During the past few decades, the number of large public warehouse stores, also known as big-box stores, has grown significantly across the United States and Europe. Large steel storage racks are used in such facilities in order to effectively take advantage of the available space and put on display, for the shopping public, the maximum possible amount of goods. Occupant safety in these facilities during earthquake events depends both on the structural performance of the building and on the performance of the storage racks, while the performance of the racks is determined by the performance of the rack frames and the response of the stored goods. Earthquake shaking may cause pallet contents to spill or topple off racks and rack frames to collapse or overturn. Both occurrences pose a significant life-safety hazard to the exposed shopping public and, therefore, the mitigation of this hazard should be a part of the objectives of any seismic design procedure. This thesis focuses on the behavior of contents stored on steel storage racks and proposes measures for the reduction of hazards associated with content shedding. The effects, on the content response, of (i) several coefficients of friction at the interface between merchandise and rack shelves and (ii) different loading conditions of the rack, are investigated, while the concept of inclined shelves as a measure for reduction of the probability of content overturning is introduced. The concept of inclined shelves refers to back-to-back or back-to-wall rack configurations with their shelves slightly tilted towards the inside or towards the wall, respectively, and represents the anticipated tendency of the merchandise to move inwards, when in motion, due to the contribution of the weight component parallel to the inclined shelf. An analytical model describing the dynamic behavior of pallet contents on rack shelves under earthquake excitation is developed based on rigid body dynamics, Coulomb friction and Newtonian impact laws. This model is implemented in a computer code and parametric incremental dynamic analysis (IDA) studies are conducted examining the effects of coefficients of friction, loading conditions and shelf inclination on the merchandise shedding fragility. A two stage experimental study consisting of pull and shake table tests is conducted to verify the response trends identified by the parametric studies and to provide information on the calibration of the analytical model and on the validity of the assumptions made during its development. During the pull tests, loaded pallets of different weights are pulled over a rack shelf, while during the shake table tests, high intensity ground motions are imposed on the base of a single level - single bay back-to-back rack specimen. Taking advantage of the large amount of experimental data, the analytical model is extended to better capture the observed behavior and a comparison of numerically computed and experimentally measured response is performed for all tests. Finally, two parametric IDA studies are conducted using the updated analytical model. The first study investigates the effects of the inclined shelving on the content shedding fragility for the configuration used during dynamic testing, while the second study investigates the effects of the vertical component of the base excitation on the response by introducing vertical motion components in the context of incremental dynamic analysis.

This book presents the main outcomes of the first European research project on the seismic behavior of adjustable steel storage pallet racking systems. In particular, it describes a comprehensive and unique set of full-scale tests designed to assess such behavior. The tests performed include cyclic tests of full-scale rack components, namely beam-to-upright connections and column base connections; static and dynamic tests to assess the friction factor between pallets and rack beams; full-scale pushover and pseudodynamic tests of storage racks in down-aisle and cross-aisle directions; and full-scale dynamic tests on two-bay, three-level rack models. The implications of the findings of this extensive testing regime on the seismic behavior of racking systems are discussed in detail, highlighting e.g. the confirmation that under severe dynamic conditions “sliding” is the main factor influencing rack response. This work was conceived during the development of the SEISRACKS project. Its outcomes will contribute significantly to increasing our knowledge of the structural behavior of racks under earthquake conditions and should inform future rack design.

The project focuses on the seismic design of static steel pallet racks, which are widely adopted in warehouses. Despite their lightness, racks can be loaded with tons of valuable goods, a live load by far higher than the self-weight, opposite to what happens in usual civil engineering structures. The loss of these goods during an earthquake may represent, for the owner, a very large economic loss, much larger than the cost of the whole rack on which the goods are stored or of the cost for its seismic upgrade. Hence, solution of the problems connected with safe and reliable design of steel storage racks in seismic areas has a very large economic impact. The objective of the SEISRACKS2 project is to increase knowledge on actual structural behaviour and ductility of steel pallet racks, and to assess design rules for earthquake conditions by full-scale testing and numerical simulation. Main outcomes of the research are: 1. Detailed reports on the different aspects investigated; 2. Validation or invalidation of the rules in the current version of FEM 10.2.08; 3. Improvements and extension of the current rules in order to optimize the seismic behaviour of structures designed according to European rules; 4. Definition of standardized experimental procedures to qualify structural elements of rack structures to be used in seismic areas; 5. A new software tool for the design of rack structures under seismic loads.

