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This paper presents the results of an experimental study performed on concrete structural walls subjected to vertical and cyclic lateral loads. The purpose of the study is to experimentally investigate the seismic behavior and performance of composite steel–concrete coupled walls with regular openings and conventional reinforced coupling beams. The paper also addresses the manner in which the use of steel fibers reinforced concrete and various composite steel–concrete connections influence the hysteretic performance of the walls. Four of the total five experimental specimens had centrally aligned openings, while the fifth one was designed as a solid wall and served as reference. The experimental specimens present various cross-sectional arrangements, thus the testing matrix comprises of a total of three composite steel–concrete walls with central openings (CSRCW) with steel profiles partially embedded on the edges, one conventional reinforced concrete wall (RCW) with central openings and the solid specimen, which is also a composite steel–concrete wall. Based on the experimental results, it was observed that by embedding supplementary steel fibers in the concrete matrix, the ductility loss due to openings could be regained and significantly improved. The composite connection between structural steel and concrete web panel of the walls could successfully resist until the specimens reached the ultimate failure. The paper therefore concludes on the performance of various structural solutions and details by highlighting strengths and weaknesses of the systems.

The detection of face tampering in videos created by artificial intelligence techniques (commonly known as the Deep Fakes) has become an important and challenging task in network security defense. In this paper, we propose a novel attention-based deep fake video detection method, which captures the sharp changes in terms of the facial features caused by the composite video. We utilize the convolutional long short-term memory to extract both spatial and temporal information of DeeFake videos. Meanwhile, we apply the attention mechanism to emphasize the specific facial area of each video frame. Finally, we design a decoder to further fusion multiple frames information for more accurate detection results. Experimental results and comparisons with state-of-the-art methods demonstrate that our framework achieves superior performance.

An experimental study according to EC4 on deconstructable steel-concrete composite bolted shear connectors is carried out to investigate the effect of various bolt size, concrete strength, bolt strength and clearance size between the precast concrete slab and bolt on the static behaviour of this type of composite connection. Shear load capacity for the first bearing, average major slip at the first bearing, maximum shear load capacity per bolt, slip corresponding to the maximum shear load capacity, maximum average slip between the precast concrete slab and steel beam and failure modes are assessed. A total of 12 composite specimens were tested according to EC4 with different parameters using deconstrcutable bolted shear connectors. In addition, two steel-concrete composite connection specimens using welded headed stud shear connectors were tested as control specimens to determine the influence of prefabricated concrete panels and deconstructable friction-grip bolted shear connectors on the performance of the steel-concrete composite connection. The experimental results show that deconstrcutable steel-concrete composite bolted shear connectors have completely different behaviour compared to welded headed stud shear connectors. Furthermore, a 3D finite element model of the steel-concrete composite connection having precast concrete slabs and deconstructable bolted shear connectors was performed. Numerical model was verified against experimental results, and was shown to accurately simulate their observed structural behaviour.

Aircraft lug joint is the key part of load transfer. In order to improve the safety of lug joint, on the premise of meeting the design requirements of static strength and fatigue, the composite connection lug structure design technology of different metal materials is proposed in this paper. Firstly, the damage safety design and life reliability analysis of the lug structure are studied theoretically. Secondly, based on the concept of damage safety design and the design principle of deformation coordination, the design method of composite connection lug with deformation coordination is proposed, and the thickness ratio of single ear is 0.8:1:0.8. Finally, the reliability of the composite lug is analyzed. The results show that the structural design scheme of aluminum-titanium composite ear piece can meet the requirements of static strength and damage tolerance, and compared with the conventional ear structure, the failure probability of structure mission life is greatly reduced when the weight of the composite connection lug is only increased by 4.9%. The proposed method can effectively guide the structural design of composite ear piece.

Moisture damp has been identified as one of the most harmful agents of multilayer composited insulation, which can seriously accelerate its degradation, cause unexpected failure, and even lead to catastrophic accidents. This article proposes a nonintrusive method for moisture inspection of multilayer insulation structure based on terahertz (THz) technology with a focus on the cable terminal of the electric multiple units (EMUs). First, a three-layer scattering model is established based on the actual structure of the composite cable terminal, and theoretical analysis is performed to reveal the potential application mechanism. Based on that, an artificial model of a three-layer structure is then built on which the insulation damp test is carried out. Finally, the THz spectrum and THz imaging tests are performed. Results show that the frequency-domain signal can effectively identify the moisture inside the multilayer composited insulation. The imaging results in the frequency domain of the sample can accurately determine the geometric parameters of the damp area. By further analyzing the time-domain spectroscopy, the thickness of insulation affected by moisture can be identified quantitatively. This article verifies the feasibility of THz technology in inspecting the moisture dampness of multilayer composite insulation and its potential application in the damp condition assessment of EMU cable terminals.

