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Cementitious coatings are widely used to protect steel structures from fire, yet there are concerns about its performance in earthquakes, where partial damage to the fire protection could potentially compromise the fire safety of steel structures. In this paper, results from a series of experiments are presented to quantify the damage in cementitious fire resistive coatings under cyclic loading. Steel plates of various sizes are first tested under cyclic loading, which exhibit greater damage than the specimens subjected to monotonic loading. A steel column is subjected to cyclic load along with another subjected to monotonic load are both coated with 20 mm thick cementitious fire resistive material and tested to investigate the damage patterns in a more realistic setup than steel plates. Tensile transverse cracks on the flange, vertical cracks along the flange tip, and interfacial debonding of the coatings are the main forms of coating damage, which appear with a lower story drift ratio compared to the monotonically loaded column specimen.

This paper presents a general framework for the dynamic analysis of high-speed maglev trains running on elastic transitional viaducts, a complicated problem that lacks an efficient analysis tool. Unlike the straight and circular tracks, both the curve radius (CR) and height difference (HD) between the outer and inner rails vary along the transitional track. To start, the motion of each vehicle of the train running over a transitional track is expressed by a set of trajectory coordinates, with their orientations given in the Euler angles as functions of the CR and HD. The elastic transitional viaduct is simulated by finite elements in the global coordinates. For the maglev trains, the electromagnet force-air gap model is used to account for the interaction and coupling effect between the moving vehicles and supporting viaduct. By applying the proposed framework to the Shanghai maglev line (SML), the dynamic responses of the maglev vehicles running on the transitional viaduct are studied and compared with those on the straight and circular viaducts. Moreover, the effects of transitional track length and cant deficiency on the coupled system are investigated. The results show that for vehicles running on the transitional track, the levitation forces and vehicle’s angular velocity are highly related to the rate of change of HD of the track. The length of the transitional viaduct affects significantly all the vehicle’s responses. The increase of deficient cant angle causes a sharp increase in the responses of the transitional viaduct in both the radial and rotational directions.

Polyvinyl butyral (PVB) is often used in laminated glass and windscreen for its high ductility and good adhesion with glass. Previous studies have shown that the mechanical properties of PVB are both rate-dependent and temperature-dependent. To investigate mechanical properties of PVB material under different strain rates and different temperatures, a series of tensile tests on 1.52 mm-thick PVB specimens are carried out, covering designed engineering strain rates from 0.1/s to 300/s and temperatures from −30 °C to 40 °C, using an Instron high-speed servo-hydraulic testing machine and temperature box. Corresponding true stress-true strain curves are obtained. The testing results are then analyzed and empirical formulae are derived for key mechanical property parameters. Finally, based on G’Sell model, dynamic constitutive equations are given at different temperatures for PVB.

This work investigates the delamination behaviour of polyvinyl butyral (PVB) laminated glass under quasi-static loading based on a cohesive zone model (CZM) with an isotropic bilinear traction - separation (T – δ) law. It presents a 2D model of a through-cracked tensile (TCT) test within an implicit finite element framework of the commercial software ANSYS. Test results from literature are used to calibrate the adhesion properties of the PVB-glass interface in a numerical cohesive zone approach. The previous TCT tests were performed at a loading rate of 6 mm/min and a temperature of approx. 22 °C. Three different PVB adhesion grades, i.e., BG R10 (low), BG R15 (medium) and BG R20 (high) are considered. Given the uncertainty in the identification of adhesion parameters, including interfacial fracture energy, cohesive strength and stiffness, a parametric analysis is conducted quantifying the influences of model parameters on the simulation results. The study allows for decoupling of individual parameters in the calibration. Then, interfacial fracture energies and cohesive strengths of the PVB-laminated glass are calibrated by matching the force – displacement curves of the numerical simulations with those from the TCT experiments. One representative case was chosen for each adhesion grade. We obtain interfacial fracture energies of 425 J/m2, 650 J/m2 and 1000 J/m2 for BG R10, BG R15 and BG R20 PVBs, respectively, while the corresponding cohesive strengths are 3 MPa, 5 MPa and 10 MPa, respectively. Moreover, based on numerical simulation results, the conversion of energy during the delamination process is extracted and discussed. The mixed-mode delamination mechanism is investigated by calculating the mode I and mode II energy release rates with respect to different PVB thicknesses and adhesion. The results show that the proportion of the mode I energy release rate is around 30%∼40% of the total energy release rate at the stable delamination stage and increases with PVB thickness. The presented study contributes to the adhesion properties of various types of PVB interlayers reported in open literatures and proposes a methodology for the unique identification of adhesion properties.

