International Science Index

International Journal of Architectural and Environmental Engineering

Effect of Correlation of Random Variables on Structural Reliability Index
The problem of correlation between random variables in the structural reliability analysis has been extensively discussed in literature on the subject. The cases taken under consideration were usually related to correlation between random variables from one side of ultimate limit state: correlation between particular loads applied on structure or correlation between resistance of particular members of a structure as a system. It has been proved that positive correlation between these random variables reduces the reliability of structure and increases the probability of failure. In the paper, the problem of correlation between random variables from both side of the limit state equation will be taken under consideration. The simplest case where these random variables are of the normal distributions will be concerned. The case when a degree of that correlation is described by the covariance or the coefficient of correlation will be used. Special attention will be paid on questions: how much that correlation changes the reliability level and can it be ignored. In reliability analysis will be used well-known methods for assessment of the failure probability: based on the Hasofer-Lind reliability index and Monte Carlo method adapted to the problem of correlation. The main purpose of this work will be a presentation how correlation of random variables influence on reliability index of steel bar structures. Structural design parameters will be defined as deterministic values and random variables. The latter will be correlated. The criterion of structural failure will be expressed by limit functions related to the ultimate and serviceability limit state. In the description of random variables will be used only for the normal distribution. Sensitivity of reliability index to the random variables will be defined. If the reliability index sensitivity due to the random variable X will be low when compared with other variables, it can be stated that the impact of this variable on failure probability is small. Therefore, in successive computations, it can be treated as a deterministic parameter. Sensitivity analysis leads to simplify the description of the mathematical model, determine the new limit functions and values of the Hasofer-Lind reliability index. In the examples, the NUMPRESS software will be used in the reliability analysis.
Pragmatism in Adaptive Reuse of Obsolete Industrial Land in China
Major cities in China has experienced a shift from production based on manufacturing industry to tertiary industry. How to make a better use of existing obsolete industrial land within urban cores has become a difficult problem for many policymakers. City governments regard old manufacturing industrial land as an important source of land to facilitate the development of the cities. Despite the announcement of policies in promoting that, a large portion of industrial land is still not properly redeveloped and most of them became obsolete. The study uses the project of Xinyi International Club as a case to examine the process of adaptive reuse of obsolete industrial space in Guangzhou, China. It attempts to elucidate the underlying mechanisms by identifying the key forces from both the government and the private sectors in influencing the process. The study found that market forces in transforming industrial space are exerting a strong impact on the existing land use planning system in Chinese cities. Pragmatic relaxation of the formal land use the regulatory framework and government supportive land-use intervention have also been crucial towards achieving successful implementation of the restructuring project and making it a showcase. This study questions whether these extraordinary measures, in particular, the use of temporary land use permit, are sustainable in facilitating the transformation of derelict industrial land, and in informing future industrial land-use restructuring policies. It concludes that, while the land use regulatory system in China is becoming increasingly dynamic and flexible, it remains ill-equipped in responding positively to the market, which is characterized by an increasing bargaining power of the private sector. A comprehensive appraisal of the overall impacts of these adaptive re-uses on society is wanting.
Tokyo Skyscrapers-Technologically Advanced Structures in Seismic Areas
The architectural and structural analysis of selected high-rise buildings in Tokyo is presented in this paper. The capital of Japan is the most densely populated city in the world and moreover is located in one of the most active seismic zones. The combination of these factors has resulted in the creation of sophisticated designs and innovative engineering solutions, especially in the field of design and construction of high-rise buildings. The foreign architectural studios (as, for Jean Nouvel, Kohn Pedesen Associates, Skidmore, Owings & Merill) which specialize in the designing of skyscrapers, played a major role in the development of technological ideas and architectural forms for such extraordinary engineering structures. Among the projects completed by them, there are examples of high-rise buildings that set precedents for future development. An essential aspect which influence the design of high-rise buildings is the necessity to take into consideration their dynamic reaction to earthquakes and counteracting wind vortices. The need to control motions of these buildings, induced by the force coming from earthquakes and wind, led to the development of various methods and devices for dissipating energy which occur during such phenomena. Currently, Japan is a global leader in seismic technologies which safeguard seismic influence on high-rise structures. Due to these achievements the most modern skyscrapers in Tokyo are able to withstand earthquakes with a magnitude of over seven degrees at the Richter scale. Damping devices applied are of a passive, which do not require additional power supply or active one which suppresses the reaction with the input of extra energy. In recent years also hybrid dampers were used, with an additional active element to improve the efficiency of passive damping.
Sustainable Environmental Management through the Comparative Study of Two Recreational Parks in Nigeria
The role of a recreational park in human and environmental development has attracted much interest in the recent time. Recreation parks' development could act as an effective planning strategy to enhance environmental sustainability, social cohesiveness, and users' quality of life. Similarly, parks enhance neighbourhood's aesthetics, refresh the air and enhance humans' contact with nature. In this connection, recreation parks create natural surroundings of rural areas for leisure, relaxation, recreation, psychological and physical comfort of the people. The purpose of this paper is to investigate the effectiveness of the two recreational parks' development as a strategy for neighbourhood's environmental improvement, sustainability and the recreationists' cohesiveness. A total number of 158 survey questionnaires were distributed to the tourists at Ikogosi cold and warm spring in Ekiti state as well as Olumirin waterfalls, Erin-Ijesa, Osun State, in South-West, Nigeria. The quantitative results of the analyzed data with Relative Importance Index (RII) revealed that recreation parks provide optimum opportunities for users' social cohesiveness and well-being while parks' sustainable environment could be enhanced base on the provision of essential facilities, services, and future developmental plans. It is recommended that for recreation parks to realize their full potential in environmental sustainability, adequate maintenance and provision of essential facilities becomes imperative.
