Scientia Iranica
Volume:23 Issue: 5, 2016

This paper puts forward a framework for optimal mitigation of regional risk to enhance the resilience of civil infrastructure. To meet this objective, probabilistic models, methods, and software are developed and applied. The work is conducted within a new reliability-based approach, in which reliability methods compute risk. This contrasts several contemporary approaches for risk analysis. Risk, in this context, denotes the probability of exceeding monetary loss. Evaluating such probabilities requires probabilistic models for hazards, response, damage, and loss. This motivates the following contributions in this paper. First, a new computer program is developed that is tailored to conduct reliability analysis with many interconnected probabilistic models. It orchestrates the interaction of models through an object-oriented architecture. Second, a library of probabilistic models for regional seismic risk analysis are developed. The library includes new models for earthquake location and magnitude and building response, damage, and loss. Third, probabilistic methods for multi-hazard risk analysis are developed and applied in a large-scale regional analysis. The results are cost exceedance probabilities and insights into the seismic risk of the region. Finally, sensitivity measures are developed to identify the buildings whose retrofit yields the most reduction in regional risk, i.e., the most resilience of the region.

Rapid urbanization is among the most important causes of ecological degradation across different spatial scales ranging from global to regional and local. While, protection of ecological health and resiliency has a profound effect on human being and welfare, it is essential for planners to incorporate ecological considerations into landscape and urban planning in order to realize wiser management of the future changes in harmony with sustainable development goals. This research introduces an approach to combine imperviousness indicator with landscape metrics to provide quantitative information on the spatiotemporal dynamics of Shiraz region. Landsat images are used to map the land cover of Shiraz region in 1976, 1990, 2000 and 2005. Using landscape metrics, spatial composition and configuration of impervious surface have been quantified. The metrics indicated increase in the size and connectivity of impervious surfaces. Results reveal that the growth of urbanization has had tremendous effects on the size and connectivity of natural landscapes particularly agricultural areas and wetlands.Furthermore, two urban growth scenarios have been generated for the year 2021 using modeling and compared using the aforesaid indices. The results point out that smart growth scenario, in which the land is efficiently used, is ecologically a more resilient option.

This study introduces an empirical equation for estimation of Aerosol Optical Thickness (AOT) and visibility reduction based on three main dust indices of Normalized Di erence Dust Index (NDDI), Brightness Temperature Di erence (BTD), and Thermal infrared Dust Index (TDI). The implementation of NDDI, BTD, and TDI in dust enhancement over bright to dark background was evaluated. The thresholds of BTD over dust and cloud pixels revealed the capability of Moderate Resolution Imaging Spectroradiometer (MODIS) images in separating dust from underlying bright surfaces and clouds. The results indicated that solar reffective bands were insucient to precisely separate dust from clouds, but combination of solar reffective bands and thermal infrared bands synergistically improved the accuracy. The evaluation of results revealed the remarkable correlation of AOT with dust enhancement indices over 11 synoptic stations: BTD (R2 = 0:73), NDDI (R2 = 0:67), and TDI (R2 = 0:71). Hence, AOT and visibility reduction were obtained using multi-regression equation using NDDI and BTD as variables. The accuracy assessment indicated good correlation (R2 = 0:74) between both estimated AOT and the AOT reported by Air Quality Control stations. Moreover, the results con rmed the advantage of proposed AOT as a consistent index for dust enhancement over bright surfaces and dust classi cation as well.

The e ects of climate and meteorological factors on urban problems such as air pollution, heat island, and urban hydrology have increasingly become important in terms of mitigation and adaptation issues during the recent years. In the present paper, we discuss some of the climate or meteorological factors a ecting air pollution in Tehran. Tehran is a unique megacity in terms of geographic setting, being mountainous and an ever-expanding urban area that su ers from acute air pollution and heat waves episodes. Recent records of air pollutants also show increased trends with some low-frequency variability caused by chaotic atmospheric motions. Moreover, the wind speed has also decreased as a result of the aerodynamic surface roughness increase and probably the decrease in the passage of cyclones over the mid-latitudes according to the recent ndings. Mixed-layer height over the city, due to higher-surface heat fluxes (mainly due to the reduction in surface albedo, anthropogenic heat, and lower green spaces), is expected to increase; although it is favorable for reduction in some air pollutants such as CO, it is not eligible for ozone. Finally, an integrated framework for actions regarding impacts, emissions, urban climate change, and monitoring including adaptation and mitigation towards a climate-change resilient city is proposed.

