摘要：A mechanical model recently developed for the shear strength of slender reinforced concrete beams with and without shear reinforcement is presented and extended to elements with uniformly distributed loads, specially focusing on practical design and assessment in this paper. The shear strength is considered to be the sum of the shear transferred by the concrete compression chord, along the crack, due to residual tensile and frictional stresses, by the stirrups and, if they exist, by the longitudinal reinforcement. Based on the principles of structural mechanics simple expressions have been derived separately for each shear transfer action and for their interaction at ultimate limit state. The predictions of the model have been compared to those obtained by using the EC2, MC2010 and ACI 318-08 provisions and they fit very well the available experimental results from the recently published ACI-DAfStb databases of shear tests on slender reinforced concrete beams with and without stirrups. Finally, a detailed application example has been presented, obtaining each contributing component to the shear strength and the assumed shape and position of the critical crack.

摘要：Performance-based design is more holistic and flexible than prescriptive design for providing safety in large complex buildings. Here, a multi-agent method to model the egress patterns of evacuees is combined with a microscopic pedestrian simulation model used to analyze the forces between individuals in a densely populated enclosed space in a crowd crushing and trampling analysis （CroC＆Ts）. The system is used to model egress patterns in a typical crowd evacuation simulation. The simulations indicate that some individuals will die from crushing in 2 m and 4 m wide exits in emergencies. The simulations also show that the fatality probability increases when barriers obstacled the path and when the egress distances were lar- ger. The simulations validate the conclusions of the stranded crowd model （SCM） and provide quantitative predictions of the crowd crushing and trampling risk. Therefore, the CroC＆Ts can provide performancebased egress designs for large pubic buildings and improve crowd safety management and emergency planning.

摘要：We evaluate the hydrogen depletion ability of the hydrogen depletion system for Chinese Pressurized Reactor 1000(CPR1000), which has been applied in nuclear power plants with pressurized water reactors;moreover, we introduce a new device that can continuously monitor hydrogen concentration inside the CPR1000 containment building. Experimental studies show that a moveable hydrogen autocatalytic recombiner alone can sufficiently deplete hydrogen under the condition of a design-basis accident, and 33 passive autocatalytic recombiners placed in the areas of high hydrogen concentration satisfy the hydrogen depletion requirements under the condition of a beyond-design-basis ***, the hydrogen concentration monitoring system is designed and installed based on the approach of detecting the temperature increase caused by the catalytic reaction of hydrogen. In conclusion, the hydrogen depletion capacity of the CPR1000 meets the requirements, and the system's safety can be enhanced by the improved hydrogen concentration monitoring system.

摘要：Super-long span bridges demand high design requirements and involve many difficulties when constructed,which is an important indicator to reflect the bridge technical level of a *** the past three decades,a large percentage of the new long-span bridges around the world were built in China,and thus,abundant technological innovations and experience have been accumulated during the design and *** paper aims to review and summarize the design and construction practices of the superstructure,the substructure,and the steel deck paving of the long-span bridges during the past decades as well as the current operation status of the existing long-span bridges in China.A future perspective was given on the developing trend of high-speed railway bridge,bridge over deep-sea,health monitoring and maintenance,intellectualization,standard system,and information technology,which is expected to guide the development direction for the construction of future super long-span bridges and promote China to become a strong bridge construction country.

摘要：In this paper,we utilize the variational limiting equilibrium(LE) procedure to theoretically determine the slope stability of homogeneous coral sand in the South China *** establishing a reasonable functional and calculating its extremum,we can deduce the stability factor of a coral reef identical to that obtained by upper bound *** determine the accuracy of the results obtained using the variational LE procedure,we present some classical examples of homogeneous sand slopes without a hard shell and compare our results with those obtained by the upper bound theorem of plasticity.A series of extensive calculations and comparisons reveal that the results obtained by our proposed analysis method and those obtained using classical methods are slightly different,but the variational results are *** the other hand,our method solves some stability factors for reef slopes covered with a hard shell,which indicates that the existence of a hard reef shell may significantly enhance the stability of a reef slope,and that there is strong nonlinear relationship between reef stability and the mechanical characteristics of the reef shell,such as its thickness and ***,based on the variational results presented in this paper,we present a useful chart that offers a convenient and straightforward way to determine the maximum stability factor of reef *** into account the influence of the hard reef shell,we found that,in some limit equilibrium cases,the limit stability factor and critical height of a coral slope could be improved ***,this issue deserves careful attention in engineering practice.