The Ecological Urbanism as an Oppurtunity to Solve City Problem
The world’s population continues to grow resulting in steady migration from rural to urban areas. Increased numbers of people and cities hand in hand with greater exploitation of world’s resource. Every year, more cities are feeling the devastating of this impact of this situation. During the 1970’s, some of eco-concept were applied to urban settings, one of them is Ecological Cities. A non-profit organization, Urban Ecology, was founded in California in 1975 to 'rebuild cities in balance with nature'. Efforts to synthesize ecological and urban planning approaches were slowed somewhat in the 1980s, but useful refinements were made. Consideration of social impact acknowledges that the ecological design is not just about ecology itself. It is also about questioning and redefining our understanding of the ecology. When ecologist did recognize the existence of cities, they were usually concerned with resource flows. One popular approach was to study the flow and transformation of energy through urban ecosystem. This research method is descriptive method, following LEED Certification which is the international standard of the sustainable building, is more widely applied. But there remains problem that the moral imperative of sustainability and by implication of sustainable design, tends to supplant the disciplinary contribution. Sustainable design is not always seen as design excellence or design innovation. This can provoke the skepticism and cause the tension those who promote disciplinary knowledge and those who push for sustainability. The challenges of rapid urbanization and limited of global resources has become more pressing. So, there is a need to find an alternative design approaches. The urban, as the site of complex relation (economy, political, social, cultural), need a complex problem solving that can solve current and future condition. The aim of this study is to discussed about conjoining of ecology such as public park and sustainable design.
Effective Wind-Induced Natural Ventilation in a Residential Apartment Typology
In India, cooling loads in residential sector contribute to 45% of its total energy consumption. The market penetration of air-conditioners is expected to rise by 2040. Natural Ventilation (NV), however, possesses great potential to save significant energy consumption especially for residential buildings in moderate climates. As multifamily residential apartment buildings are designed by repetitive use of prototype designs, deriving individual NV based design prototype solutions for a combination of different wind incidence angles and orientations would provide significant opportunity to address the rise in cooling loads by residential sector. This paper presents the results of NV performance of a selected prototype apartment design with a cluster of four units in Pune, India, and an attempt to improve the NV performance through design modifications. The water table apparatus, a physical modelling tool, is used to study the flow patterns and simulate wind-induced NV performance. Quantification of NV performance is done by post processing images captured from video recordings in terms of percentage of area with good and poor access to ventilation. NV performance of the existing design for 8 wind incidence angles showed that of the cluster of 4 units, the windward units showed good access to ventilation for all rooms, and the leeward units had lower access to ventilation with the bedrooms in the leeward units having the least access. The results showed improved performance in all the units for all wind incidence angles to more than 80% good access to ventilation. Some units showed an additional improvement to more than 90% good access to ventilation. This process of design and performance evaluation improved some individual units from 0% to 100% for good access to ventilation. The results demonstrate the ease of use and the power of the water table apparatus for performance based design to simulate wind induced NV.
Development of Historic Bagh-e Dasht in Herat, Afghanistan: A Comprehensive Field Survey of Physical and Social Aspects
Bagh-e Dasht area is situated in the northern part of Herat, an old city in western Afghanistan located on the Silk Road under a strong influence of Persian culture. In the beginning, Bagh-e Dasht area was developed for gardens and palaces nearby Joy-e Injil canal during Timurid Empire in the 15th century. It is assumed Bagh-e Dasht became settlement in the 16th century during Safavid Empire. The oldest is in the southern part around the canal bank which is characterized by Dalans, sun-dried brick arcades, often with houses constructed above them. Also, traditional houses in this area built in sun-dried bricks with domical vault roofs. Bagh-e Dasht is one of the most preserved settlements of traditional houses in Herat. This study examines the transformation of Bagh-e Dasht area regarding Dalans, where traditional houses with domical vault roofs are preserved relatively well until now. The aim of the study is to examine the extent of physical changes of the area regarding Dalans as well as changes of houses and the community. This research contains original and unpublished results in architecture history. The roof types of houses in the area are investigated through high resolution satellite images. The boundary of each building and space is determined by both the field survey and aerial photographs of the study area. A comprehensive field survey was then conducted to examine each space and building of the area, as well as questionnaire to the residents of the Dalan houses and interviews of the Wakil (Chief) of the area, a local historian, residents and traditional builders. The study finds that the oldest part of Bagh-e Dasht area, the southern part, has both Dalans and domical vault roof houses. The part next to the oldest in the north has only domical vault roof houses. Outside of these parts, the houses have modernized flat roofs. This may show the process of historical development in Bagh-e Dasht area.
Understanding Consumer Recycling Behavior: A Literature Review of Motivational and Behavioral Aspects
Recycling is an important aspect of a sustainable society and depends to a large extent on consumers’ willingness to provide the voluntary work needed to take the first critical step in many return logistics systems. Based on a systematic review of articles on recycling behavior, this paper presents and discusses the findings in relation to Fogg’s Behavioral Model (FBM). Through the analysis of a corpus of 72 articles, the most important research contributions on recycling behavior are summarized and discussed. The choice of using FBM as a framework provides a new way of viewing previous research findings, and aids in identifying knowledge gaps. Based on the review, this work identifies and discusses four areas of potential interest for future research.
