Abstract:Four unidirectional prestressed space frames set at the critical height (24 m) and the critical span (18 m) were designed according to the Chinese codes, including two frames of the second, third seismic grade in intensity-category seven and two frames of the first, second seismic grade in intensity-category eight ("strong column-weak beam" in the middle nodes of the first seismic grade frame was weakened by the suggested method), based on the OpenSEES framework, elastoplastic time history analysis method was used to analyze the structural seismic performance and capacity under the bi-directional seismic waves. The results showed the yielding degree of every frames in both directions was acceptable and the global seismic capability was good. Besides, the frames which took a lower seismic grade had a slightly larger global seismic response. but the difference was not obvious. An ideal "beam hinge mechanism" was formed in the direction of RC frames and a "column hinge mechanism" was formed in the direction of PC frames, the lateral stiffness and seismic capability of PC frames were better than RC frames'. The PC frame of the first seismic grade formed hinges in middle columns effectively after weakening "Strong Column-Weak Beam", but hinges in side columns were still unavoidable, thus it was considerable to strengthen side columns.

Abstract:Effective section method (ESM) is widely used in the design of cold-formed steel structures. However, the influence of distortional buckling of members was hot considered. A new method for the load carrying capacity of cold-formed steel members, direct strength method (DSM), can effectively estimate the ultimate strength for local, distortional buckling and interactive buckling. However, it is not used for beam-columns. The stability behavior of C-shaped cold-formed members eccentrically compressed around the major axis was analyzed. The effects of Length of member, eccentricity and width-thickness ratio of webs, flanges and edge stiffeners on ultimate strength of members were examined in this study. A calculation method of ultimate strength was proposed based on the original DSM axial compression/bending formulas and the finite element analysis results.

Abstract:By applying the ideal of energy dissipater to nonstructural components, yielding energy dissipation partition (YEDP) was proposed. The YEDP could provide quantifiable stiffness under minor earthquakes and adjustable energy dissipation capacity under major earthquakes. The static cyclic loading tests of YEDP with different number of energy components were completed, and the energy dissipation mechanism and failure mode of YEDP were got understanding. Based on the quantitative relationship between number of energy components and hysteresis curve parameters, the method which using column unit of IDARC program to simulate YEDP was proposed. The dynamic time-history analysis of 6-storey reinforced concrete frame under different YEDP set programs were carried out, the results show that YEDP could effectively reduce the seismic response of the structure. The interlayer displacement of structure decreases significantly with the increasing of number of YEDP, but be changeless with the increasing of number of energy components in the YEDP when the number of YEDP is same.

Abstract:In the application of distributed optical fiber structure health monitoring, quantitative analysis of cracks is difficult. The effect of tensile, bending and folding on optical fiber and the influence degree of various factors needs to be studied. In this paper, the influence of frequency shift on optical fiber angle is tested and the effect of frequency shift caused by axial tension is compared. A new calculation formula based on BOTDA distributed optical fiber sensing is proposed and applied to crack imaging of software. The experimental results show that the change of the optical fiber angle has a great influence on the experimental results after the crack is generated, and the fracture imaging is closer to the real situation after taking the angle factor into account. Therefore, when using distributed optical fiber to monitor concrete cracks, the angle should be taken into account.

Abstract:In order to investigate the stress responses of reinforced concrete column subjected to the couplings of axial compression and sulfate attack, this paper applied an existed diffusion-reaction equation of sulfation in concrete to obtain a relationship between the sulfate-induced damage degree and the ion concentration and the corrosion time. On the basis, a concrete-corroded constitutive model related to the damage degree and a calculating approach for stress responses of concrete under the couplings of axial compression and sulfate attack were proposed. Through numerical solution on these models, the changes of sulfate ion concentration, damage degree, strain and stress in concrete with the corrosion time were analyzed. Results show that the sulfate ion concentration and damage degree has a gradient distribution in concrete, and they are obviously influenced by the two-dimensional interactions in the cross section. With the increase of corrosion time, the damage zone gradually moves inward the cross section, and its width has a gradual increase, and the stress in the damage zone increases firstly and then has a gradual decrease, but in the no damage zone, the stress has a basically linear increase. In the process of sulfate attack, there produces the stress redistribution in concrete under axial compression.

