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Qin S.,Chongqing University | Yang X.,Chongqing University | Lu J.,China Northwest Architecture Design and Research Institute Co. | Pi T.,Chongqing University
Brick and Block Masonry: Trends, Innovations and Challenges - Proceedings of the 16th International Brick and Block Masonry Conference, IBMAC 2016 | Year: 2016

In order to find out the deformability and properties of autoclaved aerated concrete block masonry and establish its full range stress-strain curve, an experimental research was carried out on 9-groups, 27 masonry specimens in all, of short columns under axial compression. This experiment is based on the standard test method, and use the additional jack to make up the insufficient rigidity of the compression-testing machine. The crack and failure mode, deformation behavior and the full range stressstrain curves were obtained. The research results showed that the failure process and behavior of the autoclaved aerated concrete block masonry were similar to other brick masonry, but the developing mode of fracture was different. The elastic modulus of the autoclaved aerated concrete masonry is larger than the value suggested in the Chinese technical code CECS289-2011 and the ACI530-13. According to the experimental results, a theoretical full range stress-strain curve was obtained by fitting method. The full range stress-strain curve is represented by 3-segments, the rising section is composed of a straight line and a curve, and the descending section is a single curve. This theoretic curve is closer to the measured curve. © 2016 Taylor & Francis Group, London.

Xu Z.-D.,Nanjing Southeast University | Gai P.-P.,Nanjing Southeast University | Zhao H.-Y.,China Northwest Architecture Design and Research Institute Co. | Huang X.-H.,Nanjing Southeast University | Lu L.-Y.,Nanjing Southeast University
Nonlinear Dynamics | Year: 2017

Multi-dimensional earthquake isolation and mitigation device (MEIMD) is a newly developed structural vibration control device. First, the horizontal and vertical property tests are performed to study the influences of excitation frequency and displacement amplitude on the dynamic properties of the MEIMD. In order to accurately describe the nonlinear characteristics of the device caused by the complex viscoelasticity, an integrated mathematical model based on fractional-derivative equivalent standard solid model is then proposed. Next, the horizontal and vertical shaking table tests on a 1/5-scale three-story steel frame structure equipped with and without the MEIMDs are presented, respectively. Finally, a dynamic response analysis method considering the nonlinearity of the MEIMD is proposed to analyze the dynamic responses of the controlled structure. The analysis results show that the MEIMD can provide excellent horizontal isolation ability, and good vertical isolation performance can be achieved through selecting reasonable pre-pressure value of the springs. The proposed mathematical model and dynamic response analysis method can effectively describe the nonlinearity of the MEIMDs and the structure with MEIMDs. © 2017 Springer Science+Business Media Dordrecht

Wu J.,Tsinghua University | Wang G.-Q.,Tsinghua University | Wang G.-Q.,China Northwest Architecture Design and Research Institute Co. | Cao Z.-P.,Tsinghua University | And 4 more authors.
Huanjing Kexue/Environmental Science | Year: 2014

A pilot-scale experiment about the process of “thermal pretreatment at 70℃/thermophilic anaerobic digestion” of waste activated sludge of high solid content (8%-9%) was conducted. The process employed thermal treatment of 3 days to accelerate the hydrolysis and thermophilic digestion to enhance anaerobic reaction. Thus it was good at organic removal and stabilization. When the solid retention time (SRT) was longer than 20 days, the VSS removal rate was greater than 42.22% and it was linearly correlated to the SRT of the aerobic digestion with the R2 of 0.9153. It was suggested that SRT of anaerobic digestion was 25 days in practice. VSS removal rate and biogas production rate of the pilot experiment were similar to those of the run-well traditional full-scale sludge anaerobic digestion plants (solid content 3%-5%) and the plant of high solid content using German technique.

