Full-scale Experimental Study Research Articles

Full-scale modeling and experimental study of a gas neutron tube with a Penning ion source

This paper studies full-scale gas neutron tube modeling, including the following processes: gas discharge combustion in a Penning ion source, particle motion in an ion optical system, and modeling the in-target processes, such as sputtering, diffusion, thermal desorption of hydrogen isotopes, and nuclear reactions. Plasma modeling in quadrupole electric and axial magnetic fields was based on the electrostatic particle-in-cell method with molecular kinetic processes. The TechX Vsim software package was used. The neutron tube element sputtering by ions was simulated using SRIM/TRIM software based on Monte–Carlo methods. The OpenFOAM, as an open integrated platform for numerical simulation in continuum mechanics, was used to calculate the hydrogen thermal desorption activated by ion irradiation. The time-dependent neutron yield modeling was performed using the Geant4 software based on Monte–Carlo methods with CHIPS-TPT VNIIA-developed library. In addition, an experimental study of a gas neutron tube with a Penning ion source was conducted here as well. Details are given on the experiment and measurement technique used in this study. The operating characteristics for the gas neutron tube, including amplitude-time characteristics of current flashes (discharge and extraction currents), were determined. The neutron flux dependencies on the discharge current at various accelerating voltages were also obtained. Finally, a comparison between the experimental and calculated results is presented.

Full-scale experimental study on tribological performance of FPBs for highway bridges with various solid lubricants under fast loading

Friction pendulum bearings (FPBs) have proven to be effective for the seismic isolation of highway bridges. Previous studies often employed scaled model shaking table tests to investigate dynamic responses of the structures or quasi-static tests to assess the hysteretic performance of FPBs. However, it is noteworthy that the stress on the friction surface is reduced due to the size effect in scaled model in shaking table tests, while quasi-static tests of prototype bearings cannot simulate the sliding velocity experienced during seismic events, which is a sensitive parameter for the performance of FPBs with solid lubricant plates. Research on the performance of full-scale FPBs under fast frictional loading is very limited. This paper addresses this knowledge gap by studying the velocity demand for a highway bridge with FPBs and conducting fast sliding performance tests using full-scale FPBs. The results indicate that under a 0.2 g PGA earthquake, the velocity demand for FPBs can reach 0.5 m/s. Through testing full-scale FPBs at various loading speeds, it was found that solid lubricant plates by UHMWPE material exhibit poor thermal stability during wear tests, solid lubricant plates by PTFE material lack sufficient tangential tear strength under fast loading, and solid lubricant plates by PET material show good wear resistance but have a high breakaway force and levered maximum force during the running-in stage. Subsequently, this study developed ultra-high performance friction plate (UHPF) as the solid lubricant for FPBs, achieving ideal hysteretic performance under fast loading. The full-scale FPB specimens in this paper are the ones manufactured for the continuous beam bridges in the Shenzhen-Zhongshan Sea-crossing Link project in China. The dimensions of the bearing, axial load, and loading speed is much more stringent than those in previous FPB tests, providing results that are highly important for engineering applications.

Full-scale experimental and numerical study of smoke spread and temperature distribution in a room-corridor structure building

This paper aims to study the smoke spread and temperature distribution inside a full-scale room-corridor structure building. A series of experiments and simulations with different fuel properties and fuel configurations (crib and pool fires) were carried out. There was a barrier at the top of the left end of the corridor, and the end wall was on the right side. The fire source was located in the room. The evolution of the smoke spread process, pressure distribution, and temperature distribution in rooms and corridors were obtained and analyzed. The results indicate that the barrier and the end wall hinder the smoke spread and make it to accumulate below the corridor ceiling. This causes the smoke layer height of the corridor to be lower than the top of the door, which changes the pressure distribution inside and outside the room and also affects the temperature distribution. Based on the changes of pressure distribution, some correction formulas for the gas flow rate and mass flux at the opening are proposed. Under the effect of the barrier and the end wall, the smoke temperature in the room and the corridor increases. A smoke temperature decaying model along the corridor direction is proposed. Some methods are used and compared to calculate the smoke layer height based on the vertical temperature distribution. The smoke layer height determined by the buoyancy frequency method is most consistent with the experimental observation values.