Abstract:Firstly, four groups of timber beams with shrinkage cracks in diversified depth were made and one-third loading method to observe the experimental data and record the ultimate bearing capacity was carried out. Then, according to the experimental data, combining finite element stress analysis, and the model of bilinear constitutive model of wood, the critical indicators which indicated that bending failure become shear failure and the corresponding ultimate bearing capacity formula were deduced. After that, the bearing capacity formula was simplified as the bearing capacity reduction coefficient curve. Finally, by comparing theoretical analysis with experiment, the results show that the theoretical values of ultimate bearing capacity coincide well with the test values, and the test phenomenon is consistent with the judgement of the critical indicator.

Abstract:This paper firstly conducted push-out test and dynamic signal test on CFST. The difference of nonlinear vibration characteristics of CFST in different working conditions in push-out test was analyzed. And the influence factors of nonlinear characteristics of CFST were studied. The first order of vibration signal was extracted by utilizing analytical mode, the relationship of frequency-amplitude was obtained by Hilbert transform. The test results of three CFST members show that the nonlinear vibration characteristics first increase then decrease in all loading process, and the characteristics are affected by the interaction between steel tubular and concrete. The interface of cementation is weaken by the poor quality of concrete placement, thus the nonlinear characteristics is relatively low when the concrete debonding isn't occurred.

Abstract:The Kiewitt-8 single-layer reticulated domes were taken as case study. Considering the influence of geometric nonlinearity and temperature on the properties of the material, the dynamic behavior of the single-layer reticulated domes subjected to blast loading in different fire stages was simulated. According to the B-R criterion, the dynamic stability critical overpressure loads of K8 single-layer reticulated domes subjected to blast loading in different fire stages could be determined by the relationship between the peak overpressure of blast and the structural dynamic response. And the influence of parameters such as the rise-span ratio, the roof load and the constraint settings on the dynamic stability of single-layer reticulated domes subjected to blast loading in different fire stages were analyzed. The results show that fires have a great influence on the dynamic stability of the reticulated domes under the impact of explosion, When the maximum temperature of the reticulated dome rods rises to more than 500℃, the anti-explosion ability of the dome greatly decreases. The rise-span ratio, the roof load and the restraint settings have different effects on the anti-blast ability of the reticulated domes in different fire stages.

Abstract:Based on three-dimensional large deformation finite element method utilizing coupled Eulerian-Lagrangian algorithm, the penetration responses of square spudcan in strong over soft clays were numerically simulated. The effects on the penetration resistance curve were studied of the strength ratio of the bottom clay layer to the top clay layer, the relative thickness of the top layer, the unit weight of soil, and the coefficient of earth pressure at rest. The soil deformation mechanism of punch-through failure during penetration was investigated. The results show that the strength ratio of the bottom clay layer to the top clay layer and the relative thickness of the top layer significantly affects the penetration resistance of square spudcan footings. The peak bearing capacity factor of square spudcan decreases somewhat with the decrease of the coefficient of earth pressure at rest. The penetration resistance curve does not obey the available equation proposed by other authors due to the possible difference of unit weight of the top layer and the bottom layer. The square spudcan footings experience punch-through failure when the proposed dimensional parameter in terms of footing width, the unit weight and undrained strength of upper soil is less than a critical value in the condition that the thickness of upper clay layer is defined and the difference of unit weight of the layers is not appreciable.

Abstract:A new hyperbolic p-y curve was derived to generally simulate then onlinearity of piles in layered soils, and the new p-y curve was presented containing parameters such as the initial ratio of elastic foundation coefficient, the initial elastic foundation coefficient,characteristic value of lateral displacementfor soils, and etc.. Model test of six timber piles and two steel piles in two groups settled in layer soils with upper clay and lower sand were done. The calculated lateral displacements of model piles both at the top and at the ground are consistent with the test values by p-y curve method, and the new hyperbolic p-y curve is verified. While the characteristic value of lateral displacement for layered soils increases, the displacement and the maximum bending moment of the pile decrease, the maximum shear and the maximum soil pressure around the pile increase. The variety of characteristic value of lateral displacement for the lower sand has extremely small effect on mechanical property of the pile, then the characteristic value of lateral displacement for lower soils can be defined as the same as that of the top soil during engineering application.

