Use of ANSYS for Thermal Analysis in Mass Concrete

With the increasing development of Brazil in recent years, major engineering construction works have been designed and built, partieutarly those involving large volumes of mass concrete, such as in the case of dams. Mass concrete, due to its large size and volume, presents a considerable temperature rise caused by cement grain hydration. This temperature rise can be sufficient to cause concrete crack and/or cracking, which may lead to serious problems. In this paper, we sought to study heat generation and temperature field in mass concrete through ANSYS software, which uses finite element method to analyze the problem. This program allows temperatures to be checked for different concrete ages. With that, it is possible to evaluate the temperatures obtained and the factors influencing the results in a short period of time at a low cost. With the help of the software, it is possible to check the temperatures for different concrete properties by analyzing them on different concreting days. Therefore, it was possible to establish that the properties of the concrete directly influence the temperature evolution phenomenon.     

Design Drivers for Affordable and Sustainable Housing in Developing Countries

Current demand for housing worldwide has reached unprecedented levels due to factors such as human population growth, natural disasters and conflict. This is felt no more so than in developing countries which have experienced disproportionate levels of demand due to their innate vulnerability. Many current approaches to housing delivery in developing countries continue to utilize inappropriate construction methods and implementation procedures that are often problematic and unsustainable. As such affordability and sustainability are now vital considerations in the international development debate for housing the poor in developing countries in order to meet the long term sustainable development goals and needs of housing inhabitants. This paper utilized an extensive scoping study to examine the various facets impacting on design decision making relative to sustainable and affordable housing delivery in developing country contexts. Aspects of affordability, sustainability, design decision making, appropriate technology use, cultural awareness, as well as current barriers to affordable and sustainable construction in developing countries are examined in detail. Results highlighted the capability of indigenous knowledge, skills and materials as well as selected appropriate technology transfer and cultural awareness by foreign bodies can be utilized in innovative ways in addressing current housing needs in many developing country contexts.     

The Role of Architectural Considerations in Seismic Performance of Buildings： A Case Study in Iran

Experience from recent earthquakes such as Gilan, Zanjan, Bam and Lorestan earthquakes in Iran indicated that the constructed buildings are vulnerable against earthquake. Vulnerability of these structures is due to various reasons such as designing without considering seismic regulations, problems of regulations （design goals）, implementation problems, changing of the building occupancy class, increasing the weight of building stories, adding new stories to the building and changing in architecture of building without considering structural system. So the main objective of this research is to examine the features of building configuration and their effects as for the damages to buildings in past earthquakes. For this purpose, initially four occurred earthquakes in Iran are selected as case study. Then three types of buildings （steel structure, concrete structure and masonry buildings） are analyzed with details. Results showed that the most of damages are occurred in the old steel structures and masonry buildings which their ages are more than 25 years. The study showed that most of the buildings in the study area are steel structure and masonry buildings while concrete structures are infrequent which most of them had no or slight damages. Therefore, the importance and need to enhance the performance of available buildings against earthquake forces by rehabilitating methods would be more important than before. Also results indicated that the decisions related to architectural plan which have significant effect on seismic performance of buildings, can be divided into three categories： configuration of building, restrictive formal architectural plan and dangerous structural components, as these categories are not obstacle of each other, it is possible that each category has an influential effect on others. So organizing the design decisions in this way is very important so as to manage their effects and interdependencies.     

用回收的砖块作混凝土骨料的可能性

Recycling in the building and construction industry is becoming more and more important. In many western European countries, facilities and institutions have already been established to recycle waste generated from construction and building industry. However, in Yugoslavia, little attention has been paid to recycling some of the by-products (wastes as rejects) of some building materials‘ production facilities, such as brick and tile industries. This is perhaps, because of certain industrial wastes, which make them unsuitable for further use.The present study shows, however, that clay brick wastes/rejects can be used as aggregate for producing light-weight concrete.     

Long Run Relationships,Vertical Integration and International Competition： Can They Contribute to Explaining Regional Construction Cost Differences？

The existence of opportunistic behavior by contractors or sub-contractors in the bidding process encouraged by the governance structure of construction companies as well as the kind of relationship that exist between contractors and clients is thought to have some bearing on the rising construction cost observed in some regions of Sweden. Three hypotheses that are intended to test the impact that long run relationship between contractors and developers, vertically integrated firms, and the increase of international competition could have on the construction cost increase levels were tested on a predetermined number of projects from six cities in different regions. The semi-structured survey produces inconclusive results. Long run and collaborative relationship was prevalent in small region though respondents in this region did not draw strong connection between construction cost increase levels and the kind of observed relationship. In Stockholm region, short-term relationship was mostly prevalent. Vertical integration and foreign competition impacts on construction costs were not significant in either region.     

