Stages Of Engineering Design Research Articles

Modified Method of Selection on a Topographic Plan for Reconstructing a Three-Dimensional Scene of Urban Space

The article presents a method for identifying contours in a topographic plan, which is a highly noisy binary image of a city development plan. The method of reconstruction is based on use of wave algorithm of Lee. The modified algorithm is compared with the classic wave algorithm. Its modification is proposed, which is aimed at reducing the execution time of the algorithm. Highlighted contours in use for building urban models of objects in scenes of space. Closed contours are recognized on the image, which are then classified into various objects: building outlines, inscriptions, service symbols, etc. Topographic plans are the main initial data at all stages of architectural planning and engineering design. They contain information about the geometry of the foundations of buildings and their position among other objects. Result of work of algorithm — the textured 3D-scene consisting of models of buildings.

Design Strategy of Emergency Pools at Source Water Protection Areas

The pollution problem arising from the flushing of initial rainwater and wastewater from accidents while transporting dangerous goods to source water protection areas needs to be solved as soon as possible. Therefore, the design of corresponding environmental protection measures should be considered in the engineering design stage. It is necessary to analyze the specific work in combination with engineering examples. Under this background, this paper first briefly expounds the precautions in accident risk analysis and the design of tank capacity and tank body. Finally, by analyzing actual cases, this paper systematically studies the design strategy of emergency pool in source water protection area, hoping to provide new development ideas for the upgrading of relevant work.

Application Skills of BIM Technology in Highway Engineering Design Stage

Application Skills of BIM Technology in Highway Engineering Design Stage

Design Selection for New In-Flight Food Delivery and Waste Collection System of Commercial Passenger Transport Aircraft using TOPSIS

One of the important airline services that can influence the passengers’ loyalty is the in-flight meal service. In this study, the conceptual design process of new in-flight food delivery and waste collection system is carried out using the standard engineering design method to improve the current system. A critical step in this process is the design concept evaluation and selection where the best alternative design concept solution is chosen for further development. The Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) method is applied to facilitate the selection process of the best design concept for the new improved in-flight food delivery and waste collection system. The design evaluation criteria for the TOPSIS assessment procedures are taken from previous work done on design requirements analysis for the new in-flight food delivery and waste collection system. Similarly, five alternative design concepts for the new system are taken from the results of the previous research work done. Furthermore, an online public survey is conducted to acquire the assessment rating of all alternative design concepts for each design evaluation criterion. The assessment rating is assigned using a simple Likert rating scale. From the resultant TOPSIS ranking, Concept 3 has emerged as the best design concept with a closeness rating of 0.9589, which is very close to 1. For future research work, this selected final design concept for the new in-flight food delivery and waste collection system will be forwarded to the next engineering design stage for further development.

Real-time NOx estimation in light duty diesel engine with in-cylinder pressure prediction

Recently, there have been numerous efforts to cope with automotive emission regulations. Various strategies to reduce engine-out NOx emissions and proper after-treatment systems, such as selective catalytic reduction (SCR) and lean NOx trap (LNT), have been taken into account in the engine research field. In this study, real-time engine-out NOx prediction model was established where zero-dimensional NO and NO2 models were combined with in-cylinder pressure model. During the procedure for estimating NO and NO2 (NOx), a real-time prediction model of in-cylinder pressure was applied so that the inputs to the NOx prediction model could be provided only by the data acquired from the engine control unit (ECU). This implies that an in-cylinder pressure sensor is not necessarily required to properly predict the engine-out NOx in real time. The real-time NOx estimation model was validated through the worldwide harmonized light-duty vehicle test cycle (WLTC) without a pressure sensor, and the total NOx error during the mode was comparable with the total NOx error of the portable NOx sensor. This real-time NOx estimation model can ultimately contribute to minimizing tail-pipe NOx emissions by influencing both emission calibration at the engine design stage and the management of NOx after-treatment systems where NOx conversion efficiency is heavily affected by the NO2/NO ratio.