The transparent ionomer material SentryGlas® or SG for short is widely used as interlayers in laminated glass and is also a potential adhesive in laminated connection. The material’s shear modulus is of practical interest before glass breakage because it allows a shear transfer between glass components. Due to the viscoelasticity behaviour of the material, its modulus is significantly dependent on the working conditions. This work investigates the effects of temperature, time, and strain rate on SG’s shear small-strain modulus from the point of practical application. The shear property at room temperature is obtained from the results of shear tests. Based on the viscoelastic theory, the time and temperature dependence within the actual application range is quantitively determined from DMA measurements. The glass transition temperature associated with modulus decline is then recalibrated. The effect of strain rate is also qualitatively measured. Finally, the time-temperature dependent equations of shear modulus are applied to numerical simulation of a long-term loading test on framed ionomer interlayer laminated glass.

In this paper, an analytical model for determining the iso-damage curves for framed monolithic glass panels subjected to blast loading is proposed. Two typical damage levels corresponding to different conditions in GSA/ISC are classified, namely (a) the glass crack limit and (b) glass fragments invading with a certain velocity. The nonlinear dynamic responses and failure modes of framed monolithic glass under different blast loadings are firstly analysed numerically. Then critical states of glass panel in both impulsive region and quasi-static region of the pressure-impulse (P-I) diagram are defined. Based on the energy balance approach, an analytical method is proposed for determining the pressure asymptote and the impulse asymptote of framed monolithic glass for different damage levels. The proposed method is verified through comparison with published experimental data and numerical results. The method can be applied for any framed monolithic glazing with different dimension and thickness and provides a practical approach for engineering design and hazard level estimation of framed monolithic glass against blast loading.

Universal couplings cause additional moments on the sleeve shaft of work roll. The problem becomes more obvious in the wide and heavy plate mill due to the large tilt angle and the great rolling torque, which may affect the deflection of roll system and the screw-down load deviation. Aiming at the structural characteristics of the drive system of a 5000 mm wide and heavy plate mill, additional moment models acting on the work roll are established, and the influence coefficients of the additional moment of the main drive system are obtained according to Mohr integral method. The screw-down load deviation affected by the additional moment is calculated based on the influence function method. Results show that the additional moment of the work roll drive end has little effect on the screw-down load deviation. And the fluctuation period of the additional moment is 180° with the input shaft rotating. The additional moment enlarges with the tilting angle increasing. If the tilt angle is equal to 4.82°, the vertical additional moment is about 8.5% of the output torque of motor shaft, while the horizontal additional moment is about 4.2% of that.

Steel reinforced concrete column has been widely applied in high-rise buildings and long-span structures. In this paper, an analytical study is carried out for predicting the axial compressive behavior of steel reinforced concrete (SRC) column using cross-shaped steel section with flanges. Firstly, respective material models were established for different components in the composite cross-section, including highly confined concrete, partially confined concrete, unconfined concrete, steel section as well as steel reinforcement. For highly confined concrete, the interaction mechanism between steel section and confined concrete has been investigated, based on which a uniaxial stress-strain relation is established. For partially confined concrete, as the hoop may not yield, an iterative procedure is applied to calculate the real stress in hoops and then the effective lateral confining pressure. For steel section, the biaxial stress state is considered in the material model. Based on section analysis method, a unified analytical model is then proposed and verified through comparison of analytical results with test results on SRC and partially confined SRC (PSRC) short columns. At last, a simplified method for calculating the real stress of the hoop and then the strength of partially confined concrete was proposed to avoid the iterative process and save the computing time.