Locally Reinforced Triaxial Braids: Mechanical Properties and Process Analysis
In order to further enhance material and cost efficiency of automotive parts from carbon fiber reinforced plastics, the approach of applying local reinforcements has proven to be effective. For braided hollow profiles, however, technical possibilities to achieve process integrated adaption of a components mechanical properties are limited. Therefore, a novel braiding configuration for cycle-time-neutral application and overbraiding of local reinforcement fiber tapes is considered. This technique allows laminate lay-ups with additional unidirectional or biaxial reinforcement layers of various types, materials and weights between standard braiding layers. This study is intended to demonstrate that the described braiding technique allows improved mechanical performance of triaxial braids by use of low-ondulation reinforcement textiles. Furthermore, the influence of reinforcement layers on the interlaminar properties and laminate damage resistance is investigated. For this purpose, multiple band-shaped reinforcement textiles are selected (spread heavy tow rovings, woven and non-crimp fabric) and are used for production of square hollow profiles by means of the modified braiding process and RTM (Resin Transfer Moulding). Coupon testing (tension, compression, short beam shear test, bending) and microscopy are performed. Latest results confirm the desired increase of in-plane properties, which can be associated with reduced fiber ondulation. Furthermore, three-point bending tests on square hollow profiles are carried out in order to compare reinforced braids with standard braids on component level. For comparison, the mechanical characteristics gained from coupon testing are used to build a Finite Element model of the component bending test in ABAQUS. The approaches’ applicability for high-volume production is evaluated with overall good results. Advantages and weaknesses are outlined as well as potential concepts for further improvement, e.g., for enhanced accuracy of reinforcement application.
Residual Plastic Deformation Capacity in Reinforced Concrete Beams Subjected to Drop Weight Impact Test
Concrete is commonly used for protective structures and how impact loading affects different types of concrete structures is an important issue. Often the knowledge gained from static loading is also used in the design of impulse loaded structures. A large plastic deformation capacity is essential to obtain a large energy absorption in an impulse loaded structure. However, the structural response of an impact loaded concrete beam may be very different compared to a statically loaded beam. Consequently, the plastic deformation capacity and failure modes of the concrete structure can be different when subjected to dynamic loads; and hence it is not sure that the observations obtained from static loading are also valid for dynamic loading. The aim of this paper is to investigate the residual plastic deformation capacity in reinforced concrete beams subjected to drop weight impact tests. A test-series consisting of 18 simply supported beams (0.1 x 0.1 x 1.18 m, ρs = 0.7%) with a span length of 1.0 m and subjected to a point load in the beam mid-point, was carried out. 2x6 beams were first subjected to drop weight impact tests, and thereafter statically tested until failure. The drop in weight had a mass of 10 kg and was dropped from 2.5 m or 5.0 m. During the impact tests, a high-speed camera was used with 5 000 fps and for the static tests, a camera was used with 0.5 fps. Digital image correlation (DIC) analyses were conducted and from these the velocities of the beam and the drop weight, as well as the deformations and crack propagation of the beam, were effectively measured. Additionally, for the static tests, the applied load and midspan deformation were measured. The load-deformation relations for the beams subjected to an impact load were compared with 6 reference beams that were subjected to static loading only. The crack pattern obtained were compared using DIC, and it was concluded that the resulting crack formation depended much on the test method used. For the static tests, only bending cracks occurred. For the impact loaded beams, though, distinctive diagonal shear cracks also formed below the zone of impact and less wide shear cracks were observed in the region half-way to the support. Furthermore, due to wave propagation effects, bending cracks developed in the upper part of the beam during initial loading. The results showed that the plastic deformation capacity increased for beams subjected to drop weight impact tests from a high drop height of 5.0 m. For beams subjected to an impact from a low drop height of 2.5 m, though, the plastic deformation capacity was in the same order of magnitude as for the statically loaded reference beams. The beams tested were designed to fail due to bending when subjected to a static load. However, for the impact tested beams, one beam exhibited a shear failure at a significantly reduced load level when it was tested statically; indicating that there might be a risk of reduced residual load capacity for impact loaded structures.
Solving the Overheating on the Top Floor of Energy Efficient Houses: The Envelope Improvement
Although various energy rating schemes and compulsory building codes are using around the world, there are increasing reports on overheating in energy efficient dwellings. Given that the cooling demand of buildings is rising globally because of the climate change, it is more likely that the overheating issue will be observed more. This paper studied the summer indoor temperature in eight air-conditioned multi-level houses in Adelaide which have complied with the Australian Nationwide Houses Energy Rating Scheme (NatHERS) minimum energy performance of 7.5 stars. Through monitored temperature, this study explores that overheating is experienced on 75.5% of top floors during cooling periods while the air-conditioners were running. This paper found that the energy efficiency regulations have significantly improved thermal comfort in low floors, but not on top floors, and the energy-efficient house is not necessarily adapted with the air temperature fluctuations particularly on top floors. Based on the results, this study suggests that the envelope of top floors for multi-level houses in South Australian context need new criteria to make the top floor more heat resistance in order to: preventing the overheating, reducing the summer pick electricity demand and providing thermal comfort. Some methods are used to improve the envelope of the eight case studies. The results demonstrate that improving roofs was the most effective part of the top floors envelope in terms of reducing the overheating.