Flow-Assurance-Management Strategy Considerations for a Deepwater Gas Field

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 202254, “Flow-Assurance Challenges for China’s First Deepwater Gasfield Development in South China Sea,” by Lawrence Khin Leong Lau, Kun An, and Xian Di Tang, CNOOC, et al., prepared for the 2020 SPE Asia Pacific Oil and Gas Conference and Exhibition, originally scheduled to be held in Perth, Australia, 20–22 October. The paper has not been peer reviewed. The complete paper describes the key flow-assurance challenges for a deepwater gasfield development in the South China Sea and the considerations and steps taken to achieve an overall flow-assurance-management strategy. The discussion covers early-stage feasibility studies through the stage of project execution at the time of writing. In addition, flow-assurance analysis is highlighted as a key input for startup and commissioning guidelines as well as operating procedures. Project Background This gasfield development consists of a semisubmersible more than 100 km offshore in the South China Sea. The water depth is approximately 1500 m, with a minimum seabed temperature of less than 4°C. The design incorporates Eastern and Western production loops spanning more than 40 km of the subsea production system (SPS) in total. Line size for the Eastern and the Western production loops are selected according to the total of production wells located in respective areas. The entire production system, including topsides facilities, subsea flowlines, risers, and other key SPS elements such as subsea manifolds, is designed with potential future development tie-ins in mind. Long subsea tiebacks, coupled with typical deepwater characteristics, require a robust flow-assurance- management strategy. A dedicated flow-assurance team was assembled across sectors such as subsurface, drilling and completion (D&C); subsea umbilicals, risers, and flowlines (SURF); control and instrumentation; and topsides process engineering. During the feasibility-study stage, more than 10 deepwater subsea production wells were grouped by characteristics. Analysis was performed for the most-representative wells selected from each group during this development stage to determine the range of the operating envelope and to identify all related risks. As development progressed into the detailed engineering-design stage, a detailed flow-assurance-scope analysis was completed for each well to ensure full coverage. This analysis considered scenarios including well unloading, well testing, precommissioning, first gas, steady-state production, planned and unplanned shutdowns, and hot and cold restarts. Any risks identified were assigned mitigation strategies and then were incorporated into design philosophy and operating guidelines or were specifically detailed in operating procedures. Primary Flow-Assurance Challenges Region-Specific Flow-Assurance Challenges. Flow Assurance as an Independent and Integrated Discipline. The creation of a cross-disciplinary flow-assurance team differs significantly from previous management approaches in which flow-assurance scopes were embedded in different disciplines and managed separately by teams such as subsurface, D&C, SURF, and topsides. The team described in the paper had the goal of implementing flow-assurance design and strategy with a truly integrated approach to maximize efficiency, optimize costs, and minimize impact on the environment.

Rheological studies of municipal sewage sludge slurries for hydrothermal liquefaction biorefinery applications

Hydrothermal liquefaction (HTL) is a thermochemical process that can convert organic materials in sewage sludge into crude-like oil. Knowledge of the rheology of sewage sludge as a feedstock is important for the design of a HTL Biorefinery as it provides essential information for pumping, pipeline design and heat transfer processes. This study aims at elucidating the rheological behaviour of sewage sludge slurries. Rheological parameters of sludge obtained from different stages in Wastewater Treatment Plants were estimated and used to calculate the pumping power required for slurry transportation in pipelines as part of the front-end engineering design stage for a biorefinery. Sludge slurries were determined to be Non-Newtonian with shear thickening characteristics. Statistically, the Herschel-Bulkley rheological model best fitted the experimental data with a yield stress. The apparent viscosity of municipal sewage sludge slurries measured within a shear rate range from 10 s−1 to 300 s−1 were determined to be between 0.008−0.05 Pa.s for stockpiled biosolids, 0.04−0.11 Pa.s for sludge without polymer dosage and 0.1−0.2 Pa.s for dewatered sludge with polymer. Power requirement for pumping sludge slurries were in the order: Stockpiled biosolid < Sludge without polymer dosage < Sludge with polymer dosage.

A comparative study of in-pile behaviors of FeCrAl cladding under normal and accident conditions with updated FROBA-ATF code

Accident tolerant fuel (ATF) concepts are at present still in the engineering design stage. FeCrAl, which has great oxidation resistance in high temperature steam environment, is an ATF potential cladding material with higher research priority. However, considering its features, including high thermal expansion, low creep rate and strong absorption of neutron, further evaluation on its in-pile behaviors is still necessary for future industrial application. To address this issue, the self-developed fuel performance analysis code, FROBA, was further developed into a new version named FROBA-ATF. A transient heat transfer model was added into the code’s thermo-hydraulic module for transient simulation, the rigid mechanical model was rewritten into unrigid for ATF cladding and material properties of FeCrAl cladding were also added. These updated modules were introduced and the updated code was assessed in this paper. On this basis, a comparative study on in-pile behaviors of UO2-FeCrAl fuel rod and UO2-Zr4 fuel rod under normal and accident conditions were performed in this paper. Even through the performance analysis revealed that FeCrAl cladding could greatly reduce the oxidation thickness, the thermal performance of UO2-FeCrAl fuel rod was unsatisfactory due to its higher thermal expansion and lower creep rate, especially at beginning of life. With geometry optimization, the steady-state performance of UO2-FeCrAl fuel rod was enhanced. What’s more, the thermal and mechanical performance of the improved UO2-FeCrAl was evaluated and compared under Loss of coolant accident (LOCA) and Reactivity Initiated Accident (RIA) conditions. The results showed that the optimized ATF had better thermal performance, lower cladding hoop stress, and could provide more coping time under accident conditions.