摘要：The multiple cracking and deflection hardening performance of polyvinyl alcohol fiber reinforced engineered cementitious composites(PVA-ECC)under four-point flexural loading have been *** with different binder combinations and W/B ratios(from 0.44 to 0.78)providing satisfactory PVA fiber dispersion were specially *** of pre-existing flaw size distribution modification on deflection hardening behavior was comparatively studied by adding 3 mm diameter polyethylene beads into the mixtures(6%by total volume).Natural flaw size distributions of composites without beads were determined by cross sectional *** crack number and crack width distributions of specimens after flexural loading were characterized and the possible causes of changes in multiple cracking and deflection hardening behavior by flaw size distribution modification were *** results from the view point of deflection hardening behavior were obtained from metakaolin incorporated and flaw size distribution modified PVA-ECCs prepared with W/B=*** dual roles of W/B ratio and superplasticizer content on flaw size distribution,cracking potential and fiber-matrix bond behavior were *** size distribution modification is found beneficial in terms of ductility improvement at an optimized W/B ratio.

摘要：Two attics were constructed as part of a building renovation project at the University of West *** first attic is described as a traditional ventilated attic,with open-ings in the soffits and a small dormer vent on the *** second attic is described as a sealed attic(with no ventilation),and open-cell spray foam insulation installed on the underside of the roof *** study was undertaken to demonstrate hypoth-esized performance differences between attic *** and relative humidity sensors were installed to measure the condition of the air in the two attics spaces,and measurements were taken at 15 minute *** of relative humidity were later calculated as dew point and specific *** studies are often conducted by comparison of attics in separate buildings under different use *** project offers a unique opportunity to explore data collected from a single structure,and provides support for existing research on attic design in southern *** resultant data show significant differences in attic temperatures,with the sealed attic exhibiting a much more thermally stable *** were also significant differences in attic dew points and specific humidity,although these dif-ferences appear to be much less *** were analyzed using independent t-tests to establish significant differences between ***,the sealed attic performed better than the ventilated attic,although dew point and specific humidity remain concerns.

摘要：Based on a detailed illustration for bridge life cycle design which comprises the processes of service life design,aesthetics design,performance design,environmental and ecological design,inspection,maintenance and repair design as well as cost analysis,this paper presented a general framework for bridge life cycle design comprising three design phases and six design processes.

摘要：In design and construction of low/high rise buildings, different forms of construction can be applied such as concrete shear wall structural system and framed structural system without or with masonry infill walls. At present, most buildings in East Africa are constructed as reinforced concrete framed structures with strong masonry infill, but during design, engineers assume that the masonry infill panels have zero contribution in offering load resistance. Due to the problem above, a study with an objective of finding out the influence of masonry panels on the properties of reinforced concrete infilled frame under vertical load has been done. Three types of models： reinforced concrete frame model, masonry model and reinforced concrete frame with masonry infill, were investigated using finite element technique. In additional to the finite element analysis, laboratory models were prepared and tested so as to check the validity of the analytical results. The obtained results have led to an establishment of a mathematical model which may be useful to the design engineers since masonry wall panels can now be considered as load bearing elements. Such consideration of frame together with masonry leads to an accurate and optimal design of the frame, resulting into lesser amount of reinforcement and geometrical properties of the frame.

摘要：engineering designs for mountainous highways emphasize compliance checking to ensure safety. However, relying solely on compliance checking may lead designers to minimize costs at the expense of high risk indicators, since the overall risk level of the highway design is unknown to the designers. This paper describes a method for the simultaneous consideration of traffic safety risks and the associated cost burden related to the appropriate planning and design of a mountainous highway. The method can be carried out in four steps: First, the highway design is represented by a new parametric framework to extract the key design variables that affect not only the life-cycle cost but also the operational safety. Second, the relationship between the life-cycle cost and the operational safety risk factors is established in the cost-estimation functions. Third, a fault tree analysis (FTA) is introduced to identify the traffic risk factors from the design variables. The safety performance of the design solutions is also assessed by the generalized linear-regression model. Fourth, a theory of acceptable risk analysis is introduced to the traffic safety assessment, and a computing algorithm is proposed to solve for a cost-efficient optimal solution within the range of acceptable risk, in order to help decision-makers. This approach was applied and examined in the Sichuan–Tibet Highway engineering project, which is located in a complex area with a large elevation gradient and a wide range of mountains. The experimental results show that the proposed approach significantly improved both the safety and cost performance of the project in the study area.