Use Of Building Research Articles

Vision-based digital shadowing to reveal hidden structural dynamics of a real supertall building

Vision-based digital shadowing is a highly efficient way to monitor the health of buildings in use. However, previous studies on digital shadowing have been limited to laboratory experiments. This paper proposes a novel computer-vision-based digital shadow workflow and presents its successful application in a real engineering case. In this case, a 345.8-m supertall building experienced unexpected shaking under normal meteorological conditions. This study established a digital shadow of the building using three-dimensional displacement measurements based on super-resolution monocular vision, revealing the hidden structural dynamics and inherent mechanical reasons for the abnormal shaking. The proposed digital shadowing workflow is a feasible roadmap for developing vision-based digital shadows of real-world structures using low-cost cameras. The abnormal vibration event in the supertall building considered in this study is the first of its type worldwide. The results of this study offer practical strategies and invaluable insights into the prevention and mitigation of this type of global risk, thereby contributing to the lifespan extension of buildings in use worldwide. Furthermore, with the increasing number of general sensing devices, such as surveillance cameras in cities, the proposed method may unleash the immense potential of general sensing devices in achieving the leap from structural health monitoring to city health monitoring.

Buildings’ façades as catalysts for urban regeneration: mitigating the “touristic bypass effect” in Finiq's Small Towns.

The municipality of Finiq, located in the Vlorë region, is an administrative division that encompasses multiple small towns and provides local government services such as public works, education, and health services. It is well known for its scenic landscapes and natural beauty, including forests, hills, and rivers which have the potential to drive economic growth through tourism. In addition, the proximity to Saranda and Greek regions could help to perceive tourism as a catalyst for economic regeneration. However, the lack of adequate infra- structure and appropriate services for both tourists and local communities does not facilitate this growth process in many villages of the municipality. Despite the various administrative and governmental efforts, orientated at aligning their intentions and actions with the goals of supranational European projects, they often require very long timelines to be realized. Furthermore, within the Feniq municipality, the most important cultural and archaeological attractions, often related to ancient times, are located in natural areas outside the existing urban center. This geographical location may cause a "bypass" effect where tourists do not visit the city center and negatively impact its economic growth. This phenomenon suggests that, on one hand, tourists will not be able to comprehend the authentic identity of local cultures, and on the other hand, small towns within the Finiq municipality may not realize optimal economic advantages from tourism. This process is also encouraged by the qualitative conditions of the towns, which are characterized by numerous buildings with a high degree of degradation and a constant presence of urban voids. Urban voids refer to abandoned or underutilized urban areas that do not meet the needs of local communities and represent a loss of economic, social, and environmental potential. These areas can be the result of factors such as economic recession, deindustrialization, or population migration to more prosperous areas. A key role in the regeneration of such areas does not only involve the design of adequate open urban spaces but also the redevelopment of buildings that face them and, in particular, their façades, which assume a public connotation in that context regardless of the building's use. The redevelopment of buildings’ façades that face these urban voids can play a crucial role in urban regeneration by increasing urban quality, identity, and tourist flows. These façades represent architectural backdrops that, if adequately redeveloped, contribute to triggering re- generative processes by increasing urban quality, and on the other hand, enhance the towns’ identity, strengthening, at the same time, the tourist flows. This contribution aims to investigate the role played by the façades in the urban regeneration process, showcasing international examples that emphasize it. The study explores how the implementation of successful international strategies in redeveloping existing facades on urban voids can help to overcome the challenges facing the Finiq municipality and drive eco- nomic growth through urban regeneration. The findings of this study will provide valuable insights into the role of buildings’ façades redevelopment that faces existing urban voids in promoting sustainable urban regeneration.