Engineering and microstructure properties of contaminated marine sediments solidified by high content of incinerated sewage sludge ash

Management of incinerated sewage sludge ash(ISSA) and dredged contaminated marine sediments(CMSs) is a great challenge for Hong Kong and other coastal cities due to limited landfilling capacity.The present study investigates the use of high content(20% of sediment by mass) of ISSA in combination with cement/lime for solidification/stabilization(S/S) treatment of CMSs to provide a way to reuse the wastes as construction materials.The results showed that ISSA being a porous material was able to absorb a large amount of water rendering a more efficient solidification process of the marine sediment which normally had a very high water content(～80%).The S/S treatment improved the engineering properties of the sediment,but reduced the workability,especially for the lime-treated samples.Lime can be used to replace ordinary Portland cement(OPC) for better heavy metal immobilization and carbon emission reduction.The hardened sediment samples prepared with 10% of lime and 20% of ISSA could attain a strength of 1.6 MPa after 28 d of curing.In addition,leaching tests confirmed that there was no environmental risk induced by these stabilized materials.The formation of hydrated cementitious compounds including calcium silicate hydrate(C-S-H)/calcium aluminate silicate hydrate(C-A-S-H)/hydrocalumite/calcite was mainly responsible for the strength development in the ISSA/lime-treated sediments.     

Effective Utilization of Concrete Sludge as Soil Improvement Materials

The amount of muddy soil generated from various kinds of construction sites is always problematic. It is very difficult to treat muddy soil because of its low strength and high water content. But, the reuse of muddy soil is necessary to reduce the total amount of industrial wastes. Surplus concrete is also in a similar situation. Coarse and fine aggregates are removed from surplus concrete as an intermediate treatment, however, concrete sludge still remains. The authors propose a reuse method that involves the muddy soil being mixed with concrete sludge as an improvement material. The possibility of the utilization of concrete sludge was investigated through laboratory experiments. As a result, it was found that the unconfined compressive strength of the improved soil mixed with concrete sludge increased as the curing proceeded.     

Private Housing in U.S.A.

The United States is among the few countries which have the highest percentage of private housing ownership. This article is divided to three parts to tackle the various aspects of private housing: finance and market; design and construction. The figures of new construction house become the thermostat of American economy, and the home building is seen as the locomotive of US national economy. Measured by the housing price and annual income ratio (PIR)     

Sustainable Methods and Techniques in Old and New Public Constructions

This article is about the methods and techniques used in the building ＂retrofit＂ in modernist style designed by the architect Affonso Eduardo Reidy in the fifties, and also about the project of the new Rio de Janeiro MIS （Museum of Image and Sound）, under construction, by The North-American office Diller Scofidio ＋ Renfro, both located in the city of Rio de Janeiro. These constructions present a wide view of the concept of sustainability, not commonly used in public buildings in Brazil. In the building designed by Reidy, which belongs to the State of Rio de Janeiro, the regeneration to host the new headquarters of the State Department of Taxation and Finance respected its original characteristics and used smart and sustainable design techniques, as well as recyclable materials. On the other hand, the project of the new museum at Copacabana Beach was entirely planned on sustainable bases and it includes the application of building techniques concerning that purpose. This article presents a study of these two cases and evaluates the techniques and materials used in one another. Observing the principles of sustainability in construction is a pioneering initiative of the State Government. This article aims at making the scientific community aware of the needs of immediate adoption of sustainability techniques in Civil Engineering, not only in the construction of new buildings, but also in the regeneration of the existing ones, as well as the need of imperious adoption of sustainable techniques when it comes to maintainability.     

低收入群体住房：克罗地亚转型经济展望

The transition process in the housing and construction industry has embraced deep structural changes on the side of both suppliers and buyers. As a new independent country, Croatia has been undergoing a complex process of transition towards a market environment. The country was exposed to war in the early 1990s, that has resulted in targeting major portion of its potentials towards the reconstruction of destroyed/damaged property.A comprehensive reconstruction should involve all forms of market-friendly, social, environmental, and economic policy to ensure good quality of life as well as regional and sustainable development. However, it is important to notice that the efficient privatization and establishing an effective private sector is an unavoidable pre-condition for the overall economic development as well as an efficient housing industry. Therefore, the increasing role of the private sector strongly correlates with the successful market transformation and the time needed to catch up with the needed growth. This paper introduces low-income housing as the perspective of the Croatian transition economy.     

Causes of Buildings＇ Abandonment in the Years 1960-1990

When a relatively new building is not being fully utilized, there must have existed, at one time, a change in its initial conditions. The aim of this research is to study the changes in the initial conditions which cause buildings to be underutilized and analyze whether the demolition was justified. Causes can be found in problems due to the building＇s management, as the owners make the main decisions concerning the buildings. Additionally problems are due to the location where the building is constructed because site conditions changes a lot in one generation. The use of the building can also be a cause of abandonment as the original use can end before the lifespan of the building. Architectural style can be dated as fashions and styles change rapidly. Finally, causes can be in the physical condition of the buildings： structure, construction, installations and adherence to current regulations. In this article, the authors provide guidelines demonstrating how buildings of a past generation which were initially considered obsolete, can be properly reused.     

