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Partially encased concrete (PEC) has better mechanical properties as a structure where steel and concrete work together. Due to the increasing amount of construction waste, recycled aggregate concrete (RAC) is being considered by more people. However, although RAC has more points, the performance is inferior to natural aggregate concrete (NAC). To narrow or address this gap, lightweight, high-strength and corrosion-resistant CFRP can be used, also protecting the steel flange of the PEC structure. Therefore, carbon fiber reinforced polymer (CFRP) confined partially encased recycled coarse aggregate concrete columns were studied in this paper. With respect to different slenderness ratios, recycled coarse aggregate(RCA) replacement ratios, and number of CFRP layers, the performance of the proposed CFRP restrained columns are reported. The RCA replacement ratio is analyzed to be limited negative impact on the bearing capacity, generally within 6%. As for the slenderness ratio, the bearing capacity increased with it. However, wrapping CFRP significantly increased the bearing capacity. Considering the arch factor, a simple formula for calculating the ultimate strength of CFRP-confined partially encased RAC columns is developed based on EC4 and GB50017-2017. By comparison with the experimental values, the error is within 10%. [ABSTRACT FROM AUTHOR]

In order to study the performance of partially precast partially encased assembled composite beam (PPECB) in reducing costs and reducing carbon dioxide (CO2) emissions, this paper obtained the bearing capacity of PPECBs by a static test. Considering the load conditions and beam height conditions as constraints, the steel-concrete composite beam (SCCB) and reinforced concrete beam (RCB) were optimized and designed based on the principle of fully utilizing the advantages of steel and concrete. On the basis of investigating the quantity of different materials, the cost and CO2 emissions of the three different types of beams were analyzed. The cost and CO2 emission of the PPECB are the lowest, and SCCBs have the highest cost and CO2 emissions. This paper can provide reference for design choice and further research from the perspective of cost and CO2 emission and lay a solid foundation for the realization of economic and environment-friendly buildings. [ABSTRACT FROM AUTHOR]

In order to study the seismic behavior of steel frame-bent structures, the pseudo-dynamic test was carried out on a 1:10 model of the steel frame-bent structure selected from a large thermal power plant main building built in the zone with a seismic design intensity of 8 degree. The seismic responses such as acceleration, displacement, hysteretic property, stiffness and energy dissipation were analyzed. The results show that the steel frame-bent structure has good ductility and good plastic deformation capacity. The inter-story drift is relatively large on the bottom story and the second story, namely the weak stories. The maximum inter-story drift of the model structure under intensity of 8 degree frequent and rare earthquakes are all less than their limit values regulated by the present seismic code. The steel frame-bent structure can satisfy the demand of seismic design in intensity of 8 degree zones and has good seismic behavior. [ABSTRACT FROM AUTHOR]

Through the experimental study on the model of a three-bay and five-story steel frame-bent structures under low cycle reversed loading, the failure condition of frame-bent structures was observed. The load-displacement, hysteretic loops and skeleton curve of tested model were obtained. The failure mechanism, hysteretic behavior, ductility, energy dissipation capacity and stiffness degradation were investigated. The results show that the failure mechanism of steel frame-bent structures is the first occurrence of beam-hinge and then column-hinge mechanism. The hysteretic loops are plump. The average of the overall ductility factors is greater than 4. The equivalent viscous damping coefficient is 0.189. The steel frame-bent structure exhibits excellent seismic behavior, and can be adopted in high seismic fortification zones. The inter-story drift is relatively large on the bottom story and the second story, namely the weak stories. And there are large seismic forces at the coal hopper beams, which must be paid attention in design. [ABSTRACT FROM AUTHOR]

In order to study seismic behavior of steel frames with irregular joints, a 1: 10 scale pseudo-dynamic test was conducted based on a prototype of steel frame-bent structures for 1 000 MN large thermal power plant. The earthquake waves included El Centro wave, Taft wave and Lanzhou wave were inputted, and the maximum accelerations of these ground motions were respectively equivalent to minor earthquake of 8 intensity and 7.5, 8 seismic fortification intensity and rare earthquake of 8 and 9 intensity. The strain distribution and responses of acceleration and displacement were recorded. Experimental results show that the frame structure in rare earthquake of 9 degree intensity has not been destroyed. The hysteresis characteristics, amplification coefficient of acceleration and the displacement and energy dissipation time history curves show that steel frames with irregular joints have better ductility and seismic behavior generally. However, with huge stiffness and vertical loads, coal scuttle beam next to irregular joints has different rule of inter story displacement distribution between from the beam without irregularity. Plastic hinge at the end of the column below the girder occurs earlier because of obvious phenomenon of 'strong column-weak beam' in the area of the irregular joints, which is a disadvantage of energy dissipation and seismic resistance. [ABSTRACT FROM AUTHOR]