Papers by Author: Yuan Feng Wang

Abstract: The damping characteristic and dynamic responses of the concrete-filled square steel tubular (CFST) columns were numerically investigated in this paper. Finite element iteration method in the hysteretic damping system for CFST materials was presented, and an improved method considering viscous damping dynamic equilibrium equation with hysteretic damping model was also proposed. Based on the proposed methods, the loss factor and dynamic response of CFST columns subjected to the earthquake and harmonic loadings were effectively calculated. The results indicate that the stress-dependent damping method induces a larger dynamic response, and the loss factor of the CFST columns increases with the increase of the stress amplitude and lower steel ratio.

Abstract: Faced the reality of high energy consumption in China’s building sector, it is imperative to research and develop new technologies in China’s building sector vigorously. Undoubtedly, it is mature in building energy saving technology in China. Numbers of appropriate technologies have been developed and applied in China, especially in the utilization of renewable energy. Therefore, this paper summarized four main popular building energy saving technologies, i.e. energy saving technologies of building envelope, energy saving technologies of building services and equipment, utilization of renewable energy and building energy management.

Abstract: Based on concrete creep calculation model B3 and mechanical characteristics of concrete-filled steel tube (CFT) beam-column members of large eccentricity, a creep calculation model of CFT beam-column members of large eccentricity is constructed, which accords with mechanisms of concrete creep, and creep characteristics of concrete core of CFT beam-column members of large eccentricity have been taken into account. The model is verified against previous creep experiments for CFT beam-column specimens, by changing model B3 for ACI209, CEB90, GL2000 model, elastic continuation and plastic flow theory. The results show that introduction of model B3 to predicting creep of CFT beam-column members with a large eccentricity is necessary. Using the model, a study is then carried out on the effects of practical design parameters, such as concrete mix (e.g. water to cement ratio ( ), aggregate to cement ratio ( )), steel ratio and eccentricity ratio, on creep of CFT beam-column members with a large eccentricity.

Abstract: The effect of fly ash in improving the mechanical properties of concrete is investigated and the existing concrete strength development models are studied. Based on the chemic reactivity properties between fly ash and cement, an appropriate concrete strength model are chosen, and a new model for the fly ash strength factor combing Maturity method is built up and the factors are regressed by existing experimental datum. A total of 24 concretes, including two concretes were produced with two partial fly ash replacement ratios (23.7%, 32.7%). The cubic samples produced from ash fly concrete were demoulded after a day, and cured at standard temperature ( in GB/T 50081-2002) with 100% relative humidity until 28 days, then cured in water. The compressive strength tests were carried out on the cubic specimens at different ages. The compressive strength with time was evaluated by using the new predicted model. It was found that the calculated results by new method are fit the experimental data well.