Influence of zeolite and cement additions on mechanical behavior of sandy soil

It is well known that the cemented sand is one of economic and environmental topics in soil stabilization.In this instance,a blend of sand,cement and other materials such as fiber,glass,nanoparticle and zeolite can be commercially available and effectively used in soil stabilization in road construction.However,the influence and effectiveness of zeolite on the properties of cemented sand systems have not been completely explored.In this study,based on an experimental program,the effects of zeolite on the characteristics of cemented sands are investigated.Stabilizing agent includes Portland cement of type Ⅱand zeolite.Results show the improvements of unconfined compressive strength(UCS) and failure properties of cemented sand when the cement is replaced by zeolite at an optimum proportion of 30%after 28 days.The rate of strength improvement is approximately between 20%and 78%.The efficiency of using zeolite increases with the increases in cement amount and porosity.Finally,a power function of void-cement ratio and zeolite content is demonstrated to be an appropriate method to assess UCS of zeolite-cemented mixtures.     

Investigation in Mathematical Models of Chloride Diffusion Coefficient in Concrete Exposed to Marine Environment

Degradation of RC （reinforced concrete） in maritime structures has become a worldwide problem due to its excessive costs of maintenance, repair and replacement in addition to its environmental impacts and safety issues. Degradation of both concrete and steel which is the main reason of reduction in the service life of RC structures strongly depends on the diffusion process of moisture and aggressive species. In this paper, the major and popular mathematical models of diffusion process in concrete are surveyed and investigated. Predominantly in these models, the coefficient of chloride diffusion into the concrete is assumed to be constant. Whereas, experimental records indicate that diffusion coefficient is a function of time. Subsequently, data analysis and comparisons between the existing analytical models for predicting the diffusion coefficient with the existing experimental database are carried out in this study. Clearly, these comparisons reveal that there are gaps between the existing mathematical models and previously recorded experimental results. Perhaps, these gaps may be interpreted as influence of the other affecting parameters on the diffusion coefficient such as temperature, aggregate size and relative humidity in addition to the water cement ratio. Accordingly, the existing mathematical models are not adequate enough to predict the diffusion coefficient precisely and further studies need to be performed.     

Augmented Reality Applied to Building Assessment with Building Information Model Visualization

AR （augmented reality） is a technology that adds information to the real world adding virtual elements to its visualization in real time. AR used in AECO （architectural, engineering, construction and operations） can contribute in augmenting visualization during design, construction and operation of the buildings. This article presents a study that applies AR to building assessment with BIM （building information） model visualization. The use of AR on existing applications for smart phones and tablets is validated. AR proposed an adaptation of the method of POE （post-occupancy evaluation） subsidized. Traditional POE process model involves three phases： planning, conducting and applying. In order to incorporate AR, it is proposed a total restructuring of the planning phase, developing the research instruments in three steps： 3D modeling, model treatment and AR application development. It was observed that for POE studies, the 3D models are in large scale and need to be detailed for precise comparison. BIM models for facility management, representing building use situation, are of the highest level of detail. A balanced point between simplicity and representativeness was the solution adopted in this experiment for uploading and downloading performance issues. This article presents and discusses findings for the new proposition for the activity of research instruments development for the planning phase of POE with AR as well as initial tests with first results and difficulties faced.     

An experimental study on using a mass radiant floor with geothermal system as thermal battery of the building

Storing thermal energy in mass concrete floors would have a major impact on the stability of the temperature in buildings. The concept of a thermal battery refers to storing the supplied radiant heat and releasing this heat the next day through radiation and convection. In this study,an approach is introduced to examine the idea of thermal battery in thick concrete flooring( 1.22 m) using the earth as a heat source. Controlled experiments were built and conducted on an instrumented 3000 m~2 industrial facility. The heating radiant floor combining with ground source system was operated during off-peak hours and the ai conditioning system was disabled for 24 h during the test period.The heat pumps were operated in single stage using less powe compared to when operated on demand. Indoor air temperature showed that 100 °F( 37. 78 ℃) supply temperature at the groundsource heat pump would be enough to maintain a stable warm temperature during cold days. Two weather conditions in the winter were selected to do the tests. The second test had a colder ambient temperature to verify the procedure. The indoor air temperature showed that the night heating system performs well for both cases because it maintained a constant temperature for the entire operational day even in the daytime when every heating unit was off. This approach of applying the heating at nighttime with lower electricity rates would lead to significant operational cost savings in the building.     