Full-scale experiments on wave transmission and stability of oyster shell-filled bag berms

Oyster shell-filled bags have been used in engineered reefs and living shorelines as a nature-based solution to attenuate wave energy and stabilize shorelines. However, due to limited scientific data, uncertainties persist in accurately predicting the performance of these reefs, which can hinder a more widespread adoption. In particular, there is a lack of information on wave transmission through, and the stability of, oyster shell-filled bag berms with different configurations and relative freeboards. To address this knowledge gap, a full (1:1) scale experimental flume study was conducted to measure the wave transmission and stability of six different oyster shell-filled bag berms under a range of incident wave conditions and water levels. The findings from the experimental tests were used to propose empirical equations for wave transmission and stability, which can assist practitioners in predicting the performance of these engineered reefs.

RESEARCH OF THE STRESS-STRAIN STATE OF PRECAST REINFORCED CONCRETE HOLLOW CORE SLABS UNDER THE ACTION OF A CONCENTRATED AND UNIFORMLY DISTRIBUTED LOAD

The scientific work is devoted to a comprehensive study of the stress-strain state of prefabricated hollow-core floor slabs, establishing the nature of deformation, as well as determining the characteristics of crack resistance, deformability and load-bearing capacity experimentally under short-term loads. The experimental data obtained were confirmed by theoretical calculations. The scientific novelty of the experiments carried out within the framework of the presented work lies in the improvement of the principles of direct design of floor slabs from commercially produced beam slabs, the possibility of determining the stress-strain behavior of a slab structure using the formed ends. The method of monitoring the stressed behavior of a slab structure was also further developed. For the first time, the results of full-scale experimental studies of the stress-strain behavior of a prefabricated slab, carried out using the hydraulic loading method, have been obtained, and the features of the deformation of a slab embedded in the wall of a multi-story building have been experimentally established. The article provides recommendations for the practical use of the research results obtained, and also develops technical specifications for the production of concrete slabs during design and construction. The developed proposals were used in the construction of residential buildings in Kharkiv. When using the recommended grade of concrete C25/30 (instead of the actual grade C20/25 tested), the rigidity of the slab increases and its deflections will be smaller. Based on the data obtained from the experimental testing of the slabs, a generally positive test result should be stated. During further serial production of slabs, periodic testing of batches of slabs should be carried out in accordance with DSTU B V.2.6-53:2008. In this case, the slabs are accepted according to the indicators of strength, rigidity, crack resistance, fire resistance limits, frost resistance limits, as well as water resistance of slabs intended for use in aggressive environments. Keywords: concentrated load, testing, concrete, calculation, deflection, transverse force.

Full-scale experimental study on combustion characteristics and smoke temperature of double-source fires in different tunnels

Through a series of full-scale fire tests conducted in three different tunnels, the common characteristics of combustion and smoke temperature of double pool fires in actual operation tunnel environments are investigated. The evolution process of the coupling effects of shielding entrainment and thermal feedback enhancement is revealed. It is found that the ventilation state and the fire source spacing can alter the dominant relationship between the shielding entrainment effect and the thermal feedback enhancement effect, resulting in different evolution patterns of combustion characteristics and smoke flow patterns of double pool fires in tunnels. The heat release rate increases by 4 times when the double pool fire flames merge under the longitudinal ventilation compared with the double pool fire flames without fusion under the natural ventilation. The flame tilt angles of double pool fires were determined through the image processing method, and the prediction model of the flame inclination angle of downstream fire sources was established, considering fire source spacing. At the same time, the characteristic of temperature measured by Fiber Bragg Grating in double-source fire scenarios was investigated, developing a model to predict the longitudinal temperature rise distribution. It is found that the maximum temperature rise prediction model based on steady-state fire has poor applicability in the weak-plume fire scenario of full-scale tunnels. The analysis of the smoke flow patterns shows that the two-stage ventilation is more suitable for smoke control compared to full longitudinal ventilation in tunnel double-source fire accidents, especially for ensuring the safety of individuals trapped in the area between the two fire sources.

