In the current research project, three work packages have been adopted. Firstly, ambient vibration measurements have been performed in a number of buildings in order to obtain the building's dynamic properties. Secondly, Finite Element Models have been created in order to check the inelastic properties of selected buildings for different earthquake hazard levels. Finally, a long-term structural health monitoring system using low-cost sensors will be adopted in order to monitor and validate the response of critical infrastructure as well as inform local staff and building occupants of earthquake impact in real-time warning.

RC frames with infill walls account for a large portion of building stocks, particularly for low to medium-rise buildings in Asia and other parts of the world. Based on past studies and the observed responses of these buildings during earthquakes, infill walls play an important role in the structural response of buildings under seismic excitations. Disregarding their influences on the seismic design and evaluation of structures could be potentially dangerous. However, the interaction between the frame and the infill wall is very complex. Therefore, a reliable numerical model is necessary. A novel multi-strut macro finite element model was used in this study to perform vulnerability assessment of an example low-rise RC frame. Data-driven empirical formulas for predicting the equivalent strut parameters were developed and calibrated based on a comprehensive experimental database and regression analysis. The application of the proposed approach for an RC frame simulation was examined.

This paper proposes a smart queue management system for delivering real-time service request updates to clients' smartphones in the form of E-Ticket by using the Bluetooth Low Energy in broadcasting advertising packet mode. The proposed system aims at reducing the dissatisfaction with services with medium to long waiting times. To this end, the system allows carriers of digital tickets to leave the waiting areas and return in time for their turn to receive service.

An accidental explosion can cause severe damage to the structure and its inhabitants. Then, this paper provides an interesting comprehensive, Comprehensive Blast Analysis (CBA), to demonstrate the severity of non-structural elements by analyzing the structural and non-structural responses. For the structural response, the acceleration response was measured and represents the absorbed energy of the main structure affected by fragments of non-structural elements by using the concept of Arias intensity. For non-structural elements, the kinetic energy of fragments was used to express the severe damage to people. Moreover, the Applied Elements Method (AEM) was used to interpret the numerical outcomes of structural and non-structural responses. The purpose of the current study is to compare the severity of outer-cladding materials, which are brick and reinforced concrete walls, damaged to the residual structure and inhabitants.

1. Introduction

Compared to the rural environment, cities tend to be warmer due to their uncontrolled growth which is known as the urban heat island (UHI). UHI causes increasing risk of a wide range of illnesses including heat exhaustion, heat stroke, and even mortality. Besides, it leads to high power consumption due to the increased need for indoor cooling, which in turn leads to a positive feedback loop and higher land surface temperature (LST). Dhaka, the capital of Bangladesh, is expanding at double the rate of any other region of the country which also increasing temperature [1]. This study analyzed the growth of Dhaka and its impact on LST and UHI from 2001 to 2020. Besides, green recovery measures had been applied in various cities across the globe have been evaluated to recommend UHI mitigation measures for the city.

2. Data and Methods

The UHI was estimated using daily LST (MOD11A1) data from the Moderate Resolution Imaging Spectroradiometer (MODIS). In addition, we used MODIS annual land cover (LC) data (MCD12Q1) to calculate the city's footprint. In order to examine Dhaka's expansion, we used the city clustering algorithm (CCA) [2] to map out the city's boundaries for all years between 2001 and 2020. The urban LST were studied over the specified urban region. Daytime and nocturnal LST were utilised to examine the impact of urbanisation on LST. At last, statistical analysis was used to assess temperature rise in urban areas relative to their non-urban surroundings.

3. Results

The CCA estimated areal extend of all years between 2001 and 2020 showed an increase in the size of the city by 362 km² in 2020 compared to 2001. The major expansion happened in the north. Figure 1 shows the geographical distribution of LST of Dhaka city and its adjacent areas in 2001 and 2020. Above the city's heavily populated part, the temperature can reach over 32^oC, although it seldom rises beyond 26^oC in the surrounding rural area, demonstrating the presence of a heat island. This means that in certain parts of Dhaka city, the temperature is almost 6^oC higher than in the surrounding non-urban areas. In recent years, the UHI increase was most pronounced in the city's northern and eastern neighborhoods due to more development in those regions.