A large number of variables are involved in the optimization of cable-stayed bridges, which makes the optimization impractical when many load cases are considered. To reduce the number of variables to be optimized, a discrete phases approach for structural optimization is developed in this study. The approach couples the finite element method with the genetic algorithm optimization approach. The design variables are divided into two categories: (i) main variables: number of stay cables, I-girder inertia, concrete slab thickness, and tower dimensions; and (ii) secondary variables: I-girder dimensions, stay-cable areas, and pre-tensioning forces. Two design objectives are tested: (i) lightest deck mass; and (ii) lowest material cost. Three load cases are considered: (i) dead and truck plus lane live loads; (ii) dead and lane live loads; and (iii) dead load. The results show the importance of considering the truck loads in structural optimization and the efficacy of the phases approach for different objectives.

As the closed-circuit television (CCTV) security industry transitioned from analog media to digital video recorders (DVRs) with digital storage, the law enforcement community struggled with the means with which to collect the recordings. New guidelines needed to be established to determine the collection method which would be efficient as well as provide the best quality evidence from live DVRs. A test design was developed to measure, quantify, and rank the quality of acquisition methods used on live systems from DVRs typically used in digital CCTV systems. The purpose was to determine guidelines for acquiring the best quality video for investigative purposes. A test pattern which provided multiple quantifiable metrics for comparison between the methods of acquisition was used. The methods of acquisition included direct data download of the proprietary file and open file format as well as recording the video playback from the DVR via the available display monitor connections including the composite video, Video Graphics Array (VGA), and high-definition multimedia interface (HDMI). While some acquisition methods may provide the best quality evidence, other methods of acquisition are not to be discounted depending on the situation and need for efficiency. As an investigator that needs to retrieve video evidence from live digital CCTV systems, the proprietary file format, overall, provides the best quality evidence. However, depending on the circumstance and as recording technology continues to evolve, options other than the proprietary file format may provide quality that is equal to or greater than the proprietary file format.

Steel-concrete hybrid solutions with replaceable fuses as coupling elements and appropriately detailed composite connections have shown their efficiency to design safe and easily repairable earthquake-resisting structures. In this general framework, the behavior of a possible steel to concrete composite connection to be used in a recently suggested Hybrid Coupled Wall (HCW) system, consisting of a reinforced concrete shear wall coupled with steel side columns via dissipative steel shear links, is studied in this paper. The steel shear links are bolted to a steel profile either partly embedded or passing through the RC wall. The connection zone is designed in such a way that the damage always occurs in the steel shear links (fuses) prior to any damage in the RC wall in general and in the connection zone in particular. The emphasis lies therefore on the characterization of a suitable “steel link + embedded composite connection within the RC wall” configuration and on the evaluation of an appropriate embedment length allowing the concentration of seismic damage to the replaceable steel links. To this purpose, two joint configurations are designed based on a capacity-based approach, namely “partly embedded” and “completely passing through” steel beam, and are examined through detailed FE analyses. A parametric study is carried out to provide sufficient insight into the system in terms of strength, stiffness and local bearing strength, in view of validating the proposed design procedure.

Previous research showed that wind characteristics were influenced by terrain. To accurately calculate the wind-induced bridge response, this article presented a comprehensive investigation of the wind characteristics of a trumpet-shaped mountain pass by long-term monitoring. Basic strong wind characteristics such as the wind rose, turbulence intensities, turbulence length scales, turbulence spectra and normalized cross-spectrum were discussed using 10 min intervals. Due to the different types of terrain on the two sides of the bridge site, this article attempted to reflect the influence of the terrain on the wind characteristics in different wind directions. The scatter plots of wind characteristics were presented directly on the terrain map. The effects of the turbulence characteristics, mean wind speed and aerodynamic admittance function on buffeting response of the composite cable-stayed bridge were discussed by the multimode coupled frequency domain. The results show that the wind profile is extremely twisted. The larger turbulent integral scale and the lower turbulence intensity appear in the direction along the river. The effect of the mean wind speed on the buffeting response is greater than that of the fluctuating wind characteristics. The aerodynamic admittance function proposed by Holmes has the largest reduction in buffeting response.