PVB-laminated glass has been widely adopted for building windows as safety glass due to its significant post-crack load bearing capacity. To achieve a better understanding of the mechanical behaviour of framed PVB-laminated glass under explosion, a series of field blast tests were carefully designed and conducted aiming to study the dynamic responses and failure modes of framed PVB-laminated glass subjected to various blast loadings. The reflected overpressure and displacement time histories were measured in the tests. In particular, DIC technology was adopted to record the 3-D deflection field of the glass panel, which is essential for analyzing the dynamic response feature of laminated glass panels under blast loading. Three typical failure modes, i.e. global flexural failure, local punching failure and mixed failure, were identified and corresponding failure mechanisms were analyzed. Finally, the test results were used to check the effectiveness of different design approaches. The results from this study can provide reference for further blast resistant analysis and design for framed PVB-laminated glass.

The dry sliding tribological properties of hybrid PTFE/Kevlar fabric composite were investigated under ambient and different vacuums, loads, sliding velocities, and temperatures. The results showed that hybrid PTFE/Kevlar fabric composite displayed lower friction coefficient in vacuum than that in ambient and satisfactory antiwear performance in low vacuum and middle vacuum, but poor antiwear performance in high vacuum. In vacuum, the friction coefficient and wear rates decrease with the increasing of sliding velocities, loads and temperature within a certain range. But the higher temperature of 60 °C detriments the friction coefficient and wear rate. Textile structure also has an obvious influence on the antiwear performance. The main wear mechanism in vacuum including plastic deformation, micro-cutting, fatigue damage and abrasive wear.

Maglev, offers competitive journey-times compared to the railway and subway systems in markets for which distance between the stations is 100-1600km owing to its high acceleration and speed; however, such systems may have excessive vibration. Field measurements of Maglev train-induced vibrations were therefore performed on the world's first commercial Maglev line in Shanghai, China. Seven test sections along the line were selected according to the operating conditions, covering speeds from 150 to 430km/h. Acceleration responses of bridge pier and nearby ground were measured in three directions and analyzed in both the time and frequency domain. The effects of Maglev train speed on vibrations of the bridge pier and ground were studied in terms of their peak accelerations. Attenuation of ground vibration was investigated up to 30m from the track centerline. Effects of guideway configuration were also analyzed based on the measurements through two different test sections with same train speed of 300km/h. The results showed that peak accelerations exhibited a strong correlation with both train speed and distance off the track. Guideway configuration had a significant effect on transverse vibration, but a weak impact on vertical and longitudinal vibrations of both bridge pier and ground. Statistics indicated that, contrary to the commonly accepted theory and experience, vertical vibration is not always dominant: transverse and longitudinal vibrations should also be considered, particularly near turns in the track. Moreover, measurements of ground vibration induced by traditional high-speed railway train were carried out with the same testing devices in Bengbu in the Anhui Province. Results showed that the Maglev train generates significantly different vibration signatures as compared to the traditional high-speed train. The results obtained from this paper can provide good insights on the impact of Maglev system on the urban environment and the quality of human life nearby.

To evaluate hysteretic performance of welded Q690D high-strength steel H-section columns, cyclic loading test and numerical simulation were carried out. Firstly, cyclic loading test was performed on two H-section Q690D HSS welded columns with nominal axial compression ratio of 0.35. The observed failure mode is elastic–plastic local buckling of component plates. Hysteretic curves and skeleton curves of the test specimens show that the tested columns have a good energy dissipation capacity. Then, a finite element model was developed to simulate the hysteretic behavior of Q690D beam-columns and verified through comparison of numerical and experimental results. It is found that residual stresses are of ignorable influence on the ultimate bearing capacity of beam-columns. With the verified finite element model, extensive parametric analyses were conducted to investigate the effects of component plate slenderness ratio, column slenderness ratio and axial force ratio on the hysteretic performance of the Q690D H-section columns. Based on the observation and analyses of the experimental and numerical hysteretic curves, a trilinear moment-curvature hysteretic model for welded Q690D steel H-section column was proposed.