Network pricing is an effective transportation demand management scheme to reduce traffic and control air pollution, particularly in CBD’s. In this study, congested area cordon entry and Park-and-Ride (P/R) facility use are priced for automobiles. Increase in these prices may reduce private auto demand by impelling some of them into using public transport from the origin of their trips, or encouraging them to park their cars at the P/R facilities and use buses, or pay the entrance fee and drive inside the cordon. A Markov decision process has been devised to findan optimal policy for pricing the P/R facilities and cordon entry in a city within a variable demand context. This process is sensitive to weather condition (more favorable atmospheric condition allows lower prices). It leads to a balance between the costs of pollution hazards to the public at large on one side, and the cost imposed upon auto drivers to take the next best decisions and their travel times and costs on the other side: thus giving a resilient character to the city. The model has been applied to the network of a large urban area, and the results are analyzed. Suggestions for further research end the discussion.

The changes of soil organic carbon and soil carbon decomposition are influenced by temperature and precipitation changes. In the present study, the changes of soil organic carbon under climate change scenarios were estimated by the Rothamsted Carbon model in different land-use areas in north and northeast of Iran. The total soil organic carbon was observed 106.2 tC/ha in the study area. The changes of soil organic carbon was estimated to be 980 soil sample under A2 and B2 senarios by using RothC model in various land-use areas. Future temperature and precipitation data under both scenarios were predicted by LARS-WG weather generator model based on the IPCC AR4. The simulated results of soil organic carbon illustrated that over the period 2010-2065, SOC will decrease in the study area. The simulation of soil organic carbon strongly suggests that SOC levels will decline due to temperature increase and decline on precipitation, particularly in cultivated lands. SOC is expected to decrease under A2 climate scenario by 8.3 tC/ha and 13.36 tC/ha by the year 2030 and 2065, respectively. Likewise, under the B2 scenario, SOC will have decreased by 8.58 tC/ha and 13.81 tC/ha by the year 2030 and 2065, respectively.

During recent years, Shape Memory Alloys (SMAs) have been e ectively used to control the seismic response of structural systems. Recovering the residual strains upon unloading (super-elasticity) or by heating (shape memory e ect) is the main characteristic of SMA materials. This paper explores the eciency of a proposed application of steel & SMA bolts in improving the seismic behavior of connections in steel Moment Resisting Frame (MRF) structures. A new semi-rigid, end-plate, beamcolumn connection is introduced, which is based on parallel application of steel and austenite-phase SMA bolts. A number of 3-D steel MRF structural models with di erent numbers of stories and mass eccentricities are considered. These structural models that are designed by employing the conventional rigid and the proposed semi-rigid connections are subjected to bi-directional earthquake records that have been scaled according to ASCE7-05 procedure. Extensive nonlinear dynamic time history analyses are conducted to evaluate the eciency of the steel & SMA based connections in enhancing the seismic performance of the structural models. The obtained results indicate that the proposed steel-SMA connection is highly promising and can eciently reduce the seismic response parameters of the structural systems. Steel bolts of the end-plate connections contribute both to shear force transfer (from beam to column) and dissipation of the input seismic energy through hysteresis behavior. On the other hand, parallel application of steel and SMA bolts in the connections reduces the story drifts as well as the induced forces in the structural elements while decreasing the permanent story displacements. The main goal obtained is to keep the beams away from the formation of plastic deformation. OpenSees platform is used for generating the structural models and performing the numerical analyses.

Present study’s target is to depict an inclusive construction waste management (CWM) plan looking at the total project life cycle. This holistic approach was called Integrated Construction Waste Management (ICWM). This research program was conducted through several consecutive academic dissertations at Civil Engineering Department of SUT and was firstly aimed to identify waste sources throughout project life cycle. Concurrent research efforts were focused on project delivery methods evaluation e.g. contract type effect on waste generation amount along with appropriate guidelines/incentives development that could promote ICMW. These studies were conducted via field observations and questionnaire surveys where respondents were educated, skilled and experienced construction industry experts. The research findings indicate that construction waste origins/processes should be determined separately during construction projects life cycle to devise exclusive solutions accordingly. Furthermore, cost-plus contract, which is common in local residential projects in Iran is identified an improper contract type from construction waste generation standpoint. Incentive based programs, project stakeholders training, salvage plan establishing for all materials before project initiation and apt documentation for future CWM planning are identified effective/practical ICWM solutions. Finally it was concluded that thriving ICWM is going to be a teamwork result rather than responsibility of a sole stakeholder e.g. contractor.

