| Summary, etc. |
The study entitled Protecto-R: Development of High-Stability Wave-Dissipating Concrete Block aimed to develop and determine the stability performance, wave-dissipating capabilities of three (3) Protecto-R designs. Additionally, a comparative cost-estimate of the three designs was be conducted and compared to the conventional tetrapod considering the actual dimensions of the designs in a 60-meter by 72-meter area. This thesis presents the findings of the study that was conducted during the first and second semesters of the academic year 2023-2024 in Barangay May-Iba, Teresa, Rizal. As an archipelago, the Philippines highly depends on coastal regions for commerce. However, the country is vulnerable to coastal hazards that are being amplified by the adverse effects of climate change. Tetrapod, the widely used wave-mitigating structure, has shown great results from the past but the increase of sea level globally reduces the effectiveness of the said structure. To address this problem, the researchers designed and developed three scaled concrete blocks that aim to outperform the tetrapod in terms of block stability and wave-dissipating efficiency. Scaled physical modelling tests was conducted to simulate wave-structure interactions under harsh plunging wave conditions. The tests for the evaluation of block involved damage expression to determine the percentage of the number of damaged blocks against the total number of blocks. Hydraulic wave action was used to determine block stability number. Wave gauges were placed strategically to determine the reflection coefficient, and a discharge collector was put to place to determine the wave overtopping discharge rate. This study utilizes developmental and experimental research designs to investigate the performance of the three (3) Protecto-R designs. Specifically, the researchers endeavored to enhance the design parameters of Xbloc, a concrete block structure commonly utilized for wave-dissipation. The modifications entail adjustments to the dimensions of its wings, tail, beak, and a uniform opening size. Class AA mixture proportion was used for all concrete blocks. Due to the scaled nature of the experiment, materials needed for the mixture proportions were scaled down to a factor of 1:50. To assess the performance of the blocks, the researchers set the parameters for the plunging wave conditions having a mean significant wave height of 7.7 cm relative to sea water level, peak wave period of 1.2496 seconds, a constant sea water level of 22.50 cm. The blocks were subjected to 250 and 500 wave series cumulatively. The results for hydraulic stability showed that Design A, B, and C resulted in a stability number of 0.6310, 0.7179, and 0.8707, respectively while Tetrapod has a stability number of 87.4160. Damage percentage of Design A, B, and C resulted 14.29%, 0.00%, and 14.29%, respectively while Tetrapod is 60.22%. In terms of dissipation, Design A, B, and C resulted in a wave overtopping discharge of 0.2797 cm3 /s/cm, 0.3275 cm3/s/cm, and 0.2855 cm3/s/cm, respectively while Tetrapod is 0.3242 cm3/s/cm. The dissipation coefficient of Design A, B, and C has a value of 0.8567, 0.8828, and 0.8881 while Tetrapod resulted in a value of 0.8834. With the comparative cost estimate of the concrete blocks, Design A has a total cost of ₱84,402,025.20. Design B has a total cost of ₱78,224,872.70. Design C has a total cost of ₱59,245,333.80. Lastly, Tetrapod has a total cost of ₱114,440,841.52. Based on the results of the study, the researchers concluded that Design C is the best Protecto-R design in terms of performance alone. Design C is also economical due to its lowest cost compared to other designs and Tetrapod. The researchers proposed several recommendations for further studies on wave-mitigating structures. This includes incorporating rounded edges along the design geometry, conducting a field testing of the actual size of concrete blocks in a coastal environment, and calculating the maintenance and lifecycle costs of the concrete blocks over their expected lifespan considering different factors such as inspection, repairs, and replacement of damaged blocks. |