Identifying the Need of Adaption to Heatwaves for Energy Efficient Houses Top-Floors
There are increasing reports on overheating and cooling demand in energy efficient dwellings, although various energy rating schemes and compulsory building codes are being employed worldwide. To find the accurate location of overheated rooms in dwellings, this paper studied the summer indoor temperature pattern which was monitored in eight air conditioned multi level houses. These houses comply with the Australian Nationwide Houses Energy Rating Scheme (NatHERS) minimum energy performance of 7.5 star from 10. The minute by minute monitored temperature of these houses were converted to hourly. The hourly temperature of four consecutive summer months, (December, January and February 2011 2015) were analyzed. As there is no threshold to evaluate overheating in Australian houses, the initial threshold for identifying overheating is based on 32 °C. The rooms with running air conditioner that their maximum daily temperature were above this threshold were marked as overheated. The number of days with overheating on top floors and low floors were found for eight houses. The investigation is conducted more in depth by calculating the ‘Number of Overheating Hours’ and ‘Weighted Exceedance Hours’ for one house through seven years (2011-2017) minutely monitored temperature based on 26 °C as overheating threshold. The outputs showed that overheating were experienced on 75.5% of top floors during cooling periods while the air-conditioners were running and low floors were cool. During the four studied summers, the top floor maximum daily air temperature was above 32 °C for about 22.5 days with running air conditioners. Results demonstrated that top floors of multi level dwellings are exposed to the outdoor air temperature fluctuations. However, there was no overheating on low floors. Based on the results, this study highlights that the energy efficiency regulations of Australia have significantly improved thermal comfort on low floors, but not on top floors. The conclusion recommends that top floors of multi level houses in South Australian context remarkably need to be adapted with heat events in order to: prevent the overheating, reduce the summer pick electricity demand and provide thermal comfort.
Predictability of Thermal Response in Housing: A Case Study in Australia, Adelaide
Changes in cities’ heat balance due to rapid urbanization and the urban heat island (UHI) have increased energy demands for space cooling and have resulted in uncomfortable living conditions for urban residents. Climate resilience and comfortable living spaces can be addressed through well-designed urban development. The sustainable housing can be more effective in controlling high levels of urban heat. In Australia, to mitigate the effects of UHIs and summer heat waves, one solution to sustainable housing has been the trend to compact housing design and the construction of energy efficient dwellings. This paper analyses whether current housing configurations and orientations are effective in avoiding increased demands for air conditioning and having an energy efficient residential neighborhood. A significant amount of energy is consumed to ensure thermal comfort in houses. This paper reports on the modelling of heat transfer within the homes using the measurements of radiation, convection and conduction between exterior/interior wall surfaces and outdoor/indoor environment respectively. The simulation was tested on selected 7.5-star energy efficient houses constructed of typical material elements and insulation in Adelaide, Australia. The chosen design dwellings were analyzed in extremely hot weather through one year. The data were obtained via a thermal circuit to accurately model the fundamental heat transfer mechanisms on both boundaries of the house and through the multi-layered wall configurations. The formulation of the Lumped capacitance model was considered in discrete time steps by adopting a non-linear model method. The simulation results focused on the effects of orientation of the solar radiation on the dynamic thermal characteristics of the houses orientations. A high star rating did not necessarily coincide with a decrease in peak demands for cooling. A more effective approach to avoid increasing the demands for air conditioning and energy may be to integrate solar–climatic data to evaluate the performance of energy efficient houses.
The Effect of Shank-Space on the Thermal Performance of Shallow U-Tube Ground Heat Exchangers
Space conditioning accounts for 50% of the energy consumed by Europe’s building stock. Curtailing such an energy consumption through the adoption of energy efficient technologies has now become essential. The Ground Source Heat Pump (GSHP) is one such technology which is capable of delivering heating and cooling with enhanced energy-efficiency. The distinctive component of a GSHP is the Ground Heat Exchanger (GHE) which normally consists of an underground circuit of pipes through which a circulating liquid absorbs or rejects heat. As ground temperatures get increasingly stable with depth, vertical GHE, consisting of a U-tube encased within a borehole backfilled with thermally conductive grout, are the most common setup. Research on GHE has mainly focused on either improving the materials used (e.g., pipework, grout) or improving the configuration adopted (e.g., the centre-to-centre distance between the two vertical pipe branches of a U-tube, i.e., the shank-space or the borehole spacing arrangement). Specifically, in relation to shank-space, researchers have observed how the shank-space is an important factor which may influence the heat transfer performance of U-tube GHE. In this area, most of the research carried out has focused on vertical boreholes with typical depths of around 100m, as commercially these are the ones which are used, primarily to ensure that enough contact area to reject or absorb the heat is available. However, reaching such depths is not always possible and other design limitations, such as for example, the requirement for limited interaction with the water table, may require that a system makes use of shallower GHE (up to 50m depth). To the authors’ best knowledge, specific research on shallow GHE is however lacking. To address this aspect, a 3D steady-state Computational Fluid Dynamics (CFD) model of a U-tube GHE was used to investigate the influence of varying shank-spaces on the thermal performance of two isolated vertical shallow U-tube GHE, one 20m deep and the other 40m deep. Borehole diameter was taken as 0.3m. To facilitate the computational process, the simplified 3D steady-state CFD model makes use of an innovative approach, whereby the U-junction at the bottom of the U-tube is eliminated. To ensure confidence in the results obtained using this simplified model, the model was first validated against available experimental and numerical studies performed for full U-tube models. As one would expect, the results show that for the 20m deep borehole containing the vertical U-tube, the temperature drop of the circulating fluid varies for different shank-spaces and is lowest for the closest shank space (0.76K) and highest for the widest shank-space (0.85K). It is observed however that this temperature drop is not linear with increases in shank-space and that for the modelled setup, thermal performance improvement drastically diminishes beyond the 0.15m shank-space, and is practically insignificant for the 0.205m and the 0.26m shank-spaces. Similar results, although with higher values were obtained for the 40m deep 0.3m diameter borehole/U-tube configuration, indicating that for shallow U-tube GHE absolute temperature of the fluid is more dependent on the length of pipework than the effect of shank-space.