Верифікація гідродинамічної моделі кавітуючих насосів РРД за теоретичними та експериментальними передавальними матрицями насосів

Cavities at the pump inlet may lead to inadmissible cavitation self-oscillations in the feed system of liquid-propellant rocket engines (LPREs) and to POGO instability if the oscillation frequency of the liquid is close to that of the rocket structure. Because of this, it is important to prevent both cavitation and POGO oscillations as early as at the engine and rocket design stage. This calls for a reliable mathematical model of the dynamics of LPRE cavitating pumps. In this paper, a hydrodynamic model of LPRE cavitating pumps is verified using theoretical and experimental transfer matrices of cavitating pumps. The experimental transfer matrix was borrowed from Brennen, Meissner, Lo, and Hoffman’s work because it features the least spread of values among the matrices reported in the literature. The theoretical matrix was borrowed from Pilpenko and Kvasha’s work where is was constructed for a cavitating pump as a distributed-parameter system. Four versions of the hydrodynamic model of LPRE cavitating pumps are verified, and six possible model coefficients are considered. Only one coefficient, namely, the liquid inertance at the cavity location, takes a physically meaningless negative value, which makes its use impossible. The verification results show that a four-coefficient model of cavitating pipe dynamics adequately describes cavitation effects in LPRE pumps over the frequency range up to 200 Hz. The four coefficients are the cavitation elasticity, the cavitation resistance, the cavity-caused disturbance transfer delay time, and the cavity time constant or the cavitation resistance distribution coefficient.

An evaluation on in-pile behaviors of SiCf/SiC cladding under normal and accident conditions with updated FROBA-ATF code

Although there are still controversial opinions and uncertainty on application of SiCf/SiC composite cladding as next-generation cladding material for its great oxidation resistance in high temperature steam environment and other outstanding advantages, it cannot deny that SiCf/SiC cladding is a potential accident tolerant fuel (ATF) cladding with high research priority and still in the engineering design stage for now. However, considering its disadvantages, such as low irradiated thermal conductivity, ductility that barely not exist, further evaluations of its in-pile behaviors are still necessary. Based on the self-developed code we recently updated, relevant thermohydraulic and mechanical models in FROBA-ATF were applied to simulate the cladding behaviors under normal and accident conditions in this paper. Even through steady-state performance analysis revealed that this kind of cladding material could greatly reduce the oxidation thickness, the thermal performance of UO2–SiC was poor due to its low in-pile thermal conductivity and creep rate. Besides, the risk of failure exists when reactor power decreased. With geometry optimization and dopant addition in pellets, the steady-state performance of UO2–SiC was enhanced and the failure risk was reduced. The thermal and mechanical performance of the improved UO2–SiC was further evaluated under Loss of coolant accident (LOCA) and Reactivity Initiated Accident (RIA) conditions. Transient results showed that the optimized ATF had better thermal performance, lower cladding hoop stress, and could provide more coping time under accident conditions.

Neutronics influence of poloidal nonuniform neutron wall loading on helium-cooled ceramic breeder blanket for CFETR