Surface temperature and power generation efficiency of PV arrays with various row spacings: A full-scale outdoor experimental study

Quantifying the relationship between surface temperature and power generation efficiency of solar photovoltaics (PV) is critical to their practical implementation. Although empirical models have been developed on this, they were mainly based on indoor laboratory tests, ignoring a practically significant arrangement factor. Therefore, a combined outdoor experimental and empirical study on PV array systems considering various row spacings was undertaken through this study. Experimental results indicated that solar irradiance shows a relatively more prominent effect than row spacing and wind speed in outdoor environments. During the practical arrangement, it is only necessary to ensure that there is no shadow between the adjacent rows of PV arrays in practical applications, and the possible cooling effect brought by excessive row spacing may not be pursued. However, this does not mean that row spacing can be ignored when predicting surface temperature and power generation efficiency. Based on the data from our long-term experimental tests, empirical models to predict solar PV's surface temperature and power generation efficiency were developed, considering various row spacings. Comparison showed that the models developed in this study can reduce the mean relative error of the previous model's predictions from 20% to 5%, which proves the necessity of including row spacing in the models. This study's developed models and research outcomes pave the way for future large-scale practical analysis of solar PV arrays.

Full-scale experimental study and modelling of pile-beam joint for prefabrication restoration technology of ocean engineering

Ocean engineering structures are susceptible to severe damage caused by adverse weather conditions. The question of accelerating post-disaster restoration is the focus for ocean engineering resilience. In this regard, this study proposed the prefabrication restoration technology and investigated the mechanical properties of the key pile-beam joint. Full-scale experiments are conducted to analyze the pile-beam joint, followed by the development of the Pile-beam Joint Assessment Model (PJAM) for mechanical assessment. PJAM is subsequently applied to evaluate a restoration case at Shantou Port, facilitating informed decision-making. The main findings are as follows: (1) The flexural performance of the pile-beam joint is crucial in prefabrication restoration as it influences the assembly performance and impact resilience of the new-old structure. (2) Stiffness reduction in the pile-beam joint is primarily attributed to interface weakness, resulting in stiffness and bearing capacity values of 64.3 % and 95.5 %, respectively, compared to the cast-in-situ joint. (3) Elastic and plastic properties of the pile-beam joint are governed by the compression interface and rebar properties, respectively. The compression interface size significantly enhances joint performance, while rebar properties affect ultimate bearing capacity and ductility. (4) PJAM enables a parametric quantitative assessment of pile-beam joints. In the case study, a 31 % size enlargement scheme combined with a 51 % rebar arrangement is identified as achieving performance comparable to the cast-in-situ joint. This research addresses the critical joint challenge in prefabrication restoration, providing a theoretical basis and practical demonstration to enhance post-disaster resilience in ocean engineering structures.

Dynamics of cool surface performance on urban microclimate: A full-scale experimental study in Singapore

The Urban Heat Island (UHI) effect has been a cause of concern on human-induced impacts to urban climate. Construction materials absorb incoming solar radiation, causing additional sensible heat release to the urban environment resulting in urban air temperature changes. It has been proposed that covering the built-up surfaces such as building roofs and walls as well as road pavements, with cool surfaces which reflect most of the incoming solar radiation, could reduce heat absorption by construction materials and the subsequent heat release to urban environment. This paper, reports an experimental study of cool coating in a full-scale site setting located in Singapore during the summer months of tropical climate. The experimental site consists of four parallel industrial buildings forming two similar side-by-side street canyons. One of the canyons (‘Cool Canyon’) was cool coated on the roofs, walls and the road pavement whereas the other canyons remained as it was (‘Conventional Canyon’) as control. Air temperature, surface temperature, sensible and latent heat fluxes in the two canyons were monitored for analysis of thermal exchanges between the build-up surfaces and the canyon micro-environment. The Cool Canyon had up to 30% reduction in sensible heat release from the built-up surfaces which resulted in the air temperature in Cool Canyon being cooler than that in the Conventional Canyon by up to 2°C around 16:00 h. An analysis of pedestrian thermal comfort in the two canyons was also conducted using Universal Thermal Climate Index (UTCI). When compared to the Conventional Canyon, the Cool Canyon provides improved thermal comfort to pedestrians with up to 1.5°C reduction in UTCI. The paper also presents a critical analysis on thermal comfort due to the cool road in the middle of the street canyon.

