Li H.-Z.,Central Research Institute of Building and Construction |
Hu L.-M.,Tsinghua University |
Hu L.-M.,State Key Laboratory of Hydroscience and Engineering |
Xin H.-B.,Central Research Institute of Building and Construction
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2015
The groundwater pollution by organic contaminants is becoming more and more severe, making groundwater remediation be imperative. The researches on the remediation technology are of theoretical and practical importance. Based on the review of in-situ groundwater remediation technology for organic contaminants and micro-nano bubble MNBs technology, MNB technology is proposed for groundwater remediation. The scheme using MNB for in-situ groundwater remediation is introduced. The contaminants can be removed by biodegradation enhanced by MNB. The numerical simulation results of in-situ application show a great enhancement on dissolved oxygen and a significant influence zone for contaminant removal. The MNB technology is effective, energy-efficient and environment-friendly to clean up contaminants, which has great potential in groundwater remediation. ©, 2015, Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering. All right reserved.
Cao Q.-Y.,Central Research Institute of Building and Construction |
Sun W.,Nanjing Southeast University |
Hao T.-Y.,Central Research Institute of Building and Construction |
Su B.,Central Research Institute of Building and Construction
Beijing Gongye Daxue Xuebao/Journal of Beijing University of Technology | Year: 2013
Based on brittleness evaluating index of concrete, the normal concrete, fly ash concrete, lightweight aggregate concrete, fiber concrete and polymer-modified concrete were selected as sample, and the size effect on flexural strength by the method of the Bazan's size effect law was presented to show the brittleness degree of concrete. The Bazant's size effect law gave a very good fit to the flexural strength of concrete measured from beams of different sizes. As observed in the size effect curves, the fracture behavior of lightweight concrete seemed more brittle than that of the other HPC, and fiber concrete and polymer-modified concrete showed less brittle than normal concrete, moreover, fly ash was less benefit for brittle decreased. Linear elastic fracture mechanics may still be less applicable to concrete in the normal size range than nonlinear fracture mechanics.
Xin H.,Central Research Institute of Building and Construction |
Zhou X.,China Academy of Building Research
World Information on Earthquake Engineering | Year: 2011
Liquefaction of low plasticity fine soils is observed during past earthquakes. It shall bear in mind at investigating seismic safety of engineering site that evaluation of liquefaction potential is carried out of the fine soils and the effective measure of liquefaction mitigation is taken. Based on recent earthquake discovery and research developments, the liquefaction criteria are suggested of the fine-grained soils to Chinese code for seismic design of buildings.
Qin S.,Wuhan University |
Han D.,Central Research Institute of Building and Construction |
Xu J.,Wuhan University |
Liao H.,Wuhan University
Journal of Geomatics | Year: 2015
In order to improve the accuracy of foundation pit settlement prediction, the paper, according to the characteristics of foundation pit deformation, builds reverse accumulative gray model based on the GM(1, 1) model. Combined with characteristics of accumulative sequences in opposite-direction, the paper puts forward a kind of GOM (1, 1) model whose integral parameter, initial value and background value are optimized at the same time, to improve the prediction results. In the end, an application is given to demonstrate that the optimized GOM (1, 1) model can improve the prediction precision of the foundation pit deformation, which proves the practicability and effectiveness of the optimized model.
Xu J.,Wuhan University |
Long F.,Wuhan University |
Wang T.,Wuhan University |
Ma X.,Wuhan University |
Han D.,Central Research Institute of Building and Construction
Journal of Geomatics | Year: 2015
In this paper, based on the real-time, high speed, high accuracy, non-contact surveying characteristics of the terrestrial 3D laser scanning technology, the method and data processing of vibration by non-contact measurement to tower buildings using line scan mode of the 3D laser scanner are studied. Through experiments and analysis, the results show that this measurement method is not only able to synchronize the building site by non-contact measurement, but also can achieve satisfactory accuracy.
Zhou C.,Beijing Jiaotong University |
Zhou C.,Tongji University |
Bai X.,Beijing Jiaotong University |
Zhao F.,Central Research Institute of Building and Construction |
And 2 more authors.
Jianzhu Jiegou Xuebao/Journal of Building Structures | Year: 2013
To study the axial compressive performance of circular concrete short columns strengthened with lateral pre-stressed fiber reinforced polymer (FRP), 25 specimens were manufactured and tested under axial compression. The main factors considered in the experiment included concrete strength, cross section size, spacing of stirrup, initial damage and surface treatment of the specimens, pre-stressing level, type and layers of FRP. The failure mode and the stress-strain curve of each specimen were obtained from the experiment and the impact on confining effect of various factors was analyzed. Experimental results show that the strength and ductility of circular concrete columns strengthened with lateral pre-stressed FRP can be improved significantly relative to the un-strengthened specimen, the stress hysteresis of lateral FRP can be avoided by pre-stressing, and the high strength of FRP can be better used. When the pre-stressing of lateral FRP within 0~0.20 times of its ultimate tensile strength, the strength and ductility of specimens increase with the increase of lateral FRP's pre-stressing. The strengthening effect will be reduced when the pre-stressing of lateral FRP reacheds 0.25 times of its ultimate tensile strength. So the pre-stressing of lateral FRP should be controlled within 0~0.20 times of its ultimate tensile strength in practice.
