in particle physics and related research, including cosmic-ray and astro-particle physics. Since many years, IPPOG has been actively supporting the International Cosmic Day organized by DESY and the International Muon Week organized by Quarknet. In 2015 IPPOG started work on establishing a universal portal through which successful cosmic-ray study programmes can reach out to teachers and students around the world. This common web platform is being developed by IPPOG in the frame of its new IPPOG web pages. It will contain all information for schools interested in taking part in cosmic-ray experiments and analysing real data in classroom; also instructions about how to build, borrow, or purchase cosmic-ray detectors. The platform will also facilitate collaboration and exchanges between the experiments’ project managers and advertising of related events.

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Ali, Suhaib J., Amer M. Ibrahim i Sarmad Shafeeq. "Experimental Study and Numerical Simulation of Plane Steel Frame with Rubberized Connecting Technology Subjected to Seismic Effect". Engineering and Technology Journal 39, nr 3A (25.03.2021): 415–25. http://dx.doi.org/10.30684/etj.v39i3a.1500.

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This paper representsexperimental and numerical study the behavior of the rubberized steel frame connections. One single-bay, one-story without elastic buckling are cyclically tested. The experimental specimens are simulated and analyzed by the ABAQUS program. Four specimens of steel plane portal frame are investigated under horizontal reversed cyclic loads. The specimen connections are developed by using different diameters of composite steel bolts/rubberinstead of conventional steel bolts to connect the beams with columns. The yield and ultimate strength, ductility, envelope curves, and damping ratio of these specimens are analyzed and compared. The finite element method is used to establish and verify the results of the laboratory test. The results of the experimental and numerical tests gave a large load-carrying capacity, reduction in the stresses, excellent ductility and energy dissipation capacity, and remarkably improved damping ratio.

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Lendvai, Anita, Attila László Joó i László Dunai. "Experimental full-scale tests on steel portal frames for development of diaphragm action – Part I experimental results". Thin-Walled Structures 132 (listopad 2018): 729–39. http://dx.doi.org/10.1016/j.tws.2018.06.001.

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SAKAGUCHI, Akihiro, Masayoshi KURASHIGE, Tadatoshi FURUKAWA, Yoshiyuki MURATA, Rieko UEKI, Hiroyuki TSUBOSAKI, Katsunobu SHIOMI i Katsuhiko IMAI. "EXPERIMENTAL STUDY OF AN INNOVATIVE R/C BUILDING REINFORCEMENT METHOD UTILIZING STEEL PORTAL FRAMES". Journal of Structural and Construction Engineering (Transactions of AIJ) 69, nr 578 (2004): 147–54. http://dx.doi.org/10.3130/aijs.69.147_1.

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Ghasemi, Navid, Ennia Mariapaola Acerra, Claudio Lantieri, Andrea Simone, Federico Rupi i Valeria Vignali. "Urban Mid-Block Bicycle Crossings: The Effects of Red Colored Pavement and Portal Overhead Bicycle Crossing Sign". Coatings 12, nr 2 (26.01.2022): 150. http://dx.doi.org/10.3390/coatings12020150.

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This paper aims to investigate the effectiveness of some mid-block bicycle crossing elements by analyzing the drivers’ behavior, when approaching the bicycle crossings in a real road experiments with 18 participants. The eye-tracking instrument has been used to monitor the driver’s visual behavior during the test in an instrumented vehicle with GPS (global positioning system) and an inertial measurement unit (IMU). In particular, the drivers’ gaze was investigated frame by frame while approaching the mid-block bicycle crossings. The results showed that the red colored pavement increased the visibility of the mid-block crossing zone to 65.3% with respect to zebra crossing 59.6%. The drivers’ visual field was also narrowed by the portal overhead bicycle crossing sign and, consequently, drivers reduced their velocity and looked more to the vertical signs by 28%. The drivers’ speed reduction helped drivers to see the mid-block crossing elements from a greater distance with a higher fixation duration.

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Kumar Jagarapu, Durga Chaitanya, i Arunakanthi Eluru. "Experimental Studies on Portal Frames made with Palm oil Shell Light Weight Fiber Reinforced Concrete". Journal of Physics: Conference Series 1979, nr 1 (1.08.2021): 012002. http://dx.doi.org/10.1088/1742-6596/1979/1/012002.