Full-scale experimental and structural characterization study of shield tunnel reinforcement under ground stacking loads

To investigate the internal force response characteristics and reinforcement effects of the shield tunnel segment structure in the presence of ground load disturbances in the Hangzhou Metro, full-scale tests were conducted on three-ring misaligned assembled segments using a self-developed "Shield Tunnel Segment Hydraulic Loading System." The study examined the structural characteristics of tunnel segments under the influence of different ground resistance coefficients (λ) and eccentric loads (P), and explored the reinforcement effects of the internal tension ring method from multiple perspectives. The research results indicate that under different ground resistance coefficients (λ), the sensitivity of internal force response is concentrated in the waist concrete, with a maximum bending moment reduction of 88.8%. The effective rate of bending stiffness tends to flatten, joint bending moment transfer effects strengthen, and the bearing capacity of the segments significantly increases after reinforcement, leading to a more uniform overall structural response. Under different eccentric loads (P), the bending moment of the segments after reinforcement approximates central symmetry with a reduced distribution range. The rate of change of the effective bending stiffness (η) shifts from "rapid" to "slow," and the variation of joint bending moment transfer coefficient (ζ) stabilizes. The reinforcement with steel rings significantly enhances the overall stiffness of the segments and reinforces the joint bending moment transfer effect. The reinforcement effect of the segments can be evaluated through the bending moment transfer coefficient and effective bending stiffness. After reinforcement, the bearing capacity of the segments is noticeably enhanced, and significant forces are observed at two locations in the right waist joint, where the combination of steel plates and segments exhibits optimal performance.

Strong column-weak beam relationship of 3D steel joints with tubular columns: Assessment, Validation and Design proposal

The study of moment connections in steel structures subjected to cyclic loads has been extensively studied, providing a great number of requirements, including the strong column-weak beam relationship, to guarantee a satisfactory cyclic performance. However, investigations on the cyclic performance of moment connections considering the bidirectional and axial load effects simultaneously with tubular columns are limited. This study aims to assess and validate the strong column-weak beam relationship of 3D steel moment connections using reduced order models. The simplified model (reduced order model) approach was employed to extend the range of beam and column elements sizes and reduce the experimental and computational costs. These models were calibrated from full-scale experimental studies. A great number of configurations with different beam and column sizes without loss of reliability and structural representativeness of the studied phenomenon were studied. A total of 13640 simplified models were developed. Results show a cyclic behavior controlled by the strong column-weak beam relationship to modify the joint's failure mechanism. The increasing of strong column-weak beam relationship and the biaxial effect caused degradation of the strength and stiffness as well as in dissipated energy. An optimal strong column-weak beam relationship was obtained for all joint configurations analyzed. Finally, a robust design procedure is proposed, ensuring the cyclic behavior of end-plate moment connection with built-up box column including biaxial effect and axial load. Therefore, the use of this type of moment connection can be used in special and intermediate moment frames designed according to Seismic provisions.

Improved gas influx distribution estimation using interfacial area transport equation (IATE) enabled two-fluid model: An advanced modeling and full-scale experimental study

Gas influx management is a critical aspect of petroleum drilling operations, which aims to prevent the uncontrolled outflow of formation gas and the potential consequences caused by blowouts. This study investigates the distribution of gas influx and the interfacial area concentration (IAC) during gas influx circulation operations through a combination of full-scale experiments and advanced numerical simulations.Experiments were conducted to simulate downhole gas influxes by injecting Nitrogen gas into the base of a 5,160-foot-deep experimental wellbore, which was filled with water. A Distributed Fiber-Optic Sensing (DFOS) system was installed in the wellbore to obtain high-resolution acoustic and temperature data and monitor the gas influx behaviors when circulated out of the annulus. Various types of measurements were obtained to analyze the gas influx length, slip velocities, void fraction distribution, and dispersion behaviors. In addition, an advanced numerical simulator was developed based on a modified Two-Fluid Model and the Interfacial Area Transport Equation (IATE) to simulate the gas influx behaviors. The model estimations were compared to the experimental measurements for validation of accuracy and further insights.The numerical modeling framework, based on the interfacial area transport equation, effectively captured bubble interactions, including mechanisms including bubble breakage and coalescence, by estimating the interfacial area distribution. The gas influx dispersion during circulation was analyzed using both model estimations and experimental data. Good agreement was observed between the model predictions and experimental data, including multi-depths gauge measurements and the DFOS data.This is a novel application of the IATE in well-scale multiphase flow simulations, which has proved to be an effective tool for predicting the dynamics of gas influx distributions. The outcomes of this study provide critical insights into the design and optimization of gas influx management during Managed Pressure Drilling (MPD).