A Case Study of Nine Post-Hydrocarbon Ready Homes

A typical 2bed dwelling at Howgate Close, after 16months of occupation, has a daily average energy bill of 10pence/day/dwelling [1] It is proffered that Howgate Close may be the most energy efficient group of dwellings of its type, in the UK [2]. Howgate Close is a residential neighbourhood of nine single storey dwellings, operating free of fossil fuels, they are post-hydrocarbon ready. The development is located in Nottinghamshire, UK, and was completed in June 2022. All nine homes are a net annual generator of surplus renewable energy, with little to no heating demand. Six of the nine homes remain naturally heated, with no resort to the electric underfloor heating system. Exceptionally high levels of energy efficiency have been achieved with third-party verification, the As-Built SAP Rating of 143A [3] Such a rating places these homes in the top 0.01% of the 12million registered UK Energy Performance Certificate‘s (EPC) [4]. This paper provides a building Case Study that evidences performance standards making comparisons with the UK Building Regulation Compliance Standards [5] Howgate Close’s exceptional energy efficiency can be described as an aggregation of marginal gains [6] This paper is a prelude to more forensic analysis of Howgate’s in-use building performance, with the installation more advanced monitoring equipment in May 2024 for a period of two years. EWI Pro, Dr Harrall and Nottingham Trent University (NTU) are to undertake further data dissemination, providing a more forensic Howgate Case Study for ISEC 2025.

Multi-typology and multi-scale maps of the in-use building material stock in China

China's rapid urban expansion and population migration have led to a substantial increase in building material stocks (MS). Understanding these stocks is crucial for effective planning and managing the built environment. This study analyzed in-use building MS in China from 2000 to 2020 at different spatial scales and resolutions and employed typological data as a bridge addressing information gaps in non-residential buildings and the spatial scale discontinuity issue in MS analysis. At the macro scale, MS in China increased from 70 gigatons (Gt) in 2000 to 133 Gt in 2020. Non-residential and non-urban MS played substantial roles, constituting 41.8 % and 47.9 % in 2020, respectively. In highly urbanized regions, the proportion of residential building MS decreased due to the prevalence of more functional buildings. Some southern provinces had MS from rural areas even exceeding 50 %, emphasizing the importance of considering rural areas in construction resource management. At a high-resolution scale using GIS data, differences emerged between the analysis and statistical data. These differences, especially in estimating residential and commercial building MS, may be attributed to the mixed-use of building types in Chinese cities or unclear delineations of land use types. We advocate for further research to explore these variations, establishing consistent MS methods across different spatial scales and providing decision-makers with effective data support and analytical tools.

Experimental study of occupants' situational awareness during a fire by sounding of wireless, interconnected alarm smoke detectors at a small‐scale hostel that was originally a single‐family house

AbstractIn recent years, there has been an increasing demand for small‐scale hostels, such as vacation rentals, known as “minpaku” in Japanese, which were originally single‐family houses. To convert these buildings for use as accommodation facilities, improvements must be made to fire evacuation safety measures. An effective and reasonable measure for this improvement is the installation of wireless, interconnected alarm smoke detectors. We conducted experiments to examine how sleeping guests recognize these alarms when they are activated. Eleven participants experienced the alarm sounding while sleeping at night and while awake during the daytime at a wooden cottage. They were exposed to three different sounding patterns. In the sleeping experiment, 9 of 11 participants were woken up by alarms sounding in other rooms, while the remaining two were woken up by alarms in their own rooms. However, those two participants had difficulty understanding the meaning of the voice alarm clearly. The voice stated, “Other detector was activated,” indicating a fire in another room and urging evacuation, even though there was no smoke in their room. Comprehension of the alarm system is essential for guests to understand its intentions accurately and make proper decisions regarding evacuation.

An integrated assessment of the financial and environmental impacts of exterior building insulation application

