Expansion / Debottlenecking of Industrial or Oil & Gas plants is a common phenomenon and many a times such expansion has to be located within limited plot boundaries posing multiple challenges in locating the equipment and design & execution of supporting civil structures. In some cases, finalized supporting civil structures are not feasible to implement due to additional challenges such as additional underground utilities not identified in as-built survey that may arise during execution stage affecting project schedule. Generally, such unique design challenges are not encountered in Greenfield project development. This paper presents the typical constraints encountered in expansion projects, key parameters required to finalize the innovative solutions and measures / methods adopted to overcome the constraints in most effective and economical way in one of the major brownfield project without affecting safe functioning of existing plant. Vibration transmissibility to structures / equipment from new equipment or old equipment vice versa, physical constraints in supporting / routing new piping, underground utilities present in the plot are some of the major challenges faced during detail engineering. Enhancing existing supporting structures for new codal requirements (e.g. revised seismic definition) and enhanced design life to support additional loads of new project in addition to existing ones are some of the additional challenge faced during engineering and construction of the brown field projects Key parameters to be studied / considered while arriving optimal civil engineering solutions to challenges encountered, dynamic properties of new or existing equipment, foot print and founding details of existing foundations, underground utilities present in the plot / boundaries, presence of ground water table, execution feasibility of proposed new civil structures under plant operating conditions thereby avoiding plant or unit shutdowns etc. The solution arrived may have to be revised based on additional challenges that may unfold during execution stage. Fit for purpose supporting structure configurations, out of box structural designs, usage of unique material etc., are some of the methods adopted in arriving safe and economically sound design to overcome the constraints. Brownfield expansion in constrained plots of existing plants is a common phenomenon in all industries. Fit-for-purpose solution needs to be arrived considering constraints applicable to that equipment / plot while maintaining Plant safety and integrity. Similar approaches may be adopted to mitigate challenges in brownfield expansion of other plants to arrive at cost-effective & safe solutions.

In today's challenging work and business environment, swift response to structural integrity concerns is the need of the hour to minimize the damages that will reduce down time, specifically in oil & gas sector. The solution devised to address structural concerns shall prevent further failure of structural members and avert major catastrophic accidents, as they support process equipment and piping. This paper outlines case studies of such structural failures, potential reasons of incidents and approaches followed in restoring structural integrity in a safe and economical way that ensures uninterrupted plant operation. Key parameters to be studied / considered while arriving solutions to structural damage / incidents include reliability of data, primary cause of incident, inventory of readily available material, execution feasibility under plant operating conditions thereby avoiding plant or unit shutdowns and manpower skillsets. Due to various constraints, the solution arrived may be temporary that averts multiple structural failures or a major accident. Further studies would be required to identify the root cause and to confirm or enhance the implemented solution that will reaffirm long term integrity of structure. In almost all of the incidents, some of the common steps followed for swift restoration of structural integrity include conducting a site survey to identify and judge the probable cause, reviewing available data, structural assessment and details of material in stock. After analyzing numerous factors, diverse approaches unique to each incident were considered in arriving a solution that is fit-for-purpose. Structural integrity issues, if not attended swiftly, can worsen the situation leading to safety concerns and major accidents. Solutions adopted for various incidents ensured restoration of structural integrity with minimal consequences. Suggested improvements and recommendations were implemented and no further issues were reported until this time.

In Oil & Gas plants, steam is supplied to different process units such as turbines & reboilers through piping and is routed on pipe racks. The steam system is encountered with typical problems such as condensate accumulation, hammering, vibrations, condensate discharge, etc. These can cause serious damages to the piping and supporting systems. Such operational and design issues related to steam service can affect the integrity of Plant structures. This paper presents the improvements that are considered in steam lines and their supporting structures which assures high safety and integrity of the system. Steam traps are provided to filter out condensate and non-condensable gases without letting steam escape from steam pipes. Faulty working of steam traps causes accumulation of condensate resulting in hammering which induces heavy vibration and impulsive loads. The impact loads are not accounted in structure design as their magnitude can't be precisely computed due to its complexity and dynamic nature. These accidental loads can have destabilizing effects on the system such as failure of pipe supports, supporting structure, consequential damage of neighboring pipes etc. Conventional practice of open discharge of steam trap condensate on concrete substructure is another cause of concern. Comprehensive study of failure of piping & structural systems at different plants was undertaken to identify possible root causes and realize mitigation measures. To address the deficiencies identified and to further enhance safety, various improvement options were studied and optimal solutions to steam system design were finalized. Some of the improvements proposed included positive isolation / blinding of steam lines to avoid condensate build up, removal of abandoned steam lines, periodic condition monitoring of steam traps, installation of automatic Wireless Acoustic Monitoring system for steam traps, design prerequisites for cantilever supports, sampling and testing of supplied structural bolts as a part of QA/QC, routing of condensate drain discharge to plant drainage system. Suggested improvements and recommendations were implemented and no further issues were reported until this time.