Analysis and Design of Modular Pipe Rack Structure

Abstract

Modular construction is the process of developing a prefabricated structure at offsite location, transporting & installing it to designated site location. Modules are generally a set of pre-assembled equipment and ancillaries such as piping, cable trays, etc. assembled at module yard within the structural framing arrangement. Size of modules vary based on design, installation, interfacing and transportation constraints. The use of modular structures has certain advantages compared to conventional stick-built construction. Various structural analysis is required to be carried out for operating condition, lifting condition and transportation condition for modular structure design. The transportation of modular structure can be carried out by one or more of following modes: Truck transportation, SPMT (Self-Propelled Modular Transporter) transportation and Barge transportation. The major challenge in modularization is understanding of structural behaviour during the different phases of module life cycle. As there are different stages involved in the modularization, one should have a thorough knowledge about additional loads & different boundary condition, which would act on the structural elements during transportation and lifting condition. Therefore, it is important to understand the behaviour of modular pipe rack structure and simulate it precisely in the mathematical model during different phases. The current study includes structural behaviour, analysis & design aspects of truck mounted pipe rack modules during all modularization phases i.e. operating, lifting and transportation (truck & barge). Three types of pipe rack have been considered for the study i.e. typical pipe rack, air fin cooler mounted pipe rack and battery limit pipe rack. Further, two different framing arrangement have been considered (i) based on connection between module & stick built structure and (ii) conceptual layout for force transfer. P-Delta analysis has been performed for serviceability check and direct analysis method has been carried out for the strength design as per AISC 360-05. ASCE 7-05 has been used for loads and load combination and Noble Denton guideline has been used for transportation and lifting analysis. Here, an attempt is made to develop the procedure for designing and standardizing of truck mounted modules for pipe rack. Parametric study is performed for standardization of such pipe rack modules for different wind and seismic conditions.