METHOD OF EVALUATING REMAINING LIFE OF FERROCONCRETE SMOKE AND VENT INDUSTRIAL STACKS Russian patent published in 2009 - IPC E04H12/28 G01N3/00 

FIELD: building industry.

SUBSTANCE: invention refers to building industry, particularly to the process of evaluation industrial ferroconcrete smoke and vent stacks of technological condition. The method of evaluating remaining life of ferroconcrete smoke or vent industrial stacks consists in measuring in the process of stack assessment in its reference sections the values of parametres changing during stack operation and effecting the degree of its safe operation, in assessment on base of these measurements the values of criteria characterising the degree of safe operation of the stack, in comparison of calculated values of criteria with their limit values, and in successive evaluation of remaining life of the stack using obtained and limit values of criteria of number of stack operation years. During evaluation a sample of material of heat insulating layer is taken and grade of material of heat insulating layer is determined; on the base of the grade the following is determined: value of heat conductivity, and limit value of tensile stress for vertical reinforcement [R_s]; as variable during stack operation and effecting the degree of its safe operation the following parametres are measured: thickness of concrete δ_b and thickness of heat insulating layer δ_t, diametre δ_S of vertical reinforcement, ultimate stress [R_b] of concrete for compression and the value of stack slope; further for each year following the evaluation of stack operation using measured and project values of concrete thickness δ_bP, of heat insulating thickness δ_tP, of diametre δ_SP of vertical reinforcement and of ultimate stress [R_bP] of concrete for compression there are determined corresponding forecast values of concrete thickness δ_bV , of thickness of heat insulating layer δ_tV, of diametre δ_SV of vertical reinforcement and of ultimate stress [R_bV] as criteria characterising the degree of safe operation of the stack; with using forecast values of variable parametres and with consideration of measured slope of the stack and concrete heating, and including heat conductivity of the heat insulating layer there are assessed maximum values of stresses - compressing forces σ_bVΣ in concrete and tensile stresses σ_SV in vertical reinforcement; as ultimate value of parametres there is determined: for concrete - forecast ultimate stress of compression [R_bV], also values of criteria are determined for each year following the evaluation of stack operation, while remaining life is determined as minimal number of years following the evaluation of stack operation, for which values of criteria of safe operation are not less, than their corresponding ultimate values, respectively - σ_bVΣ<[R_bV] and σ_SV<[R_S].

EFFECT: evaluation of remaining life of industrial ferroconcrete smoke and vent stacks.

6 cl, 16 dwg