Suitable solvent and the related solution thermodynamics of fosfomycin phenylethylamine (FPEA) are essential for its purification by cooling crystallization. Two candidate solvents of ethanol and water are systematically investigated and compared, including the solubilities in them from 278.15 to 348.15 K with an interval of 5 K and the dissolution enthalpies at different concentrations at 303.15 K, which were measured using a static equilibrium method and solution calorimetry at atmospheric pressure, respectively. In addition, densities of FPEA in the two solvents at a diluted region were accurately measured for compositional analysis of equilibrium samples. Meanwhile, we explored the thermal stability of solid FPEA by using thermogravimetry. Crystalline FPEA was thermal stable blow 378.15 K and its molar heat capacity increased from 42.2 to 119.7 J·mol−1·K−1 when heated from 308.15 to 363.15 K, as determined by differential scanning calorimetry. When FPEA was further heated, it started to decompose at around 453.15 K without prior melting and then continued to decompose in several steps with the subsequent increase of temperature. When it was dissolved in the two solvents, endothermic effect was observed and the molar enthalpy of dissolution FPEA in ethanol at infinite dilution was about 2 kJ/mol higher than that in water, suggesting more hydrogen bond formation in water. The molality solubility of FPEA in water was generally higher than that in ethanol, but the difference decreased significantly with the increase of temperature. From 347.15 down to 279.15 K, the solubility in water decreased from 1.292 to 0.237 mol·kg−1, while that in ethanol decreased from 1.247 to 0.084 mol·kg−1, which justified the suitableness of using ethanol as the solvent for the cooling crystallization of FPEA with respect to product yield. The thermodynamic functions of solubility and solvation processes were estimated. An integrated approach by van't Hoff plot, enthalpy-entropy compensation analysis and solution calorimetry showed that enthalpy-entropy compensation was occurring in the dissolution of FPEA in both solvents and the enthalpic effect dominantly controlled the Gibbs free energy change of the process.

The ionomer material is widely used as interlayers in the laminated glass, and its tensile property plays a decisive role in the post-fracture response of the laminated glass. Since the ionomer material is a kind of polymer, its mechanical behaviour is highly affected by strain rate and temperature. In this work, two series of uniaxial tensile tests, low strain rate series (10−3s−1~10−1s−1) and medium to high strain rate series (1 s−1~800 s−1), were conducted over a wide temperature range (−40 °C~80 °C). Details of the test setup and corresponding true stress-true strain curves are presented. Characteristic mechanical parameters are then identified to evaluate the temperature and strain rate effects. It was found that higher strain rate and lower temperature result in higher strength and stiffness but lower ductility. The material shows apparent plasticity as more than 80% deformation is unrecoverable. Based on the observations, G’Sell model is adopted to build the temperature-dependent dynamic constitutive model, which is then validated through comparison between the predicted results and the published test data.

A novel method combined with fabric embossing (embossing with fabric template) and thermal annealing is proposed to prepare multistage textured superhydrophobic polytetrafluoroethylene (PTFE) surface. Multistage (four-stage) textures of microscale Y-grooves (≈175 µm), F-grooves (≈10 µm), warts (≈3 µm), and nanoscale dendrites (≈380 nm) were obtained. The multistage textures endowed the PTFE surface with better superhydrophobicity, comparing with the two-stage textures with Y-grooves and F-grooves or the two-stage textures with warts and dendrites. Optimum superhydrophobicity is obtained at thermal annealing temperatures 345 °C and 360 °C.

Recovery of fluorine from wet-process phosphoric acid (WPA) to produce ammonium fluoride (NH4F) and sodium fluoride (NaF) provides an environmentally-friendly route to purify WPA and produce high value-added fluoride salt. The solubility data and the related electrolyte thermodynamics are essential for a rational separation design of pure NH4F from aqueous NaF solution by crystallization. In this contribution, the solubilities of NH4F in aqueous NaF solutions of different concentrations from dilute to saturated were systematically measured at 298.15 K using a dynamic synthesis method. Experimental results show that the presence of NaF in the solution could significantly decrease the solubility of NH4F due to the common-ion effect which was decreased by 72.4% when the molality of NaF was only around 0.015 mol/kg. The data can be used to determine the yield of NH4F and liquid composition in the vacuum evaporative crystallization of NH4F. The mean activity coefficients of NH4F at saturation were determined from the experimental solubility data and then correlated with the extended Debye-Hukel equation and the Pitzer model. With four adjustable parameters, both models are able to accurately calculate the experimental data over a wide range of salt concentrations. The average relative deviations between the experimental and calculated logarithm of mean activity coefficients of NH4F from the two models are 1.43% and 2.29%, respectively. The binary and ternary ionic parameters for the Pitzer model are found to be concentration dependent and the correlations of them as functions of ionic strength are proposed.

