scholarly journals Fast Falling Weight Deflectometer Method for Condition Assessment of RC Bridges

2021 ◽  
Vol 11 (4) ◽  
pp. 1743
Author(s):  
Mauro Coni ◽  
Fausto Mistretta ◽  
Flavio Stochino ◽  
James Rombi ◽  
Mauro Sassu ◽  
...  
Keyword(s):  
Test Procedure ◽  
Cost Effective ◽  
Dynamic Force ◽  
Falling Weight Deflectometer ◽  
Annual Average Daily Traffic ◽  
Short Period ◽  
Cost Efficient ◽  
Action Measures ◽  
Falling Weight ◽  
The Impact

In this paper, the use of Fast Falling Weight Deflectometer (Fast-FWD) is analyzed as a non-destructive and quick test procedure to evaluate the efficiency of short-span bridges. The Fast-FWD is an instrument that can produce a broadband dynamic force up to an impact value of 120 KN: The impact is constant and replicable, providing accurate action measures of bridge stiffness in a truly short period (30 ms). In this paper, a single-span reinforced concrete bridge is investigated, using the Fast-FWD. The considered bridge, approximately 12.0 m long and 15.5 m wide, was in critical condition. The bridge is in a suburban principal road near to the City of Cagliari in Sardinia (Italy), with an Annual Average Daily Traffic of 13,500 vehicles/day, and was suddenly closed, creating serious problems for urban mobility. In these conditions, the investigation through other standard techniques is time-consuming and labor intensive. For this reason, it is important to introduce methods that can be rapid, accurate and cost-efficient. In this paper, bridge stiffness values obtained during the in situ experimental campaign were compared with finite element models values. The Fast-FWD has the potential to provide engineering information that can help us to better understand bridge condition, in a rapid and cost-effective procedure.

scholarly journals Assessing the impact of free-roaming dog population management through systems modelling

2021 ◽  
Author(s):  
Lauren M. Smith ◽  
Rupert J. Quinnell ◽  
Conor Goold ◽  
Alex M. Munteanu ◽  
Sabine Hartmann ◽  
...  
Keyword(s):  
Wildlife Conservation ◽  
Cost Effective ◽  
Fertility Control ◽  
Population Management ◽  
Population Increase ◽  
Use Of Resources ◽  
Efficient Reduction ◽  
Cost Efficient ◽  
Responsible Ownership ◽  
The Impact

AbstractFree-roaming dogs can present significant challenges to public health, wildlife conservation, and livestock production. Their own welfare may also be a concern, as free-roaming dogs can experience poor health and welfare. Dog population management is widely conducted to mitigate these issues. To ensure efficient use of resources, it is critical that effective, cost-efficient, and high-welfare strategies are identified. The dog population comprises distinct subpopulations characterised by their restriction status and level of ownership, but the assessment of dog population management often fails to consider the impact of the interaction between subpopulations on management success. We present a system dynamics model that incorporates an interactive and dynamic system of dog subpopulations. We identify that methods incorporating both fertility control and responsible ownership interventions (a reduction in abandonment and an increase in shelter adoptions) have the greatest potential to reduce free-roaming dog population sizes over longer periods of time, whilst being cost-effective and improving overall welfare. We suggest that future management should be applied at high levels of coverage and should target all sources of population increase, such as abandonment, births, and free-roaming owned dogs, to ensure effective and cost-efficient reduction in free-roaming dog numbers.

scholarly journals Cost-Effective Alternatives to Conventional Charpy Tests for Measuring the Impact Toughness of Very-High-Toughness Steels

2018 ◽  
Vol 140 (2) ◽  
Author(s):  
Enrico Lucon
Keyword(s):  
Electrical Discharge Machining ◽  
Test Procedure ◽  
Cost Effective ◽  
Moderate Increase ◽  
Type Specimens ◽  
Charpy Test ◽  
Line Pipe ◽  
High Toughness ◽  
The Impact ◽  
Very High

For modern plate steels exhibiting high toughness and ductility, the conventional Charpy test is ostensibly stretched beyond its limits of applicability. Impact tests yield absorbed energy values in excess of 300–400 J, which are associated with limited material fracture and mostly derive from plastic deformation of the specimen (bending), friction, and vibrations of the swinging hammer. It would be therefore very desirable to measure the actual fracture toughness of very-high-toughness steels by means of an alternative specimen and/or methodology, entailing just a moderate increase of cost and test complexity with respect to Charpy testing. The investigation presented here was aimed at establishing a reasonable, yet cost-effective test procedure utilizing Charpy-type specimens for measuring the dynamic toughness of high-toughness steels, such as line pipe steels. Promising results have been obtained from notches cut by electrical-discharge machining (EDM) using a thin wire of 0.1 mm diameter, as compared to specimens where an actual crack was generated and propagated by fatigue at the root of the machined notch.