In the literature, optimum thermal insulation thickness on building's exterior was examined by many researchers. Optimum insulation thickness was generally studied with the aim of minimizing the total cost, and suitable values were determined within this scope. In this study, it has also considered the amount of CO2 released into the atmosphere due to the fuels used in building heating and cooling processes, as well as insulation materials, in addition to the total cost. This study has been focused on optimization of the determination of the ideal insulation thickness of buildings by simultaneously minimizing the total cost and CO2 emission, using the knee point approach. In this context, a multi-objective optimization study has been conducted for thermal insulation applied to buildings located in different climatic zones considering the solar radiation. A comprehensive analysis has been carried out to determine the impact of the heating source type (natural gas, electricity, fuel oil), insulation material (expanded polystyrene, extruded polystyrene, mineral wool, polyurethane foam), climatic zone (I, II, III, IV) and the purpose of the building's use (summer house, winter house or all-season house) on the optimum insulation thickness. The degree-day approach has been used to calculate annual energy consumption, and accordingly the life-cycle cost (LCC) method has been used in economic analysis. The optimum insulation thicknesses have been calculated with two separate objectives: one to minimize only the total cost and the other to minimize only the CO2 emissions. It has been found that when the primary goal of insulation application is to minimize CO2 emissions, the calculated optimum insulation thicknesses are consistently higher compared to situations where the main goal is minimizing total cost. Furthermore, for various climatic zones and different purpose of the building's use, an ideal insulation thicknesses that simultaneously minimizes both the cost and CO2 emissions have been identified. In this research, the equations providing environmentally optimum insulation thicknesses to minimize CO2 emissions have been derived and presented to researchers. Finally, the conclusion is drawn that the knee point approach can be applied in insulation scenarios where two objective functions need simultaneous optimization.

Post occupancy evaluation of IEQ parameters in residential buildings

The post-occupancy evaluation (POE) is a performance assessment of buildings in use that can help property owners and managers better understand how well a facility is working, how its performance compares to similar structures or set benchmarks, and how a building might be improved. A solid grasp of how a building works can explicitly link its actual performance to either new or existing building innovations or remedial measures. While there is a lot of information on POE in commercial buildings, there's not much in the residential sector. In this mini project, it is focussed to assess the satisfaction levels of the occupants and to quantify the IEQ parameters in a residential building. Sample sizes are determined, based on which a detailed questionnaire survey is conducted for the research. The city of Kochi, is the primary location considered due to its vivid factors both geographically and climatically.The project focuses on to identify the resident satisfaction level , quantify the IEQ parameters in a residential building and to suggest remedies if required. The findings and the results are analysed based on different factors. The findings will be useful for the prioritisation of the performance criteria of the buildings.

Integrated post-occupancy evaluation and intervention that achieve real-world zero-carbon buildings

Many building standards are available worldwide to support sustainable building design. However, most of them only define compliance before occupancy, overlooking the real building usage and its implications for meeting zero-carbon targets. This research proposes a systematic post-occupancy evaluation and intervention (POEI) protocol to analyse real building performance and support cost-effective and zero-carbon upgrading. The novelty lies in integrating novel diagnostic data science techniques to identify performance gaps, advanced physics-driven energy modelling iteratively calibrated with POE data to disaggregate energy use by end-use, and cost-optimal intervention analysis. The POEI protocol has been validated in a university building. The results demonstrated the POEI benefits for the cost-optimal upgrading of in-use building assets based on real needs. By optimising control, reducing demand, increasing efficiency, and implementing renewables, the building can reach the nearly zero-carbon building target with a payback period of 13 years and a 23 % lower life-cycle cost compared to the baseline scenario. Building energy management interventions were identified as the most important actions to reduce the performance gap, reducing energy consumption by 20 % and carbon emissions by 24 %. The results also highlight the critical role of Information and Communication Technologies (ICT), which may represent up to 49 % of energy use in the future zero-carbon building scenario if overlooked.

Sustaining health and well-being in the built environment

Abstract Public health is strongly interconnected with the physical, social, and economic environment, and with people's needs, preferences, and behaviours. Physical factors affect human health and well-being (e.g., temperature, light, sound, air), as much as spatial qualities (e.g., physical activity, active communities), and feelings of safety and security (e.g., mental health, restoration). The design, operation and maintenance of the built environment can reduce health threats to inhabitants, allowing them to flourish and thrive. Yet, although human factors are starting to be implemented in building criteria and rating tools (e.g., Flourish Wheel, WELL Building Standard, etc.), comprehensive frameworks are needed to combine metrics and methods, and systematically evaluate health and well-being in buildings. This can allow to recommend guidelines and interventions that policy-makers can adopt to improve standards in the building stock, including housing that is today a crucial public health priority. This research critically consolidates existing metrics and methods to benchmark health and well-being in built spaces and proposes, through a wide interdisciplinary perspective, a robust and practical set of tools to support human experience and outcomes within the built environment. The study first elaborates on the common definitions of health and well-being in buildings. Through a systematic review, using the PRISMA and PICOC approaches, health and well-being metrics and methods are then identified. A framework and post-occupancy evaluation protocol are then developed, to be implemented within an interactive tool. The protocol can be used as a toolkit to, holistically, measure and benchmark health and well-being in buildings in use. The tool brings the evaluation toolkit together and provides recommendations. This study wishes to offer a valuable contribution towards securing public health, improving the qualities of the habitats that sustain a large part of our daily life. Key messages • Physical environment affect human health and well-being through physical factors, spatial qualities, and feelings of safety and security. • Measuring and benchmarking health and well-being in buildings and providing recommendations contribute to securing public health of the inhabitants, and improving the qualities of the habitats.