Abstract:In order to investigate the influence factors of normal bonding properties between mortar and mechanical pressing raw-soil brick, the tensile bond strength test was made between mortar and mechanical pressing raw-soil brick with different interfacial condition.There were 72 specimens in total and three ages including 7d, 14d and 28d.The failure mode and the change rules of normal adhesive strength in different ages between raw-soil brick and mortar were explored. The influence of interfacial condition and ages on normal adhesive strength and failure mode was studied. The results show that interfacial condition and ages both have an influence on normal adhesive strength, which is improved along with ages and is decreased because of roughing. The normal bonding properties between mortar and mechanical pressing raw-soil brick is impacted by the type of mortar evidently. The reference for engineering application of raw soil mechanism brick is provided by the research results.

Abstract:The preparation technology of reactive powder concrete (RPC) and slurry infiltrated fiber concrete (SIFCON)were adopted respectively, according to the multi scale structure characteristic of cementitious composites, the preparation technology of the ultra-high-toughness cementitious composite(UHTCC) reinforced by calcium carbonate whisker and micro steel fiber were studied, and the compressive strength, flexural strength, bending strength and mechanical properties uniaxial tension of different mixture proportions were tested. The ratio of flexural-compressive strength, toughness index and other more index were used to evaluate the toughness of the UHTCC. The experimental results indicate that the compressive strength, flexural strength, bending strength, ductility and toughness of UHTCC are much higher than those of general steel fiber concrete. The bending strength of UHTCC and the toughness index I₂₀ are up to 65.1MPa and 49.21 respectively. False strain-hardening behavior of UHTCC are achieved under uniaxial tension. The ultimate tensile strain of UHTCC can reach 4%~8%. Compared to RPC technology, higher toughness are obtained using SIFCON technology.

Abstract:There are humidity problems in rural residence in hot and humid areas and condensation occurred on the ground, which affects indoor living quality and health of residents. The basic way to control the ground condensation is to improve the ground temperature, and to determine the thermal performance of the ground. In this paper, thermal and moisture parameters as well as ground temperature of rural residence in Chongqing were measured and the rural residence model was established for simulating damp proof function of overhead ground and insulation ground. The results show that the effect of overhead ground on the damp proof is significant. It could reduce the time of condensation on the ground by more than 90%. Based on the fact that the effect of overhead ground on damp proof is widely accepted,it is proposed that the low thermal resistance of insulation ground for damp proof is 0.5 m²·K/W.

Abstract:This study was conducted based on one year field measurement of indoor and outdoor environment parameters in a typical traditional dwelling of Huizhou in China. The indoor comfort was evaluated based on the measured multi-environment parameters. According to the analysis, the characteristic of cold winter and cool summer in Huizhou traditional dwellings is demonstrated by the measured data. It shows that the dwelling has a good indoor environment and thermal comfort in spring and autumn. The indoor thermal comfort is also good during summer due to good natural ventilation and sun shading, etc. While the indoor thermal comfort is not fully satisfactory during winter due to the poor air tightness. In addition, acoustic environment is complying with relevant standards for all the rooms. However, the visual environment can't reach the standards of modern architecture design lighting in the most of time.

Abstract:Architectural external shading is an important measure for building energy saving, but single and improper shading may hinder the heat insulation, lighting, ventilation and vision of the room, and reduce the comfort of indoor environment. With the aim of comprehensive energy saving, this paper put forward the optimal design method of architectural external shading. Taking Chongqing as an example, based on the analysis of climate characteristics, the exterior shading forms of south and west orientation with good comprehensive performance were studied. Simulating the general office space to build an experimental platform of composite external shading, its insulation, shading, lighting and ventilation effects were tested and inspected. The results show that the optimized external shading devices have good lighting, ventilation and vision effects as well as obvious cooling effect.

