Abstract:In order to study the variation regularity of mean wind pressure coefficients on gasholder with interference and the transformation of different distance of interference effect, pressure measurements were conducted in wind tunnel on a rigid structural model. Results showed that in the case the interferential gasholder was located in the front, the mean wind pressure coefficients of windward side would dramatically decrease; the interferential gasholder was located in the rear, the mean wind pressure coefficients of lee side would increase; two gasholder were parallel to each other, the mean wind pressure coefficients of windward side would decrease; distance had a influence on the interference effect, interference effect varid with changes of distance; the safety reserve of code values was sufficient on windward and crosswind side but slightly insufficient in windward side.

Abstract:A typical measurement-section was selected, and concrete strain meters were embedded to make measurement for diaphragm walls on the construction of Station of Metro Line 7&9 of Chegongmiao Station of Shenzhen Metro. The internal force change of diaphragm walls was discussed, and the reliability of diaphragm walls was evaluated. Results showed that with the increasing of the excavation depth of foundation pits, the variation of stresses of diaphragm walls was observable. According to the strain data from field measurement, safety factors of diaphragm walls were calculated, which turned out to meet national code. Meanwhile, it can be concluded that diaphragm walls were in the safe status. In the end, the variation relationship of their internal force, which would provide some references for the design and construction of similar projects in the future, was obtained.

Abstract:One shear wall totally reinforced with steel bars and the other four shear walls partly or totally reinforced by CFRP bars in the longitudinal direction were tested under the reversed cyclic loading. Based on the analysis of the crack width, crack distribution and lateral deformation of the five shear walls, the influence rules of the reinforcement methods of partly or totally reinforced by CFRP bars on the self-centering performance such as residual crack and residual deformation of reinforced concrete shear walls were researched. The results showed that the crack loads of the shear walls with CFRP bars were lower than that of reinforced concrete shear wall. The shear walls with CFRP bars had more cracks and more extensive crack distribution. The maximum crack widths, residual crack widths and residual deformations decreased by 60%, 70%, and 90%, respectively, which indicated the shear walls reinforced by CFRP bars had excellent self-centering performance.

Abstract:The concrete and steel columns subjected to a combination of vertical load and horizontal earthquake action are used to study the influence of correlations between loads in failure function on design reliability of seismic capacity of columns. According to the current Code for Design of Concrete Structures and Code for Design of Steel Structures, the correlations between moment and axial force are analyzed for different columns. Through comparisons of different columns in several frame structures, the similarities and differences are investigated between the load interaction curves and those considered in codes. It is indicated that the load interaction curves under this combination match well with those considered in codes for RC columns with compression failure and steel columns with I-shaped section, and they are all negatively correlated straight lines approximately; the load interaction curve of RC column with tension failure is largely different from that considered in codes, and obviously has some positive correlation parts. Based the complex failure function, reliability of columns under this combination is analyzed with the Monte Carlo method and current statistics of load and resistance. The results show that:(1)the reliability indexes of seismic capacity vary lightly with different load effect ratios based on axial force for steel columns and RC columns with compression failure, and are close to those based on the codes; (2)the reliability indexes vary greatly with different load effect ratios based on axial force for RC columns with tension failure, and are also largely different from those based on the codes; (3)the reliability indexes are lower than those based on the codes for RC columns with tension failure when the load effect ratio based on axial force is negative, as a consequence, the current reliability-based design method of columns may be unsafe in this case.

Abstract:Residual displacement between girders would have occurred after the main shock. And it would get further destroy (like pounding and unseating) with the excitation of aftershocks. Conclusions draw from the comparation on the response of continuous bridge with or without Cable-sliding expansion joints (CMEJs) under the excitation of seismic sequence. Relative displacement between girders gets effective restrained during the whole seismic process with the CMEJs which get great meaning for avoiding pounding and unseating. With the contribution of the CMEJs, all the girders work together causing the relative displacement between girder and the pile decreased. And the pier force also gets optimized.