There is much emerging interest in operating Unmanned Aerial Systems (UAS) at long-range distances. Unfortunately, it is unclear whether network connectivity at these distances is sufficient to enable applications with stringent performance needs. In this paper, we consider this question in the context of video streaming, an important UAS use-case. We make three contributions. First, we characterize network data collected from real-world UAS flight tests. Our results show that while dropouts (i.e., extended periods of poor performance) present challenges, there is potential to enable video streaming with modest delays, and correlation of throughput with flight path (both distance and orientation) provides new opportunities. Second, we present Proteus, the first system for video streaming targeted at long-range UAS settings. Proteus is distinguished from Adaptive Bit Rate (ABR) algorithms developed for Internet settings by explicitly accounting for dropouts, and leveraging flight path information. Third, through experiments with real-world flight traces on an emulation test-bed, we show that at distances of around 4 miles, Proteus reduces the fraction of a viewing session encountering rebuffering from 14.33% to 1.57%, while also significantly improving well-accepted composite video delivery metrics. Overall, our results show promise for enabling video streaming with dynamic UAS networks at long-range distances.

Background and aim: Most of the Mixed Reality models used in the surgical telepresence are suffering from discrepancies in the boundary area and spatial-temporal inconsistency due to the illumination variation in the video frames. The aim behind this work is to propose a new solution that helps produce the composite video by merging the augmented video of the surgery site and the virtual hand of the remote expertise surgeon. The purpose of the proposed solution is to decrease the processing time and enhance the accuracy of merged video by decreasing the overlay and visualization error and removing occlusion and artefacts. Methodology: The proposed system enhanced the mean value cloning algorithm that helps to maintain the spatial-temporal consistency of the final composite video. The enhanced algorithm includes the 3D mean value coordinates and improvised mean value interpolant in the image cloning process, which helps to reduce the sawtooth, smudging and discolouration artefacts around the blending region. Results: As compared to the state of the art solution, the accuracy in terms of overlay error of the proposed solution is improved from 1.01mm to 0.80mm whereas the accuracy in terms of visualization error is improved from 98.8% to 99.4%. The processing time is reduced to 0.173 seconds from 0.211 seconds. Conclusion: Our solution helps make the object of interest consistent with the light intensity of the target image by adding the space distance that helps maintain the spatial consistency in the final merged video., 27 pages

The paper presents and discusses the dynamic response of a curved cable-stayed bridge in Venice (Italy). Two distinct experimental campaigns in 2010 and 2011 led to identifying the bridge dynamic characteristics in operational conditions. The dynamic identification included the characterization of both the deck and cables response. The authors developed a highly refined finite element (FE) model of the bridge, mirroring up to twelve experimental modes. An updating procedure drove the estimate of the optimum parameters associated with the lowest discrepancy with the experimental modal parameters. The calibrated model was the base of a parametric analysis on the effects of the deck curvature, cables arrangement and tower cross-section inertia on the bridge dynamics. Specifically, the authors developed fourteen FE models of the bridge distinguished by the lack and different arrangement of the stay cables, the increasing value of the deck curvature and the tower cross-section inertia. The analysis intends to quantify the impact of the design choices of cable-stayed bridges on the modal parameters.

In the structural engineering field, injection moulded Glass Fibre Reinforced Polymer (GFRP) components are typically used as parts or accessories of fastening systems. In this paper, an extended numerical and experimental study on a Timber-Concrete Composite Connection (TCCC) realized with an injection-moulded GFRP notch fastened to the timber beam with self-tapping screws is presented. Numerical simulations performed to predict the performance of the investigated TCCC in terms of force-displacement curves are compared with the outcomes from forty push-out tests. Results demonstrate how the GFRP notch assure the full exploitation of the screws withdrawal capacity without incurring in sudden concrete failures independently from the type of concrete used (normal and light-weight).

Mass timber panels (MTPs) are a new generation of engineered wood panels that are available in large plane dimensions to facilitate fast floor construction with the obvious environmental be...