Post-earthquake damage in cementitious passive fire protection (PFP) systems is a serious fire safety hazard in steel frame structures, because it is unaccounted for at the design stage. This is of greatest concern after small to moderate earthquakes as modern structural components are designed to resist them with no damage. However, PFP systems are not currently subjected to any design regulations for seismic loading and therefore their performance cannot be quantified. Additionally, the inaccessibility of cementitious coatings hampers the evaluation of their remaining fire resistance capacity following earthquakes by means of visual inspections. This paper proposes an integrated multi-hazard framework using finite element analysis (FEA) for assessing the remaining fire resistance capacity of PFP protected steel frame structures subjected to moderate earthquakes. This multi-hazard framework is presented in the open source software environment OpenSEES, and provides structural engineers with a practical solution to access the fire safety concern associated with the PFP damage.

Cementitious coatings have been widely used as fire protection for steel structures, but they are vulnerable to structural deformations or vibrations, which may lead to reduction in their effectiveness and cause severe economic loss in the event of a fire. For buildings in practice, the problem can be critical because the coatings are assumed to be in good condition as they are usually hidden underneath architectural finishes, making it difficult and expensive to carry out routine inspection. To determine the actual fire resistance of a building after a moderate or severe loading event or a relatively long period of service, it is imperative to understand the performance of the coatings and to develop effective damage estimation methodologies. Loading conditions in a real buildings can be complex, however as there is inadequate previous work in this field, it is considered more important at this stage to determine the fundamental damage mechanisms in cementitious coatings on steel members subjected to axial loading, as investigated in this paper through experimental and numerical studies. At first, tests are carried out to obtain mechanical properties of the coating and the bond properties between the coating and the steel substrate. Then, a series of monotonic loading tests are conducted on axially loaded steel members to observe damage propagation in coating specimens. Subsequently, a cohesive zone finite element (CZFE) scheme is presented for modelling the damage with both interfacial and internal damage considered. The effectiveness of the proposed CZFE scheme is validated by comparison with different numerical approaches, interlaminar stress analysis and monotonic loading tests. From monotonic loading tests and CZFE numerical analyses, damage mechanisms in cementitious coatings on axially loaded steel members are clearly revealed. Under tensile loading, the damage begins with interfacial cracks at both ends, followed by transverse cracks within the coating resulting in its ultimate fracturing into segments. Under compressive loading, the damage also initiates at the ends with interfacial cracks and propagates towards the centre until the coating completely peels off. The findings from this research build a solid foundation for estimating the damage of cementitious coatings for trusses and large space structures, as most of the structural components in these structures are axially loaded. This work also provides an effective approach for further research on understanding damage mechanisms in cementitious coatings in steel frame structures under more realistic loading conditions.

With the increase in mechanical strength, the yield to tensile strength ratio becomes more close to 1 and the elongation ratio appears a significant decrease, indicating a deterioration in the ductility and seismic behavior of high strength steel (HSS). For seismic design, understanding of the ductility and cyclic behavior in material level is important to guarantee the abilities of structural steel members to endure expected inelastic deformation under severe earthquake actions. This paper presents an experimental evaluation on the uniaxial cyclic behavior of Q460C steel through 6 cyclic loading tests. The specimens were cut and machined from both steel plates and flanges of hot-rolled H-shaped steel with the nominal yield strength of 460 MPa. For the purpose of comparing to normal strength steel, additional cyclic loading test was conducted on Q345B steel. Full hysteretic loops were achieved for HSS as well as normal strength steel. Based on the observations of the test results, a simple piece-wise model was developed for predicting the cyclic behavior of high strength steel, with considering the observed Bauschinger effect and cyclic strain hardening. To verify the accuracy of the proposed hysteretic model for HSS, quasi-static cyclic loading tests of Q460C steel beam-columns were simulated. The comparison between the experimental and predicted moment–curvature curves showed a good agreement, indicating a reasonable efficiency of the proposed trilinear kinematic hardening model in predicting the hysteretic behavior of HSS beam-columns.