Estimation of Natural Ventilation Rates in an Office Room with 145 mm-Diameter Circular Openings Using the Occupant-Generated Tracer-Gas Method

Natural ventilation in a building is an effective way to achieve acceptable indoor air quality. Ventilation dilutes contaminants such as bioeffluents generated by occupants, substances emitted from building materials, and the water vapor generated by occupants’ activities. In a building that requires heating and cooling, adequate ventilation is crucial to minimize energy consumption while maintaining healthy indoor air quality. However, measuring the actual magnitude of the natural ventilation rate, including infiltration through the building envelope and airflow through the building openings, is not always feasible. Although international and national standards suggested the required ventilation rates to maintain acceptable indoor air quality in buildings, they did not offer action plans to achieve or evaluate those design ventilation rates in buildings in use. In this study, the occupant-generated carbon dioxide (CO2) tracer gas decay method was applied to estimate the ventilation rates in an office room in Seoul, South Korea, from summer to winter. Using the method, real-time ventilation rates can be calculated by monitoring indoor and outdoor CO2 concentrations without injecting a tracer gas. For natural ventilation in the test room, 145 mm-diameter circular openings on the fixed glass were used. As a result, first, the indoor CO2 concentrations were used as an indicator to evaluate how much the indoor air quality deteriorated when all the windows were closed in an occupied office room compared to the international standards for indoor air quality. Moreover, we found out that the estimated ventilation rates varied depending on various environmental conditions, even with the same openings for natural ventilation. Considering the indoor and outdoor temperature differences and outdoor wind speeds as the main factors influencing the ventilation rates, we analyzed how they affected the ventilation rates in the different seasons of South Korea. When the wind speeds were calm, less than 2 m/s, the temperature difference played as a factor that influenced the estimated ventilation rates. On the other hand, when the temperature differences were low, less than 3 °C, the wind speed was the primary factor. This study raises awareness about the risk of poor indoor air quality in office rooms that could lead to health problems or unpleasant working environments. This study presents an example of estimating the ventilation rates in an existing building. By using the presented method, the ventilation rate in an existing building can be simply estimated while using the building as usual, and appropriate ventilation strategies for the building can be determined to maintain the desired indoor air quality.

SSI-LSTM network for adaptive operational modal analysis of building structures

Various operational modal analysis (OMA) methods have been developed to identify the modal parameters of buildings in use. Recently, efforts have been expended to solve the existing problems associated with accuracy and computational time of OMA methods using deep learning algorithms of convolution neural network (CNN) and deep neural network (DNN). Considering that the result of modal parameters involves a process associated with the extraction of the dynamic characteristics by separating the periodic modes based on a complex ambient vibration response, the neural network technique, whereby the outputs of the past and present data are independent and static, may not be suitable for application in OMA. In this study, an adaptive, stochastic subspace identification long-short term memory (SSI-LSTM) method is proposed to evaluate the variations of the modal parameters as an indicator of the dynamic characteristics of a structure in the time history data of the structural response measured in real-time. Both past and present responses can be considered in the adaptive SSI-LSTM method and can estimate the natural frequency that changes with aging and damage to buildings. Simultaneously, as the deep learning method is basically used, the problems of accuracy and computational time continuously raised in the OMA method can be solved. The proposed method can configure the OMA method using the modal parameter results from the ambient vibration response and SSI for direct network learning. The covariance-driven SSI (SSI-COV) method is used to construct the training data for the proposed adaptive SSI-LSTM method. The proposed SSI-LSTM method is verified by applying it to a simulation model with four degrees-of-freedom and a three-story experimental model. Lastly, the practicality of the proposed method is validated using the response obtained from a 55-story high-rise building.