Methodology for studying the efficiency of new structural and technological solutions for the restoration of building structures' suitability for use

The article presents the developed, scientifically based methodology for introducing the construction practice of new structural and technological solutions for restoring building structures in reconstruction or capital repair conditions. This technique is based on the practical experience of surveying building structures, establishing the type and extent of damage, and the need for their reinforcement. The authors found that more than 70% of repair and restoration work on structures must be performed using classic technologies, 20% of cases require using existing modern methods, and almost 10% - develop new forms of repair and restoration work.
 In the publication, the authors present methods of researching the effectiveness of new structural and technological solutions for restoring the operational suitability of building structures. Experimental studies of new structural and technical solutions should be performed in several stages: laboratory and experimental model studies, by checking the results in real conditions at construction sites.
 A structural diagram of the research methodology of the latest and new structural and technological solutions for restoring the operational suitability of building structures has been developed, which offers a set of steps that allow, based on their results, to obtain new structural and technological solutions that can be applied in practice and have high quality. Each research stage of such solutions is characterized in detail, and a set of necessary elements is defined, allowing each stage to be implemented.
 In the case of the study of fundamentally new and complex structural and technological solutions for repair and restoration works of building structures, full-scale experimental studies are performed. It is assumed that such studies are carried out directly on single structures that need to be restored to operational suitability and subsequently observed during a certain period of operation.
 The developed methodology made it possible to carry out several research works. As a result, new constructive and technological solutions for restoring building structures were introduced into construction practice.

Full-scale experimental study of the characteristics of electric vehicle fires process and response measures

Fire accidents are a source of concern for electric vehicles (EV). The spread of fire caused by thermal runaway (TR) in a scenario with a high concentration of EVs can result in a serious disaster. In this study, a full-scale EV fire experiment was conducted using thermal abuse to investigate response strategies to EV fires caused by TR. The pattern of TR fires spreading in EV was also investigated. The suppression capabilities of fire blankets, water spray, and compressed air foam on EV fires in the early stages were analyzed. During the test, the temperature distributions inside and outside the vehicle were measured. The maximum temperature recorded in the passenger compartment near the roof was 919.7 °C. The length of the jet flow was estimated from the images, with the longest being approximately 2.56 m. The fire suppression test demonstrated that the fire blankets effectively extinguished flames, and the temperature inside the car gradually decreased. A water mist device can reduce temperature and put out flames. The compressed air foam effectively extinguished the fire, with an average cooling rate of −9.8 °C/s. These results provide information on EV fire response strategies.

Experimental investigation and modeling for assembled precast hollow components in full-assembled underground station application

Full-assembled underground station (FUS) is a novel prefabricated underground station that fully uses assembled precast hollow components (PHC). The PHC with joint constraint and hollow-section effects determines the performance of the FUS. This study foremost conducted a multigroup full-scale experimental study on PHCs. A finite element analysis was performed to analyzed the relationship between joint constraint effect and hollow-section effect. A mechanical model of the assembled PHC was proposed. The hollow-section effect of PHC was assessed, and the results were applied to FUS. The main conclusions are as follows. (1) The performance of the PHC with the proper hollow-section size ratio (SR) meets the design requirements, whereas one with large SR may cause insufficient performance redundancy. (2) The bending performance of assembled PHC strengthens with the increase of joint constraint. The hollow-section effect only manifests in the PHCs with robust joint. (3) An SR ≤ 0.5 has a limited effect on PHC performance, whereas an SR ≥ 0.5 accelerates performance degradation. Furthermore, the hollow-section distribution rate (DR) presents a competing relationship between the PHC performance and weight reduction. (4) The application of the mechanical model on Shenzhen Metro FUS achieved promising benefits. The mechanical properties of PHC were comparable to those of solid components with sufficient weight reduction. This study provides technical guidance for the development of Shenzhen Metro and facilitates FUS application in low-carbon cities.