Determination of the Relative Humidity Profiles in an Internal Micro-Climate Conditioned Using Evaporative Cooling
Driven by increased comfort standards, but at the same time high energy consciousness, energy-efficient space cooling has become an essential aspect of building design. Its aims are simple, aiming at providing satisfactory thermal comfort for individuals in an interior space using low energy consumption cooling systems. In this context, evaporative cooling is both an energy-efficient and an eco-friendly cooling process. In the past two decades, several academic studies have been performed to determine the resulting thermal comfort produced by an evaporative cooling system, including studies on temperature profiles, air speed profiles, effect of clothing and personnel activity. To the best knowledge of the authors, no studies have yet considered the analysis of relative humidity (RH) profiles in a space cooled using evaporative cooling. Such a study will determine the effect of different humidity levels on a person's thermal comfort and aid in the consequent improvement designs of such future systems. Under this premise, the research objective is to characterise the resulting different RH profiles in a chamber micro-climate using the evaporative cooling system in which the inlet air speed, temperature and humidity content are varied. The chamber shall be modelled using Computational Fluid Dynamics (CFD) in ANSYS Fluent. Relative humidity shall be modelled using a species transport model while the k-ε RNG formulation is the proposed turbulence model that is to be used. The model shall be validated with measurements taken using an identical test chamber in which tests are to be conducted under the different inlet conditions mentioned above, followed by the verification of the model's mesh and time step. The verified and validated model will then be used to simulate other inlet conditions which would be impractical to conduct in the actual chamber. More details of the modelling and experimental approach will be provided in the full paper The main conclusions from this work are two-fold: the micro-climatic relative humidity spatial distribution within the room is important to consider in the context of investigating comfort at occupant level; and the investigation of a human being's thermal comfort (based on Predicted Mean Vote – Predicted Percentage Dissatisfied [PMV-PPD] values) and its variation with different locations of relative humidity values. The study provides the necessary groundwork for investigating the micro-climatic RH conditions of environments cooled using evaporative cooling. Future work may also target the analysis of ways in which evaporative cooling systems may be improved to better the thermal comfort of human beings, specifically relating to the humidity content around a sedentary person.
Thermal Simulation for Urban Planning in Early Design Phases
Thermal simulations are used to evaluate comfort and energy consumption of buildings. However, the performance of different urban forms cannot be assessed precisely if an environmental control system and user schedules are considered. The outcome of such analysis would lead to conclusions that combine the building use, operation, services, envelope, orientation and density of the urban fabric. The influence of these factors varies during the life cycle of a building. The orientation, as well as the surroundings, can be considered a constant during the lifetime of a building. The structure impacts the thermal inertia and has the largest lifespan of all the building components. On the other hand, the building envelope is the most frequent renovated component of a building since it has a great impact on energy performance and comfort. Building services have a shorter lifespan and are replaced regularly. With the purpose of addressing the performance, an urban form, a specific orientation, and density, a thermal simulation method were developed. The solar irradiation is taken into consideration depending on the outdoor temperature. Incoming irradiation at low temperatures has a positive impact increasing the indoor temperature. Consequently, overheating would be the combination of high outdoor temperature and high irradiation at the façade. On this basis, the indoor temperature is simulated for a specific orientation of the evaluated urban form. Thermal inertia and building envelope performance are considered additionally as the materiality of the building. The results of different thermal zones are summarized using the 'Degree day method' for cooling and heating. During the early phase of a design process for a project, such as Masterplan, conclusions regarding urban form, density and materiality can be drawn by means of this analysis.
Use of Shipping Containers as Office Buildings in Brazil: Thermal and Energy Performance for Different Constructive Options and Climate Zones
Shipping containers are present in different Brazilian cities, firstly used for transportation purposes, but which become waste materials and an environmental burden in their end-of-life cycle. In the last decade, in Brazil, some buildings made partly or totally from shipping containers started to appear, most of them for commercial and office uses. Although the use of a reused container for buildings seems a sustainable solution, it is very important to measure the thermal and energy aspects when they are used as such. In this context, this study aims to evaluate the thermal and energy performance of an office building totally made from a 12-meter-long, High Cube 40’ shipping container in different Brazilian Bioclimatic Zones. Four different constructive solutions, mostly used in Brazil were chosen: (1) container without any covering; (2) with internally insulated drywall; (3) with external fiber cement boards; (4) with both drywall and fiber cement boards. For this, the DesignBuilder with EnergyPlus was used for the computational simulation in 8760 hours. The EnergyPlus Weather File (EPW) data of six Brazilian capital cities were considered: Curitiba, Sao Paulo, Brasilia, Campo Grande, Teresina and Rio de Janeiro. Air conditioning appliance (split) was adopted for the conditioned area and the cooling setpoint was fixed at 25°C. The coefficient of performance (CoP) of air conditioning equipment was set as 3.3. Three kinds of solar absorptances were verified: 0.3, 0.6 and 0.9 of exterior layer. The building in Teresina presented the highest level of energy consumption, while the one in Curitiba presented the lowest, with a wide range of differences in results. The constructive option of external fiber cement and drywall presented the best results, although the differences were not significant compared to the solution using just drywall. The choice of absorptance showed a great impact in energy consumption, mainly compared to the case of containers without any covering and for use in the hottest cities: Teresina, Rio de Janeiro, and Campo Grande. This study brings as the main contribution the discussion of constructive aspects for design guidelines for more energy-efficient container buildings, considering local climate differences, and helps the dissemination of this cleaner constructive practice in the Brazilian building sector.