BNC connectors are the standard video connectors for professional equipment. They’re used for conveying the composite video signal—that is, the analogue signal in which the luminance and chrominance signals are composited together and travel along one cable. BNC connectors are constructed so they lock together and can’t be pulled undone accidentally. The male and female RF connectors look almost the same. The male RF connector has a round metal collar surrounding a bare inner wire, which can be rounded off or quite sharp and raw. The female RF connector has a similar round metal collar surrounding a slim connection socket. They’re easy to use because they just slip together, but they don’t lock into place. 8-pin connectors transmit video and audio in both directions between a VCR and a TV or monitor. 8-pin connectors transmit video and audio in both directions between a VCR and a TV or monitor.

Prefabricated bridge deck panels are a popular option for new construction and bridge rehabilitation. Further, ultra-high-performance concrete (UHPC) has become a common option for closure...

This paper presents a low-damage solution for self-centering steel and composite beam-to-column connections, with the issue of beam-growth being particularly addressed by permitting the con...

The slim floor system has been used mainly due to the structural and constructive advantages of it, such as the capacity to overcome large spans with the low height of the composite floor system. There is a lack of finite element modelling researches of composite connections between the slim floor system and columns, especially with the concrete infilled steel tube columns. This paper presents the numerical approach based on the solid modelling, for the simulation of the nonlinear structural behavior of composite connection between partially encased composite beam and concrete infilled steel tube column; in this model, the composite beam represents the slim floor. The ABAQUS finite element code was used to investigate the behavior of composite connection that consists of a shear steel plate and negative reinforcement of the composite slab. In this paper, the authors discusses the procedures to the numerical model construction including finite elements and boundary conditions. Besides, the influence of stress-strain relationships for concrete and steel and the parameters that defines each model are presented and discussed, as well as the different steel to concrete interface conditions. Based on the results obtained, the effectiveness of the numerical model developed was verified against experimental results showing a good agreement response for the Moment vs. Rotation response, as well as the moment resistance of the composite connection. Resumo A utilização do sistema de piso misto de pequena altura, de aço e concreto tem-se dado, principalmente, devido às boas características estruturais e construtivas como a capacidade de vencer vãos consideráveis com baixa altura do sistema laje-viga. Apesar disso, há carência de estudos voltados ao comportamento das ligações entre o sistema de piso de pequena altura e os pilares, sobretudo quando o pilar é misto preenchido. Diante disto, o presente estudo traz uma metodologia para o desenvolvimento de modelo numérico que represente o comportamento de uma ligação mista entre viga mista parcialmente revestida e pilar misto preenchido; a viga mista representa o piso misto de pequena altura. Para tanto foi utilizado o pacote computacional ABAQUS. A ligação mista viga-pilar consiste de chapa passante e armadura negativa da laje mista com fôrma de aço incorporada. São apresentados os procedimentos para a construção do modelo numérico, desde escolha dos elementos finitos e condições de vinculação, incluindo amplo estudo sobre o efeito dos modelos constitutivos dos materiais e dos parâmetros que definem cada modelo constitutivo dos componentes da ligação mista bem como das diversas interfaces aço-concreto. O modelo numérico mostrou-se bastante robusto e representou de forma satisfatória a resposta Momento vs. Rotação bem como a rigidez inicial e o momento resistente da ligação mista.

The modern age is driven by video streaming services. Video streaming vendors allow the viewers to view the digital content on televisions, desktops, laptops, phones, electronic gadgets, etc. The video streaming platforms run on the monthly subscription model, wherein the streaming services acquire licensing rights to the digital content and further make the content available to the customers based on the type of subscription chosen by a user. As the over-the-top (OTT) platforms gain popularity in video streaming services, delivery of preference-based digital content to the consumers seem to bring about a paradigm shift in video streaming services. However, the consumer can view only one content at one time as the transmission station broadcasting the composite video signal accommodates separate video channels on separate frequency windows by applying modulation techniques. The paper discloses a novel method for embedding multiple video frames into a single video stream by utilizing a genetic algorithm, such that multiple consumers can view multiple preference-based video contents at one time.

