فهرست مطالب

Advance Researches in Civil Engineering - Volume:1 Issue: 1, 2019
  • Volume:1 Issue: 1, 2019
  • تاریخ انتشار: 1398/01/21
  • تعداد عناوین: 7
  • Gholamreza Andalib, Vahid Nourani Pages 1-8
    In this study, the ability of threshold based wavelet denoising Least Square Support Vector Machine (LSSVM) and Artificial Neural Network (ANN) models were evaluated for forecasting daily Multi-Station (MS) streamflow of the Snoqualmie watershed. For this aim, at first step, outflow of the watershed was forecasted via ad hoc LSSVM and ANN models just by one station individually. Therefore, MS-LSSVM and MS-ANN were employed to use entire information of all sub-basins synchronously. Finally, the streamflow of sub-basins were denoised via wavelet based thresholding method, then the purified signals were imposed into the LSSVM and ANN models in a MS framework. The results showed the superiority of ANN to the LSSVM, MS model to the individual sub-basin model, using denoised data with regard to the noisy data, e.g., DCLSSVM=0.82, DCANN=0.85, DCMS-ANN=0.91, DCdenoised-MS-ANN=0.94.
    Keywords: Stream flow, denoising, artificial neural network, least square support vector machine, multi-station, Snoqualmie watershed
  • Ali Ramazan Burujerdi, Morteza Jiryaei Sharahi Pages 9-14
    Sloping ground near the footings have an adverse effect on their performance. Slope increases the settlements of the footings and while it reduces their bearing capacity. In the present paper, a footing with rough base has been considered for the analysis. The bearing capacity factors have been determined with the consideration of resistance of soil above the foundation level. A simple limit equilibrium method has been used to evaluate bearing capacity. The parameters considered for the analysis include the distance between edge of slope and center of footing, slope angle and foundation depth. It is observed from the analysis that bearing capacity reduces as distance between footing and the edge of the slope decreases. Increase in slope angle cause the reduction in the bearing capacity.

    Keywords: Bearing capacity, Footings, Limit equilibrium method, Slopes
  • Mohammad Amin Jabalamel, Ehsan Saghatforoush, Hamidreza Athari Nikooravan Pages 15-24
    Having so many old and burnout hospitals in third world countries is one of the major problems in the health sector. This issue besides low per capital hospital beds has led to many problems in the health department. In big cities, the possibility to provide land for the construction of alternative hospitals is very costly and non-economic and even impossible. Considering the complexities of building a new hospital, the only solution is making reforms in the hospitals through renovation or rebuilding the project. Moreover, increased general inflation and currency fluctuations in third world countries make most hospitals and medical centres into trouble, which this issue results in increased medical costs. Thus, cost savings in hospitals have a significant impact on their workflow and consequently patient satisfaction in terms of quality of services. Lack of proper implementation of hospital spaces reform projects has challenged realization of these savings. Building Information Modelling (BIM) is revolutionizing how to design and implement buildings. Moreover, it is not just a 3D tool in CAD, but it is a kind of database, which makes possible providing a wide range of information about features and relations among various sections of a building. This study aims to evaluate the need to recognize and measure the reduction of duplications in the hospital spaces reform projects using BIM, in order to make significant savings in waste of hospitals’ resources. In-depth literature review method is applied to collect proper data aiming to introduce BIM as a tool to reduce costs of hospitals’ reforms. This study helps project stakeholders in the field of health infrastructure to better understand the importance of BIM application to prevent various financial wastes in the projects and fulfil their decisions with better recognition.
    Keywords: Duplication, Spaces reform, Hospital construction, Building Information Modelling, BIM
  • Sara Ataii, Abbas Ghalandarzadeh, Majid Moradi Pages 25-31
    Maximum shear wave velocity is one of the most important dynamic parameters of soils which contributes in estimating the dynamic behaviour of soils through the maximum shear modulus. There are different methods for measuring shear wave velocity either in laboratory or in the field. One of the laboratory methods that recently has become popular due to its simplicity, is use of Bender Elements in soil samples. Contrary to its simplicity, it has several uncertainties in its data interpretation. Frequency at which the shear wave velocity is measured is one of the effective parameters that significantly affects the clearance of received wave. This article presents results from a laboratory investigation into the shear wave velocity measurement of remolded specimens of Firoozkooh sand. Specimens were subjected to 13 different levels of frequency and 11 different levels of confining pressure. Results shows that by increasing the confining pressure, the frequency at which the received wave has the best clearance, increases. It also shows that frequency dependence of soils increases by increasing the confining pressure.
