Engineering Journal of Research and Development

BUILDING FOOTPRINT EXTRACTION FROM TRUE ORTHOPHOTO BY GEOSPATIAL SEGMENT ANYTHING MODEL

Thepchai Srinoi, Thirawat ฺBannakulpiphat, Phisan Santitamnont — Thu, 27 Jun 2024 00:00:00 +0700

Building data is essential for visualizing the population or environment in some areas. The classic method of creating data layers is delineation from satellite imagery or orthophoto, which takes more human and time resources. Presently, there are free and open building footprints, but the completeness of buildings is not great, especially in urban areas. Recently, there is an available geospatial segment anything model that we can experiment with, and there is an urban mapping project from an unmanned aerial vehicle that processed true orthophoto with a ground sampling distance of 5 centimeters. Accordingly, there was a study of building footprint extraction with this model in the faculty of science and engineering at Chulalongkorn University. We do a completeness assessment of the building footprint with Intersection over Union (IOU). The research showed that IOUs are higher than 0.9 in both areas. Those said that extracted footprint data is nearly the same as self-delineation, which is the alternative way for building footprint generation with high positioning accuracy and completeness.

EVALUATING DROUGHT-PRONE AREAS USING WATER ACCOUNTING AND WEAP MODELLING IN NON-IRRIGATED AREAS

Preeyaphorn Kosa, Thanutch Sukwimolseree, Paweena Chunko — Thu, 27 Jun 2024 00:00:00 +0700

The Lam Takhong River Basin is the upstream area of the Mun River Basin, a significant and economically vital region in Nakhon Ratchasima province. The economic activities in the Lam Takhong River Basin contribute to its importance, and it is an area prone to drought issues annually. However, government agencies in the area lack information on specific locations affected by drought, the months of water scarcity, the quantity of water deficits, and the water demand for agriculture and consumptive uses. This crucial data is currently insufficiently collected and analyzed. Therefore, the objective of this study is to analyze areas at risk of drought on a sub-district and monthly basis by establishing a water account and assessing drought conditions using the WEAP model for areas outside the irrigation command area in the Lam Takhong River Basin. The study findings reveal that, for the overall water account in the Lam Takhong River Basin, the percentage of water used compared to the rainfall amount ranges from 46.02% for Case 1 to 60.09% for Case 5. Despite this, the water demand is relatively low compared to the rainfall input into the basin. The outflow from the basin in Case 1 to Case 5 is estimated at 2,887.39 , 2,699.18 , 2,510.97 , 2,322.76 and 2,134.55 million cubic meters, respectively. Additionally, the WEAP model indicates 19 sub-districts, 21 sub-districts, 22 sub-districts, 24 sub-districts, and 26 sub-districts meeting the criteria for drought-prone areas for Case 1 to Case 5, respectively.

PERFORMANCE OF UNPAVED ROAD REINFORCED WITH TRIAXIAL GEOGRIDS SUBJECTED TO BEARING PRESSURE

Thu, 27 Jun 2024 00:00:00 +0700

This article studies the effectiveness of unpaved roads reinforced with triaxial geogrids. The unpaved road comprises subgrade and base layers. The subgrade and base considered in this study were low-plasticity clay and crust rock, respectively. The model test was performed in a square steel mold 1.5 m in width and 1.2 m in height. The subgrade thickness was fixed at 0.8 m, whereas the crust rock thicknesses varied from 0.05 to 0.2 m. The triaxial geogrid was inserted between the subgrade and the crust rock layers. The static bearing capacity tests were conducted on the unpaved road models according to the standard TIS 1253-62. The results show that using the triaxial geogrid enhances bearing capacity by 1.46 times and reduces the crust rock thicknesses. Thus, the triaxial geogrid reinforcement can be effectively utilized in unpaved road construction.

BEHAVIOR OF UNPAVED ROAD REINFORCED WITH TRIAXIAL GEOGRID SUBJECTED TO BEARING PRESSURE

Thu, 27 Jun 2024 00:00:00 +0700

This research presents an improvement of unpaved roads using triaxial geogrid installed between the base and subgrade layers. The impact of installing geogrid at different intervals and the bearing capacity of unpaved roads with and without geogrid reinforcements were studied. The unpaved road samples included a 0.8-m-thick high plasticity clay and 0.2-m-thick crushed rock. The samples were prepared in a square steel mold 1.5m in width and 1.2 m in high, and the geogrid was installed at the interface between the high plasticity clay and the crushed rock, as well as at the mid-depth of the crushed rock layer. Testing was conducted under static load test conditions according to standard TIS 1253-62. Results show that when improving the unpaved roads with triaxial geogrid reinforcement, the bearing capacity increases by a factor of 1.63, and settlement reduces under the working pressure.

STUDY OF BEHAVIOR AND VALUE OF STEEL-FIBER-REINFORCED CONCRETE COLUMNS SUBJECTED TO CYCLIC LOADING

Nattanon Rattanachai, Natawut Chaiwino — Thu, 27 Jun 2024 00:00:00 +0700

Building damage or impacts due to large earthquakes in Thailand has resulted in the requirement of earthquake-resistant design for new buildings, especially in high earthquake-prone regions. The current building regulation has also extended more areas considered earthquake-prone zones. However, most of the new buildings or houses in high-risk areas, which are not regulated, do not adopt the seismic design standard due to an increase of project cost. Hence, partial reinforcement of structures with an emphasis on low cost is another option to prevent or mitigate damage from earthquakes. This research aims to study strengthening methods for reinforced concrete columns using steel fibers and additional stirrups, and to compare both in terms of structural performance and cost. Three columns were tested under lateral cyclic loads to determine the efficiencies of steel fibers and additional stirrups by an enhancement in column ductility. Besides, a one-story reinforced concrete building was selected as a sample for a cost analysis and value evaluation of two different strengthening techniques. Value was considered from a ratio of a percentage increase in ductility to a percentage increase in cost. The study has found that strengthening columns with steel fibers and additional stirrups improved the ductility by 103 and 33 percent, respectively, and increased the total cost of the columns by 2.56 and 0.57 percent, respectively, which were the values of 40 and 58, respectively.

BUILDING HEIGHT ESTIMATION PRODUCTION FROM OPEN SATELLITE IMAGERY BY GRADIENT BOOSTING REGRESSION TECHNIQUE

Thepchai Srinoi, Thirawat Bannakulpipat, Phisan Santitamnont — Thu, 27 Jun 2024 00:00:00 +0700

Building height data is crucial for urban environment studies, urban physical quantity calculations, three-dimensional mapping, and spatial analysis. This research focuses on estimating building heights in the Bangkok urban area using freely available RADAR and optical satellite imagery. The study employs gradient boosting regression techniques, leveraging building height data from a digital surface model obtained through unmanned aerial vehicle (UAV) mapping for model training and testing. Results indicate that combining RADAR and optical imagery yields higher accuracy than using a single type of imagery. The gradient boosting regression model using mixed satellite imagery achieved RMSE of 11.726 meters for buildings under 100 meters and 7.915 meters for buildings under 50 meters. However, the method exhibits limitations, including a low coefficient of determination, making it challenging to accurately estimate the heights of very tall buildings.