Dynamic Modeling of Energy Systems Adapted to Low Energy Buildings in Lebanon
Low energy buildings have been developed to achieve global climate commitments in reducing energy consumption. They comprise energy efficient buildings, zero energy buildings, positive buildings and passive house buildings. The reduced energy demands in Low Energy buildings call for advanced building energy modeling that focuses on studying active building systems such as heating, cooling and ventilation, improvement of systems performances, and development of control systems. Modeling and building simulation have expanded to cover different modeling approach i.e.: detailed physical model, dynamic empirical models, and hybrid approaches, which are adopted by various simulation tools. This paper uses DesignBuilder with EnergyPlus simulation engine in order to; First, study the impact of efficiency measures on building energy behavior by comparing Low energy residential model to a conventional one in Beirut-Lebanon. Second, choose the appropriate energy systems for the studied case characterized by an important cooling demand. Third, study dynamic modeling of Variable Refrigerant Flow (VRF) system in EnergyPlus that is chosen due to its advantages over other systems and its availability in the Lebanese market. Finally, simulation of different energy systems models with different modeling approaches is necessary to confront the different modeling approaches and to investigate the interaction between energy systems and building envelope that affects the total energy consumption of Low Energy buildings.
Machine Learning Approach to Project Control Threshold Reliability Evaluation
Planning is understood as the determination of what has to be performed, how, in which sequence, when, what resources are needed, and their cost within the organization before execution. In most construction project, it is evident that the inherent nature of planning is dynamic, and initial planning is subject to be changed due to various uncertain conditions of construction project. Planners take a continuous revision process during the course of a project and until the very end of project. However, current practice lacks reliable, systematic tool for setting variance thresholds to determine when and what corrective actions to be taken. Rather it is heavily dependent on the level of experience and knowledge of the planner. Thus, this paper introduces a machine learning approach to evaluate project control threshold reliability incorporating project-specific data and presents a method to automate the process. The results have shown that the model improves the efficiency and accuracy of the monitoring process as an early warning.
Labor Productivity and Organization Performance in Specialty Trade Construction: The Moderating Effect of Safety
The notion of performance measurement has held great appeal for the industry and research communities alike. This idea is also true for the construction sector, and some propose that performance measurement and productivity analysis are two separate management functions, where productivity is a subset of performance, the latter requiring comprehensive analysis of comparable factors. Labor productivity is considered one of the best indicators of production efficiency. The construction industry continues to account for a disproportionate share of injuries and illnesses despite adopting several technological and organizational interventions that promote worker safety. Specialty trades contractors typically complete a large fraction of work on any construction project, but insufficient body of work exists that address subcontractor safety and productivity issues. Literature review has revealed the possibility of a relation between productivity, safety and other factors and their links to project, organizational, task and industry performance. This research posits that there is an association between productivity and performance at project as well as organizational levels in the construction industry. Moreover, prior exploration of the importance of safety within the performance-productivity framework has been anecdotal at best. Using structured questionnaire survey and organization- and project level data, this study, which is a combination of cross-sectional and longitudinal research designs, addresses the identified research gap and models the relationship between productivity, safety, and performance with a focus on specialty trades in the construction sector. Statistical analysis is used to establish a correlation between the variables of interest. This research identifies the need for developing and maintaining productivity and safety logs for smaller businesses. Future studies can design and develop research to establish causal relationships between these variables.
Visualizing the Commercial Activity of a City by Analyzing the Data Information in Layers
This paper aims to demonstrate how network models can be used to understand and to deal with some aspects of urban complexity. As it is well known, the Theory of Architecture and Urbanism has been using for decades’ intellectual tools based on the ‘sciences of complexity’ as a strategy to propose theoretical approaches about cities and about architecture. In this sense, it is possible to find a vast literature in which for instance network theory is used as an instrument to understand very diverse questions about cities: from their commercial activity to their heritage condition. The contribution of this research consists in adding one step of complexity to this process: instead of working with one single primal graph as it is usually done, we will show how new network models arise from the consideration of two different primal graphs interacting in two layers. When we model an urban network through a mathematical structure like a graph, the city is usually represented by a set of nodes and edges that reproduce its topology, with the data generated or extracted from the city embedded in it. All this information is normally displayed in a single layer. Here, we propose to separate the information in two layers so that we can evaluate the interaction between them. Besides, both layers may be composed of structures that do not have to coincide: from this bi-layer system, groups of interactions emerge, suggesting reflections and in consequence, possible actions.
