The suitable repair forecasting is needed for proper maintenance of the buildings. The appropriate maintenance planning should be based on the prognostic analysis of the repair needs. However, in Poland, maintenance p...The suitable repair forecasting is needed for proper maintenance of the buildings. The appropriate maintenance planning should be based on the prognostic analysis of the repair needs. However, in Poland, maintenance planning is currently not seen as a long-term system. Repairs are understood as extemporary work and are carried out exclusively on the basis of intermittent inspections and controls. One of the numerous factors determining maintenance planning is exploitation reliability conditioned by durability. This article presents a proposal to determine the prediction of operational reliability of the building constructed using traditional technology. The method of behaving and changing the reliability of the building throughout its use will be useful in planning renovations. The presented analysis includes apartment buildings erected in a traditional technology and regards them as technical objects. For such approached buildings, it is proposed to apply rules applied for mechanical and electrical objects. The probability of the exploitation of a building without any breakdowns in a given period of time is defined as exploitation reliability.展开更多
All technical objects are at risk of damages during the consecutive years of their usage. Reliability of an object is an essential issue during its usage. The main problem is the strive to eliminate damage formation. ...All technical objects are at risk of damages during the consecutive years of their usage. Reliability of an object is an essential issue during its usage. The main problem is the strive to eliminate damage formation. Predicting the reliability of an object should allow qualitative and quantitative analysis of the possibility of occurrence of unfavorable events. The adaptation of mathematical models describing the degradation processes in mechanical and electronic devices creates opportunities to develop diagnostic standards for buildings erected in traditional technology. The article presents the methodology of prediction of reliability of a building, and the values of performance features are defined by the parameters of the Weibull distribution function.展开更多
The paper gives an example showing that the utilization of prescriptive rules in some situations can lead to strong underestimation of the real risks and inadequate fire safety assessment of buildings.The issue seems ...The paper gives an example showing that the utilization of prescriptive rules in some situations can lead to strong underestimation of the real risks and inadequate fire safety assessment of buildings.The issue seems to be very important as the prescriptive rules in many European countries are the only allowed and acceptable by the authority’s method of building fire safety assessment.The building presented in this paper is an exemplary bakery plant consisting of several premises of a different purpose and method of use,e.g.:technical facilities,production depot,distribution and storage spaces,long-term storage cool rooms,etc.The whole building that consists of single-story technological(production and storage)part and(located on two stories)office parts was approved as a singular fire zone with a total usable area of 6280 m2.The technological area includes production facilities,storage depots of raw materials,packages and finished products,as well as cold stores and a number of auxiliary function rooms.In the second(having two stories)part of the building some social rooms,administrative areas and offices are localized.The total height of the building(at the highest point)does not exceed 10.5 m.Due to the Polish regulations the parameters determining the fire-related requirements of individual structural elements of the building(especially in terms of their fire resistance)are the surface area,the average value of the fire-load density and the presence of the risk of possible explosion.The building was designed based on the assumption that the average fire-load density does not exceed the level of 1000 MJ/m2.The analysis and calculations carried out during the exploitation phase of the building confirmed the compatibility with the assumptions adopted,but the actual volume,estimated at the level of 974 MJ/m2 proved to be very close to the limit value.Exceeding of the limit value of 1000 MJ/m2-due to provisions given in a state regulations-would automatically double the formal requirements for the resistance of the structural elements from R30 to R60.When assessing the real risk,especially in case of the large-surface-area buildings with varying ways of use of the premises,the average values of fire-load density may not properly reflect the real threat of fire.This is confirmed in the present facility,where in approximately 47%of the total area of the building the fire-load density doesn’t exceed 100 MJ/m2.Surfaces for which the fire load density exceeds 4000 MJ/m2(in extreme cases,it’s 5644 MJ/m2)represent only about 11%of the total area.It is worth mentioning that the fire-load density exceeding 4000 MJ/m2 due to the national regulations and codes of design would increase the criterion of structural resistance to R240.A completely separate issue is the fact that the oldest part of the building was completed in violation of some basic technical and construction requirements,so that the structure of this part of the building currently does not meet any criteria for fire resistance.This prompted the owner to implement some solutions that will not only lead the property to become fully consistent with the state regulations but also raise the level of security over the required standards,especially in the areas particularly vulnerable to fire.Presented case study shows that the adopted method of determining the requirements for fire resistance,especially based on the average value of fire-load density,in selected cases can lead to significant underestimations and result in incorrect assessment of a building fire safety.展开更多
