With the continuous expansion of the city scale,the number of high-rise buildings is growing rapidly.At the same time,the cases of casualties and property losses caused by the detachment accidents of the external wall surface from the high-rise buildings are common,which has brought huge safety risks to the urban space environment.In order to study the characteristics and rules of external wall surface detachment,more than one thousand domestic detachment cases of high-rise building external wall surface covering last 20 years were collected to analyze the basic patterns as well as the main influencing factors of different types of external wall surface,and the disease formation mechanism and detachment causes were also sorted out.Statistics shows that high-rise building external wall surface detachment can be affected by geographical location,construction time,using time and detachment season,among them,the finish coat and external thermal insulation composite systems(ETICS)in 5 to 10 years and 5 years respectively the highest proportion of detachment,curtain finish coat of the smallest and low dispersion,ETICS average detachment area is the largest and dispersion.In addition,on the basis of summarizing the existing prevention and control measures,other strategies and future key research directions were further discussed,so as to provide reference to avoid the occurrence of the high falling accident caused by the detachment of the external wall surface and ensure the safety operation and maintenance of high-rise buildings.
In order to study the failure situation of integral prefabricated fired partition board(fired wall board)under earthquake,seismic performance of full-scale reinforced concrete(RC)frame structure with fired wall board under the low cyclic loading test was carried out.The whole process of stress failure was observed,test data was analyzed,and the design advice was given.The research results show that the failure mode of fired wall boards is different from that of cement-based wall boards,which is mainly shown as crack extension,expansion and gathering,broken into pieces at the gathering place of cracks and dropped,so that steel wire mesh mortar surface layer should be used in high intensity area.The clamp should be set because it plays a role in preventing the wallboard and fragments from toppling out of the plane.
Because of the instantaneous and complex nature of explosion load,few scholars have studied the classification of near and far field explosions.In addition,reinforced concrete(RC)slabs have different failure modes during near and far field explosions.Therefore,the reliability of the numerical model was first verified based on the discussion of the failure modes of RC component under close-in,near and far field explosions.Subsequently,the limit values of explosion classification were proposed and verified by numerical simulation.Finally,the calculation formula of explosion peak overpressure was proposed through numerical fitting so as to predict the explosion peak overpressure under different conditions.
The heating energy consumptions of 53 rural residences in a village in Chifeng area were field tested.Based on the measured data of heating energy consumption,the house type characteristics of the typical rural residences,heating modes and heating energy consumption distribution characteristics in the area were mainly analyzed.The partial correlation analysis method was used to analyze the factors influencing the heating energy consumption of rural residences in the area.Furthermore,the relevant suggestions for clean heating solutions in the area were provided.The results show that there are various house types of the rural residences in Chifeng area,and the heating demand varies widely.Approximately the average indoor temperature of 57%of rural residences can reach 15℃,and the average annual heating energy consumption per household can reach 79.05 GJ.The most significant factor influencing the annual heating energy consumption is the number of heating rooms,indicating that the heating modes of rural residences and demands of rural households need to be fully considered when making clean heating schemes.
Steel structure buildings are widely used due to their high strength,light weight,low carbon,energy saving and reusability.The traditional steel structure beam-column connection joints are mostly welded or bolted welded,which are inconvenient to install and easy to leave safety hazards.A new type of fabricated joint with full bolt connection,safety and reliability was proposed.The finite element models of traditional and new fabricated joints were established,and stress,load-displacement curve and energy dissipation capacity of the two types of joints were compared and analyzed.The analysis results show that compared with traditional joints,the stress in the core area of the new fabricated joints is smaller,and the beam hinge mechanism can be realized.The hysteresis curve is full,the bearing capacity is increased by about 22.95%,and the ductility coefficient is increased by about 14.89%.The seismic performance of the new fabricated joints is better.