Duration dependence of night-time noise effect for passively cooled residential bedrooms.

The Acoustics, Ventilation, Overheating: Residential Design Guide ("The AVO Guide") was launched by the Association of Noise Consultants and Institute of Acoustics in January 2020. It provides a methodology for assessing the adverse effect due to break-in of external transport noise through façade openings provided for the purpose of mitigating overheating (i.e. passive cooling). Figure 3-2 of the AVO Guide indicates qualitatively how the SOAEL (Significant Observed Adverse Effect Level) is expected to vary with the duration for which the 'overheating condition' occurs. However, no quantitative guidance regarding the dependence on duration is given. This study describes how the methodology used in the WHO Night Noise Guidance for Europe 2009 to evaluate outside-to-inside level difference can be extended to provide a quantitative definition of the SOAEL for transport noise affecting passively cooled residential bedrooms at night. A quantitative version of the AVO Guide Figure 3-2 is derived and presented. Comparison is made with the duration/frequency independent values suggested in the recently published Approved Document Part O ("ADO"). Commentary is also provided regarding the urgent need for better availability of relevant information on the frequency of occurrence of window openings for residential buildings in use.

Circularity and LCA - material pathways: the cascade potential and cascade database of an in-use building product

Improving circularity in the building sector entails ensuring greater material efficiency to avoid virgin material extraction. To assist stakeholders in decisions regarding salvaging an in-use building product, the potential further uses of this salvaged product and its materials should be determined. In other words, its cascade potential should be determined given circular strategies, i.e. to reuse, repurpose, repair sequentially. To predict the cascade potential, a database is required that combines (acquired) product data, assembly characteristics and process data, e.g., info on the process to melt old steel. This database is referred to as a cascade database. The aim of this research is to study steps to form this database, specifically, the combination of product passports and an LCA process database. Hereto, major existing European data tools are considered. For product data, material passports and digital product passports initiatives are identified and compared. For process data, LCA databases are considered. Interactions between these data tools are a possible way to set up a partial cascade database. A workflow is then described- on how to acquire data on the cascade potential of a product from such a database. We note that the cascade database also relies on extensive (economic) forecast models, data collection and stakeholder interaction. Setting up such an extensive database and generating all possible cascading paths is a challenging, if not unachievable, feat. Nevertheless, even limited applications of this database might help reach a more circular economy.

Circularity and LCA - material pathways: cascade potential and cascade environmental impact of an in-use building product

Improving circularity in the building sector entails ensuring greater material efficiency to avoid virgin material extraction. To assist stakeholders in decisions regarding salvaging an in-use building product, requires to predict and assess the potential further productive uses of that product and its materials. The range of possible cascade material paths originating from the in-use building product X and their assessments comprise the cascade potential of product X. Method: To determine the cascade potential and impact, we work further on existing efforts done in the field of circularity and life cycle assessment (LCA). This entails discussing scenario models to predict cascade material pathways over time, and multifunctionality solutions to assess those pathways. Due to the fact that the environment is a complex system and long term forecasting is required, the cascade potential can never be exactly determined. Therefore, we first set up conceptual formulas and then discuss steps to make these formulas feasible. Furthermore, the effort to generate the cascade paths originating from a product, can also be used to form circular systems that adhere to carbon mitigation pathways.

A reservation-based parking behavioral model for parking demand management in urban areas

The rapid increase in car ownership has become a land-use problem in many cities which have limited land for parking. It also has adverse impacts on congestion, air quality, energy consumption, as well as losses in productivity, among other consequences. The problem worsens in some cities due to the adoption of inefficient mandatory minimum parking policies for new projects, according to a building's use and size, which incentivizes driving. Therefore, it is necessary to assess appropriate parking management policies that maximize social welfare. In this regard, this paper presents a reservation-based parking behavioral hybrid choice model for parking demand management policies in urban areas, that appropriately represents the behavior of private vehicle users when choosing their parking site. The proposed model is statistically significant and consistent with expected behavior and microeconomic theory. The results demonstrate that the possibility of reserving a parking space has a significant impact on car parking market share on- and off-street. The three latent variables included in the model (pro-parking attitude, perception of risk for parking on- and off-street) have a significant effect on the modal split and the evaluation of appropriate parking policies that consider heterogeneity. The latent variable that most impacts the modal shift is the pro-parking attitude, which can generate up to 7% change in the modal partition.