Abstract:Three different static loading protocols were used in the lateral loading experiment on SIP wall covering with oriented strand board (OSB), and failure forms and shear performance of the SIP wall were recorded and analysed treated by three loading protocols:ISO 22452, ASTM E72-05 and ASTM E564-06. The results showed that shear performances of the SIP walls under the three loading protocols were different, ultimate bearing capacity and ultimate displacement were the largest one, and the ductility factor was the middle one which loaded by ISO 22452, the value were 46.06kN, 71.83mm, 3.31 respectively; while ultimate bearing capacity was the middle one, ultimate displacement and ductility factor were the largest one which loaded by ASTM E72-05, the datas were 40.66kN, 76.97 mm, 4.07 respectively; ultimate bearing capacity 37.73 kN, ultimate displacement 54.92 mm and ductility factor 2.91 were the smallest treated by ASTM E564-06 among the three loading protocols. Failure forms of the walls under the three loading protocols were similar, there were little influence on failure forms caused by the three loading protocols used in this research.

Abstract:The current analysis method of pile foundation under horizontal load are analyzed comprehensively. First, mechanics model of rigid pile in slope considering pile lateral stress is established. Second, according to the principle of limit equilibrium, the bending moment and stress equilibrium equation of rigid pile in slope under lateral load are proposed. Then the pile lateral ultimate bearing capacity and horizontal resistance coefficient along the depth increasing linear are developed using p-y curve method. The proposed method is applied in the case study, and the results verified the rationality and feasibility of this method by comparative analysis with the existing finite element calculation methods. Finally, the method is used to perform a series of parametric analyses, such as angle of slope, pile soil contact surface coefficient and horizontal resistance coefficient, and some significant conclusions are drawn. The slope Angle, contact surface coefficient of pile and soil has significant impact on the load displacement curve of rigid pile, and the resistance coefficient of pile side soil impact load displacement curve of is not obvious under the action of the lateral load.

Abstract:A sequencing batch biofilm filter was a novel technology based on SBBR. As the sequencing batch biofilm filter was not efficient for phosphorus removal in the treatment of domestic sewage, FeSO₄ 7H₂O was added to the SBBF in order to achieve chemical aided biological phosphorus removal, which was meaningful for nitrogen and phosphorus removal in wastewater treatment. When concentrations of Fe(Ⅱ)varied from 0.03 to 0.3 mM, it indicated that 0.2 mM Fe(Ⅱ) might be a proper dosage. When 0.2 mM Fe(Ⅱ)was added to the bioreactor at the end of influent phase for one month, the effluent TP remained stable at below 0.5 mg/L, and the removal of COD and nitrogen were not affected. The average removal efficiencies of COD、NH₄⁺-N、TN and TP were 84.9%、83.2%、46.3% and 88.2%, respectively. The parameters of reactor effluent were stable to achieve the A standard "discharge standard of pollutants for municipal wastewater treatment plant (GB 18918-2002)".

Abstract:Chitosan is a natural basic amino polysaccharide substance with many functional amino and hydroxyl groups on the molecular chain. So that it can become a potential flocculant. P(CS-AD) flocculant is graft copolymerized by chitosan (CS) and acrylamide (AM), acryloyloxyethyl trimethyl ammonium chloride (DAC) with UV irradiation. The effects of key factors on the intrinsic viscosity such as monomer concentration, chitosan percentage, cationic degree, photoinitiator concentration, and illumination time are discussed. The optimal synthesis conditions are determined:monomer concentration 30% to 40%, the percentage of chitosan 10%~20%, cationic degree 30%~40%, photoinitiator concentration 0.3%~0.5%, illumination time 120 min. The maximum intrinsic viscosity is 1865 mg/L after optimization. Infrared spectroscopy, scanning electron microscopy (SEM), and differential thermal analysis (TG-DTA) are used to characterize the graft copolymer. Diatomite water samples are used to verify its flocculation performance, and flocculation test results show that P (CS-AD) flocculation performance is significantly better than the commercially available polyacrylamide (PAM).

