Mitigation of Progressive Collapse by the Activation of the Elasto-Plastic Catenary Behaviour of R.C. Slab Structures

2014 ◽  
Vol 8 (1) ◽  
pp. 122-131 ◽  
Author(s):  
Fabrizio Palmisano

Mitigation of progressive collapse was highlighted in 1968 with the collapse of the Ronan Point building in the United Kingdom. Technical standards followed suit with increased requirements and recommendations to encourage the design and construction of more robust buildings. The intent has been to establish a design process that recognizes and considers the potential that buildings could experience abnormal and extreme loads or events that seriously compromise one or more critical load-carrying elements. This article aims to show that if the main goal of the design is to protect human lives in these extreme conditions, even sacrificing the building functionality, simple measures such as the activation of the elasto-plastic catenary behaviour of the slab reinforcement, could be very effective to increase the building robustness without substantially increasing the cost of a structural system.

Buildings ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 19 ◽  
Author(s):  
Osama Mohamed ◽  
Rania Khattab

This paper evaluates the practice of using moment connections in the perimeter of the structural system and shear connections within the interior connections of the three-dimensional structural system from the perspective of resistance to progressive collapse. The enhanced resistance to progressive collapse associated with using moment resisting connections at the perimeter as well as internal to the three-dimensional system is assessed. Progressive collapse occurrence and system resistance are determined using the alternate path method which presumes a primary load carrying-member is notionally removed. The paper compares the structural response determined using linear elastic, non-linear elastic and non-linear dynamic analyses. Linear and non-linear static analyses are found to be incapable of capturing the response pursuant to the loss of the primary load carrying member. The analysis procedures used in this study followed (for the most part) the United States Department of Defense Guide for Progressive Collapse Resistant Design of Structures.


1993 ◽  
Vol 27 (5-6) ◽  
pp. 381-390 ◽  
Author(s):  
John Upton

The European waste water industry will need to develop denitrification processes to remove nitrogen as pressures increase to reduce nutrient levels discharged in effluents. In the USA deep bed filter technology has been used extensively to provide denitrification to levels less than 5 mg/l TN. This paper describes this technology and the full scale performance at some waste water plants in Florida, USA. This paper also describes a pilot study in the United Kingdom at Severn Trent Water. The results of the pilot plant study indicate that denitrification in deep bed sand filters is a sound robust technology using methanol addition. Nitrogen removals greater than the 70% required in the EC Directive 1991 are possible at winter sewage temperatures. The process is most suitable for achieving nitrogen removal at trickling filter plants. The cost of methanol addition is calculated to be ₤10/1000m3.


Author(s):  
Jacqueline B. Barnett

The application of ergonomics is important when considering the built environment. In order to create an environment where form follows function, a detailed understanding of the tasks performed by the individuals who will live and work in the facility is required. Early involvement in the project is key to maximizing the benefit of ergonomics. At Sunnybrook and Women's College Health Sciences Centre in Toronto, Canada, this early intervention was embraced during the design process of a behavioural care unit for aggressive patients. The ergonomist was involved in three phases of design; user needs analysis, block schematics and detailed design. The user needs and characteristics were established using a combination of focus groups, interviews, direct observation, task analysis and critique of current working environments. The challenge was to present the information to the design team in a useful manner. The format chosen was a modification of Userfit (Poulson 1996) that outlined the various characteristics of the patient group and the design consequences with “what does this mean for me” statements. During the block schematics phase an iterative design process was used to ensure that the ergonomic principles and the user needs were incorporated into the design. Ergonomic input was used in determining the room sizes and layout and to ensure work processes were considered. Simple mock-ups and anthropometric data assisted in illustrating the need for design changes. Examples that highlight the areas of greatest impact of ergonomic intervention include the patient bathrooms, showers and tub room. Significant changes were made to the design to improve the safety of the work and living space of the end users. One of the greatest challenges was having an appreciation for the individual goals of the team members. Ensuring there was adequate space for equipment and staff often resulted in recommendations for increased space. This in turn would increase the cost of the project. The architect and, later in the project, the engineer had goals of bringing the project in on budget. The final design was very much a team effort and truly die result of an iterative process. The sum of the individual contributions could not match the combined efforts. It was only through the ergonomic contributions in this early design phase that the needs of the staff, patients and families could be so well represented. The success of the iterative process provides the foundation for bringing ergonomics considerations into the early design stages of future projects.