Associating occupants' interaction with windows with air change rate --One case study

Air change rate (ACR) significantly influences the indoor thermal environment and indoor air quality. Moreover, as a matter of fact, ACR varies with time during natural ventilation. However, to date only a few studies have accounted for the dynamic ACR for the actual in-use buildings. To address this issue, a field measurement of outdoor/indoor environments and the window state was conducted in a dormitory in Beijing in spring, summer, and autumn. Transient Mass Balance Equation (TMBE) method associated with the extended Kalman filter (Hereinafter referred to as Kalman filter method) was adopted to obtain the dynamic results of the ACR. Then the correlations of outdoor/indoor environments with the ACR and the probability of window opening were investigated. The results confirm the validity of Kalman filter method for tracking the dynamic nature of natural ventilation in residential units, and further demonstrate that occupants' interaction with windows does not simply refer to opening/closing windows, but also refer to adjusting the extent of the window being open in response to occupants' ventilation needs. Therefore, in addition to the probability of window opening, ventilation needs, i.e., the dynamic ACR, as the underlying trigger for window opening behavior, should be used as an indispensable part of describing occupants' interaction with windows. This study provides a complete framework to describe occupants’ interactions with windows by combining the dynamic ACR and the probability of window opening.

Optimisation of thermal comfort and indoor air quality estimations applied to in-use buildings combining NSGA-III and XGBoost

Indoor environmental quality (IEQ) monitoring of in-use buildings has become essential in recent years due to the COVID-19 pandemic, as it significantly affects the well-being, health and productivity of building users. Nevertheless, knowing in real time the environmental conditions in large multi-zone areas is a difficult issue. Thus, the use of machine learning techniques to estimate indoor conditions has increased considerably. The aim of this paper is to present an interpolation model, based on an optimised extreme gradient boosting algorithm, to estimate every minute the indoor temperature, relative humidity and CO2 concentration inside buildings. These estimations are obtained without requiring permanent monitoring in the occupied zone. The optimisation, focused on finding the minimum number of monitoring devices needed to provide accurate interpolations, is performed using the multi-objective genetic algorithm NSGA-III. This methodology was applied in a research centre in the north-western Spain. The results show that the optimised or reduced model is capable of estimating indoor temperatures and relative humidity with relative errors below 6% and CO2 levels below 10%.

The Influence of the Properties of Thermal - Insulation Materials on the Thermomoist Indicators of a Building

One of the basic measures of energy efficiency in residential buildings is the reduction of heat and coolant pressure, when external structures - walls, ceilings - contain thermal insulation material, as a result of which heat and cold losses are reduced, as a result of air-and moisture permeability. Their number is largely determined by the climatic zone of the building, construction, sources of heat and cold, fuel and electricity prices in this region. In such practice, first of all, attention is paid to the problems of the optimal thickness of the thermal insulator, the installation location, since improper installation in the structure can cause water condensation, which will lead to partial wear of the structure, since the properties of reinforced-concrete layers will deteriorate. This concerns the peculiarities of carrying out thermal insulation works and their necessity both in under construction and in buildings in use. However, even in these conditions, when discussing the thermal effect of thermal insulation on structures, due attention is not paid to individual structures, especially walls, moisture problems. Consideration of insulators with more or less efficient energy and heat engineering characteristics, when it was found that there is a significant difference between their results and effects, aroused particular interest in the study of the problem. This is followed by a study of the influence of the presence of thermal insulation in the structure on the cold load required for cooling, revealed a pattern of cost changes in the case of insulating materials with more or less properties - foam.