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Li, Guo-Qiang, Wei Ji, Cheng-Yuan Feng, Yao Wang i Guo-Biao Lou. "Experimental and numerical study on collapse modes of single span steel portal frames under fire". Engineering Structures 245 (październik 2021): 112968. http://dx.doi.org/10.1016/j.engstruct.2021.112968.

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Lou, Guobiao, Chenghao Wang, Jian Jiang, Yaqiang Jiang, Liangwei Wang i Guo-Qiang Li. "Experimental and numerical study on thermal-structural behavior of steel portal frames in real fires". Fire Safety Journal 98 (czerwiec 2018): 48–62. http://dx.doi.org/10.1016/j.firesaf.2018.04.006.

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Yeh, Fang-Yao, Kuo-Chun Chang i Wen-Cheng Liao. "Experimental Investigation of Self-Sensing Carbon Fiber Reinforced Cementitious Composite for Strain Measurement of an RC Portal Frame". International Journal of Distributed Sensor Networks 11, nr 11 (styczeń 2015): 531069. http://dx.doi.org/10.1155/2015/531069.

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Öztürk, Ferhan, i Selim Pul. "Experimental and numerical study on a full scale apex connection of cold-formed steel portal frames". Thin-Walled Structures 94 (wrzesień 2015): 79–88. http://dx.doi.org/10.1016/j.tws.2015.04.004.

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YAMAGUCHI, Kazuhiro, Masahiro INAYAMA, Satoshi SHIMURA, Taishi HATAKEYAMA i Naohito KAWAI. "EXPERIMENTAL STUDY ON WOODEN SEMI-RIGID PORTAL FRAMES WITH PARAMETERS OF SPAN, HEIGHT AND VERTICAL LOAD". Journal of Structural and Construction Engineering (Transactions of AIJ) 78, nr 683 (2013): 119–28. http://dx.doi.org/10.3130/aijs.78.119.

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Blum, H. B., i K. J. R. Rasmussen. "Experimental and numerical study of connection effects in long-span cold-formed steel double channel portal frames". Journal of Constructional Steel Research 155 (kwiecień 2019): 480–91. http://dx.doi.org/10.1016/j.jcsr.2018.11.013.

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37

Paolacci, F., i R. Giannini. "An experimental and numerical investigation on the cyclic response of a portal frame pier belonging to an old reinforced concrete viaduct". Earthquake Engineering & Structural Dynamics 41, nr 6 (28.09.2011): 1109–27. http://dx.doi.org/10.1002/eqe.1175.

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Brandonisio, Giuseppe, Elena Mele i Antonello De Luca. "Closed form solution for predicting the horizontal capacity of masonry portal frames through limit analysis and comparison with experimental test results". Engineering Failure Analysis 55 (wrzesień 2015): 246–70. http://dx.doi.org/10.1016/j.engfailanal.2015.06.001.

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Quaglini, Virginio, Carlo Pettorruso, Eleonora Bruschi i Luca Mari. "Experimental and Numerical Investigation of a Dissipative Connection for the Seismic Retrofit of Precast RC Industrial Sheds". Geosciences 12, nr 1 (6.01.2022): 25. http://dx.doi.org/10.3390/geosciences12010025.

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Past earthquakes have highlighted the seismic vulnerability of prefabricated industrial sheds typical of past Italian building practices. Such buildings typically exhibited rigid collapse mechanisms due to the absence of rigid links between columns, beams, and roof elements. This study aims at presenting the experimental and numerical assessment of a novel dissipative connection system (DCS) designed to improve the seismic performance of prefabricated sheds. The device, which is placed on the top of columns, exploits the movement of a rigid slider on a sloped surface to dissipate seismic energy and control the lateral displacement of the beam, and to provide a recentering effect at the end of the earthquake. The backbone curve of the DCS, and the effect of vertical load, sliding velocity, and number of cycles were assessed in experimental tests conducted on a scaled prototype, according to a test protocol designed accounting for similarity requirements. In the second part of the study, non-linear dynamic analyses were performed on a finite element model of a portal frame implementing, at beam-column joints, either the DCS or a pure friction connection. The results highlighted the effectiveness of the DCS in controlling beam-to-column displacements, reducing shear forces on the top of columns, and limiting residual displacements that can accrue during ground motion sequences.