Abstract After its conceptual design, the Chinese Fusion Engineering Test Reactor (CFETR) is now at the stage of detailed engineering design. During this stage, many detailed factors should be considered for the components in the CFETR. In this paper, the neutronics influence of poloidal nonuniform neutron wall loading (NWL) is studied for helium-cooled ceramic breeder (HCCB) blanket of the CFETR. The blanket is divided into five parts along the poloidal direction. Each part is composed of the armor, the first wall, tritium breeders, neutron multipliers, and the manifold in the flow distribution zone. The nuclear heat deposition and the tritium breeding performance of the CFETR HCCB blanket are studied with symmetrical and stepped NWL distributions. The results obtained from the uniform NWL distribution are also presented as the reference. For each NWL distribution, the nuclear heat deposition and the tritium breeding capability in different blanket parts are compared. The results show that the nonuniform NWL distribution has almost no influence on the total nuclear heat deposition or the total tritium production. The overall variation is less than 1 ‰ compared to the results under the uniform NWL distribution. However, the local performances of different blanket parts are affected obviously. The maximum variation is over 20 %, which should be focused on during the design for the flow distribution of helium coolant and purge gas. The present work aims to provide an important guidance for the detailed design and structural optimization of the blanket for the CFETR, especially for consideration of the high-level fusion power during phase II (over 1 GW).

Thermal performance analysis of multiple borehole heat exchangers in multilayer geotechnical media

Based on the finite line source (FLS) model, A heat transfer model considering both multilayer soil and multiple Borehole Heat Exchangers (BHEs) is proposed. The accuracy of the model is verified by experiments. The model is used to study the effect of thermal physical properties of multilayer geological media on the overall thermal efficiency of multiple BHEs. The dimensionless regional thermal efficiency (E) is introduced as an evaluation index of heat transfer characteristics of multiple BHEs. Under a certain geological structure, the heat transfer efficiency of multiple BHEs in homogeneous soils and multilayer soils were compared with the analytical model. The results show that the E of the multilayer multiple BHEs model is less than that of the homogeneous multiple BHEs model, with the maximum difference being 11.43% in 2,000 h. With these thermal properties and soil layer structure, the rate at which E decrease for the multilayer model is a factor of 4 higher than that for the homogeneous model. In the soil layer where the thermal interaction is the most intense, the unit Heat Transfer Rate (HTR) decreased by 25.3%. At a fixed spacing, the thermal diffusivity is the key to determining the degree of thermal interaction. Under the 4 × 4 BHEs layout, the dynamic performance loss increases by about 4% for every 1 × 10−7 m2/s increase in soil thermal diffusivity. When the multiple BHEs are in a multilayer geological media with a large difference in thermal properties (especially thermal diffusivity), a comprehensive multilayer analysis is needed to obtain the thermal efficiency of the overall multiple BHE area accurately. The multilayer multiple finite line source model can be used during the engineering design stages of a BHE field to predict the regional thermal efficiency with borehole spacing and the number of boreholes.

Improving Fuel Economy and Engine Performance through Gasoline Fuel Octane Rating

The octane number is a measure of the resistance of gasoline fuels to auto-ignition. Therefore, high octane numbers reduce the engine knocking risk, leading to higher compression threshold and, consequently, higher engine efficiencies. This allows higher compression ratios to be considered during the engine design stage. Current spark-ignited (SI) engines use knock sensors to protect the engine from knocking, usually adapting the operation parameters (boost pressure, spark timing, lambda). Moreover, some engines can move the settings towards optimized parameters if knock is not detected, leading to higher performance and fuel economy. In this work, three gasolines with different octane ratings (95, 98 and 100 RON (research octane number)) were fueled in a high-performance vehicle. Tests were performed in a chassis dyno at controlled ambient conditions, including a driving sequence composed of full-load accelerations and two steady-state modes. Vehicle power significantly increased with the octane rating of the fuel, thus decreasing the time needed for acceleration. Moreover, the specific fuel consumption decreased as the octane rating increased, proving that the fuel can take an active part in reducing greenhouse gas emissions. The boost pressure, which increased with the octane number, was identified as the main factor, whereas the ignition advance was the second relevant factor.

Preliminary Design Progress of the CFETR Water-Cooled Divertor

The Chinese Fusion Engineering and Testing Reactor (CFETR) has been performed and is in its engineering design stage. Presently, there are two options allowed for the divertors; the helium-cooled stage and water-cooled stage. The water-cooled one has been focused in this article. The configuration of CFETR divertor module was designed. The cassette design scheme and cassette box inner and outer locking systems were introduced, and the locking system was designed to compliant with the remote-handling (RH) requirements. Two divertor RH design options were provided: one is removed through lower port; the other is targets and baffles removed through upper port; supports and cassette were not removed. The other major research was the water cooling channels’ design and its pressure drop calculation. In addition, the fluid, thermal, and mechanical analyses on the outer target were done. Within 10-MW/m2 heat flux, outer target design can ensure that the temperature for all the components works within their temperature limit, and all the components meet the stress design criteria except the copper alloy pipe. The maximum primary stress induced by pressure on the copper alloy pipe appears in the local position between the two monoblocks, which exceeds the design limit. Protection components are need to be added at the gap of the future design optimization to reduce the local stress. After the thermal-hydraulic analysis on water-cooled divertor cassette, the maximum temperature and the maximum stress of cassette meet the requirements. The results of electromagnetic force analysis shows that the deformation on first wall and transition support is less than 0.5 mm, and the maximum stress is also below its tensile strength values. This article summarized the latest achievements in the design and research of CFETR water-cooled diverter in China. All the results will be of great reference for the CFETR divertor optimal design.