The performance of steel–concrete composite structural members depends on the connection at the steel–concrete interface. Structural adhesives are gaining rapid recognition as the bonding material between steel and concrete interfaces. The thickness of adhesive layer in a composite connection plays a key role in maximising the bond capacity. In this paper, the effect of the change in thickness of adhesive layer on the capacity of connection, ultimate slip at the interface, and the shear stiffness of connection have been studied. Twenty-five test specimens were cast and tested under direct shear to achieve the optimum thickness of adhesive layer. The ultimate strength and relative slip of all five adhesive layer thicknesses of steel–concrete specimens, obtained through experimental studies, were verified using finite element analysis. The failure patterns of bonded connection were also critically observed and found to be varying with adhesive layer thickness. It changes from adhesive failure to mixed (adhesive and cohesive) failure, and from mixed failure to cohesive mode of failure, with increasing thickness. At the optimum thickness, the composite interface experiences a mixed mode of failure. The effectiveness of bonded connections over mechanical shear stud connections was outlined through a comparison of the load-slip behaviour of both.

The research work reported in this paper involves investigation of the mechanical and durability performance of unstressed and stressed Tokyo Rope carbon-fiber composite cables for prestressing applications. This research is critical in order to establish the critical (allowable) stress and safety factors for the use of carbon-fiber composite cable tendons for prestressed precast-concrete members. The carbon-fiber composite cable specimens were exposed to simultaneous high alkali environment and sustained loading at different elevated exposure temperatures (22℃ and 60℃) for 3000, 5000, and 7000 h. The high alkali environment (12.8 pH) simulated the concrete pore solution and the elevated temperature was used to accelerate the aging process. The applied sustained stress on the carbon-fiber composite cable strands was equivalent to 40% and 65% of their guaranteed tensile strength. This was achieved through testing 171 carbon-fiber composite cable specimens subjected to stress levels of 0%, 40%, and 65% of their guaranteed strength, under tensile load. Also, 136 carbon-fiber composite cable specimens were tested to investigate the transverse shear strength. In addition, the durability characteristics of the constituent materials of the carbon-fiber composite cable strands were assessed to understand the long-term behavior of these materials. The results showed the effect of sustained stress on the degradation of carbon-fiber composite cable strands. Under sustained stress of 40% and 65%, the reductions in tensile strength were 10.6% and 12.3%, respectively. Scanning electron microscope results on epoxy resin indicated that no degradation is detected since the surface remains smooth without any pitting or loose material.

The impact of dropped anchor on submarine photoelectric composite cables may possibly cause electrical faults, i.e. electricity and optical signal transmission failure. In order to study the impact capacity and structural impact failure mechanism, a test setup is designed originally to examine the structural and functional integrity. A detailed finite element model (FEM) is created, considering material nonlinearity and component interaction. A parametric analysis has been performed to predict the deformation of components and impact forces, under different impact velocities and collision directions. Relationships between the armor layer indentation rate and that of internal power and optical units are achieved. The impact deformation of internal entities can be evaluated intuitively by armor layer indentation. The proposed experimental and numerical methods are well correlated, suitable to assess the impact capacity of subsea power cables and assist the protection design of subsea power cables in engineering.

A vessel-shaped floating aquaculture platform has numerous advantages over traditional high-density polyethylene gravity cages. Combined with a single-point mooring system, the unique structural form of the vessel shape can significantly reduce the environmental loads transmitted from the bow. This study used potential flow theory and dynamic composite cable theory to simulate the hydrodynamic responses of a single-point moored vessel-shaped floating aquaculture platform in waves. The motion response, mooring force response, and reaction force of the nets were simulated in regular waves and compared with experimental values. The numerical and experimental results agree well. After the validation, the response amplitude operators of the floating frames of the platform were calculated and analyzed in the frequency domain. Then, time-domain calculations were carried out to investigate the hydrodynamic characteristics of the platform. The results show that the heave and pitch responses of the front frame are significantly higher than those of the rear frames of the same platform. The increase in the number of floating frames decreases the motion responses and increases the mooring force response of the platform. The X and Z components of the hinge joint force between the floating front frames are significantly higher than those between the rear frames. Similarly, the reaction force of the nets of the floating front frame is higher than that of the rear frames under the same wave conditions.