CONDUCTING A NATURAL FIRE TEST IN THE VERTICAL CABLE TUNNEL OF A NUCLEAR POWER PLANT

The article discusses conducting a full-scale fire test in the vertical cable tunnel of a nuclear power plant (NPP). Vertical cable tunnels in NPPs are used for laying cable lines, wires, safety system lines, connecting the equipment room, and the containment of the nuclear power plant block. The paper analyses research methods and selects options that will be effectively used to determine the temperature regime in the vertical cable tunnel of NPPs with known aerodynamic, technical, and geometric parameters and fire loads. The algorithm for conducting full-scale tests in the vertical cable tunnel of an NPP is described. Based on the research, the maximum temperature in the combustion zone is reached on the fourth minute of the full-scale tests in the vertical cable tunnels of nuclear power plants. By obtaining temperature graphs in the vertical cable tunnel of the NPP, it can be observed that the highest temperature is in plane D (800–900 °C), and it depends on the location of the control point. Thermal energy propagates more intensively in the direction opposite to the filling of the space, which is opposite to the exit of combustion products and ventilation openings. The temperature in plane C is in the range of 500–800 °C. Thermal energy propagates most intensively towards the filling to the exit of combustion products. This temperature significantly deviates from the standard temperature regime, which differs greatly from the full-scale experimental study of fires in the vertical cable tunnels of nuclear power plants. It can be concluded that the standard temperature regime of a fire is not adequate for testing the fire resistance of the structural elements of vertical cable tunnels in nuclear power plants. An important conclusion of these studies is the possibility of determining the fire resistance of building structures of vertical cable tunnels of NPPs with the selection of the most severe temperature regime, according to the conducted field test. It means that research results can be used in practice in designing and evaluating the safety of such objects. Keywords: fire, natural fire tests, nuclear power plant, vertical cable tunnel.

Studying the interaction process of a solid particles flow with the hydraulic classifier flowing part

The paper provides a theoretical description of the solid particles movement process along with the horizontal flow of slurry within the hydraulic classifier flow part. Three modes of movement of solid particles are described: deceleration relative to the slurry flow at a constant speed or its increase, acceleration relative to the slurry flow at a decrease in its speed, with the speed of the slurry flow. The complex equation of solid particles motion in a horizontal co-flow of liquid. A graphic description of the process is given. A laboratory installation was developed to study the interaction of the hydraulic classifier flow part with the slurry flow. Experimental studies were carried out and quantitative process parameters were determined during the movement of rolled quartz solid particles in the size range < 1.8 mm and < 0.2 mm. For the first time in crisis economic conditions, in order to confirm the reliability of previously obtained analytical dependencies to determine the rational parameters of hydraulic disintegrators and determine the operational characteristics of equipment, full-scale experimental studies of the JPD 300-120 suction dredger equipped with an innovative ejector soil suction head with a jet disintegrator system were carried out.

Energy efficiency, visual comfort, and thermal comfort of suspended particle device smart windows in a residential building: A full-scale experimental study

Smart window controls the visible light transmittance and solar heat gain coefficient through the transition to a clear or tint state. When applied in buildings, it can be an effective solution in terms of visual and thermal environment by controlling solar radiation. Various previous studies have provided smart windows’ effective performance results related to the visual or thermal environment, however, these studies were mostly based on numerical simulations or small-scale test cells. Few studies have comprehensively analyzed smart windows’ performance when applied to real buildings. Accordingly, this study aimed to analyze and evaluate the performance of smart windows applied in residential buildings related to the visual and thermal environments from various perspectives. For this purpose, we installed suspended particle device smart windows in an apartment building, i.e., a typical residential building type in South Korea, set up related sensors and equipment and collected data from July to September 2022. Based on this campaign, we evaluated visual and thermal comfort and lighting and cooling energy performance according to the sky condition (cloudy, partly cloudy, and clear days) and smart window tinting control method (always tinting, automatic control to maintain the indoor daylight illuminance at 200 lx, and automatic control to maintain the illuminance at 400 lx). In terms of glare, on partly cloudy and clear days, smart windows effectively controlled glare regardless of the tinting control method. In terms of the indoor daylight illuminance, automated control was more effective than always tinting in terms of providing useful daylight under all sky conditions. In terms of thermal comfort, tinting at all times was the most effective on partly cloudy and clear days. The lighting energy consumption increased by 3.9–17.9% when smart windows were used, while the cooling energy consumption was reduced by 0.0–20.5%. Overall, this study revealed that the appropriate smart window operation method varied depending on the sky condition. On cloudy day, maintenance of the indoor daylight illuminance at 200 lx using automated control was efficient. On partly cloudy and clear day, the automated control (200 lx or 400 lx) was efficient in terms of visual comfort, however, in terms of thermal comfort and energy consumption, tinting at all times was effective. This suggested that completely tinting smart window in conjunction with automatic artificial lighting control to ensure proper indoor illuminance could be the most effective on a partly cloudy day and a clear day. Based on this study, it is necessary to derive more detailed optimal smart window operation strategies in terms of glare, indoor daylight illuminance, thermal comfort, and energy consumption for all seasons.