Optimization Aluminium Design for the Facade Second Skin toward Visual Comfort: Case Studies & Dialux Daylighting Simulation Model
Visual comfort is important for the building occupants to need. Visual comfort can be fulfilled through natural lighting (daylighting) and artificial lighting. One strategy to optimize natural lighting can be achieved through the facade second skin design. This strategy can reduce glare, and fulfill visual comfort need. However, the design strategy cannot achieve light intensity for visual comfort. Because the materials, design and opening percentage of the facade of second skin blocked sunlight. This paper discusses aluminum material for the facade second skin design that can fulfill the optimal visual comfort with the case studies Multi Media Tower building. The methodology of the research is combination quantitative and qualitative through field study observed, lighting measurement and visual comfort questionnaire. Then it used too simulation modeling (DIALUX 4.13, 2016) for three facades second skin design model. Through following steps; (1) Measuring visual comfort factor: light intensity indoor and outdoor; (2) Taking visual comfort data from building occupants; (3) Making models with different facade second skin design; (3) Simulating and analyzing the light intensity value for each models that meet occupants visual comfort standard: 350 lux (Indonesia National Standard, 2010). The result shows that optimization of aluminum material for the facade second skin design can meet optimal visual comfort for building occupants. The result can give recommendation aluminum opening percentage of the facade second skin can meet optimal visual comfort for building occupants.
Overcrowding and Adequate Housing: The Potential of Adaptability
Adequate housing has been a widely discussed theme in academic circles related to low-cost housing. Whereas its physical features are easy to deal with, overcrowding (related to social, cultural and economic aspects) is still ambiguous, particularly regarding the set of indicators that can accurately reflect and measure it. This paper develops research on low-cost housing models for developing countries and what is the best method to embed overcrowding as an important parameter for adaptability. A critical review of international overcrowding indicators and their application in two developing countries, Cape Verde and Angola, is presented. The several rationales and the constraints for an accurate assessment of overcrowding are considered, namely baseline data (statistics), which can induce misjudgments, as well as social and cultural factors (such as personal choices of residents). This paper proposes a way to tackle overcrowding through housing adaptability, considering factors such as physical flexibility, functional ambiguity, and incremental expansion schemes. Moreover, a case-study is presented to establish a framework for the theoretical application of the proposed approach.
Planning Politics of Dhaka City: Recent Urbanization and Gentrification
This paper will describe how a city planning can be abusive and promote gentrification in Dhaka city area in an extreme remorseless way. To our knowledge, Dhaka is enormously overpopulated, and its somewhat unrest political situation and corruption is promoting not only bruised urban growth but also this growth leering people socially and mentally. Due to globalization, whole world is in a rat race of development fiesta and Bangladesh is no longer falling back in this race. Recent political agenda is to develop the country anyhow, whether it is a good development or not. In the name of development, Dhaka city is becoming overwhelmed with flyovers, needless shopping malls and commercial complexes. This drastic urbanization is promoting gentrification. Gentrification is the process of societal change which intimidate the existing group of people from a certain place and encouraging affluent group of people on that place and eventually they take the control of that place. Process of gentrification is more capitalistic rather socially democratic. Architects are indirectly or directly related with this social change and politics is the catalyst of these social alteration. The methodology of this paper was mainly dependent on mass interviews including political leaders and activist’s interviews. Also, photographic analysis, empirical research etc. helped to create this paper. Secondary data were collected from different published and unpublished documents, relevant research articles, and books. From the study, it is clearly can be said that architects and urban designers are promoting social imbalance. The paper tried to suggest how architects and other designers can help to resist gentrification and can remain the social heterogeneity.
Investigating the Relationship between Visual Exposure and Crime Incidents by Crime Types
Crime prevention is more important to promote the safer living environment. Although various attempts had been made, Crime Prevention Through Environmental Design (CPTED) had been attracting attention, which can prevent the crime through manipulating the built environment. CPTED relies upon the proper design and effective use of the spatial physical environment of the neighborhood. The main strategies are ‘natural surveillance’, ‘natural access control’, ‘natural territorial reinforcement’. Among these, natural surveillance is effective by improving the visibility of potential offenders. However, it’s been recognized the quantifying the degree of natural surveillance be difficult. This study used Weighted and Layered Visual Access & Exposure (WLVAE) which is one of the quantitative spatial analysis models that are utilized to predict human behavioral patterns. The case study was conducted for J city in Korea and predicted the crime risky area based on the physical condition such as building shape, road width, and vacant lot etc. Next, based on 10,002 actual crime cases for three years, the relationship between visual perception and crime was examined by type of five crimes (rape, robbery, theft, violence, murder). The analysis used visual access (VE), which means visual exposure, quantifying the spatial extent of being observed in a certain spot from other points. As a result, theft revealed to occur mostly in the alley where VE value was the lowest. This means that theft of the five crimes is most affected by natural surveillance. Therefore, in order to prevent theft crime, a spatial design capable of natural surveillance is needed. This could provide a useful guideline to be applied to urban spatial design and to proactive and predictive police activities against the risk of theft crime.