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40

Lagos, Frank Silvano, Katia Christina Zuffellato-Ribas i Cícero Deschamps. "Vegetative propagation of hops (Humulus lupulus L.): Historical approach and perspectives". Semina: Ciências Agrárias 43, nr 3 (25.03.2022): 1373–94. http://dx.doi.org/10.5433/1679-0359.2022v43n3p1373.

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Hop (Humulus lupulus L.) female inflorescences are important raw materials used to produce beers, cosmetics, and medicines. Vegetative propagation is the preferred way of obtaining seedlings for commercial cultivations as female plants produce more lupulin than male plants, a component of commercial interest. It can be carried out by macropropagation (stem cuttings or rhizomes) or micropropagation. This review aimed to systematize different techniques of hop vegetative propagation, with no time frame, from searches in the main academic research bases: Capes Journal Portal, Scielo, Scopus, Web of Science, Science Direct, Google Scholar, and ResearchGate. Most studies are related to micropropagation, mainly addressing different plant regulators and concentrations, as well as types of explants and culture media, strategies to produce virus-free plants, artificial lighting, and cryopreservation. Experiments with stem cuttings are more common regarding macropropagation, but factors such as size and origin of cuttings, rooting period, and the response of different cultivars need to be better evaluated. Cultivation by cuttings allows the production of clones of female plants and micropropagation the production of virus-free clones in a short time and less physical space. Currently, micropropagation has been widely applied to cryopreservation.

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41

Lendvai, Anita, i Attila László Joó. "Experimental full-scale tests on steel portal frames for development of diaphragm action – Part II Effect of structural components on shear flexibility". Thin-Walled Structures 132 (listopad 2018): 740–58. http://dx.doi.org/10.1016/j.tws.2018.06.006.

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Baghdadi, Abtin, Mahmoud Heristchian, Lukas Ledderose i Harald Kloft. "Experimental and Numerical Assessments of New Concrete Dry Connections concerning Potentials of the Robotic Subtractive Manufacturing Technique". Buildings 13, nr 1 (12.01.2023): 210. http://dx.doi.org/10.3390/buildings13010210.

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The efficient utilization of robotic construction of structures requires a review of structural material, elements and details, while traditional construction methods face difficulties in producing some dry concrete joints, robotic methods can manufacture them efficiently. With the rapid advancement of new construction methods, more effort should be directed towards developing new types of joints manufactureable by Additive Manufacturing (AM) methods. Accordingly, considering the potential of robotic techniques, this article proposes eight new concrete dry joints. Concrete portal frames with two identical joints at the end of the beam are cast and evaluated under bending and shear. The performance of each joint, evaluated by experimental and numerical studies based on the crack distribution and stresses, was discussed. Furthermore, various aspects of the process of robotic subtractive manufacturing of the connections are discussed through the selected printed/milled geometries; likewise, geometrical accuracy by microscanning was measured, proving this technique’s capability (methodology). Based on findings, some proposed joints that can be manufactured entirely and quickly by robotic additive and subtractive techniques structurally can produce the full strength of the monolithic reference section. The rage of the capacities and initial stiffness is, accordingly, [50%, 106%] and [51%, 124%] of the monolithic elements.

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Liu, Wei, Bin Zhang, Chao Shen i Yu-Chun Li. "Stability Analysis for Spatial Autoparametric Resonances of Framed Structures". International Journal of Structural Stability and Dynamics, 4.02.2022. http://dx.doi.org/10.1142/s0219455422500651.

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The spatial dynamic instabilities of framed structures due to autoparametric resonances have been seldom investigated in the published literature. Based on the finite element method (FEM), the spatial parametric vibration equations are established for general framed structures. The Newmark’s method and the energy-growth exponent (EGE) are used to determine the stability of the spatial autoparametric resonances of framed structures. A portal frame model is used to conduct a spatial (out-of-plane) autoparametric resonance experiment. The numerical results of the autoparametric resonances are found to agree with those of the test, which proves the validity of the present theoretical formulation. A numerical example for autoparametric resonance stability analysis of a spatial frame is presented to firstly predict the three instability modes of autoparametric resonances, i.e. global unidirectional translational instability, bidirectional (diagonal) translational instability and torsional instability. When the excitation frequency is approximately twice the modal frequency of spatial vibration of a framed structure, spatial dynamic instability will occur due to autoparametric resonance. A small excitation force can cause a strong autoparametric resonance of the framed structure. The potential risk of spatial dynamic instability is revealed for the framed structures under periodic loads.