4. GREEN RECOVERY OF CITY

Adaptation strategies have been put into practise in a number of cities, with positive outcomes. Though many recognised methods of mitigation exist, owing to Dhaka's unique economic and urban structure not all of them can be used. Different anthropogenic heat sources and a wide diversity in building height make it difficult to outline adaption methods for a metropolis as vast and diverse as Dhaka. However, within a small area, a mix of green and cool roofs and plantation might work. Urban development policies can help in formulating environmentally friendly regulations for the future build-up regions and protecting current green spaces and water bodies in Dhaka.

5. Conclusion

The rising temperature in Dhaka city is a direct result of its rapid growth. A persistent upward trend in urban UHI temperature indicates future temperature increases attributable to continued urbanization. Temperature increases associated with global warming are already being felt across the country, and if they continue to climb, the situation might become intolerable. Extreme heat might pose a serious threat to public health in this densely populated metropolis which might have disastrous consequences in the years to come. The city needs actions for green recovery is needed to mitigate the UHI effect.

References

[1] A. S. M. S. Uddin, N. Khan, A. R. M. T. Islam, M. Kamruzzaman, and S. Shahid, “Changes in urbanization and urban heat island effect in Dhaka city,” Theor Appl Climatol, vol. 147, no. 3–4, pp. 891–907, Feb. 2022, doi: 10.1007/S00704-021-03872-X.

[2] S. Peng et al., “Surface urban heat island across 419 global big cities,” Environ Sci Technol, vol. 46, no. 2, pp. 696–703, Jan. 2012, doi: 10.1021/es2030438.

Historical structures are very valuable national asset of Thailand. Several cultural sites have been designated by UNSECO as the World Heritage Sites, and some sites are in the nomination process. The ancient structures in many parts of the country have been deteriorating due to aging, environmental impacts and man-made activities and they require rational conservation plans. From structural conservation point of view, modern engineering techniques can be served as efficient tools for documentation and assessment of the existing conditions of these structures prior to any intervention on them. The project “Conservation of Historic Structures by Engineering Measures” was supported by Thailand Research Fund (TRF) and National Research Council of Thailand (NRCT) during 2016 to 2021 with objectives to apply engineering measures to document and evaluate structural condition the historical structures. The study sites are Ayutthaya historical park, Sukhothai historical park, Si Thep historical park and Phanom Rung historical park. Research contents consist of survey and construction of image-based 3D model of historical sites using an unmanned aerial vehicle (UAV) and Structure From Motion (SFM) technique, dynamic test and analysis of ancient monuments and finite element analysis of the historic structures under environmental loads. The major outcome from the research is to commence documentation of the existing conditions of the historic structures for further reference and sustainable conservation plans.

A large proportion of existing low-rise buildings in Bangladesh, India, Indonesia, Nepal, China and many other countries in Asia are unreinforced masonry (URM) buildings, which are quite vulnerable to earthquake ground shaking. This is one of the key factors contributing to large social and economic losses in the past earthquake disasters. The first challenge is to find ways to replace these vulnerable non-engineered buildings with stronger engineered buildings. Reinforced concrete (RC) buildings, if properly designed and constructed, can be made much more seismic resistant. However, a large percentage of existing RC buildings are not designed in such way, making them also vulnerable to earthquake. Examples of failure mechanisms of common RC low-rise buildings are presented, and some effective seismic retrofit measures (e.g. column jacketing, buckling-restrained braces) are highlighted in this presentation. These seismic retrofit measures are new for many countries in Asia. How to promote more seismic retrofit of weak RC buildings is, therefore, another challenge. The third challenge is about the seismic risk of high-rise buildings in megacities in Asia. These high-rise buildings are structures with long natural periods, and they are quite vulnerable to long-period earthquake ground motions. Even with a low shaking intensity, such long-period ground motions can cause significant damage to high-rise buildings. Case studies on this issue are presented, and how to incorporate such long-period ground motions into the seismic design process is demonstrated. However, seismic resistant design standards in most countries still do not take into account the effects of long-period ground motions—this is the third challenge. The last challenge to be highlighted in this presentation to about structural analysis procedures for the seismic design of high-rise buildings. The most commonly used procedure by design engineers is the Response Spectrum Analysis (RSA) procedure. The response contributions from many vibration modes can be estimated by this procedure. However, the procedure has recently been found to provide inaccurate and unreliable estimates of various seismic demands in high-rise buildings, especially seismic-induced shear forces in RC walls. A new procedure called ‘Modified Response Spectrum Analysis (MRSA) procedure’ is then proposed to overcome this problem.