During the past few decades, the number of large public warehouse stores (often referred to as big-box stores) across the nation has grown significantly, changing both consumer buying habits and the public's risk of injury during earthquakes. During an earthquake, occupant safety in a big-box store depends on both the structural performance of the building and on the performance of the storage racks and their contents. Earthquake ground motions can cause storage racks to collapse or overturn if they are not properly designed, installed, maintained, and loaded. In addition, goods stored on the racks may spill or topple off. Both occurrences pose a life-safety risk to the exposed shopping public. The immediate stimulus for the project that resulted in this report was a 2003 request from the State of Washington to the Federal Emergency Management Agency (FEMA) for guidance concerning the life-safety risk posed by the storage racks in publicly accessible areas of retail stores, especially the risk of rack collapse of loss of stored goods during an earthquake. FEMA asked the Building Seismic Safety Council (BSSC) to develop the requested guidance. To do so, the BSSC established a Rack Project Task Group composed of practicing engineers, storage rack designers, researchers, representatives of the Rack Manufacturers Institute (RMI) and the Retail Industry Leaders Association, and members of applicable technical subcommittees responsible for updating the NEHRP Recommended Provisions. In developing this guidance document, the Task Group focused primarily on steel single selective pallet storage racks. It reviewed available information on storage rack performance during earthquakes and the background on the development of standards and code requirements for storage racks; assessed seismic requirements for storage racks and current practices with respect to rack design, maintenance and operations, quality assurance, and post-earthquake inspections; and examined available research and testing data. Based on its study, the Task Group developed short-term recommendations to improve current practice and formulated long-term recommendations to serve as the basis for improved standards documents such as the NEHRP Recommended Provisions, ASCE 7, and the RMI-developed storage rack specification. Over the near term, the Task Group recommends that the 2003 NEHRP Recommended Provisions requirements for steel single selective pallet storage rack design be followed and that connections be checked in accordance with a procedure to be developed by RMI. The Task Group also recommends that additional guidance presented in this report be voluntarily adopted by store owners and operators. Further, given the fact that maintenance and use of storage racks is a key element to their acceptable performance during earthquakes, store owners and operators should adopt an appropriate quality assurance plan; as a minimum, the best self-imposed practices of store owners and operators should be maintained. The Task Group's primary long-term recommendation is that the RMI specification be brought into conformance with the 2003 NEHRP Recommended Provisions, which is the basis for seismic requirements found in current seismic design standards and model building codes. The Task Group also recommends that optional performance-based and limit state procedures and component cyclic testing procedures be incorporated into the RMI-developed specification. Compliance with these procedures will demonstrate that the storage racks have the capacity to resist maximum considered earthquake ground motions without collapse. It also is recommended that regulatory bodies periodically review the quality assurance programs of stores and implement any regulations needed to satisfy life-safety concerns that relate to the securing of rack contents and rack maintenance and use.

The project focuses on the seismic design of static steel pallet racks, which are widely adopted in warehouses. Despite their lightness, racks can be loaded with tons of valuable goods, a live load by far higher than the self-weight, opposite to what happens in usual civil engineering structures. The loss of these goods during an earthquake may represent, for the owner, a very large economic loss, much larger than the cost of the whole rack on which the goods are stored or of the cost for its seismic upgrade. Hence, solution of the problems connected with safe and reliable design of steel storage racks in seismic areas has a very large economic impact. The objective of the SEISRACKS2 project is to increase knowledge on actual structural behaviour and ductility of steel pallet racks, and to assess design rules for earthquake conditions by full-scale testing and numerical simulation. Main outcomes of the research are: 1. Detailed reports on the different aspects investigated; 2. Validation or invalidation of the rules in the current version of FEM 10.2.08; 3. Improvements and extension of the current rules in order to optimize the seismic behaviour of structures designed according to European rules; 4. Definition of standardized experimental procedures to qualify structural elements of rack structures to be used in seismic areas; 5. A new software tool for the design of rack structures under seismic loads.

This book comprises the select peer-reviewed proceedings of the Indian Structural Steel Conference (ISSC 2020). The topics cover state-of-the-art and state-of-the-practice in structural engineering, and latest research in structural modeling and design. Novel analytical, computational and experimental techniques, proposal of new structural systems, innovative methods for maintenance, rehabilitation, and monitoring of existing structures, and investigation of the properties of engineering materials as related to structural behavior are presented in the book. This book will be very useful for structural engineers, researchers, and consultants interested in sustainable materials and steel construction.

Behaviour of Steel Structures in Seismic Areas comprises the latest progress in both theoretical and experimental research on the behaviour of steel structures in seismic areas. The book presents the most recent trends in the field of steel structures in seismic areas, with particular reference to the utilisation of multi-level performance bas