Abstract:Effectively evaluating the safety on the structure of large diameter PCCP pipeline broken wires and taking effective measures to repair are the ways to reduce the safety risk of broken wires during South to North Water Diversion Project large diameter PCCP pipeline operation. Based on the method of analytic hierarchy process, the hierarchy analysis mathematical evaluation model is established. The possible factors of the influences of various of South to North Water Diversion Project of underground large diameter PCCP pipe broken wires are scored by experts. At the same time, the PCCP pipeline safety failure judgment criterion and the judgment standard are established through the numerical simulation. The quantification of safety risk assessment of large diameter PCCP pipe is realized. A specific PCCP North South Pipeline engineering safety running and risk management software is developed. With real-time monitoring automation technology and the risk management system of Web-GIS, the software can perform real-time acquisition of the monitoring data, data file of electronic management and dynamic assessment and early warming of safety risk.

Abstract:Hydraulic model of water distribution systems (WDSs) is an essential tool to realize modernization management of WDSs. To make the model capable of reflecting the system's behavior with reasonable accuracy and achieving intended purposes, the parameters in it should be calibrated. The nodal demand calibration of WDS models is formulated as a nonlinear optimization problem, which is then solved iteratively using weighted least squares method. Comparing to previous studies, the proposed method deduces the analytical solution of Jacobian matrix of WDSs based on matrix analysis method, and translates the under-determined problem to over-determined by aggregating the nodal demand using demand allocation matrix, such that the computational efficiency and the reliability of calibration results were improved. A simple network is used to illustrate the computation of Jacobian matrix, the construction of gradient vectors and the aggregation of nodal demand. The practicability of the method is further validated by a real network.

Abstract:With the increase of sludge production of wastewater treatment plants, sludge treatment has become one of the hot topics in environmental engineering and environmental geotechnical engineering. Sludge-municipal solid waste(MSW) mixture landfill has been applied abroad. But the current domestic foundational laboratory test result of MSW mixture sample is not much,there is a lack of understanding on its mechanical properties and the appropriate proportion of mixed landfill. Hence domestic sludge-municipal solid waste(MSW) mixture landfill engineering accidents occur frequently. Consolidation compression experiments, three axis consolidated undrained tests and unconfined compressive strength tests are conducted to disscuss the mechanical properties of different mixing ratio of sludge-municipal solid waste(MSW) mixture. At the same time, ANSYS numerical simulation is operated to analyze the slope stability of landfill with different mixing ratio of sludge-municipal solid waste(MSW) mixture. The theoretical support on the appropriate proportion of mixed landfill and stability security of sludge-municipal solid waste mixture landfill is proposed.

Abstract:The diatomite/cellulose filter aids were prepared using raw diatomite and cellulose via sol-gel technique. The effect of cellulose/diatomite, distilled water/cellulose, EtOH/diatomite, ammonia concentration and temperature on the properties of diatomite/cellulose filter aids were investigated. The filtration efficiency of diatomite, cellulose and diatomite/cellulose filter aids was compared. The influence of diatomite/cellulose filter aids on slightly polluted water filtration was studied. Results indicated that when 40 mL distilled water dissolved 1.0 g cellulose, 20 mLEtOH carried 1.5 g diatomite, the ratio of diatomite to cellulose was 0.67, the concentration of ammonia was 5×10^-4mol/L, the temperature was 60℃,the best diatomite/cellulose filter aids were achieved. The efficiency of diatomite/cellulose filter aids was obviously better than that by diatomite and cellulose filter aids. The pollutants removal efficiency could increase by using the diatomite/cellulose filter aids in the direct filtration process to treat the micro-polluted raw water. The results showed that the combination of filtration and micro-filtration membrane could achieve excellent permeate water, which met the Standards for Drinking Water Quality(GB5749-2006).