This study presents the evaluation of seismic performance of high strength steel (HSS) beam-columns. Quasi-static experiments were carried out on four welded H-section and four box-section beam-column members fabricated from flame-cut Q460C HSS. The specimens were subjected to combined constant axial load and cyclic lateral load. The axial load was held at 30% of the yield strength of specimen during the loading history. The effects of width to thickness ratio and height to thickness ratio on the seismic behavior of HSS beam-columns were evaluated. It is found that component plate slenderness ratio has a significant effect on the deterioration behavior of beam-column under cyclic loading. According to the test results, welded Q460C HSS beam-columns with compact cross-sections show a good capacity of energy dissipation. No significant degradation was observed for the moment capacity of very compact cross-sections as class 1 under large inelastic rotation. The moderate compact cross-section belonging to class 2 shows a decrease in the moment capacity accompanied with the occurrence of local buckling when storey drift ratio is around 1/30. In addition to the obtained end moment–rotation hysteretic curves, the end moment–curvature hysteretic curves were developed to achieve more accurate descriptions of the cyclic performance of HSS specimens. Based on the generalization of experimental hysteretic curves, a trilinear hysteretic model was proposed in terms of the normalized moment–curvature relationship. This model was further compared with the experimental study to validate the accuracy in predicting the seismic behavior of HSS beam-column members.

The establishment of current design curves for predicting the maximum strengths of centrally loaded columns was mostly based on the experimental and analytical studies of mild carbon steels. In order to study the overall buckling behavior of welded high strength steel (HSS) box-columns, an experimental study on the ultimate strength of welded box-columns with a nominal yield strength of 460 MPa under axial compression was conducted. This experiment program includes six welded box-columns with slenderness varying from 38 to 80. A nonlinear finite element model considering the actually measured geometric imperfections and residual stresses was developed and verified in order to perform an extensively parametric study. The effect of residual stresses on the ultimate bearing capacity and the sensitivity of yield strength to initial geometric imperfections were investigated and discussed. The purpose of the parametric study is to select an appropriate design curve for welded 460 MPa HSS box-columns. By comparing the theoretical curves with the design curves specified in Eurocode3 and GB 50017-2003, it is found that the currently adopted design curves underestimate the ultimate bearing capacity of the welded box-columns fabricated from 460 MPa HSS plates by 18.7% and 23.2% in average, respectively. The curves b in both Eurocode3 and GB 50017-2003 show a good agreement with the generated theoretic curve for the welded box-columns with the nominal yield strength of 460 MPa buckling about both principle axes.

A strip layer method is presented for analyzing the three-dimensional deformations and stresses of large cylindrical shell rolling process. In this approach, the different radii and velocities of upper and lower rolls, the uneven distributions of deformations and stresses at the roll gap, are taken into account. The rolling deformation zone is divided into a number of strip and layer elements along the width and thickness directions, respectively. In order to reduce the optimization parameters and improve the computation efficiency, the exit lateral displacement distribution is expressed as polynomial function. Based on the fundamental principles of plasticity, the three-dimensional deformations and stresses of the deformation zone are formulated. The simulation results can be obtained quickly and easily. The fishtail spread is predicted satisfactorily on the free side, and the rolling pressure distribution is quite different from that of a conventional strip rolling. The predicted rolling force and average spread of the proposed method are in agreement with the experimental and FEM results.

The presence of residual stress in members can significantly compromise the stiffness and fatigue life of steel structural components. Researches in this area are well documented for structural members of mild carbon steels. Nevertheless, due to the difference of stress–strain relations and material properties under ambient and high temperatures, the residual stress distribution in a high strength steel member is physically different from those fabricated from mild carbon steel. It is imperative to study the residual stress distribution for structural members fabricated from high strength steel. In this paper, the residual stresses of three welded flame-cut H-section columns with a nominal yield strength of 460 MPa but different cross-section dimensions were investigated. Both sectioning and hole-drilling methods were used in the measurement and the obtained residual stresses were compared between the two methods. The magnitudes and distributions of the measured residual stresses are identical with those of carbon steel, however in relatively smaller residual stress ratios. Finally, based on the measurements, a simplified residual stress distribution for 460 MPa high strength steel members with welded flame-cut H-section is proposed.