Full-scale experimental study on seismic performance of repaired precast shear walls

To improve the framework of seismic resilience assessment and design of precast concrete (PC) structures, and to contribute to the development of loss consequence functions for PC shear walls (PCSWs), a repair method for seismically damaged PCSWs using grouted sleeve connections was investigated and the seismic performance of repaired PCSWs (RPCSWs) was verified in this study. Specifically, full-scale experimental investigations were conducted involving a reinforced concrete shear wall (RCSW) as a counterpart and two RPCSWs, which were repaired based on two damaged PCSWs (one without grouting defects and the other with a 60% defect ratio) previously tested, aiming to identify the effect of grouting defects on the damage mode of PCSWs and the corresponding repair effect. Two specimens were repaired with reference to the concrete replacement method for the RCSW. The seismic performances of the RCSW, two RPCSWs, and PCSW without grouting defects were compared. Test results indicated that the damage evolution and failure modes of the RPCSWs were similar with those of the RCSW and PCSW without grouting defects. The relative differences in the loads and displacements of the critical points of the four specimens were generally less than 5.9%. Although the seismic performance of the PCSW with grouting defects was significantly different from those of the RCSW and PCSW without grouting defects, it was restored, thus verifying the reliability and versatility of the repair method. The research outcomes can provide important reference for the repair of seismically damaged PCSWs connected using grouted sleeves as well as lay a foundation for advancement of loss consequence functions for such shear walls.

T-STUB COMPONENT BEHAVIOR OF THE BEAM TO COLUMN BOLTED FLANGE CONNECTION BASED ON A NUMERICAL ANALYSIS AND EN 1993-1-8 DESIGN CODES

Nodal joints uniting separate elements of steel structures are the most important parts of the whole structure. For the tensile zone of a connection, the study of its stress-strain state up to the limit of exhaustion of its bearing capacity is of greatest interest. There exist different design approaches to obtain the ultimate capacity of a tension-zone of a steel joint, both numerical and analytical methods. In the presented paper this has been realized using a general-purpose finite element analysis package. The application of numerical methods for modelling the tensile performance of the T-component makes it possible to compensate for the lack of data on full-scale experimental studies. Despite the widespread use of finite element analysis packages, there are still no clear guidelines for creating numerical models of such connections. Numerical analysis has taken into account important effects such as the nonlinear behavior of the material and the contact interaction of its individual elements. Finite element analyses should represent the reality in an accurate way while not being too time consuming to be set up and run. That means appropriate parameters and phenomena, such as element types or loading procedure, should be compiled in a way suitable to the problem at hand, so that the discrepancy between reality and model is sufficiently small. A FE-model with wrong representation of reality can be solved correctly with FEA, but will thereby provide inaccurate results. Therefore, one needs understanding about FE parameters and their influence on time to execute the procedure effectively. When these conditions are met, the possibility to analyze larger number of T-stubs with less user modification opens up. The analytical method for the calculation of the properties of a bolted joint established by the structural Eurocodes proposes the T-stub as a component for the characterization of the tension and compression zones in moment joints. Using the component method, which is the basis for the calculation of joints according to the EN 1993-1-8 design codes, the value of the ultimate tensile force for the T-shaped component of the dimensions adopted in the work was obtained; the obtained values of the ultimate forces were further used in the numerical experiment. Keywords: end-plate connection, numerical model, T-stub component, bolt connection.