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Liu L.,China Academy of Building Research | Wang J.,Center for Engineering Research Test and Appraisal | Han J.,China Academy of Building Research | Zhang G.,China Academy of Building Research | Wu X.,China Academy of Building Research
Jianzhu Jiegou Xuebao/Journal of Building Structures | Year: 2013

In order to study the strut-and-tie model's influence parameters including concrete strength, shear span-to-depth ratio and reinforcement ratio, etc, eight concrete deep beams were tested. The specimens experienced elastic, elasto-plastic, and damage stages. The diagonal cracks occurred between bearing and the loading point. Failure models were mainly shear and bending shear failure. The smaller reinforcement ratio specimen exhibited bending failure, and ductile characteristics. The research results show that with reinforcement ratio (less than 1.5%) increased and shear span-to-depth ratio reduced, the specimen failure becomes shear failure, and strut strength is improved obviously. If reinforcement ratio (horizontal and vertical reinforcement ratio) is less than 1.5%, maximum principal stress angle is similar to the arc tangent angle of shear span-to-depth ratio, and a maximum principal stress angle of 54-degree is suggested. Based on research results and considering the horizontal, vertical reinforcement ratio, concrete strength and shear-span ratios, suggested strut-and-tie model formulas of concrete deep beams was deduced. The calculation results are in good agreement with experimental data. Source


Han Q.,Tianjin University | Lu Y.,Tianjin University | Xu Y.,Tianjin University | Zhai C.,Tianjin University | Zhai C.,Center for Engineering Research Test and Appraisal
Tumu Gongcheng Xuebao/China Civil Engineering Journal | Year: 2015

User defined constitutive model of steel was adopted to analyze the collapse mechanism of spatial latticed steel arches considering the impact of member buckling by IDA (Incremental Dynamic Analysis) method. The weak positions and the collapse ultimate displacements of spatial latticed arch were identified. The results show that the 95% fractiles of the collapse ultimate vertical displacement ranges from 1/154 to 1/104 of the structural span under vertical ground motion records. The middle of main truss is most weak. And under horizontal ground motion records, the 95% fractiles of the collapse ultimate horizontal displacement ranges from 1/40 to 1/28 of the column height. In such case, the weak position is at the column of main truss. When considering member buckling, the webs at the one-quarter point of the main truss will buckle due to large slenderness ratio. The numerical results based on IDA method are agree well with those by shaking table tests, which can provide reference for the collapse-resistant design of spatial latticed steel arches. ©, 2015, Editorial Office of China Civil Engineering Journal. All right reserved. Source


Zhai C.M.,Center for Engineering Research Test and Appraisal | Xie Q.,Center for Engineering Research Test and Appraisal | Bai W.L.,Center for Engineering Research Test and Appraisal | Lu Y.,Tianjin University | Liu Y.,Center for Engineering Research Test and Appraisal
Electronic Journal of Geotechnical Engineering | Year: 2015

In order to investigate the temperature effect of thermal power tunnel in the city under long-term high temperature load , in this paper, a 2D finite element model of thermal power tunnel and surrounding soil was established using ANSYS. Thermal-structure coupling effect was incorporated in the finite element model. The influence of different factors such as the buried depth, the air temperature inside the tunnel and the soil properties on the temperature and thermal stress distribution in the thermal power tunnel and surrounding soil was compared. Effective data were provided to benefit engineers in reinforcement and reconstruction of lining structure of thermal tunnel. © 2015 ejge. Source


Zhai C.,Center for Engineering Research Test and Appraisal | Guo Y.,Center for Engineering Research Test and Appraisal | Lou Y.,CAS Institute of Electronics | Lu Y.,Tianjin University
Concrete Solutions - Proceedings of Concrete Solutions, 5th International Conference on Concrete Repair | Year: 2014

Structural fire design and fire prevention management face new challenges as more high-rise buildings are constructed. The evaluation of fire damage to such structures can help formulate efficient structural fire design and fire prevention management. The procedure for evaluating fire damage to concrete structures was discussed using a burnt high-rise building as an example. Such procedures included an emergency investigation of the fire site, an estimation of fire temperature, the initial division of floors and areas based on the visual damage they showed and the inspection of burnt structural members. The concrete structures were evaluated according to the degree of fire damage they received as well as their characteristics. Lastly, rehabilitation. measures for the concrete structures were proposed based on fire damage grades. © 2014 Taylor & Francis Group. Source


Zhai C.,Tianjin University | Zhai C.,Center for Engineering Research Test and Appraisal | Han Q.,Tianjin University | Lu Y.,Tianjin University | Jin R.,Zhejiang Construction Engineering Group Co.
Applied Mechanics and Materials | Year: 2012

According to inspection and assessment technology and method for the ground masonry structure, this paper presents the inspection method and results for an electric cable tunnel with masonry structure. The contents of the inspection include masonry bricks strength grading, masonry mortars strength grading, concrete strength for crest slab, reinforcement of crest slab and appearance of masonry structure. And the technologies for identification are introduced. Therefore, the key problems for safety inspection of electric cable tunnel with masonry structure are solved. The inspection items, process and identification technologies presented in this paper are effective and applicable for electric cable tunnel with masonry structure. © (2012) Trans Tech Publications, Switzerland. Source

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