Nonlinear deformation behaviors and a new approach for the classification and prediction of large deformation in tunnel construction stage: a case study

Reasonable evaluation and prediction of squeezing condition to avoid large deformation disaster in tunnels have been an important research issue. In order to accurately and rapidly predict the large deformation under complex geological conditions, this paper proposes a classification and prediction method for quick identification of large deformation in tunnel construction stage in a case study of Muzhailing Tunnel. Previous prediction methods of large deformation are usually based on the stages of geological survey and engineering design, and there are great difficulties in obtaining some prediction indexes in soft and fractured strata, such as uniaxial compressive strength. In this paper, the nonlinear deformation behaviors of surrounding rock were analyzed. The geo-stress condition, strata occurrence, rock strength, rock intactness and groundwater condition were chosen as evaluation indexes (including eight sub-indexes). The classification of large deformation was carried out based on the deformation statistics in Muzhailing Tunnel. And the fuzzy prediction was conducted and compared with other methods in engineering. The comparison results show that the new method has higher accuracy and applicability in predicting the large deformation of weak rock mass. This study provides a new approach for rapid identification and prediction of large deformation in tunnel construction stage.

МЕТОДИКА ОЦЕНКИ ОЖИДАЕМЫХ ЗАПУСКНЫХ ДЕБИТОВ ГОРИЗОНТАЛЬНЫХ СКВАЖИН НА ПРИМЕРЕ ГАЗОКОНДЕНСАТНЫХ МЕСТОРОЖДЕНИЙ

Актуальность исследования обусловлена необходимостью нефтегазодобывающему сектору проводить корректный прогноз добычных возможностей планируемых к бурению скважин как на разрабатываемых, так и на новых месторождениях, вводимых в промышленную эксплуатацию. Оценка достижимых дебитов при планировании стратегии разработки месторождения позволяет не только прогнозировать проектные уровни добычи, но и принять решение по совершенствованию стратегии запуска и разработки месторождений. Рациональное планирование снижает негативное влияние на окружающую среду и ведёт к энерго- и ресурсосбережению, также минимизирует риски невыполнения плановых показателей, что является причиной постоянной корректировки объемов добычи в меньшую сторону, ускоряет запуск новых скважин, что повышает негативное влияние процесса бурения на окружающую среду, сокращает стандартное-рекомендованное время на мероприятия и снижает качество строительства скважин. Цель: оценка потенциала пласта в той или иной зоне при выборе размещения проектного фонда скважин перед бурением, приводящая к более рациональному планированию объемов добычи углеводородного сырья, которые определяются на основании расчетов гидродинамической модели. Объект: разрабатываемые и вводимые в промышленную эксплуатацию (новые) месторождения углеводородов. Методы: индивидуальный подход к каждой скважине при определении стартовых дебитов скважин на стадии проектирования разработки месторождения. Результаты. Разработана новая методика определения запускных дебитов проектных скважин, позволяющая более точно прогнозировать начальный дебит горизонтальной скважины в определенном районе на не введенном или уже разрабатываемом месторождении нефти, газа и газоконденсата.

Radial turbine sound and noise characterisation with acoustic transfer matrices by means of fast one-dimensional models

Estimating correctly the turbine acoustics can be valuable during the engine design stage; in fact, it can lead to a more optimised design of the silencer and aftertreatment, as well as to better prediction of the scavenging effects. However, obtaining the sound and noise emissions of radial turbocharger turbines with low computational costs can be challenging. To consider these effects in a time-efficient manner, the acoustic response of single-entry radial turbines can be characterised by means of acoustic transfer matrices that change with the operating conditions. Exploiting the different time-scales of the acoustic phenomena and the change in the operating point of the turbine, lookup tables of acoustic transfer matrices can be computed. Then, the obtained characterisation can be used in mean-value engine models. This article presents a method for generating these lookup tables by means of fast one-dimensional simulations of thoroughly validated fidelity, in terms of both acoustics and extrapolation capabilities. Due to the inherent behaviour of radial turbines, the number of computations needed to fill the lookup tables is relatively small, so the method can be used as a simple preprocessing phase before mean-value simulation campaigns.