Person-borne improvised explosive devices(PBIEDs)are often used in terrorist attacks in Western countries.This study aims to predict the trajectories of PBIED fragments and the subsequent safety risks for people expos...Person-borne improvised explosive devices(PBIEDs)are often used in terrorist attacks in Western countries.This study aims to predict the trajectories of PBIED fragments and the subsequent safety risks for people exposed to this hazard.An explosive field test with a typical PBIED composed of a plastic explosive charge and steel nut enhancements was performed to record initial fragment behaviour,including positions,velocity,and trajectory angles.These data were used to predict the full trajectory of PBIED fragments using a probabilistic analysis.In the probabilistic analyses a probability of fatality or serious injury was computed.Based on the results presented,many practical conclusions can be drawn,for instance,regarding safe evacuation distances if a person were exposed to a suspected PBIED.展开更多
In theory of concrete it is assumed that concrete composites are isotropic on a macro scale. For example, it is assumed that a floor slab’s or a beam’s strength is identical in all directions and its nonhomogeneity ...In theory of concrete it is assumed that concrete composites are isotropic on a macro scale. For example, it is assumed that a floor slab’s or a beam’s strength is identical in all directions and its nonhomogeneity is random. Hence neither calculations of the load-bearing capacity of structural components nor the techniques of investigating concrete in structure in situ take into account to a sufficient degree the fact that the assumption about concrete isotropy is overly optimistic. The present research shows that variation in concrete strength along the direction of concreting has not only a qualitative effect (as is commonly believed), but also a significant quantitative effect. This indicates that concrete is a composite which has not been fully understood yet. The paper presents evaluations of ordinary concrete (OC) homogeneity along component thickness along the direction of concreting. The ultrasonic method and modified exponential heads with a point contact with concrete were used in the investigations [1-3].展开更多
Macroscopic modeling of soils is based on a number of properties that refer to the mesoscopic morphology.The most fundamental parameters of this art are:1)coupling parameters between partial stresses of components and...Macroscopic modeling of soils is based on a number of properties that refer to the mesoscopic morphology.The most fundamental parameters of this art are:1)coupling parameters between partial stresses of components and deformations of components,2)porosities,3)saturation,and 4)permeability and diffusivity,tortuosity.The main aim of this paper is to present in juxtaposition continuous one-,two-,and three-component models of geomaterials appearing in construction of embankment dams.In particular,the above mentioned features,especially saturation with water and seepage problems,modeling of fluidization yielding piping,and generalizations of the Darcy law and changes of porosity,are presented.展开更多
With the rapid development of residential real estate market, risk evaluation has been an important task in the process of project. This paper describes a risk evaluation method for residential real estate projects ba...With the rapid development of residential real estate market, risk evaluation has been an important task in the process of project. This paper describes a risk evaluation method for residential real estate projects based on fuzzy set theory which uses linguistic variables and respective fuzzy numbers to evaluate the factors. The primary weights of factors and evaluation of alternatives are determined by applying linguistic variables and fuzzy numbers. The notion of Shapley value is used to determine the global value of each factor in accomplishing the overall objective of the risk evaluation process, so the primary weights are revised, thus the importance of factors can be reflected more precisely. A major advantage of the method is that it allows experts and engineers to express their opinions on project risk evaluation in linguistic variables rather than crisp values. An illustration is presented to demonstrate the application of the method in risk evaluation. The results are consistent with the results calculated by conventional risk evaluation method. The research demonstrates that the method is objective and accurate, and is of an application value in the risk evaluation for residential real estate project.展开更多
文摘The suitable repair forecasting is needed for proper maintenance of the buildings. The appropriate maintenance planning should be based on the prognostic analysis of the repair needs. However, in Poland, maintenance planning is currently not seen as a long-term system. Repairs are understood as extemporary work and are carried out exclusively on the basis of intermittent inspections and controls. One of the numerous factors determining maintenance planning is exploitation reliability conditioned by durability. This article presents a proposal to determine the prediction of operational reliability of the building constructed using traditional technology. The method of behaving and changing the reliability of the building throughout its use will be useful in planning renovations. The presented analysis includes apartment buildings erected in a traditional technology and regards them as technical objects. For such approached buildings, it is proposed to apply rules applied for mechanical and electrical objects. The probability of the exploitation of a building without any breakdowns in a given period of time is defined as exploitation reliability.
文摘All technical objects are at risk of damages during the consecutive years of their usage. Reliability of an object is an essential issue during its usage. The main problem is the strive to eliminate damage formation. Predicting the reliability of an object should allow qualitative and quantitative analysis of the possibility of occurrence of unfavorable events. The adaptation of mathematical models describing the degradation processes in mechanical and electronic devices creates opportunities to develop diagnostic standards for buildings erected in traditional technology. The article presents the methodology of prediction of reliability of a building, and the values of performance features are defined by the parameters of the Weibull distribution function.