An Assessment of Causative Factors of Building Collapse using Physical Analysis Tests: The Case of Oko, Anambra State, Nigeria

Incessant building collapses in Anambra State Nigeria is posing serious challenges to all the stakeholders in the building industry - building consultants, governments, developers, landlords and users. This has evoked great concern to all key players of the building industry. Thus, this study assessed the causative factors of building collapses in one of the cases, a collapsed uncompleted 3-story building which was reported in Oko town, Anambra State, Nigeria. A qualitative methodology involving subsoil and geotechnical investigation and also destructive testing of collapsed structural elements including sandcrete blocks, concrete and reinforcement bars; to establish the subsoil conditions, compressive strength, the yield stress as well as ductility of the reinforcements bars was adopted for this study. The results of the test carried out on the mass concrete, revealed a compressive strength ranging from 1.4N/mm2 to 3.1N/mm2 (standard compressive strength of 25N/mm2), 6” solid block ranging from 0.3N/mm2 to 0.4N/mm2 and 6” hollow block ranging from 0.2N/mm2, (standard strength value of 1.5 N/mm2 for a non-load bearing sandcrete block in accordance to NIS: 587:2007). The tensile stress of the reinforcement bars (12mm and 16mm) ranging from 280.29N/mm2 to 303.91N/mm2 (According to NIS: 117:2004, standard yield stress value of 410N/mm2 and ductility of 12%). The CPT revealed that the subsoil is generally too soft and the fine aggregate (sand) was poor for concreting. The findings suggest that poor foundation structure, inappropriate mix of concrete, the use of substandard materials, inadequate reinforcement and poor project supervision, contributed to the structural failure that lead to the collapse of the building. Therefore, this research recommends that mandatory, periodic or conditional structural integrity assessment of buildings in use and under construction becomes an exclusive preserve of highly qualified construction professionals. Standard organization of Nigeria should be vigilant to ensure that building materials imported into the country conforms to standard requirements especially the reinforcement bars.

Old and Modern Wooden Buildings in the Context of Sustainable Development

Construction is a powerful industry that is not indifferent to the environment. Neither the maintenance of buildings in a proper technical condition nor their eventual demolition is indifferent to the environment. The main threats to the environment are still the inefficient use of construction materials and energy needed for their production and installation, as well as the emission of harmful substances to the environment at the stage of operation of buildings and their demolition. This article discusses the importance of wood as a renewable material in terms of its physical and mechanical properties. The restoration of forest areas is of great importance to the global ecosystem and the sustainable development system, reducing the threat of global warming and the greenhouse effect by reducing CO2 levels. In addition, demolition wood can be reused in construction, can be safely recycled as it quickly decomposes, or can be used as a source of renewable energy. The preservation of existing timber-framed buildings in good condition contributes to a lower consumption of this raw material for repair, which already significantly reduces the energy required for their manufacture, transport, and assembly. This also reduces the amount of waste that would have to be disposed of in various ways. Both at the stage of design, execution, and then exploitation, one forgets about the physical processes taking place inside the partitions and about the external climatic influences of the environment (precipitation, water vapor, and temperature) on which the type, intensity, and extent of chemical and biological corrosion depend to a very high degree. This paper presents examples of the influence of such impacts on the operational safety of three selected objects: a feed storehouse and an officer casino building from the second half of the nineteenth century and an 18th century rural homestead building. The research carried out on wooden structures of the above-mentioned objects “in situ” was verified by means of simulation models, which presented their initial and current technical conditions in relation to the type and amount of impact they should safely absorb. Moreover, within the framework of this paper, artificial intelligence methods have been implemented to predict the biological corrosion of the structures studied. The aim of the paper was to draw attention to the timber already built into buildings, which may constitute waste even after several years of operation, requiring disposal and at the same time the production of a substitute. The purpose of the research carried out by the authors of the article was to examine the older and newer buildings in use, the structures of which, in whole or in part, were made of wood. On a global scale, there will be considerable demand for the energy required to thermally dispose of this waste or to deposit it in landfills with very limited capacity until its complete biological decomposition. These energy demands and greenhouse gas emissions can be prevented by effective diagnostics of such structures and the predictability of their behaviour over time, with respect to the conditions under which they are operated. The authors of the article, during each assessment of the technical condition of a building containing wooden elements, analysed the condition of their protection each time and predicted the period of their safe life without the need for additional reinforcements or replacement by others. As the later reality shows, it is a very effective method of saving money and energy.