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SAILAJA, G., N. SEETHARAMAIAH i MAGANTI JANARDHANA. "EXPERIMENTAL INVESTIGATION OF A PORTAL FRAME USING MAGNETORHEOLOGICAL FLUID DAMPER". INTERNATIONAL JOURNAL OF PRODUCTION TECHNOLOGY AND MANAGEMENT 10, nr 1 (30.06.2019). http://dx.doi.org/10.34218/ijptm.10.1.2019.007.

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Ebenezer J, Sheeba, Tensing D i Vincent Sam Jebadurai S. "An experimental study on composite steel encased portal frame under cyclic loading". Research on Engineering Structures and Materials, 2022. http://dx.doi.org/10.17515/resm2022.426ie0408.

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Varanis, Marcus V. M., Arthur G. Mereles, Anderson L. Silva, Jose M. Balthazar, Angelo M. Tusset i Clivaldo Oliveira. "Modeling and Experimental Validation of Two Adjacent Portal Frame Structures Subjected to Vibro-impact". Latin American Journal of Solids and Structures 16, nr 4 (2019). http://dx.doi.org/10.1590/1679-78255435.

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"Experimental Study on Single Bay Reinforced Coconut Shell Concrete Portal Frame under Lateral and Cyclic Load". International Journal of Engineering 34, nr 8 (sierpień 2021). http://dx.doi.org/10.5829/ije.2021.34.08b.12.

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Shahmohammadi, Amir, James B. P. Lim, Charles Clifton i Mohammad Hajsadeghi. "Full-Scale Experimental Tests on Portal Frames Comprising Novel Cold-Formed Tapered Box Sections". Journal of Structural Engineering 148, nr 9 (wrzesień 2022). http://dx.doi.org/10.1061/(asce)st.1943-541x.0003379.

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Wang, Yen-Po, Di-Hung Chen i Chien-Liang Lee. "AN EXPERIMENTAL STUDY OF IN-PLANE, ARCH-SHAPED FLEXURAL DAMPER". Proceedings of International Structural Engineering and Construction 2, nr 1 (listopad 2015). http://dx.doi.org/10.14455/isec.res.2015.94.

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An innovative displacement-dependent metallic yielding damper designed to deform inelastically under in-plane flexural bending for seismic protection of building structures is proposed. The in-plane flexural damper that originated from a portal frame is modified by replacing the beam with a circular arch so that the effect of stress concentration can be minimized. Component tests of the in-plane dampers were conducted and compared with analytical results. Hysteresis of the component test indicates a consistent energy-dissipative characteristic of the damper. Moreover, seismic performance of the proposed damper via a series of shaking table tests was carried out. Excellent seismic performance of the proposed in-plane arched damper was observed. The acceleration responses in both peak and root-mean-squares of all floors are significantly reduced, and were greater in extent compared to the earthquake intensity increases.

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Ye, Dehui, Jie Tan, Yabin Liang i Qian Feng. "Experimental Study on Influence of Temperature to Control Performance for Viscoelastic Materials Pounding Tuned Mass Damper". Frontiers in Materials 8 (31.05.2021). http://dx.doi.org/10.3389/fmats.2021.676405.

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The pounding tuned mass damper (PTMD) is a novel passive damper that absorbs and dissipates energy by an auxiliary tuned spring-mass system. Viscoelastic materials are attached to the interface of the limitation collar in the PTMD so that the energy dissipation capacity can be enhanced. Previous studies have successfully demonstrated the effectiveness of PTMD at room temperature. However, in practice, the PTMD may face a broad temperature range, which can affect the mechanical properties of the viscoelastic materials. Thus, the study of vibration control effectiveness of PTMD at different temperatures is of great significance for its practical engineering application. In this paper, a series of experiments were conducted to investigate the performance of a PTMD in a temperature-controlled environment. A PTMD device was designed to suppress the vibration of a portal frame structure and tested across environmental temperatures ranging from –20°C to 45°C. The displacement reduction ratios demonstrated the temperature robustness of the PTMD. Additionally, the numerical results validated the accuracy of the pounding force model and the performance of PTMD.

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