Stochastic Failure Mode Effect And Critical Analysis (SFMCEA) on Repair and Retrofitting Projects

—FMEA is a known method in risk management that de-fines the failure that might happen and identifies its hazards on the system; this procedure can be done using the risk priority number “RPN” analysis system. This method is applied on a real repair project “Sheraton Hotel” located in Cairo city near the Nile River where they had to make urgent repairs to avoid failure and collapse of the building. This study concentrated on developing the results and most common failures that might happen in any emergency project by determining the severity, occurrences, and detection to get the overall RPN of each failure. Two methods were used to rank the risks, the first one is the traditional approach which is based on getting one value for the severity, occurrence, and detection. On the other hand, the other method is getting a range of values (3 values) for the severity occurrence, and detection. The results showed that using the traditional form of RPN resulted in three major risks such as ineffective work penalties, complex contractor’s policies, and risks related to contract agreement. On the other hand, the use of a probabilistic analysis showed that the top risks are ineffective work penalties, problems with contract agreement, and unfavorable contract.


Introduction
Failure mode effect analysis is considered a risk management practice that can help in determining and ranking potential failure modes and extreme errors in any process, system, and project while ensuring the availability of several solutions to any mistake. Determining the potential failure is normally done through the use of an expert's opinions and brainstorming techniques especially for experts working in the field. Each failure mode is then ranked through the use of risk priority number which is measured for each potential failure mode in the project. The risk priority number is measured using severity, occurrence, and detection that are given by experts in the field [2].
Failure Mode Effect Analysis was initially applied in 1949 by the U.S Army in order to improve their military operations [4]. The same technique was then used by Nasa at the beginning of 1963 in order to improve their reliability needs and optimize their safety analysis [2]. Since then, this technique kept on developing until being used in various industries such as aerospace sector, mechanical sector, and construction sector [4]. In addition, other different techniques were done to modify various domains to ensure estimation of risks as [3] presented FMEA design as an alternative for the common technique that was used in design practices. In addition, risk FMEA was also used and presented in order to assess risks in construction industry. Other different techniques such as risk priority number (RPN) was also presented which is used to examine the impact of any risk using severity rates, occurrence rate, and detection where the combination of all these factors yields the risk priority number value. All these changes were made in order to adequately present the exact condition and real scenario of each risk. Risk FMEA also presented another factor known as risk score which is calculated through multiplying the impact and occurrence rate [4]. Fuzzy FMEA was also recommended to be used to assess any schedule chain and ensure completion of projects on the assigned duration [8]. Risk assessment value was introduced to FMEA where this factor can help in assessing the reliability of any element while assessing failure possibility in any proposed element [9]. [6] conducted research about Improving the Quality Procedure Performance for Steel Structures Components Assembly using failure mode effect analysis. They say that FMEA is an effective procedure to reach the weaknesses of most technical systems by investigating the potential failure of a process. In this research, by conducting much different failure mode effects on possible failures that cause some defects and examining some improvements in maintenance program, obedience welding, as well as a scarfing machine. All these improvements were done to avoid costly improvements and modifications and to reduce time and health wastage. This paper discussed the potential use of FMEA in the construction sector and especially for repair and retrofitting projects.

Method
The methodology of this paper is based on a quantitative analysis through the use of risk priority number as a tool of risk analysis. The initial step was going through a literature review to collect some of the common risks and issues that are faced in repair and retrofitting construction projects, then these risks were then evaluated by an expert through a personal interview. This expert was the project manager of Sheraton in Cairo and provided all required details and circumstances that were faced in the project. The concept of risk priority number and its use is well introduced below.
Risk priority number is a calculated approach to determine and evaluate the percentage of risk on a specific method, steps, or any type of processes. It is calculated by determining the severity, occurrence, and detection of a process and mutilating all givens to reach a risk priority number whether this step is in risk or not. However, this method can be applied on one process per time and then comparing the results with the other processes, but not the complete project with only one RPN step. The only reason for calculating RPN is to manage to decrease the total percentage and take into consideration the failure that might happen before it actually happens. RPN consist of three major components multiplied together to get the overall risk rate: • Severity: it is an estimated value of how the next user or component will understand the effect of failure and such theory depends on the reactions that may be taken to overcome such failure.
• Occurrence: it is often called likelihood which represents the estimated number of how much the failure will occur during the process or production lifetime.
• Detection: it is often termed as effectiveness. It is the estimated value of how effective the detection of failure is before reaching the customer. The description of each factor is shown in table 1. 85 Notice that each failure has 3 probabilities (Optimistic, most likely, pessimistic), probability for each failure and multiplying all these factors gives the RPN value and multiplying this RPN value with the probability gives the probabilistic RPN value. Furthermore, by applying 90% certainty rule of PERT which is as follows: (1) The project manager then provided the range of values for the severity, occurrence, and impact according to the performance of work in the project and major issues that were faced during its renovation.

