Abstract:A comparative study was made of the indicators about the sharing among different green building rating tools (GBRTs) used in USA, UK, Germany and China. Results show that the sharing is becoming a more and more important part of GBRT. In different GBRTs, the distribution of sharing indicators is different, and so is the contribution rate , which is up to 6.23%. For Chinese GBRT, sharing platform of post-operation evaluation is anticipated and the sharing index is proposed to measure the sharing during the operation stage, which contributes to the development of green building evaluation and design.

Abstract:To consider the crack bridging effect of steel fibers in fiber reinforced concrete (FRC) and its beneficial effect of restricting crack initiation and development in composite bridge deck, a calculation method of residual stress and cracking width was proposed. The main parameters influencing the residual stress f_R,1 were yielding stress of fiber σ_y, fiber volume fraction V_f, compression strength of concrete f_cm, fiber length l_f, fiber aspect ratio a. The correlation between the afore mentioned parameters and the residual stress was derived. Based on the linear regression analysis from test results of 35 three-point bending tests on notched beam recorded in the literature, an equation to calculate f_R,1 with 95% confidence level was proposed. Including the contribution of residual stress in the calculation method for the composite structure under negative moment suggested by Eurocode 4, a crack width calculation method for FRC composite bridge deck was proposed. A FRC composite bridge deck specimen subjected to negative moment loading was used to validate the calculation method. The results show that the calculated rebar stress and crack width fits well with the tested value.

Abstract:The multi-pylon cable-stayed bridge is a feasible scheme for spanning wide rivers and valleys. However, the ultra-high piers of multi-pylon cable-stayed bridges in mountainous areas can decrease the overall stiffness of the bridge structure, which makes its mechanical response different from those of ordinary multi-pylon cable-stayed bridges. To study the influence of ultra-high piers on the mechanical behaviour of three-pylon cable-stayed bridge in deep and wide valleys, a typical three-pylon cable-stayed bridge under construction is taken as an example. The index and calculation method for mechanical response are firstly established. Then, the effects of the pier height, pier height difference and stiffness of girder and pylon on the displacement at the top of the pylon, bending moment at the bottom of the pier and deflection at the mid-span are analyzed. The results show that: when the pier height increases, the additional bending moment at the bottom of the pier caused by the traffic lane load and the temperature decreases while longitudinal displacement at the top of the pylon and deflection at the mid-span of the girder increase; the difference of the pier height has a great influence on the internal force of the pier and the lower pier will bear more bending moment; the structural displacement can be better controlled by increasing the stiffness of the pylon.

Abstract:The pseudo-static tests of six high-strength, low-elastic-modulus and high-ductility stainless steel reinforced concrete columns were conducted. By comparing with the ordinary reinforced concrete columns, failure patterns, hysteretic curves, skeleton curves, displacement ductility, bearing capacity and the influences of axial compression ratio and longitudinal reinforcement ratio on its seismic behaviors were analyzed. The results show that stainless steel specimens suffer axial and flexural failure at the end of columns. The hysteretic curves of stainless steel specimens are similar to those of ordinary steel specimens, but stainless steel specimens show better energy dissipation capacity. The displacement ductility coefficients of stainless steel specimens are slightly smaller than those of ordinary steel specimens, but the yield displacements and ultimate displacements of stainless steel specimens are larger than those of ordinary steel specimens by 21%~24% and 2%~19% respectively. The ratios between the calculated values and test values of the flexural capacity of stainless steel specimens are similar to those of ordinary steel specimens, with an average value of 0.79, which has a certain safety reserve. When the stirrup spacing is greater than 100mm, the restraint effect on the bearing capacity of specimens is not obvious.

Abstract:In order to study the non-linear failure state of materials, local components and integral structure of multi-story subway station under earthquake action, a 1:10 large-scale pushover test was carried out in the background of a multi-story subway station project in Shanghai. According to the seismic response characteristics of underground structures, loading mode was in the form of inverted triangular displacement carried out by means of multi-point coordinated loading by three actuators. Development process of cracks, plastic hinges formation sequence and pushover curve were studied. Failure patterns and modes of the whole structure and central columns were contrasted. Critical performance data points of the structure was given. On account of the pushover test results, the seismic performance of deep metro station structure was also comprehensively analyzed, which can provide reference for designs of similar structure based on seismic performance.