Thermal hydraulic design and analysis of updated CFETR water cooled ceramic breeder blanket

The Water Cooled Ceramic Breeder (WCCB) blanket is one of the candidates for Chinese Fusion Engineering Test Reactor (CFETR). In the engineering design stage of CFETR, an updated design of WCCB blanket was proposed corresponding to the latest core parameters (major radius=7.2 m, minus radius=2.2 m). The design aims at covering the CFETR multiple fusion powers (including 200 MW, 500 MW, 1 GW and 1.5 GW) while satisfying the tritium self-sufficiency. To develop the thermal-hydraulic design of the WCCB blanket, thermal-hydraulic analyses were carried out following a theoretical-computational approach based on the finite volume method and adopting the CFD-code Fluent. The results show the inlet/outlet temperatures of cooling channels are in good agreement with the PWR conditions (285℃ inlet temperature, 325℃ outlet temperature). The temperatures of blanket components are below the allowable temperature of the corresponding material (pebble bed-900℃, structural component-500℃). The feasibility of the thermal hydraulic design of the updated blanket was verified.

A graphical inherent safety assessment technique for preliminary design stage

User-friendly plants are needed for equipment failure to not seriously affect its safety, productivity, or efficiency. Safer and user-friendly plants can be designed through the implementation of hazard prevention strategies during the design phase, which is known as the concept of inherent safety. The Graphical Inherent Safety Assessment Technique (GISAT) for preliminary engineering design stage is presented in this paper. GISAT incorporates information obtainable from the process flow diagram (PFD) in the assessment of inherent safety features of a process. This technique evaluates three inherent safety parameters, namely flammability, explosiveness, and toxicity. GISAT also utilises accident statistics in the construction of its graphical rating as the hazard level indicator for chemical process equipment assigned under five groups—reactor, heat transfer equipment, separation equipment, storage tank, and other equipment. In this technique, quantity of the chemicals involved in an equipment represents the weightage of the assessment that is used to identify the root-cause of hazards in each equipment. Hydrodealkylation process of toluene (HDA) to produce benzene is used as a case study to demonstrate the application of GISAT. The results indicate that heat transfer equipment E102 as safer in terms of flammability compared to other equipment while all equipment were found to be safer in term of explosiveness. Separation equipment V102, heat transfer equipment E102, and recycle gas compressor C101 were found to be safer in terms of toxicity. Meanwhile, heat transfer equipment E101, E102, and E103 as well as gas compressor C101 are regarded as safer in terms of fire, explosion, and toxic release combination type of accident as represented by the GISAT Total Score. After the level of hazard in each equipment have been identified, hazard prevention strategies can be applied to equipment with higher level of hazard for hazard reduction.

Risk Management Of EPC (Engineering Procurement Construction) “Siberut Agregated Biomass Gasification Power Plant” Project in Civil Engineering Design Stage

The Construction of EPC (Engineering, Procurement, Construction) Siberut Aggregated Biomass Gasification Power Plant is the first power plant project in Indonesia that uses bamboo as fuel to produce electricity. Judging from the complexity of the project, it is necessary to carry out risk management for the identification and detailed analysis of the risks or uncertainties that occur in the project, especially the design engineering stage. This study uses interview methods and surveys that are implemented in the google form questionnaire to make it easier for respondents to assess risks provided. Risk assessment uses a Likert scale to determine the level of probability and impact. Next step is risk mapping to determine mitigation efforts. There are 15 independent risk variables and 1 variable risk binders obtained from interviews and literature studies. It is known that 6.67% of the risk is included in the criteria of low risk (minor risk), 73.33% of the risk is included in the criteria of moderate risk (high risk), and 20% of the risk is included in the criteria of high risk (extreme risk). From the data projected onto the risk treatment table so that the results of 6.67% risk are acceptable (acceptable), 20.00% risk is unacceptable, 73.33% undesirable risk. Risk mitigation for 16 identified risks comes from detailed specification issues, incompatibility and implementation of drawing, and multitasking engineering resources. Most risk ownership is directed to the implementing contractor, but not limited to the owner, subcontractor, planning consultant, and supervisory consultant.