Ai X.Q.,Tongji University |
Li J.,Tongji University |
Chen J.,Tongji University |
Meng H.,Central Research Institute of Building and Construction
International Efforts in Lifeline Earthquake Engineering - Proceedings of the 6th China-Japan-US Trilateral Symposium on Lifeline Earthquake Engineering | Year: 2014
Shaking table tests of the underground cement pipe with connection joints under non-uniform excitation is investigated in this paper. In order to simulate the non-uniform earthquake excitation, different seismic waves with spatial correlation are applied to two tables along the axis of the pipe. The experimental results of the pipe joints displacement are presented in the paper. The experimental study could provide useful data for further pipe-soil interaction mechanism research and numerical analysis.
Yang H.,Chongqing University |
Sun Y.,Chongqing University |
Zhang R.,Central Research Institute of Building and Construction |
Bai S.,Chongqing University
Tumu Gongcheng Xuebao/China Civil Engineering Journal | Year: 2014
Due to the damage mechanism of reinforced concrete moment-resisting frames that plastic hinges developed mainly at columns ends in 5 · 12 Wenchuan Earthquake, the strong column and weak beam measures are strengthened in 2010 Chinese seismic design code. The new values of MAFC, namely the moment amplification factor of column ends, are similar to the suggested values in former researches for the 1st and the 2nd anti-seismic grades. However, the values of MAFC for the 3rd anti-seismic grade of lower earthquake intensity region are insufficient. In this paper, five regular reinforced concrete plane frames located at II-type site with different earthquake intensity regions and different anti-seismic grades were designed according to Chinese code. The influence of several factors on strong column and weak beam measures was analyzed, such as the reinforcing bars in the site-casted slab, bottom longitudinal bars of beam, et al. Nonlinear analysis model is established with the principle of beam sidesway mechanism, which implies that stress of longitudinal bars of columns end sections is below yield stress under strong earthquake excitation with the exception of lower end section of the first floor. For every frame, 30 earthquake waves are selected, nonlinear dynamic responses under rare earthquake excitation are analyzed based on the OpenSees framework, and statistical analysis of the MAFC demand are carried out. The results show that MAFC of 1.3 for 7 intensity region 3rd anti-seismic grade in Chinese seismic design code is obviously small. The value should be increased and additional calculation principle of taking negative bending moment of beam ends with smaller absolute value to be zero at interior joints is suggested. The statistical values of the demand of MAFC for 8 intensity region 2nd anti-seismic grade and 9 intensity region 1st anti- seismic grade are a little bigger than the corresponding values in Chinese seismic design code. With respect to the demand of MAFC based on practical longitudinal bars of beam and nominal strength, the discreteness and the variety of statistical characteristic value along the height are comparatively small. The contribution of the reinforcing bar of slab is considered, so it is a relatively better expression of strong column and weak beam measures. For these cases, MAFC for the 1st and the 2nd anti-seismic grades in Chinese seismic design code needs to be increased.
Xin R.,Xi'an University of Architecture and Technology |
Xin R.,Central Research Institute of Building and Construction |
Yao J.,Xi'an University of Architecture and Technology
World Information on Earthquake Engineering | Year: 2013
According to the general laws of the earthquake damage phenomenon, three typical kinds of failure modes of multi-story masonry wall, i.e. window belly wall, window pier wall and mixed of the two and damage distribution were proposed. The characters of three different failure modes were analyzed and comparative study on seismic performance of structure with various failure modes was carried out. In respect to seismic behavior, the masonry structure with window belly wall is better than that with windew pier wall The shortcomings of the masonry structures design method expounded in current design codes of China were put forward which may provide a reference to the improvement and amendment of the current codes.
He Z.-Q.,Central Research Institute of Building and Construction |
He Z.-Q.,China Jingye Engineering Co.
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2010
This project is one of the largest scale foundation pits in the central city of Beijing, and its depth is 15 m and floor area is 33000 m2. Many unidentified underpasses and caves are densely distributed, many line pipes with the maximum depth of 9.0 m exist along with the major road just beside the west side of the pit, and three first-class national protection trees are standing just beside the top fringe of the pit. For the protection of rare trees, the design takes the wind load into consideration and the support system is made up of shoring piles and two rows of prestressed anchors, and necessary watering is arranged to satisfy their growth needs, this method ensures the safety of those valuable trees. For the support system at the west side is the soil nailing wall of 7.0 m at the upper and shoring piles together with one row of anchors at the lower part, anchors are located on the capping beams and their angles are adjusted to avoid the 9 m-depth pipeline. For other areas the anchored soil nailing wall is successfully fulfilled with special treatments for all the possible underpasses and caves which may cause water flush during the raining period. The above methods are of some significance for similar foundation pits involved with issues about protection of adjacent trees and intricate underground circumstances.