Composite connections are key components that dissipate energy and provide ductility. This work performed push-out tests on 20 specimens to elucidate their mechanical properties. Timber-to-concrete (TC) connections with U-steel (TC-U) and screws (TC-S) were designed to investigate the influence of U-steel on the mechanical properties of composite connections. The failure modes, initial stiffness levels, maximum load capacities, and ductility values of TC-U and TC-S connections were analyzed. The test results showed that U-steel could provide sufficient stiffness to prevent the screws from shearing off and effectively improve the load capacity and ductile performance of TC-U connections over those of TC-S connections. Based on the obtained test results, a mathematical model was proposed to predict the nonlinear behaviors of composite connection-based load-slip curves. The Bayesian method was introduced to estimate the model parameters and quantify the corresponding uncertainty using the given test data. The identified parameters and uncertainty provide references for the design of TC connections.

During earthquakes, concrete slabs in composite beams are subjected to cyclic compressive and tensile stresses. Previous experimental tests indicated that the strength in the cyclically loaded stud connections degraded faster than in ordinary monotonic push-out tests. To assess the mechanical performance of the local composite connection, this research first calibrates a finite element analysis (FEA) model of subassembly specimens. Using the experimentally validated FEA model, a parametric study was conducted with various stud and reinforcement sizes and configurations, material properties, slab widths, and loading protocols. A comprehensive analysis quantified the effects of influential factors on mechanical behaviour and performance. The results were compared with the previously constructed equations to assess the ultimate stud connection strength. As a novel approach from a previous study, the stud connection stiffness is newly evaluated, using classical theory and empirical formulae and a new mathematical model was proposed.

This paper deals with the connection of timber beams and precast concrete slabs. The connection of timber and concrete has many advantages associated with the efficient use of both materials, not only in terms of their stress. Timber is a natural renewable material. It can be achieved some savings of volume of the concrete by its application and thereby also reducing of the environmental burden. By the combining of the timber and ultra-high performance concrete (UHPC), it can be designed very subtle, bearable, aesthetic and durable structures. The conventional timber-concrete composite structures are most often realized by joining of the timber beams and the cast in-situ reinforced concrete slabs. However, the cast in-situ slab is not very suitable for UHPC application and it has some structural disadvantages, in particular the need to protect the timber beams against moisture penetration from the fresh concrete mix, the need for formwork, etc. The prefabrication eliminates some disadvantages of the cast in-situ design, increases the quality of the structure and speeds up the construction process. In the case of the timber-concrete composite structures, the prefabrication has a positive impact on the reduction of the concrete shrinkage projections as the development of deflections and the redistribution of internal forces between the connected parts of the cross-section. Some special coupling elements must be used for connection in the case of precast slabs. This paper summarizes the research findings in the field of development of special coupling elements for composite timber-precast concrete structures. The development of the new coupling elements for pedestrian and cyclist timber-UHPC composite footbridges is presented.

This paper presents an instantaneous frequency (IF) tracking method based on conjugate-pair decomposition, and describes a signal filtering methodology that is employed to eliminate unwanted frequencies. The proposed methodology is verified and compared with Hilbert–Huang transform method by numerical simulation, steel beams and composite cable-stayed bridge experiment. The results show the proposed method has good robustness, adaptability and anti-noise capability which can be used to accurately extract the instantaneous frequency in complex environments; in addition, the extracted frequencies are close to each other using conjugate-pair decomposition and Hilbert–Huang transform. Moreover, the proposed method may be further applied in structural damage identification.

This paper presents a finite element analysis (FEA) model for the panel zone of connections between concrete-filled square steel tubular columns (CFSSTCs) and steel–concrete composite beams with external diaphragms under cyclic loading. Six composite connection tests are adopted to validate the feasibility of the FEA model. Parametric studies are carried out to study the influence of the following parameters on the shearing capacity and deformation in panel zone: ratio of width to thickness of column, the concrete strength of panel zone, the axial load ratio of the column and the ratio of depth to width of panel zone. A constitutive model of shear performance is then proposed for the panel zone of the composite connections. The proposed model is featured with a favorable accuracy, and could be applied to predict and evaluate the shearing degenerate and destruction of large-scale and complex composite connections.

