Effect Of Fierce Wind Hazard On The Group Low-rise Residential Buildings In Coastal Rural Areas

Natural disasters are one of the most important global problems we have to face nowadays.Fierce wind disasters caused by storms,typhoons or hurricanes are the most frequent and in-fluential ones.China is a typical country suffering typhoon events quite often along its about 17,000 kilometers coastal line from the south to the east coastal area.In recent years,typhoons have made the economic losses increased significantly although the casualties decreased ob-viously.Wind disaster statistics show that wind-induced loss is mainly caused by the destruc-tion of low-rise residential buildings in vast rural areas,so it is quite common to see the regional damaged or collapsed low-rise buildings during and after fierce winds because of their poor wind resistance due to the regional structural types and environment.Compared with the re-search on high-rise wind-resistance,there are few research on wind resistance of low-rise res-idential buildings.It is of urgent practical significance to carry out the special research on the wind disaster loss in typical rural regions and to develop the loss assessment software.Based on the above background and current status,the study on the loss assessment of low-rise residen-tial buildings under the fierce winds mainly includes the following contents:(1)Taking the two-story brick-concrete structure building with gable roof commonly seen in the southeast coastal area as the research object,the overall wind-resistance ability under wind loads is analyzed by finite element simulation.The wind loads are obtained by the con-version of pulsating wind speed simulated by the Davenport power spectrum.The simulated wind speed duration is 5 min,and the reference wind speed is 35 m/s at the elevation of 10 m(12th wind scale).The finite element analysis results show that the maximum inter-layer dis-placement angle of the structure and the main tensile/compressive stress of each main load-bearing member are smaller than the failure limit,but both the envelope components of roof panels and door and windows have been damaged.Therefore,wind resistance research on low-rise residential buildings should focus on the envelope structure.(2)The failure characteristics of the low-rise residential building under the strong wind load are systematically analyzed and summarized.Taking the group low-rise buildings as the research object,the damage of different envelope components(roof tiles,roof panels,doors and windows)under wind loads is simulated by MATLAB based on random sampling method.Firstly,considering the change of building area density and wind direction,FLUENT is used to simulate the wind-induced interference effect between group buildings,and the wind pressure coefficient simulation results are applied to the calculation of surface wind load of low-rise residential buildings.Besides,based on the interaction between different envelope components and the physical properties of the components,the damage of the envelope components for group residential building under different wind directions,different wind speeds,and different building area densities are simulated.Finally,based on the simulation results,statistical anal-ysis is carried out to obtain the influence degree and influence law of the change of the building area density and the building position on the damage of the envelope structure.(3)The research on the construction loss assessment of rural buildings caused by strong winds in coastal areas is carried out.Combined with the damage characteristics of the enve-lope structure and the investigation report after the disaster,matrices of damage coefficients are established for the envelope structure and the main load-bearing structure respectively for the low-rise buildings.A fierce wind-induced construction loss model for villages and towns is proposed,which takes into account the influencing factors such as the structure type,the preservation degree,and the interaction between buildings group.According to the damage characteristics of the envelope structure and the wind damage model for group residential buildings,combined with the engineering practice,the damage intervals of each envelope component and the main load-bearing structure are divided,and different damage levels of the damaged buildings are defined.Finally,the wind damage vulnerability curves of low-rise residential buildings with different structural types and different preserved degrees are ob-tained.Compared with the current research,the loss assessment of the low-rise residential buildings after wind hazard in this paper can comprehensively reflect the impact characteris-tics of more factors,clear evaluation criteria,and wider application scope.(4)Based on the advantages of ArcGIS in geographic information data processing and image display,the VB.NET language is used for subsequent development of ArcGIS.A Ty-phoon Disaster Management System capable of realizing typhoon wind speed calculation,wind hazard induced loss prediction for rural buildings,and direct economic loss analysis of build-ings is established.At the same time,in order to verify the validity of the analysis model and analysis method proposed in this thesis,and to check the degree of conformity between the simulation results and the actual situation,a field investigation is conducted in Yunmei Village,Xiamen City,a typical typhoon-prone area.Then,the corresponding typhoon damage simula-tion and prediction are carried out after inputting the various types of building information into the system.The simulation results are in good agreement with the existing disaster investiga-tion reports,which verifies the feasibility and effectiveness of the system and the loss assess-ment method.