through Mini Modular ‘Cap Structures’
in Gas Processing Projects
CASE STUDY / LESSONS LEARNED
By Abdulrahman Shukri, Mohammed AlShuhail, Abdulaziz Almuaili, Abdulaziz AlSoufi and Ahmed Abu Fayyah
Fadhili Gas Increment Project
Saudi Aramco
Dhahran, Saudi Arabia
Abstract
This paper presents a construability approach for the assembly and erection of a Steel-Structure Branch Piperack that extends from the Main Piperack and provide connectivity to associated Vessels and Exchangers. This approach has been studied and implemented in Saudi Aramco’s Fadhili Gas Increment Project (FGIP). The concept introduces a mini-modular strategy of the elevated segment of a branch Piperack, known as the Cap Structure for steel-structure pipe-rack erection, which is pre-assembled separately and lifted as a single modular for final installation in top of the erected stick built steel structure, combining the flexibility of the stick-built method with the efficiency of modularization. This approach significantly reduces work-at-height exposure, allows parallel progress between ground-level and elevated works, and shortens total erection duration by approximately 50% in comparison with conventional methods of installation. The methodology provided improvements in safety and efficiency, offering a replicable model for future projects that are similar in nature.
- Introduction
Steel structure erection is one of the most critical activities in large industrial and gas-processing projects. Conventional stick-built methods rely on sequential assembly and bolting at height, which exposes workers to elevated hazards and extends the overall execution timeline. In contrast, modular construction offers safer and faster assembly at ground level but is often constrained by transportation limits, crane capacities, and complex interface management.
To address these limitations, the project team in FGIP developed a hybrid field innovation called the Cap Structure. The method isolates and pre-assembles the uppermost portion of tall steel structures at ground level as a compact mini-module, which is later lifted into place. This strategy bridges the gap between stick-built and modular construction, allowing the project to capitalize on the advantages of both systems.
The main objectives of introducing the Cap Structure were to enhance safety by minimizing work at height, accelerate schedule performance through parallel work execution, and avoid the limitation of maximum height level in manlift.
- Cap Structure Concept and Design
2.1 Concept Overview
The Cap Structure represents the highest section of a steel structure equipment designed for full ground-level assembly prior to installation. It incorporates all primary and secondary members, platforms, handrails, and access ladders connected through bolted joints to achieve precise alignment. After pre-assembly and quality verification, the completed segment is lifted and installed on top of the lower stick-built frame using a single, well-coordinated crane operation.
The idea emerged during constructability reviews when the team identified that isolating the upper tier could significantly improve safety and progress without changing the overall structural design. By treating this upper segment as a self-contained mini-module, most work traditionally done at elevation was shifted safely to ground level.
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How to cite this article: Shukri, A., AlShuhail, M., Almuaili, A., AlSoufi, A., Fayyah, A. A. (2026). Enhancing Steel Structure Erection Efficiency through Mini Modular ‘Cap Structures’ in Gas Processing Projects, PM World Journal, Vol. XV, Issue I, January. Available online at https://pmworldjournal.com/wp-content/uploads/2026/01/pmwj160-Shukri-et-al-Enhancing-Steel-Structure-Erection-Efficiency.pdf
About the Authors
Abdulrahman Shukri
Kingdom of Saudi Arabia
Abdulrahman Shukri is a certified Lead Auditor for Quality Management Systems (ISO 9001:2015) and a Project Management Professional with six years of experience in engineering and executing large-scale oil and gas projects. He currently serves as a Project Engineer on the Fadhili Gas Increment Project at Saudi Aramco, leading Steel Structure activities. His work focuses on project engineering practices, structural systems, and quality management in industrial environments. He holds a Bachelor’s degree in Chemical Engineering from Yanbu Industrial College, Saudi Arabia. Mr. Shukri can be contacted at shukri1414@gmail.com
Mohammed Alshuhail
Kingdom of Saudi Arabia
Mohammed Alshuhail is a Certified Associate in Project Management (CAPM) specializing in project execution, with two years of hands-on experience supporting key capital programs at Saudi Aramco. With engineering foundation and project Management skills, he contributes to effective planning, risk awareness, coordination and construction activities. He earned his Bachelor’s degree in Mechanical Engineering from King Fahd University of Petroleum and Minerals (KFUPM).
Abdulaziz Alsoufi
Kingdom of Saudi Arabia
Abdulaziz Alsoufi is a mechanical engineer with over 8 years of experience at Saudi Aramco, where he has played a key role in critical energy projects and operating facilities. Currently contributing to the Fadhili Gas Increment Project, Abdulaziz brings a robust technical background and hands-on expertise to the design, implementation, and optimization of mechanical equipment. He earned his Bachelor’s degree in Mechanical Engineering from King Abdulaziz University, and throughout his career, he has demonstrated a commitment to operational excellence and engineering innovation within the oil and gas industry.
Abdulaziz Almuaili
Kingdom of Saudi Arabia
Abdulaziz Almuaili is a senior process engineer with over 10 years of experience in Commissioning, Operations and Project Management within the gas industry. Currently serving in one of the most accelerated projects at Saudi Aramco in Saudi Arabia, he has previously led several projects commissioning and Plant Operations. He holds a Bachelor’s degree in Chemical Engineering from Tennessee Tech University in the United States of America.
Ahmed Abufayyah
Kingdom of Saudi Arabia
Ahmed Abufayyah is an experienced Project Management professional with over 11 years of experience in mega and complex projects across both downstream and upstream sectors. A certified Project Management Professional (PMP), he brings deep expertise in project planning, execution, and delivery within highly demanding programs. He holds a Bachelor’s degree in Mechanical Engineering from King Fahd University of Petroleum and Minerals (KFUPM), and is recognized for driving project outcomes through leadership, technical insight, and compliance.