Weibin K.,Xi'an Jiaotong University | Weibin K.,China Northwest Architecture Design and Research Institute Co. | Min Z.,Xi'an Jiaotong University | Min Z.,China Northwest Architecture Design and Research Institute Co. | And 4 more authors.
Energy Procedia | Year: 2015

In this paper, a radiant heating system is introduced, which was developed based on the model of capillary radiant terminal (CRT) combined with solar thermal energy usage and phase change thermal storage (PCTS) technology. The aim of this work is to investigate the feasibility and the stability of the system that could be applied into residential buildings in the actual construction. The indoor thermal environment based on the tested system is analyzed in this paper. According to the weather condition of Xi'an, the winter average solar insolation and the ambient temperature were 9.14 MJ/m2 and 8.9oC, respectively. The experimental results show that the average heating capacity of the designed system was about 1.08 kW for a typical sunny day in the winter. It was higher than the simulated heating load. As a result, the indoor air temperature reached 18oC, which sufficiently met the requirement of indoor thermal condition. It is also found that the indoor air temperature distributes uniformly and the maximum difference of the vertical temperatures was less than 3.2oC. This indicates that the indoor thermal comfort of the test room can be classified in the comfort level of A. © 2015 The Authors. Published by Elsevier Ltd.

Zhao M.,Xi'an Jiaotong University | Zhao M.,China Northwest Architecture Design and Research Institute Co. | Gu Z.L.,Xi'an Jiaotong University | Kang W.B.,Xi'an Jiaotong University | And 5 more authors.
Applied Energy | Year: 2016

Due to sustainable development, solar energy has drawn much attention and been widely applied in buildings. However, the application of solar energy is limited because of its instability, intermittency and low energy density in winter. In order to use low density and instable solar energy source for heating and improve the utilization efficiency of solar energy, a solar phase change thermal storage (SPCTS) heating system using a radiant-capillary-terminal (RCT) to effectively match the low temperature hot water, a phase change thermal storage (PCTS) to store and continuously utilize the solar energy, and an air source heat pump (ASHP) as an alternate energy, was proposed and set up in this research. Series of experiments were conducted to obtain the relation between the solar radiation utilization rate and the heating supply temperatures, and to evaluate the performance of the RCT module and the indoor thermal environment of the system for its practical application in a residential building in the north-western City of Xi'an, China. The results show that energy saving of the solar heating system can be significantly improved by reducing the supplied water temperature, and the supplied water temperature of the RCT would be no more than 35. °C. The capillary radiation heating can adopt a lower water temperature and create a good thermal comfort environment as well. These results may lead to the development of designing and distributing the solar energy for building heating during winter. © 2016 Elsevier Ltd.

Li J.,Xi'an University of Technology | Liu Z.,China Northwest Architecture Design and Research Institute Co. | Li Q.-N.,Xi'an University of Technology | Li X.-J.,Shaanxi Architectural Design and Research Institute Co.
World Information on Earthquake Engineering | Year: 2014

The seismic performance of two types'assembled monolithic short column encased by steel plate hoop and jointed by bolt or bolt bar was separately contrasted to that of ordinary reinforced concrete short columns and reinforced concrete short columns cast in situ and equipped with high strength spiral hoop. The results show that the seismic performance of two types'assembled monolithic short column is superior to that of ordinary reinforced concrete and equivalent to that of reinforced concrete short column with high strength spiral hoop; The two types of node structure connection are safe enough and can be used to practical engineering. In addition, the two types of connecting methods were compared each other and the results suggest that the short column jointed by bolt with low shear span ratio has a better seismic performance.