Using Landscape as a Local Resource: The Case of the Eastern Poland
A crucial regional development factor involves activation of endogenous potential determined by available resources. In the resource-based approach to the regional development, two kinds of resources are usually being distinguished – those that might be recreated on a different territory and the local ones, constitutive for the uniqueness and singularity of the given territorial unit. The specific resources give rise to the competitive advantages of the area, on which they appear since they are characterised by the rarity of occurrence. The rural landscape is one of such unique resources. Its character and specificity result from geographical, cultural and historical conditions. The fundamental cognitive objective of the paper shall be constituted by the spatial identification and diagnosis of the specific rural landscape in the regions of Eastern Poland (three provinces: Podlaskie, Lubelskie, and Podkarpackie), as well as by the assessment of their development-related potential. The study analyses the level of uniqueness and usability of rural landscapes evaluated by a team of experts representing the scientific community or NGOs. The term usability is understood as a landscape potential to achieve success. The term uniqueness meant a rarity, which makes it very attractive. Examined region has a diversified types and structure of landscape. Highly rated landscapes focus on protected areas and contribute to the development of other local resources (material and human resources) mainly related to the tourist function. As a result, the most attractive categories of the rural landscape contribute to the multifunctional development of the countryside.
Case Study Approach Using Scenario Analysis to Analyze Unabsorbed Head Office Overheads
Head office overhead (HOOH) is an indirect cost and is recovered through individual project billings by the contractor. Delay in a project impacts the absorption of HOOH cost allocated to that particular project and thus diminishes the expected profit of the contractor. This unabsorbed HOOH cost is later claimed by contractors as damages. The subjective nature of the available formulae to compute unabsorbed HOOH is the difficulty contractors and owners face alike and thus, dispute it. The paper attempts to bring together the rationale of various HOOH formulae by gathering contractor’s HOOH cost data on all of its project, using case study approach and comparing variations in values of HOOH using scenario analysis. The case study approach uses project data collected from four construction projects of a contractor in India to calculate unabsorbed HOOH costs from various available formulae. Scenario analysis provides further variations in HOOH values after considering two independent situations mainly scope changes and new projects during the delay period. Interestingly, one of the findings in this study reveals that in spite of HOOH getting absorbed by additional works available during the period of delay, a few formulae depict an increase in the value of unabsorbed HOOH, neglecting any absorption by the increase in scope. This indicates that these formulae are inappropriate for use in case of a change to the scope of work. Results of this study can help both parties in deciding on an appropriate formula more objectively, considering the events on a project causing the delay and contractor's position in respect of obtaining new projects.
An Enquiry to Identify Reasons for the Low Popularity of Affordable Benue Burnt Bricks amongst Low and Mid-Range Salary Earners in Benue State, Nigeria
This study was made to establish the reason(s) why Benue burnt bricks does not enjoy widespread popularity amongst low and mid-range salary earners within Benue State in spite of its affordability. The affordability of the burnt bricks is due mostly to the fact that the raw materials, laborers and production sites are all indigenous to Benue State. To provide answers, forty-seven (47) homeowners of between grade levels 1 and 6 of the state's civil service, who have their building projects still incomplete for upwards of five (5) years were asked to talk freely and independently why they opted for sand/cement hollow blocks instead of burnt bricks. The study identified the reasons for low popularity of Benue burnt bricks as: (i) homeowners perceive burnt bricks as not prestigious enough for them (ii) homeowners assume that using burnt bricks for walls lead to wastage in mortar hence costly in the end (iii) there is a serious lack of bricklayers skilled in working with burnt bricks (iv) the production process of the burnt bricks is largely crude and unregulated leading to poorly produced bricks. It is recommended that the Benue State government and other regulating agencies such as the Council for the Registration of Engineers (COREN) and Council of Registered Builders of Nigeria (CORBON) take an interest in the industry and control its output in terms of quality, shapes and sizes of the bricks.
Simulation of Natural Ventilation Strategies as a Comparison Method for Two Different Climates
Health and living in a healthy environment are important for all the living creatures. Healthy buildings are the part of the healthy environment and the ones that people and sometimes the animals spend most of their times in it. Therefore, healthy buildings are important subject for everybody. There are many elements of the healthy buildings from material choice to the thermal comfort including indoor air quality. The aim of this study is, to simulate two natural ventilation strategies which are used as a cooling method in Mediterranean climate, by applying to a residential building and compare the results for Asian climate. Fulltime natural and night-time ventilation strategies are simulated for three days during the summertime in Mediterranean climate. The results show that one of the chosen passive cooling strategies worked on both climates good enough without using additional shading element and cooling device, however, the other ventilation strategy did not provide comfortable indoor temperature enough. Finally, both of the ventilation strategies worked better on the Asian climate than the Mediterranean in terms of the total overheating hours during the chosen period of year.
Baby Cot’s Indoor Air Quality
The indoor quality of occupied space is very important for the well-being of its occupants, especially in the case of babies. The lungs of a young child are still growing and adverse conditions could affect this development. Presently little children spend a lot of their time in day care centers while parents are at work. Little is known about the effects of different indoor environmental factors present in these day care centers and the quality of air of baby cots in which the babies are accommodated in these day care centers. Therefore this research investigated the quality of the accommodation of Dutch day care centers. Besides an extensive literature research actual measurements were performed in baby cots within three-day care center. Some experiments were performed to find out the importance of the configuration and types of baby cots. This research investigated the quality of the accommodation of a Dutch day care center which led to a tool describing the quality needs (e.g., quality standard) for the accommodation of day care centers. The results of our detailed studies were compared with the results of earlier Dutch more global studies in day care centers, in which more than 60 day care centers were investigated. Also the results are compared with the outcomes of research on school ventilation. The results proved that the situation in day care centers is even worse than that of schools within the Netherlands. More attention is needed to improve the current situation.