Abstract:Based on the actual condition of concrete sulfate attack in metro shield tunnel, the sagging moment mechanical model of longitudinal joint is established, which can take into account the details of joint structure, surface concrete and bolts. Furthermore the joint section can be discretized into different compression zones. Because the constitutive calculation of concrete is carried out in full integral form, it is adapted to analyze the crush of concrete, the yield of bolt and the limit state of longitudinal joint. Comparing with numerical calculation, the results of the two methods are basically the same, which verifies the rationality of the mechanical model. The results show that under sagging moment, the effect of sulfate attack on the mechanical property of longitudinal joint is mainly manifested after the contact of concrete at the outer surface edge. Against the increasing of sulfate attack time, the ultimate bending moment of longitudinal joint decreases continuously with an average margin. Meanwhile, the maximum deformation decreases against the increasing of attack time with a different decreasing margin. When the sulfate attack thickness increases, the ultimate bending moment and the maximum deformation of longitudinal joint decrease continuously with a larger margin.

Abstract:A series of full-scale tests on longitudinal joints subjected to positive and negative moments were conducted. The joints were continuously loaded until completely damaged, and the development of joint opening, joint deflection, bolt strain and concrete strain with the bending moment were obtained. Based on the deformation and stress state of bolt, gasket and segment stress, the serviceability limit state of longitudinal joints were derived. The ultimate limit state of longitudinal joints was determined according to the ultimate bearing capacity of the joints. Finally, based on the comparison between the test results and the design results, the safety reserve of current safety factor design method was researched.

Abstract:The hardening soil model with small strain (HSS model) has become one of the most widely used constitutive models in numerical analysis of excavations because it can reflect the attenuation of soils with strain in tiny strain range. The research on small strain shear modulus of silty sand is inconsistent, despite the fact that great progress has been made in the research of typical soft soils in Shanghai. In this study, through triaxial consolidated drained test, triaxial loading-unloading-reloading drained test, consolidation test and resonance column test to measure the small strain stiffness properties of silty sand in Shanghai. The parameters for Lin-Gang involved in the hardening soil model with small strain stiffness, including the initial shear modulus, the soil strength parameters and unloading and reloading modulus. The measured parameters are compared with other soils in Shanghai and verified through practical engineering. The test results can be used as references for numerical analysis of excavation in Shanghai. It is of reference value to similar engineering.

Abstract:In order to verify the validation of car-following behavior study based on driving simulation, the natural driving experiment and driving simulation experiment were designed. The driver’s delay time, car-following distance and its standard deviation were selected as analysis index. The validity of non-time data and time data were verified by Wilcox test and survival analysis method respectively. The result indicates that car-following distance and driver’s delay time have absolute validity. The standard deviation of car-following distance has the same change trend in two different experimental environments, which means it has relative validity. In the natural driving experiment acceleration of the following vehicle, relative distance, and acceleration change status of the following vehicle effect driver’s delay time significantly. The result of validation study provides precondition for other driving-simulation-based car-following behavior research. Survival analysis result can be used for driver’s delay time modeling and car-following model optimization.

Abstract:To address the issue of queue spillbacks at bus stops due to high traffic volumes, this study focused on the queue formation, analyzed the relationship between the capacity and the traffic demand at bus stops, and proposed an intersection control approach to avoid queue spillbacks at bus stops. Firstly, a bus delay model and a dwelling time model were built. Then, the judgement models of queue spillbacks and on-schedule buses were built based on the above two models. Finally, these models were applied to a traffic control scheme and an approach to avoiding queue spillbacks at bus stops was proposed, which could also provide bus priority control. VISSIM software was used for simulation validation and the results demonstrated that the proposed control approach was able to prevent queue spillbacks at bus stops.

Abstract:Taking the crisscross node transfer facility in the urban metro transit transfer station as the research object, passenger arrival time distribution was determined by the travel distance from the door to the stairs, and then the passenger flow congestion analysis method of the node transfer facility was constructed by using the passenger flow iteration according to the basic relationship of flow between the upstream and downstream of the section of the facility and passenger flow interrelationship between the area in front of stairs, transfer platform, and stairs. Case studies show that the proposed method can quickly analyze the pedestrian congestion of the crisscross node transfer facilities with different combinations of multi-directional passenger flow when the information about the passenger flows and the pedestrian facilities layout are given.

Abstract:Systematically discusses the state-of-the-art research of parts design for additive manufacturing from the aspects of structure design with topology optimization, mesoscopic structure, parts integration, fluid pipeline and heat exchanger, and the aspects of process planning with toolpaths, buliding direction, multi-axis construction and curved layers. On this basis, AM parts integration design, multi-scale heterogeneous cellular structure design, performance-oriented process planning and process planning for continuous carbon fiber reinforced composites as the potential development directions were proposed.

