International Research Journal of Engineering and Technology (IRJET) Volume: 09 Issue: 07 | July 2022
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e-ISSN: 2395-0056 p-ISSN: 2395-0072
Analysis of Alternate Load Path Method of Modular Structures Pooja Nair1, Prabha C2 1 Pooja
Nair, M.Tech Student, Department of Civil Engineering, Mar Athanasius College of Engineering, Kothamangalam 2Prabha C, Professor, Department of Civil Engineering, Mar Athanasius College of Engineering, Kothamangalam ---------------------------------------------------------------------***---------------------------------------------------------------------
Abstract - In recent times, modular buildings and its
use the alternate path method (APM) or similarly alternate load path method. The alternate path method (APM) can be applied to study the gravity induced progressive collapse of modular steel buildings under entire module loss scenarios.
construction has gained significant importance due to its increased advantages over conventional construction practices. But the need for studying the structural robustness of modular and prefabricated buildings is still a major research gap. Out of many methodologies, the project deals with alternate load path method to identify the failure mechanism. The aim of the project was to carry out ALP analysis and to find out alternate paths through which the loads redistribute. The work also included determining the Von Mises stresses and structural response curves for different module loss scenarios. The model was analyzed using the ABAQUS software where the whole model was meshed into finite elements for analysis. The model underwent a dynamic explicit analysis where it provided with stress distribution and deflection contours and time history graphs for force and displacement.
2. MODULAR CONSTRUCTION Modular construction can allow for up to 95% of a building to be prefabricated in a controlled factory environment. This offers faster and safer manufacturing with better quality control, and reduces environmental impacts compared to traditional onsite construction. There is an increased demand for understanding the sensitivity of modular structures to local damages as the modular buildings are more vulnerable when subjected to extreme events. Modular building is a construction technique whereby building modules are prefabricated off-site. It is a type of offsite fabrication referring specifically to volumetric units which may be a structural element of a building. Modular building refers to the application of a variety of structural systems and building materials, rather than a single type of structure. Prefabrication at offsite leads to a reduced overall construction schedule, improved quality, and reduced resource wastage but there is a lack of design guidance and can have relatively small structural spans due to module transport limits. The focus is on steel framed modules rather than concrete and timber frame modules, not for lack of importance, but for lack of recent research into the structures. For inter modular connections bolted connections are preferred over on-site welding of the modules. Due to the nature of modular construction, modular buildings exhibit some distinctive structural characteristics, particularly in those assembled with steelframed units. Normally, such structures are designed to withstand not only the normal loading scenarios as in conventional buildings, but also the racking actions during transportation and craning, which are structurally more demanding. The load transfer between adjacent modules may occur mainly through the module corners. These features can potentially disadvantage structural robustness in design.
Key Words: Progressive collapse, alternate path, load redistribution, modular buildings, inter-modular connections
1. INTRODUCTION Over lately, the construction industry, modular buildings and its construction has gained significant importance owing to its advantages like safer and faster construction processes, better estimation of time and cost, less or no wastage of resources and lesser number of workers required at the site. In this form of construction, off-site factory-made volumetric units (called modules) and components are transported and assembled on-site to form an entire building. These units can be continuously supported, corner supported or non-bearing modules. The modules can be connected by rigid, semirigid or flexible connections. The analysis of the structural robustness of the modular and prefabricated buildings has not been a great matter of study. But it is very important to analyze the failure mechanisms of modular buildings since they are more vulnerable to any kind of abnormal loading condition. If the damaged structure cannot attain equilibrium after the local damage has occurred, they can lead to progressive and ultimately global collapse of the structure.
3. PROGRESSIVE COLLAPSE Progressive collapse phenomena define as the failure of one or more key load-carrying elements either accidentally or
To ensure that structural systems have adequate resistance to progressive collapse, most of design guidelines
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