High strength steel (HSS) columns have been located in the research scope of the introduction of multiple column curve to the design codes. However, the determination of current design curves for predicting the maximum strengths of centrally loaded columns was mostly based on the experimental and analytical studies of mild carbon steels. Due to some test data (e.g. residual stress distribution) of HSS columns were not available, the selection of the design curves for HSS columns was inevitably based on some assumptions which need the further confirmation of experiments. In this paper, an experimental study on the ultimate strength of welded H-section columns fabricated from flame-cut steel with the nominal yield strength of 460 MPa under axial compression was conducted. This experiment program include six welded H-section columns with varies slenderness form 40 to 80. The nominal thickness of flanges and webs are 21 mm and 11 mm. A nonlinear finite element model considering the actually measured geometric imperfections and residual stresses was established and used to perform an extensively parametric study. The purpose of the experimental and numerical studies is to find an appropriate design curve for welded 460 MPa HSS H-section columns. By comparing the theoretical curves with the design curves specified in Eurocode3 and GB 50017-2003, it is found that the currently adopted design curves can be extend to welded H-section columns fabricated from flame-cut 460 MPa HSS plates. But the curve c of Eurocode3 is very conservative when H-section columns are buckling about weak axis.

Much work on the investigation of the magnitude and distribution of residual stresses in mild carbon steel sections have been made previously. However, limited efforts have been put on residual stress measurements of high strength steel sections. The differences of stress–strain curves and high-temperature material properties between the high strength steel and mild carbon steel demands a necessary study of the residual stresses in high strength steel welded sections. In the present study, three box columns fabricated from Q460 steel plates of 11 mm in thickness with different details were used for the examination. Both sectioning and hole-drilling methods are adopted for the measurement. The measured residual stress distributions of three different box sections are presented, and the corresponding simplified residual stress pattern is proposed. By comparing with the residual stress patterns for mild carbon steel, it is found that the box section fabricated from HSS plates has the lower compressive residual stress ratio. The differences in the measurement by using sectioning and hole-drilling methods are also compared.

In order to analyze the behavior of steel columns in a fire with partial damage to their fire protection, two simple models are presented. One of the models based on the differential equation of equilibrium may be used to predict the ultimate load bearing capacity of steel columns hinged at two ends and the other may be employed to predict the critical temperature of axially restrained steel columns. The imperfections including initial flexure of steel columns and load eccentricity are taken into account in the models. The edge fiber yielding at the mid-span of a column is taken as the failure criteria for the fire-resistance of the column. A numerical application is carried out to demonstrate the effect of the damage to fire protection on the ultimate load bearing capacity and critical temperature of steel columns in a fire. The results show that the load bearing capacity is reduced at a given temperature with increasing damaged length of fire protection. The axially restrained stiffness and load ratio have a significant influence on the critical temperature of steel columns. By employing the computer models, the approach proposed in the paper has been validated and good agreement has been found.

This paper describes the first case of using hanging plastic tray for three-dimensional collection of the spat in the hatchery production of antique mactra. Different numbers of clusters (72, 90, 108) of plastic trays loaded with fine sand were hung in three tanks for three-dimensional collection of antique mactra, while the other two tanks without hanging plastic trays were controls. There was a higher survival rate in the tanks with hanging plastic trays than the controls and there was significantly increasing the survival rate of the spat as the numbers of clusters of plastic trays increased. At the end of the experiment, in the tank with most numbers of clusters of hanging plastic trays the survival spats was almost 2.6 times of that in the controls. In the early stage of the experiment there was significantly faster growth of the spat in the tank with hanging plastic trays than the controls. However, at the end of the experiment, there was significantly shorter shell length of the spat in the tank with most numbers of clusters of hanging plastic trays, and there was no significant difference in the shell length of the spat among the others tank.

Slender structures such as tall buildings and chimneys can be modeled as cantilevers with bending and shear deformation. A flexibility approach for damage identification of cantilever-type structures by utilizing the data of dynamic modes is proposed in this paper. An important advantage of the approach is that it only requires a small number of modes, so that it is convenient for practical application. The effectiveness of the approach is verified by numerical and experimental examples.