This study evaluates the effect of combining 12% rice husk ash (RHA) with varying percentages of RCC-15 spent catalyst (7%, 9%, 11%, and 13%) on the engineering properties of soft clay soil obtained from Cililin. Laboratory tests were conducted, including physical property characterization, compaction tests, and unconfined compressive strength (UCS) tests with curing periods of 0, 3, 7, and 14 days. The results show that the addition of RHA and RCC-15 improves soil compaction characteristics, indicated by an increase in maximum dry density and a reduction in optimum moisture content. Furthermore, the UCS values increased significantly with higher RCC-15 content and longer curing periods, reaching values between approximately 1.57 and 3.66 kg/cm² at 14 days. These improvements are attributed to mechanical densification and pozzolanic reactions between the stabilizing agents and soil minerals. This study emphasizes the synergistic application of agricultural and industrial waste materials for local soil stabilization, indicating that the combined use of rice husk ash and RCC-15 spent catalyst can enhance the engineering performance of soft clay while supporting sustainable and resource-efficient ground improvement practices.
Illegal parking in urban commercial corridors is commonly treated as a public-order problem. From a spatial perspective, however, it also reflects a shift in roadway function, where traffic space is temporarily converted into static space. This study examines that shift using longitudinal occupation (OL), effective width reduction (EWR), and a proposed composite measurement approach termed the Space Pressure Index (SPI). The case site is an approximately 200 m urban commercial segment where vehicles routinely park in parallel on both sides despite the absence of formal parking facilities. Data were collected through a four-day parking patrol survey covering two weekdays and two weekend days, supported by roadway-width measurements under two-sided parking conditions. The results show a clear time-dependent pattern: parking builds up and intensifies during peak commercial hours. Longitudinal occupation peaked at 120.7%, meaning that the cumulative equivalent length of parked vehicles exceeded the usable segment length during the busiest period. At the same time, two-sided parking reduced the effective width by 36.7% relative to the initial geometric width. When these two dimensions are combined, the SPI reached a maximum of 44.3%, indicating substantial functional conversion of movement space during the peak interval. Overall, the findings frame illegal parking in commercial areas as a measurable form of space competition with direct operational implications for corridor mobility. Compared with partial occupancy measures, the proposed OL-EWR-SPI approach offers a clearer segment-scale description of how roadway space is reallocated over time.
Excessive vibrations in heritage buildings located near heavy traffic often cause occupant discomfort despite adequate structural capacity. This study investigates the vibration mechanism and proposes a mitigation strategy with minimal intervention using Operational Modal Analysis (OMA) and Stochastic Subspace Identification (SSI). The identified fundamental frequency of the building is 3.09 Hz, which closely matches the dominant traffic-induced ground frequency (3.10 Hz), yielding a frequency ratio ≈ 1.0 and confirming soil–structure resonance as the governing mechanism. This resonance amplifies responses, particularly at intermediate floors. To mitigate the effect, a Multiple Tuned Mass Damper (MTMD) system with a total mass of 4 tons (≈0.54% of structural mass) is proposed. The MTMD effectively reduces dynamic amplification while remaining non-invasive, making it suitable for heritage structures. The results demonstrate that small-mass MTMD provides a practical and efficient vibration mitigation solution.
Concrete is a widely used construction material due to its strength and durability, but its quality is greatly influenced by its constituent materials and the environment. In West Kalimantan, people use scrap wire from building demolition as an additive in concrete, while clean water is limited, so peat water or seawater is often used as a mixer. This study aims to determine the effect of wire mesh usage and mixing water type on concrete compressive strength at 7, 14, and 28 days. Test specimens in the form of cubes were made with variations: normal concrete (clean water), concrete with peat water, concrete with seawater, and concrete with 1% wire mesh added to each type of water, and compressive strength testing was conducted using a compression testing machine. The results showed that peat-water concrete achieved the highest strength (119.50, 207.37, and 247.73 kg/cm² at 7, 14, and 28 days), seawater concrete produced the lowest (92.87, 182.27, and 225.90 kg/cm²), and the addition of 1% wire mesh increased early-age strength up to 186.57 kg/cm² at 7 days but its effect diminished at later ages. Thus, the type of mixing water plays a dominant role in concrete quality, while steel tie wire is more effective in increasing strength during the early stages of hardening.
This study evaluates the effectiveness of the Integrated Waste Management Facility (TPST) service in Sidodadi Sub-district, Wonomulyo District, Polewali Mandar Regency, using a spatial analysis approach based on the location–allocation method implemented in ArcGIS. The research is motivated by the high population density of Sidodadi, which has led to an increase in waste generation, while only a single TPST facility is currently operational. A quantitative descriptive method was applied, utilizing primary data from field observations and secondary spatial data, including building point data, road network data, and high-resolution satellite imagery. Spatial analysis was conducted by mapping waste generation at the building level, performing network-based distance analysis along the road network (as opposed to straight-line/Euclidean distance), and modeling TPST service coverage using a location– allocation model. The model parameters included a service distance cutoff of ≤ 1 km and facility capacity constraints based on the maximum number of households that can be served within a given facility. The results indicate that the existing TPST can serve approximately 600 households, corresponding to only about 15,84 % of the total residential buildings in Sidodadi Sub-district. Consequently, a significant proportion of densely populated residential areas remains outside the effective service coverage. This limited coverage is primarily influenced by insufficient facility capacity and service distances exceeding the defined cutoff. The study recommends the development of additional TPST facilities at strategically selected locations to increase service coverage percentage and enhance the efficiency and sustainability of waste management in Sidodadi Sub-district.