Abstract:In terms of the common green buildings techniques obtained from statistics and climate features of hot-summer and cold-winter zone in China, a case study has been done. The effects of techniques, such as the enhancement of the performance of building envelope, energy comprehensive utilization, have been analyzed. The results show that the energy-saving benefit from total heat recovery of exhaust air which reaches 35% is the biggest in those common green buildings techniques; the utilization of fresh air in interim can save 10% energy; it could save as much as 7% energy by the means of setting adjustable exterior shading or improving the thermal performance of building envelop; the energy-saving rate of light control is 12.3%, etc. The study indicates that the energy efficiency of green buildings techniques interact with each other. Therefore, a comprehensive consideration of an energy conservation scheme of green buildings must be taken. The results show comparing with the requirements of current energy-saving standards, the whole energy efficiency of green buildings can achieve 46.9%, which can save energy by 75% compared with the reference building in the current energy-saving standards.

Abstract:The study of human body's radiation heat loss and thermal comfort need to calculate the angle factor between the human body and the envelope surfaces. Firstly, the paper derived the mathematical equation to revise the result of numerical calculation of angle factor based on the discrete formula of the angle factor and the effective radiation area, and established the standard three-dimensional body model of Chinese human in sitting posture. Then, the paper calculated the angle factor between the human body and roof, wall, floor, respectively, and found that the angle factor between the human body and the front surface is greater than the rear surface. Compared numerical calculation of angle factor with semi-analytical calculation, it is found that there are good agreements between semi-analytical calculation and numerical calculation for the roof and vertical wall, but there is a larger error for the floor, and the paper has modified these errors.

Abstract:The heat transfer efficiency of air-cooled heat pump system would decrease in high outdoor temperature. Evaporative condenser gradually get wide attention due to its contribution to solve the problem. In order to study the energy consumption of heat pump with evaporative condenser, it was made a comparative study about compressor power consumption of evaporative condenser and air cooling condenser under the same conditions by orthogonal experiment and analyzed factors of efficiency. The results show that the influence of factors on power consumption and energy efficiency of compressor are as follows:inlet air temperature of condenser water volume, air velocity. Compressor power consumption increases with the increase of inlet air temperature and the decrease of air velocity. The compressor energy consumption decreases at first and then is constant with the increase of water volume.

Abstract:Aerogel glazing units (AGUs) with the high translucent insulation performance could reduce effectively energy saving in buildings. In this paper, eight kinds of AGUs were prepared and the effect on translucent and insulation performance of AGUs with different particle size and filling thicknesses was investigated. Experiments results indicate that visible light transmittance and solar radiation transmittance of AGUs increase obviously when particle size increases from 0.41mm to 0.93mm, while that change little when particle size continues to increase from 0.93mm. The heat transfer coefficient decreases about 15% when the particle size reduces from 2.7mm to 0.41mm. The increace of the thickness of aerogel effectively decrease visible light transmittance, solar radiation transmittance and heat transfer coefficient, the heat transfer coefficient of AGUs can decrease 51.43% compared with conventional double galzing at the same size. Finally, heat insulation experiments of testing insulation temperature difference of AGUs and conventional double glass were conducted, and the results reveal the temperature difference of AGUs before and after heating raise 5.4~10.2℃. Therefore,conclusion of this study give a clue to the application of this new heat insulating materials on energy saving in buildings.

Abstract:In order to improve thermal insulation property of building envelope and make the most of solar energy, a photo-thermal Trombe wall system integrated with building was presented. Experimental wall and simulation model were established, thus heat transfer performance of the wall system was tested by experiment and analyzed by simulation. It is found that the thermal insulation property of Trombe wall performs well in winter. The measured maximum temperatures of the collector, the outside and the inside of the main layer are 91.3℃, 57.9℃ and 23.4℃, while the simulated figures are 88.4℃, 58.3℃ and 17.2℃ respectively. Influenced by solar radiation, there exist vertical temperature differences on every material layers of the wall system. The measured vertical temperature differences of the collector, the outside and the inside of the main layer are 17.9℃, 31.7℃ and 2.2℃, while the simulated figures are 17.2℃, 21.9℃ and 1.2℃ respectively. The vertical temperature difference of each material layer of the wall system increases with the increase of solar radiation and decreases with the increase of air interlayer thickness.