文摘The paper gives an example showing that the utilization of prescriptive rules in some situations can lead to strong underestimation of the real risks and inadequate fire safety assessment of buildings.The issue seems to be very important as the prescriptive rules in many European countries are the only allowed and acceptable by the authority’s method of building fire safety assessment.The building presented in this paper is an exemplary bakery plant consisting of several premises of a different purpose and method of use,e.g.:technical facilities,production depot,distribution and storage spaces,long-term storage cool rooms,etc.The whole building that consists of single-story technological(production and storage)part and(located on two stories)office parts was approved as a singular fire zone with a total usable area of 6280 m2.The technological area includes production facilities,storage depots of raw materials,packages and finished products,as well as cold stores and a number of auxiliary function rooms.In the second(having two stories)part of the building some social rooms,administrative areas and offices are localized.The total height of the building(at the highest point)does not exceed 10.5 m.Due to the Polish regulations the parameters determining the fire-related requirements of individual structural elements of the building(especially in terms of their fire resistance)are the surface area,the average value of the fire-load density and the presence of the risk of possible explosion.The building was designed based on the assumption that the average fire-load density does not exceed the level of 1000 MJ/m2.The analysis and calculations carried out during the exploitation phase of the building confirmed the compatibility with the assumptions adopted,but the actual volume,estimated at the level of 974 MJ/m2 proved to be very close to the limit value.Exceeding of the limit value of 1000 MJ/m2-due to provisions given in a state regulations-would automatically double the formal requirements for the resistance of the structural elements from R30 to R60.When assessing the real risk,especially in case of the large-surface-area buildings with varying ways of use of the premises,the average values of fire-load density may not properly reflect the real threat of fire.This is confirmed in the present facility,where in approximately 47%of the total area of the building the fire-load density doesn’t exceed 100 MJ/m2.Surfaces for which the fire load density exceeds 4000 MJ/m2(in extreme cases,it’s 5644 MJ/m2)represent only about 11%of the total area.It is worth mentioning that the fire-load density exceeding 4000 MJ/m2 due to the national regulations and codes of design would increase the criterion of structural resistance to R240.A completely separate issue is the fact that the oldest part of the building was completed in violation of some basic technical and construction requirements,so that the structure of this part of the building currently does not meet any criteria for fire resistance.This prompted the owner to implement some solutions that will not only lead the property to become fully consistent with the state regulations but also raise the level of security over the required standards,especially in the areas particularly vulnerable to fire.Presented case study shows that the adopted method of determining the requirements for fire resistance,especially based on the average value of fire-load density,in selected cases can lead to significant underestimations and result in incorrect assessment of a building fire safety.
基金This work was supported by the Poland National Center for Research and Development,under the grant DOB-BIO10/01/02/2019 within the Defence and Security Programme.
文摘Person-borne improvised explosive devices(PBIEDs)are often used in terrorist attacks in Western countries.This study aims to predict the trajectories of PBIED fragments and the subsequent safety risks for people exposed to this hazard.An explosive field test with a typical PBIED composed of a plastic explosive charge and steel nut enhancements was performed to record initial fragment behaviour,including positions,velocity,and trajectory angles.These data were used to predict the full trajectory of PBIED fragments using a probabilistic analysis.In the probabilistic analyses a probability of fatality or serious injury was computed.Based on the results presented,many practical conclusions can be drawn,for instance,regarding safe evacuation distances if a person were exposed to a suspected PBIED.
文摘In theory of concrete it is assumed that concrete composites are isotropic on a macro scale. For example, it is assumed that a floor slab’s or a beam’s strength is identical in all directions and its nonhomogeneity is random. Hence neither calculations of the load-bearing capacity of structural components nor the techniques of investigating concrete in structure in situ take into account to a sufficient degree the fact that the assumption about concrete isotropy is overly optimistic. The present research shows that variation in concrete strength along the direction of concreting has not only a qualitative effect (as is commonly believed), but also a significant quantitative effect. This indicates that concrete is a composite which has not been fully understood yet. The paper presents evaluations of ordinary concrete (OC) homogeneity along component thickness along the direction of concreting. The ultrasonic method and modified exponential heads with a point contact with concrete were used in the investigations [1-3].
文摘Macroscopic modeling of soils is based on a number of properties that refer to the mesoscopic morphology.The most fundamental parameters of this art are:1)coupling parameters between partial stresses of components and deformations of components,2)porosities,3)saturation,and 4)permeability and diffusivity,tortuosity.The main aim of this paper is to present in juxtaposition continuous one-,two-,and three-component models of geomaterials appearing in construction of embankment dams.In particular,the above mentioned features,especially saturation with water and seepage problems,modeling of fluidization yielding piping,and generalizations of the Darcy law and changes of porosity,are presented.
基金the Ministry of Construction of China (No. 06-K9-22)
文摘With the rapid development of residential real estate market, risk evaluation has been an important task in the process of project. This paper describes a risk evaluation method for residential real estate projects based on fuzzy set theory which uses linguistic variables and respective fuzzy numbers to evaluate the factors. The primary weights of factors and evaluation of alternatives are determined by applying linguistic variables and fuzzy numbers. The notion of Shapley value is used to determine the global value of each factor in accomplishing the overall objective of the risk evaluation process, so the primary weights are revised, thus the importance of factors can be reflected more precisely. A major advantage of the method is that it allows experts and engineers to express their opinions on project risk evaluation in linguistic variables rather than crisp values. An illustration is presented to demonstrate the application of the method in risk evaluation. The results are consistent with the results calculated by conventional risk evaluation method. The research demonstrates that the method is objective and accurate, and is of an application value in the risk evaluation for residential real estate project.