Abstract:A new type of backfill materials using recycled brick and concrete waste as fine aggregates was designed with three cement-to-sand ratios (C/Sa) and five fly ash-to-sand ratios (FA/Sa). A series of measurements were conducted to investigate the fluidity and bleeding and mechanical properties including uniaxial compressive strength, stress-strain relationship, constitutive relation model and elastic modulus. The results showed fluidity had linear correlation on water-to-solid ratios(W/So); the range of the bleeding rates was in 4%~8% when the fluidity was within 200~250 mm. The compressive strengths had an exponential relationship to the cement-to-sand ratios and water-to-solid ratios. A constitutive relation model was put forward to describe the stress-strain relationship curve of backfill material on the base of the model of the concrete. The relationship between the unconfined compressive strength and elastic modulus was established, which could be used to calculate the modulus of backfill materials by the compressive strength directly.

Abstract:To better understand the failure mechanism of shoving on steel bridge deck overlay and guide the maintenance actions, an investigation was conducted on the performance of Beipanjiang bridge in terms of pavement shoving in Guizhou province. The Gel permeation chromatography (GPC) and Fourier Transfer Infrared (FTIR) spectrum were employed to analyze the failure mechanism of shoving from the point of molecular scale. The results showed that the asphalt aging is not the main cause for resulting in the formation of shoving disease on steel bridge deck. In addition, the reduction of adhesive strength of the second tack coat is a secondary cause for shoving disease of the steel bridge deck from the field survey research. Further, sieve analysis was performed to investigate the shoving mechanism on steel bridge deck with Gussasphalt (GA) mixture, and the results indicated that shoving failure is due to the gradation of GA mixture and poor angularity of aggregate particle rather than aging of asphalt binder.

Abstract:The shrinkage and creep of high strength concrete was affected by the mixed fly ash. The influence was directly related to the long-term behavior of structures. The shrinkage and creep experiment of C50 concrete with fly ash content 0, 12%, 24% were conducted with 100 mm×100 mm×400 mm prism specimens in the laboratory. Four kinds of current commonly used specifications for the shrinkage and creep of high strength concrete were assessed. With the experiment results and other existing research referenced, the fly ash influence coefficient and its correction model were introduced to reflect the influence of different load age and fly ash content. The analysis showed that the shrinkage and creep mode recommended from JTG D62 and GL 2000 agreed well with the measured results form the reference specimens. And the verification conclusion demonstrated that the introduced fly ash influence coefficient could be applied to the shrinkage and creep of high strength concrete with fly ash.

Abstract:Three methods used to determine luminance at tunnel portals were analyzed and compared. The three methods were look-up table method, environment diagram method and blackening method. But these methods didn't fully consider the regional environment of tunnel and luminous climate. In order to rapidly and accurately determine scenery luminance at tunnel portals, measurements were conducted in seven Congguan highway tunnels. Based on the onsite measurements, the relationship between scenery luminance at tunnel portals and horizontal illuminance were established. Statistical analysis on local light climate data were carried out to confirm standard value of luminance at tunnel portals L_S and the design reference value of typical scenery luminance at tunnel portals in Dongguan. And typical scenery luminance values of four towards in Dongguan area could be determined.

Abstract:The thermal and wet state on the ground of rural residence in Chongqing were investigated. Investigation of the rural residential and the field survey of typical residential floor were made in the season of spring and summer in Chongqing. The results showed that wet phenomenon appeared on the ground of rural residential mostly, and cement ground had the highest proportion. In June, the indoor air and ground humidity were the highest, and ground temperature was about 2℃ lower than the air temperature indoor. In wet weather, hours ratio of condensation on the ground was close to 60% in old residential buildings. Thermal performance of ground for the rural residential building should be improved.

Abstract:An urban canyon absorbs more sunlight than a flat, open surface due to multiple reflections in the canyon, increasing the urban heat island effect (UHI). One geo-engineering idea to mitigate the UHI to make the conventional pavements more reflective and to return more radiation to the sky. The urban canyon albedo (UCA) are modeled and the model with experimental observations are validated. We investigated whether increasing the pavement albedo can raise the UCA effectively based on evaluating the reflective diffuse radiation from the pavement to adjacent building walls. It is found that the ratio of building's height to the road's width determines the UCA whereas other factors acts secondary roles. During summertime reflective pavements in an urban canyon reflect a sizable additional diffuse radiation to the adjacent walls. Reflective pavements are recommended for only an urban canyon with an aspect ratio no greater than 1.0.