The rapid and uncontrolled haphazard urbanization is a serious threat to the manmade and natural environment and the socio-economic balance of our time. There is a global concern that urbanization must be oriented into responsible, sustainable, and livable urban forms. High quality of sustainable urban design plays a key role in creating these sustainable living environments. In this regard learning from culture and history, and searching together for new ways of designing is a must. In this paper the evolution of the settlements with respect to sustainable urban design in past, present & future is analyzed. The study indicates that we had sustainable urban design in pre- industrial period in an organic way; but, we alter their existing ecosystems by welcoming incompatible technological elements; elements that cause a kind of ill growth similar to cancer. In this relation a case study of urban environmental design for Darabad River valley in Tehran as a sustainable urban design project is presented in brief. Finally it is concluded that we should know that designing is a kind of altering the systems. A comprehensive wise and conscious approach similar to what we have used in Darabad River valley project is suggested for similar situations.

In the 21st century, the world population is growing at a spiraling paste. Much of this growth is occurring in developing countries, where access to food, sanitary water, education, and health is severely limited. The ever increasing urbanization highlighted the need for sustainable development based on human-environment interaction. The excessive and unplanned expansion of cities has resulted in numerous environmental predicaments due to clearly emphasized economic issues at the expense of social and environmental concerns. The most significant features of megacities are indicated in this paper and the environmental, social, physical, and economic criteria are addressed in order to attain sustainability and resilience. To examine the practical use of these criteria, extensive studies and field activities were carried out at District 14 of Tehran Municipality. The results of this study highlighted the desire of authorities to move toward sustainable development as their activities indicate environmental improvements during 2009-2014 period. At the end, several recommendations are made based on the obtained results to speed up the move toward sustainability and resiliency

A disaster is an adverse event resulting from natural processes of the Earth or sometimes from terrorist attacks. Since the concept of disaster resilience has become prominent, research and practice for making the cities resilient play an important role in urban management. Cities are composed of a variety of structures and providing the structural resiliency can protect them. Resilient structures are composed of a number of ideal performance criteria, which based on analysis, experiment, and past experience, are capable to withstand the required level of stress and deformation. In addition, durability, re resistance, and other capabilities, such as being environmentally friendly with no considerable reduction in functionality, are some of their other characteristics. In this paper, according to various design needs of structures, major in fluencing parameters are introduced in order to attain resiliency. Even though not all structures can be managed to be totally resilient, in other words to resist all types of action situations, the trend is to provide as many functions as possible. For example, not all structures can be designed to withstand wind, earthquake, and explosion. Generally, structures may be designed and built for a certain kind of actions. In the end, general considerations will be demonstrated to provide structures with speci c criteria for resiliency.

Cities are complex and dynamic Meta systems in which technological components and social interact. A variety of hazards threatens cities, so planning for resilience in the face of urban disaster is important. We are just beginning to realize the scope and magnitude of the challenges inherent in making our cities resilient to threats from natural hazards and terrorism. To meet these challenges, a national resilient cities initiative, aimed at the vision of the resilient city as the goal that cover all type of hazard mitigation. To succeed, this initiative will require changes in national disaster policy, funding for urban systems research, support for advanced education program and active collaboration among the city professions.One of the natural hazards which cities should be resilience to, is drought that is resulted from climate change. The city of Mashhad which has been faced with water crisis in recent years is selected as a case study. By analyzing the status of water resources and its changes during the periods of growth and development of the city, its function towards the resilience and sustainability is measured. Also necessary strategies for improving the water resourcescondition in order to becoming resilient and sustainable city are proposed.

Part of resilience and sustainability in any urban environment is establishment and maintaining health. Sustainability in health is a dynamic process in which growth of physical, mental and social health is guaranteed. A city is sustainable when all aspect of life such as economy, environment, health and infrastructure are well defined and very often subjected to optimization.