Case Study and Results
Sheraton Cairo is a five-star hotel in the heart of Cairo; in fact, it stands as one of Cairo's landmarks that has the commercial sign "Sheraton." Sheraton is Starwood's "leading" brand, providing luxury hotel and resort accommodation. The Sheraton hotel is located in the west of Al Giza city near al Jalaa square that is located in Aldoay district in front of the Nile river at the Center of the most beautiful sightsee-ing area in the city, only a few kilometres away from the national Museum, Oprah House, Cairo Tower, Tahrir Square, American University, and many traditional stores. The hotel was built at the end of 1970 and consists of two towers built next to each other called Nefertiti and Cleopatra. It consists of 650 rooms and wings. Sheraton Cairo provides guests with inspiring effortless experiences, sophisticated meeting rooms and restaurants. The hotel consists of 537 rooms and 113 suites most of them overlook the Nile River. Each room has all the requirements of any fivestar hotel in addition to a gym, pool, renting cars office, clinic, Spa, shops, and many other facilities. It also consists of around eight restaurants and cafes that work around the clock all of them close by midnight except for one restaurant that works 24/7. Moreover, there are eight meeting and wedding halls and those are highly equipped with all materials and resources required. The process of repairing started during the late 2007 and almost ended in 2016 where it faced many problems and issues which delayed the final submission of the project. In this case study a comprehensive questionnaire has been developed with the owner to understand the basic structure of repair projects, and develop a failure criterion to avoid any certain problems in repair and retrofitting projects in the future. Table 2 shows the RPN results for all the potential failure modes in the case study. Ranking before Probabilistic Configurations: Table 3 includes the ranking of potential failure where only including the highest RPN rank in each one of them before taking into account the probabilities of occurrence of each value. Ranking After Probabilistic Configurations: Table 4 includes the ranking of potential failure including the effect of probabilities on the highest RPN value which resulted in a totally different ranking of problems. The reason for having ineffective work penalties as the top ranked risk was basically the reason for delaying the whole renovation process as the contractor had multiple issues faced on site, and yet the owner could not assign any penalties due to rushing the process of preparing the contract documents. The use of a probabilistic configuration helps in having a range of values and somehow limits the possibility of errors due to any subjective analysis.

Conclusion
Project management is a set of principles, methods, and techniques that people use to effectively plan and control project work, this approach can be prepared by establishing a plan of resources, money, manpower, scheduling of missions and components, controlling the site, and leading the staff. One of the major components of project management is Risk management which is a very important factor in any future project since it estimates the project's success and determines if the constructed project will fail or not. One of the risk management types is failure mode effect and critical analysis FMEA which analyses the failure and how that component will affect the entire system. In the literature review, FMEA was investigated to define the process by different authors and then determine who used this method previously in engineering and other common majors and identified the results that each one of them reached. In order to define the failure and know exactly how it affects the system, it is best to use the most common failure analysis "RPN" to determine the severity, occurrence and detection of each failure. These failures were defined generally using previous studies and most common problems that might occur in each project and then extract these data results from the owner of the project, contractor, and consultant to determine the dangerous components and analyse them. After applying the RPN analysis on these results a probabilistic configuration is applied on each failure depending on the possibility of occurrence to give multiple results for each problem. After extracting the results, the RPN ranking can be applied to determine the most critical failures and then FMEA table to analyse and solve those problems.