Author(s):  
ALEXANDER FOUIRNAIES

In more than half of the democratic countries in the world, candidates face legal constraints on how much money they can spend on their electoral campaigns, yet we know little about the consequences of these restrictions. I study how spending limits affect UK House of Commons elections. I contribute new data on the more than 70,000 candidates who ran for a parliamentary seat from 1885 to 2019, and I document how much money each candidate spent, how they allocated their resources across different spending categories, and the spending limit they faced. To identify the effect on elections, I exploit variation in spending caps induced by reforms of the spending-limit formula that affected some but not all constituencies. The results indicate that when the level of permitted spending is increased, the cost of electoral campaigns increases, which is primarily driven by expenses related to advertisement and mainly to the disadvantage of Labour candidates; the pool of candidates shrinks and elections become less competitive; and the financial and electoral advantages enjoyed by incumbents are amplified.


Author(s):  
Ryoga Oura ◽  
Takashi Yamaguchi ◽  
Kentaro Arimura

<p>Bridges are composed by many structural members which interact with each other to resist against various load combinations. Considering damage repair of one of its structural members, the relationship between the recovery of the individual load-carrying capacity due to the repair of a single member and the improvement of the load-carrying capacity of the structural system is not clear. In the present study, a full-scale FE analysis has been conducted for a steel I-girder bridge system with corrosion damages which have been repaired. The analysis considered, the structural system behavior, varying the repaired areas and the type of patch members. From the analytical results, it was found that, compared to the method in which the damaged portion is completely repaired, the amount of repair can be reduced by taking into account the structural system behavior and partially repair both the damaged and the adjacent intact girders.</p>


2014 ◽  
Vol 36 (6) ◽  
pp. E1 ◽  
Author(s):  
Matthew D. Alvin ◽  
Jacob A. Miller ◽  
Daniel Lubelski ◽  
Benjamin P. Rosenbaum ◽  
Kalil G. Abdullah ◽  
...  

Object Cost-effectiveness research in spine surgery has been a prominent focus over the last decade. However, there has yet to be a standardized method developed for calculation of costs in such studies. This lack of a standardized costing methodology may lead to conflicting conclusions on the cost-effectiveness of an intervention for a specific diagnosis. The primary objective of this study was to systematically review all cost-effectiveness studies published on spine surgery and compare and contrast various costing methodologies used. Methods The authors performed a systematic review of the cost-effectiveness literature related to spine surgery. All cost-effectiveness analyses pertaining to spine surgery were identified using the cost-effectiveness analysis registry database of the Tufts Medical Center Institute for Clinical Research and Health Policy, and the MEDLINE database. Each article was reviewed to determine the study subject, methodology, and results. Data were collected from each study, including costs, interventions, cost calculation method, perspective of cost calculation, and definitions of direct and indirect costs if available. Results Thirty-seven cost-effectiveness studies on spine surgery were included in the present study. Twenty-seven (73%) of the studies involved the lumbar spine and the remaining 10 (27%) involved the cervical spine. Of the 37 studies, 13 (35%) used Medicare reimbursements, 12 (32%) used a case-costing database, 3 (8%) used cost-to-charge ratios (CCRs), 2 (5%) used a combination of Medicare reimbursements and CCRs, 3 (8%) used the United Kingdom National Health Service reimbursement system, 2 (5%) used a Dutch reimbursement system, 1 (3%) used the United Kingdom Department of Health data, and 1 (3%) used the Tricare Military Reimbursement system. Nineteen (51%) studies completed their cost analysis from the societal perspective, 11 (30%) from the hospital perspective, and 7 (19%) from the payer perspective. Of those studies with a societal perspective, 14 (38%) reported actual indirect costs. Conclusions Changes in cost have a direct impact on the value equation for concluding whether an intervention is cost-effective. It is essential to develop a standardized, accurate means of calculating costs. Comparability and transparency are essential, such that studies can be compared properly and policy makers can be appropriately informed when making decisions for our health care system based on the results of these studies.


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