RISK MANAGEMENT ANALYSIS OF BORED PILE FOUNDATION WORK USING THE FAILURE MODE AND EFFECT ANALYSIS METHOD IN GOMBEL PRESERVATION PROJECT

Gombel Lama Road in Semarang City is a strategic road connecting Upper Semarang and Lower Semarang which has a hilly topography and landslide-prone land, so that the bored pile foundation work in its preservation project has a high implementation risk. This study aims to identify the types of risks at each stage of bored pile work, calculate the Risk Priority Number (RPN) value for each failure mode, and formulate recommendations for priority risk control. This applied research uses a mixed-method approach that combines field observations, interviews, and document reviews with expert judgment questionnaires from 5 experts, analyzed using the Failure Mode and Effects Analysis (FMEA) method. The validity of the instrument is tested with the Content Validity Index (I-CVI and S-CVI), its reliability is tested with the Percentage of Agreement (PA) and the Intraclass Correlation Coefficient (ICC), while risk priority is determined through the RPN value (S×O×D) which is further analyzed with a Pareto diagram. The research results identified 40 valid failure modes in the preparation, drilling, reinforcement installation, casting, and concrete curing stages, with a total RPN of 826, an average of 21, a lowest value of 2, and a highest of 216. The highest risk failure mode is FM-23 related to concrete volume overbreak due to collapse of the borehole wall (RPN 216), followed by FM-04 related to static load of the drilling tool on the hole slope (RPN 84), and FM-30 related to water seepage affecting concrete hardening (RPN 60). Pareto analysis identified 16 of the 40 failure modes as priority groups (vital few) which contributed approximately 80% of the total risk. Risk control needs to be focused on reducing the occurrence and detection values through four main areas, namely the stability of the borehole wall and casing, the quality of bentonite and the casting process, the readiness of drilling equipment, and strengthening work and environmental safety, with actions following the control hierarchy of engineering, administrative, and personal protective equipment, accompanied by regular monitoring.