Abstract:Under dynamic conditions of vehicles, the performance and durability of proton exchange membrane fuel cells (PEMFCs) can be directly affected by internal parameters such as pressure, temperature, and gas concentration. In order to optimize the PEMFC system design and control, it is crucial to gain a more in-depth understanding of the relevant operation phenomena, including internal mass transfer, heat transfer, and chemical reaction processes. As a nonlinear, multi-input, strongly coupled system, the PEMFC involves from the atomic/molecular scale over the mesoscale of structures and materials up to components, stack, and system levels. Thus, the modeling methods of different scales from the perspectives of critical components, cells, stacks, and systems are reviewed, and the challenges and development trend of future models are expounded.

Abstract:A turbocharged direct injection miller cycle engine was selected and a low pressure exhaust gas recirculation (LP-EGR) was installed. By changing the EGR rate, the influence of LP-EGR on the combustion and fuel consumption of gasoline engine was studied. The results show that: under medium and small load conditions, fuel consumption reduces with the decreasing of pumping loss by changing the EGR rate, and the fuel consumption can be reduced by up to 8.41%. Under heavy load conditions, fuel consumption reduces with the EGR by inhibiting knock and modifying ignition time, and the fuel consumption can be reduced by up to 5.67%. Under near full load conditions, fuel consumption reduces by lowering exhaust temperature and “over injection”, and fuel consumption can be reduced by 20.4%. With the EGR, combustion will slow down and coefficient of variation will increase. With the increasing of EGR rate, the ignition time delays and the combustion duration increases, but the maximum heat release rate and the maximum temperature in the cylinder decrease. Because of optimized ignition advance angle, the maximum pressure in cylinder increases.

Abstract:A precise control method of clamping force is proposed for train electro-mechanical brake system (EMB). Firstly, the open-loop control characteristics of EMB were studied. Due to the influence of motor-loss , machining and assembly accuracy of mechanical transmission device, internal resistance, there is an error in the force transmission, resulting in poor response on EMB open-loop. Based on the PID control, the closed-loop response characteristics of the system were studied, and the clamping force optimized algorithm was designed by adding buffer process and tracking-differential. Finally, the control accuracy and tracking effect of the clamping force optimized algorithm were verified by hardware-in-loop experiments, meanwhile, the frequency characteristics of the EMB clamping force and the brake cylinder pressure of an electro-pneumatic braking system were contrastive analyzed.

Abstract:Based on some type of high-speed train, the different bogie area noise was tested and studied , which was one of the main noise sources of high-speed train in operation. Through the analogically test and analyze the noise characteristics in different bogies, it can be concluded that the main noise source in bogie areas of the intermediate trail car is wheel-rail noise at the speed level of 350km·h^-1 or below, the main noise source in bogie areas of the head and rear car is pneumatic noise, and the main noise source in bogie areas of the intermediate motor car is traction system noise. Furthermore, based on above results and some assumptions, the spectrum and contribution characteristics of major noise sources were studied and obtained for bogie areas of the head, rear and motor car. The research results can provide a basis and guidance for vibration and noise reduction of high-speed trains.

Abstract:Taking 227 photovoltaic industrial policies of China as an example, the quantitative standards of the policy strength and policy objectives of China’s photovoltaic industry were proposed. Based on this, a collaborative model of the policy objectives of China’s photovoltaic industry was constructed, and the impact of different policy objectives on the performance of the photovoltaic industry was discussed. Research indicates that there is a significant directional difference in the performance of photovoltaic industry in China when the policy objectives of photovoltaic industry are coordinated. The cultivation of photovoltaic market should be used in coordination with the policy of regulating market order. Clarifying the relationship between local and regional economic development, photovoltaic market cultivation, and independent technology research and development, and finding an effective way to achieve local and regional economic development through technological innovation become the keys to industrial technological breakthrough. Pay attention to the effective matching of “supportive” and “normative” policies, get rid of the long-term “lagging behind” state of normative industry standard policies for a long time, and formulate a comprehensive and forward-looking photovoltaic industry standard system.

Abstract:High-rise building projects being taken as the example, a study was made of the influencing factors about the construction cost for a reliable identification and reasonable quantification. On the basis of the theory of de-noising auto-encoder under deep learning as well as the neural network, a construction cost prediction model was established for nonlinear engineering projects. A case study was made of the model by a simulation prediction on the Matlab platform, which verified the proposed method for predicting the cost of engineering projects.