Behavior of zeolite-cement grouted sand under triaxial compression test

Permeation grouting with cement agent is one of the most widely used methods in various geotechnical projects,such as increasing bearing capacity,controlling deformation,and reducing permeability of soils.Due to air pollution induced during cement production as well as its high energy consumption,the use of supplementary materials to replace in part cement can be attractive.Natural zeolite(NZ),as an environmentally friendly material,is an alternative to reduce cement consumption.In the present study,a series of consolidated undrained(CU) triaxial tests on loose sandy soil(with relative density D_r=30%)grouted with cementitious materials(zeolite and cement) having cement replacement with zeolite content(Z) of 0%,10%,30%,50%,70% and 90%,and water to cementitious material ratios(W/CM) of 3,5 and 7 has been conducted.The results indicated that the peak deviatoric stress(q_(max)) of the grouted specimens increased with Z up to 50%(Z_(50)) and then decreased.The strength of the grouted specimens reduced with increasing W/CM of the grouts from 3 to 7.In addition,by increasing the stress applied on the grouted specimens from yield stress(q_y) to the maximum stress(q_(max)),due to the bond breakage,the effect of cohesion(c') on the shear strength reduced gradually,while the effect of friction angle(φ')increased.Furthermore,in some grouted specimens,high confining pressure caused breakage of the cemented bonds and reduced their expected strength.     

Evaluation of Porous Structure of Cement Pastes Made with Residual Rice Husk Ash

In several countries, the residual RHA （rice husk ash） has been produced in rice processing industries or in thermoelectric plants that use rice husk to generate heat and/or electrical energy, usually without burning process control. This causes a reduction in the amorphous silica content of residual RHA, which distinguishes them from the RHA produced according to controlled burning process, which is totally amorphous and considered a highly reactive pozzolan. In this paper, the hydration products and the porous structure of binders paste were studied by replacing, in weight of 5%, 10% and 20% of Portland cement OPC （ordinary Portland cement）, by residual RHAs named A and B, which have high and low content of amorphous silica, respectively, using microstructure evaluation techniques as XRD （X-ray diffraction）, TG （thermogravimetric） tests and MIP （mercury intrusion porosimetry）. A reducing the size of the pores of the pastes was observed according to the increase of content replacement of RHA A and RHA B.     

Design and Management of Building＇s Resources

The developed modem control systems and buildings management resource systems would be effective if they are based on previously established optimal conditions during the building design. This is one of the key issues for a responsible architecture. The focus of this paper is on sustainable design methods and techniques for saving resources and their management throughout the building lifecycle. The main subject of the present article is the characteristics of these methods and their fundamental role in sustainable resource management during the building operation. The results which are based on conducted case studies of European and international practice in the construction of sustainable buildings are implemented here. Key features of a comprehensive approach for design and construction are outlined via comparative analysis, as well as various systems for the evaluation of sustainability for already constructed buildings. The mostly used criteria and indicators for sustainability are systematized, including those related to resource consumption. By analyzing a specific example, the role of sustainable design methods is justified as an important prerequisite for effective management of building resources in the process building maintenance. According to the conducted studies, during the longest life cycle period of a building, by implementation of control systems and resource management of building, the costs are successfully optimized. Specific directions that prove the effectiveness of such systems are systematized in the paper. Innovative approaches, complex methods and measures for design and management of buildings resources are presented as results of this study.     

Guidelines for Low-Cost,Energy-Efficient House in Iraq

The goal of this study is to determine specific guidelines for Iraqi architects to contribute to the design and composition of energy-efficient housing units within the limits of a normal budget, locally available materials and technologies. These units can provide comfort despite the current energy situation in Iraq. The study is based on a computer simulation for a reference building in Baghdad, which has been selected according to the urban conditions, building legislations, housing market and statistics. The final results displayed the main recommendations and the possibility to achieve up to 50% energy reduction with a pay-back period not exceeding two years in some cases. There are some measures that have big energy saving potential. Yet, some of the measures may require big investment or have some bad environmental impacts. Some other good measures are already being implemented.     

Assessing the influence of jet-grouting underpinning on the nearby buildings

This paper focuses on the underpinning-induced ground movement due to jet-grouting. Jet-grouting technique can cause distortions as a result of an inaccurate processing sequence and/or errors made at different stages of work execution. The aim of this paper is to determine the minimum value of such movement on the basis of the findings obtained at two similar construction sites located in the Historical Center of Moscow, considering that the maximum value is usually unpredictable. Numerical simulation of the process of soil eroding agrees well with the observational data at the current stage. It was found that the minimum value of deformations （only settlement was considered in this study） due to jetgrouting is no less than 2-3 mm. By contrast, the negative scenario of deformation due to foundation underpinning is clearly demonstrated. Also, this paper provides some general solutions for excavation supporting system as well as for underpinning design.