Composite timber-concrete connections transfer shear forces between the timber component and the concrete through bolts, which improves the effectiveness of the composite action. This paper investigates the influencing factors of timber-concrete connections under shear tests on the loading-carrying capacity, with a specific focus on the effect of steel pads. A series of connections considering the variables of bolt diameters, glulam timber thickness, and the presence or lack of steel pads was tested under monotonic loading. The failure modes of different components are presented and discussed. The mechanical properties extracted from the tested force–displacement curves, including the initial stiffness, yield force, and maximum load-carrying capacity, are analysed and compared. An analytical model considering the effect of steel pads is derived based on the yield theory. The predicted load-carrying capacity of connections using the deriving formulas is consistent with the tested results, which demonstrates that the proposed method is reliable and accurate. The analysis results will provide insight into the mechanical behaviour of timber-concrete connections and guidance for the composite connection design.

The endplate blind bolted connection is a common type in concrete-filled circle steel tube (CFCST) structures. The moment-rotation relationship describes the mechanical performance of connection obviously. For the purpose of predicting the moment-rotation relationship of the endplate blind bolted connection between CFCST column and steel beam, a three-parameter exponential model is proposed in this paper based on the four-parameter exponential model. With consideration of possible failure modes, a determination method is put forward for predicting the ultimate moment. Then, the simplified mechanical model of each component is established. To predict the initial stiffness of connection, the calculation model is proposed based on the component method. The predicted results derived by proposed models agree well with the experimental results. The proposed model can avoid a lot of experiments and numerical simulations because only the configurations and material properties are required to obtain the desired parameters. In addition, it can be conveniently applied to the structural design and analysis for the connection between CFCST column and steel beam with different configurations.

Analog terrestrial TV is still a popular choice for urban societies although the migration to digital system has already begun. Video quality of analog TV was heavily influenced by performance of the antenna. Most users prefer to use indoor antenna due to its simplicity. The disadvantage of this type of antenna is the users may need to change the antenna direction repeatedly when they change to different TV channel. In this research, we designed and developed tracking system that enable indoor TV antenna to adjust its direction automatically to get optimum video clarity. This system is built by several servo motors and telescopic antennas. Composite Video Baseband Signal (CVBS) processing is used to obtain reference information regarding video clarity level conditions on TV screen. The results show that CVBS signal processing has performance in describing video clarity level. System performance has been verified from trial results on some UHF channels. Minimum tracking time is reach 23.4 second and the maximum reach 24.6 second.

The article describes the main features of experimental studies methodology of new space systems constructive solutions effectiveness. Research methodology is developed by the example of full-scale prototype of the steel and concrete composite cable space frame, which consists of space steel and concrete composite modules and flexible bottom chord. Methodology for study stress-strain state of the prototype by testing in the uniform load applied to nodes is developed. It also provides the nodes displacement definition of the prototype. According to the developed technique, stressed state of full-scale prototype of the steel and concrete composite cable space frame was studied with tensionmetric and photogrammetric methods. Equipment and devices arrangement schemes for measuring deformations and displacements of the full-scale steel and concrete composite cable space frames prototype are presented.

Wire ropes are widely used in applications where the axial stress is high and flexural and torsional stresses are relatively low. Study of their mechanical behavior encompasses many factors, bringing considerable complexity to the construction of numerical or analytical models that suitably represent their behavior, including contact stresses between rods, helical geometry, rotation of wires when extended and also, in the case of carbon fiber–reinforced polymer (composite) cables, their anisotropic behavior. In view of the lack of suitable analytical solutions, this work focuses on the updating of a finite element model by incorporating factors commonly neglected by simplified analytical approaches. The carbon fiber–reinforced polymer cable was modeled under tensile stress and under four-point bending. After that a sensitivity analysis of the main parameters governing the problem was conducted. The updating process minimized the deviation between numerical and experimental data, and the model was able to reproduce the tensile and bending behavior with deviations smaller than 1%. The adopted methodology can be extended to similar cases.

This work presents a new method for monitoring the preload torque in a composite bolted connection using an embedded fiber Bragg grating sensor. A unique washer was designed to impose a specified nonuniform strain field across the grating, causing distortion in the reflected optical spectrum. Using the full-width at half maximum bandwidth of the Bragg reflection spectrum as the preload-sensitive feature, it is shown that this feature increases monotonically—and quite linearly—with increasing applied bolt torque. It is also demonstrated that, although distorted, the spectral structure of the sensor is maintained such that it is simultaneously able to function in its typical use as a uniaxial strain sensor, thus essentially creating a dual-purpose sensor. The computational design approach is validated with a prototype experiment.