Wu J.,Xi'an University of Architecture and Technology | Bai G.-L.,Xi'an University of Architecture and Technology | Zhao H.-Y.,China Northwest Architecture Design and Research Institute Co. | Li X.,Xi'an University of Architecture and Technology
Construction and Building Materials | Year: 2015

Nowadays, energy dissipation of buildings has caused serious problems to the environment for leading to overuse of resources in China. To reduce energy consumption and protect the environment, shale that widely distributed in China and the waste, including both building waste and industrial waste are used as raw materials to manufacture fired hollow blocks with 29-row holes which ensure the insulation properties and reduction of weight. As samples, 365 mm × 248 mm × 249 mm rectangular fire hollow blocks with density of 850 kg/m3 were produced to study the mechanical and thermal properties of this wall material. The results satisfied the relevant Chinese Standard, and the block has a high compressive strength and reliable insulation performance comparing with fired common brick or other hollow blocks. Because of the excellent self-insulation characteristics, the blocks could be used directly as wall materials without requiring the usage of special insulation measures in masonry structures, which mean that this new-type material could reduce the cost of housing construction and had broad application prospect in masonry structures. Therefore, using this block could not only cut down the consumption of energy, but also could ease the pressure applied on the environment. © 2015 Elsevier Ltd. All rights reserved.

Xie Q.,Xi'an University of Architecture and Technology | Xie Q.,South China University of Technology | Li P.,Xi'an University of Architecture and Technology | Ge H.,China Northwest Architecture Design and Research Institute Co. | And 2 more authors.
World Information on Earthquake Engineering | Year: 2015

The modern architecture built in traditional style is a good carrier of innovation and inheritance of local traditional architecture culture and is unlike general modern structures because of the different structural methods. In order to investigate the seismic behavior of RC column-beam joint built in traditional style, 4 specimens with scale of 1:1.5 were tested under low-cyclic reversed loading. Some different conditions were taken into account to analyze their influence on the seismic behaviour, including the parameter of volume-strip ratio, the spacing of beam. The behaviors of joint models, such as the failure mechanism, bearing capacity, hysteresis characteristics, energy dissipation capacity and so on were analyzed. The results indicates that, 3 small core zones (upper, middle and lower core zone) appear in the RC column-beam joint built in traditional style, during loading. The initial cracking occurs in the lower core, afterwards in the upper and middle cores. And X-shaped shearing crack appears in all the three cores when the joint destroyed ultimately, especially the destruction in lower core. With the increasing of volumetric stirrup ratio, the ultimate bearing capacity of the joint improves, and the hysteretic curves become plumper. With enlargement of the space between upper and lower beam, the ultimate bearing capacity of the joint basically unchanged, and the hysteretic curves become less plumper. Compared with normal RC column-beam joint, the displacement ductility factor and the energy dissipation coefficient during limit stage of RC column-double beam joint built in traditional style are smaller, and the the ductility and energy dissipation are worse. © 2015, Science Press. All right reserved.

Dang Z.,Xi'an University of Architecture and Technology | Liang X.,Xi'an University of Architecture and Technology | Dang W.,Xi'an University of Architecture and Technology | Xin L.,China Northwest Architecture Design and Research Institute Co.
Jianzhu Jiegou Xuebao/Journal of Building Structures | Year: 2016

To study the seismic response of structure with the polyvinyl alcohol fiber-reinforced concrete (PVA-FRC) in the critical locations of members, the typical model of a ten-story frame-shear wall structure was created using the program Perform-3D. Structural nonlinear dynamic history response analysis was performed under rare earthquake with 2% probability of exceedance in 50 years, which was motivated under single-directional ground motions. The result shows that FRC can improve the seismic behavior of the model structure better as the increase of earthquake damage state. The response spectral acceleration at the fundamental period Sa(T1) is suited to be ground motion intensity measure. According to the proposed incremental dynamic analysis (IDA) method proposed by FEMA P695, the selected twenty-two pairs of ground motion records were normalized and scaled. The structural failure probability under different ground motion intensity levels is obtained based on the seismic fragility function, which is on the limit-state of collapse prevention (CP). The plastic hinge rotation of wall is proposed for use as structural response parameter of seismic fragility analysis on the limit-state of collapse prevention for the structural system of frame-shear wall. © 2016, Editorial Office of Journal of Building Structures. All right reserved.

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