    Keywords: Shear Wave Velocity, Frequency, Bender Element, Triaxial Apparatus
  • Omid Aminian, Amin Aminian Pages 32-41
    The effects of firebreak in high-rise buildings seem essential to be investigated cautiously since world trade center towers incident. Consequently, many technological advancements were achieved and numerous researches were performed. Nevertheless, in 2017, Plasco building in Iran also was set ablaze and the consequence was the full destruction of the building, claiming lives of at least 20, injuring 70 and loss of thousands of jobs. Therefore, it is crucial to investigate the effects of fire in high-rise buildings more thoroughly in order to prevent progressive collapse, a phenomenon that caused the destruction of the two landmarks. Ordinarily, to achieve this goal, methods of analysing fire effects are developed. So by choosing a logical fire scenario, design fire is extracted from time-temperature relations of design codes. After determining the firing temperature at various times, effects of temperature increase on the material's mechanical properties are investigated. Important characteristics such as concrete compressive strength, concrete and steel modules of elasticity, tensile strength, the coefficient of thermal expansion and steel rebar yielding stress are affected by alterations of temperature. Finally, by analysing structural behaviour utilizing modelling programs and comparing results of different fire temperatures and stories in which fire occurs with the initial design of the building RCC frame, it can be concluded that axial forces increases in columns are the critical condition in fire situations and in case of fire break in distinct stories, lower floors will experience a sharper surge of axial forces.
    Keywords: RCC, High-rise, Progressive-collapse, Fire, Thermal-analysis, Column
  • Hajar Ahmadi Moghadam, Mozafar Jalili Masir, Zahra Bandani Torshaki, Ali Dehghan Pages 42-48
    Gypsum plaster is a widely used building material, as it is inexpensive and mechanically strong and to make gypsum model for ceramics manufacture as modelling material. When in contact with water, calcined gypsum rehydrates through dissolution, nucleation and crystallization steps. In this work, the mixing rate of plaster with water was investigated on their effect on the properties of hardened gypsum pieces, focusing on the structure–function relationship. The mixing plaster with water was done at 120, 240, 360 and 600 rounds per minute with a constant water/ plaster ratio of 0.77. The results showed that with increasing mixing rate, the setting time decreased and the mechanical strength of the hardened piece increased. The apparent porosity, water absorption and water diffusion coefficient of the hardened piece decreased with increasing mixing rate. The microstructure of gypsum with the high mixing rate not only seems to be denser, with crystals interlaced, but also shows short crystals, which may improve the mechanical strength of the specimen. The higher mixing rate can lead to the higher rate of the nucleus formation, the smaller crystals and denser structure are formed. This material can have higher strength. 
    Keywords: Gypsum plaster, Mixing rate, Setting time, Strength, Microstructure
  • Seyyede Najme Faraghati, Maede Sadeghpour Haji, Azade Ghadimi Hamzeh Kolaei Pages 49-57
    Nowadays the proper sanitary disposal of waste is considered as one of the main options in waste management. The chemicals produced from landfills’ leachate affects the structure and characteristics of clay layers, so based on the acidity/basicity state of leachate, the study of the geotechnical properties of clay layers under the influence of these materials is very important. Therefore, in this research, the effect of PH variation on the geotechnical parameters of the soil was investigated by conducting a series of Atterberg limits, permeability and consolidation experiments on kaolinite clay and kaolinite mixture with different percentages of bentonite. In these experiments, acetic acid and sodium hydroxide were used as chemical agents representing leachate. Permeability parameters were measured via falling head method. The results of experiments show that the presence of acid and base in the kaolinite clay and the kaolinite mixture with different percentages of bentonite increases the liquid limit, plastic limit and permeability of the soil, as well as increasing the level of settling and accelerating the consolidating process. Addition of 10% bentonite also enhances the liquid limit from 36 to 41 (13%), and the addition of further 10% bentonite enhances the liquid limit from 36 to 46 (27%) at pH=7. Soil settling increases 6% when exposed to acetic acid and 17% in light of exposure to sodium hydroxide in kaolinite Permeability index is enhanced 14% with the addition of acid and 25% with the addition of base in kaolinite. increasing of 10% in bentonite to the same sample of kaolinite  soil reduces the permeability index from 21% and an addition of further 10% of bentonite, decreases the original permeability index from 1.42×10-7 to 0.61×10-7 at PH=7.
    Keywords: Geotechnical parameters, Leachate, Atterberg limits, Permeability, Consolidation