Advanced Materials Research Vols. 368-373

Abstract: Cement industry is blamed for contributing heavily to climate change, environmental deterioration and excessive energy consumption, to find alternative cements, which are environmentally friendly and low energy consumption, is scientist’s effort over last several decades and for next decades to come. Sulfoaluminate cement, invented by Chinese scientists in 1970s, is a very promising cement material as alternative to Portland cement because of its high early strength development, excellent durability, remarkable performance in aggressive exposure conditions, low energy consumption as well as low atmospheric releases. However, its expertise was not fully exercised in the past decades because it is relatively new cement material and people are short of experiences in using it. As people are facing severe challenges from environmental deterioration and energy crisis, sulfoaluminate cement sheds bright light on energy saving and greenhouse gas mitigation for the countries like China, producing massive cement each year for its superstructure and infrastructure construction. So, now is the time to turn to sulfoaluminate cement for help. This paper presents the development and application of sulfoaluminate cement in China, the properties and performances of sulfoaluminate cement, and difficulties and challenges facing us in using sulfoaluminate cement as well. Hopefully, more efforts will be exerted on its extensive application to engineering practices in foreseeable future.

Abstract: Nowadays, there are many systems can be used in multi-layer civil building, such as masonry-concrete structure, cast-in-situ concrete structure and assembled concrete structure. Each of them has its own features, and advantages in different aspects. In this paper, Vague set theory is used to comprehensively evaluate different types of multilayer civil structure system, and conclusion is made that the assembled concrete structure building performs more efficiently in both economic and social aspect, and could be popularized in our building industry.

Abstract: In order to study the mechanical behavior of the joint between concrete filled steel tubular column and beam with discontinuous column tube at the joint zone under axial pressure, the finite element analysis software ANSYS is adopted for parametric analysis and the analysis results are compared with experimental ones. The principal compressive stress is mainly transmitted by the inside area of the joint which is subjected to local compression if it is low, but extends to more outside areas of the joint if it is high. The radial compressive stress, which is the confined stress of the ring beam to the core concrete of the joint, keeps the same as that the width of the ring beam equal to the diameter of the core area of the joint. The vertical strain on the edge of the joint, which would lead to horizontal annular cracks in the side face of the ring beam, changes from tension in the whole height to tension only in the top part and compression in the lower part of the joint, which is consistent with the experimental phenomenon.

Abstract: In long-span cable-stay bridges, anchorage zone of cable-pylon is a key part to transfer cable force to pylon. Because of local concentrated force, irregular pylon section and complicated construction measures, a general mechanical analysis is unable to reflect actual stress distribution and working performance of anchorage zone. Based on Maling River Bridge in Guizhou province, China, clear finite element analysis and reliable full-scale model test for cable-pylon anchorage zone segment were carried out. Not only were design of model test and loading program introduced, but also test content and sensor arrangement were documented. In addition, details of finite element modeling were involved too, such as mesh generation, boundary condition and loading cases. Through comparison and analysis of stress increment and crack observation, the location where larger local tensile stress occurred was obtained. Corresponding anti-cracking load coefficient and safety coefficient of crack width were also presented. Parts of research findings have been used for the guidance of bridge construction.

Abstract: The sound insulation performance of Light steel structure wall directly affects the quality of housing and people’s feeling. A theoretical analysis of the wall of light steel structure residential sound insulation performance is done, and some solutions in poor lightweight wall sound insulation measures is proposed.

Abstract: The low-cycle repeated load tests were conducted for two composite frames, with reinforced concrete column and steel reinforced concrete column, respectively. The performance of the composite frames such as the failure modes, ductility, energy dissipation ability, deformation restored ability, and resistant capacity is analyzed. Experimental results show that good seismic performance can be obtained by appropriate constructional measure which can meet the seismic design requirements. Based on the analysis of test data, the reliability of the beam-to-column connections is validated, and the seismic performance of composite frames is found to be influenced mainly by vertical anti-lateral force component. Besides, the form of steel reinforced concrete column is recommended to improve the structural ductility.

Abstract: An investigation of the octagon-shaped concrete-filled double skin steel tubular columns which used PVC-U pipe to replace the steel tube as inner tube was carried out. In order to study the performances and mechanisms of the components when suffered axial load, ultimate axial bearing capacities of 9 components were tested. The cross-sectional size of the outer steel tube and inner PVC-U pipe and length of the specimen was concerned by the nominal steel ratio and the hollow ratio and slenderness ratio, respectively. The external steel tube and core concrete appeared three and four types of destruction phenomenons, respectively, but the inner PVC-U pipe did not destroy. Finally, experimental results and numerical analysis results were comparied.

Abstract: The nonlinear constitutive relations of clay are investigated with different initial stress conditions. Two series of triaxial compression tests are performed, respectively after consolidation and isotropic consolidation. On the basis of the framework of ~ model, a uniform nonlinear constitutive model is proposed by fitting of the test data. With the average slope of the unloading-reloading curve selected as the unloading modulus, the unloading function is constructed as the loading-unloading criterion. Moreover, a comparison of the experimental stress-strain curves with the predicted results by the constitutive model is made. It is shown that the model prediction is reasonable, which can reflect the stress-strain behavior of the soil under the consolidation and isotropic consolidation conditions.

Abstract: The purpose of this paper is to focus on analyzing its flexural capacity under concentrated force at the two points of a symmetrical load after the 21 old and new different degrees of damege to prestressed concrete hollow slab is strengthened with CFRP by the different paste modes and paste quantities.Meanwhile,according to the initial loading of prestressed concrete hollow slab specimens in which the plastic state, based on the elastic-plastic theory,it presents the theoretical calculation formula of the ultimate bearing capacity produced with the consideration of the secondary load of the prestressed concrete hollow slab strengthened with CFRP.Through the experimental value of the old and new specimens compared with the theoretical one, It provides design suggestions and reference for the prestressed concrete hollow slab strengthened with CFRP,and provides an experimental basis for the repairing and reinforcing practical application of the Wenchuan disaster area.

Abstract: Tianjin Tower is the tallest building in North China. It is an out-of-code super high-rise building. Considering the special structure and safety factors during the construction, this paper describes the monitoring of the construction. The problems on numerical simulation model, creep calculation model and steel plate sheer wall welding during the construction monitoring have been discussed and corresponding solutions are given. Through the comparison and studies on the results of field monitoring, the solutions in this paper have provided practical advice on performance evaluation of the structure of Tianjin Tower and construction methods of Tianjin Tower, and are of certain significance in the reference for the construction monitoring of super high-rise buildings alike.