Pavement Rehabilitation Selection Based on Mechanistic Analysis and Field Diagnosis of Falling Weight Deflectometer Data: Virginia Experience

2000 ◽  
Vol 1730 (1) ◽  
pp. 177-186 ◽  
Author(s):  
Sameh Zaghloul ◽  
Mohamed Elfino
Keyword(s):  
Life Cycle Cost ◽  
Visual Inspection ◽  
Cost Savings ◽  
Cost Effective ◽  
Construction Cost ◽  
Rehabilitation Program ◽  
Falling Weight Deflectometer ◽  
Mechanistic Analysis ◽  
The Difference ◽  
Falling Weight

The effectiveness of using the field diagnosis and falling weight deflectometer (FWD) mechanistic analysis in reducing a 65-km (40-mi) segment of asphalt pavement to project level segments is discussed, along with selecting a cost-effective rehabilitation strategy. A mechanistic-based analysis was performed on the deflection basins measured from I-85 in Virginia to backcalculate the layer moduli. The 65-km segment was divided into structurally homogeneous sections based on the back-calculated layer moduli. The data of each homogeneous section were analyzed further to assess the in situ structural capacity, to identify weak layers, to estimate the remaining structural life, and to determine the current and future rehabilitation needs. It was found that some sections have almost no remaining structural life, and others have remaining structural life of more than 10 years. A comparison was made between the FWD–field diagnosis rehabilitation program and a visual inspection rehabilitation program. Results of the comparison indicated that the visual inspection rehabilitation program resulted in selecting thicker overlays for some of the project sections (overdesigned) and thinner overlays for the other sections (underdesigned). It is estimated that the difference between the FWD–field diagnosis rehabilitation program and the visual inspection rehabilitation program for the overdesigned sections is in the range of 45 percent of the construction cost (savings). Life-cycle cost analysis (LCCA) was performed to quantify the difference between the two rehabilitation programs for the underdesigned sections. Results of the LCCA indicated that the FWD–field diagnosis rehabilitation program would result in 26 percent and 42 percent reduction in the construction cost and user delay cost, respectively.

Non-destructive and effective bridge monitoring through fast-falling weight deflectometer

2021 ◽  
Author(s):  
Mario Lucio Puppio ◽  
Fausto Mistretta ◽  
Mauro Coni ◽  
Mauro Sassu
Keyword(s):  
Large Scale ◽  
Low Cost ◽  
Dynamic Force ◽  
Falling Weight Deflectometer ◽  
The Road ◽  
New Applications ◽  
Falling Weight ◽  
Soil Instability ◽  
Climate Events ◽  
Non Destructive

<p>Recent collapses due to hydrogeological soil instability caused by extreme climate events recall the attention on a large-scale monitoring of the road infrastructures, particularly bridges and viaducts. Several studies focus the attention on both hydraulic and structural issues. In-depth systematic investigations do not suit this purpose because of time and cost investments usually carried out from local authorities. Increasing needs of available fast, low cost and reliable methods to investigate the performance of the road and bridges pushed towards new applications. The use of Fast-Falling Weight Deflectometer, conceived for airport pavements, is here applied as a non-destructive test to evaluate the stiffness of the deck and embankment of a bridge. The- Fast Falling Weight Deflectometer can produce a broadband, constant and replicable dynamic force, providing data in real time. An experimental campaign is here described on a case study of single span bridge.</p>

Impact Induced Responses of Saturated and Dry Dense Sand

2018 ◽  
Vol 9 (2) ◽  
pp. 63-85 ◽  
Author(s):  
Mohammed Y. Fattah ◽  
Adnan F. Ali ◽  
Balqees A. Ahmed
Keyword(s):  
Water Pressure ◽  
Time History ◽  
Falling Weight Deflectometer ◽  
Soil Pressure ◽  
Soil Medium ◽  
Dense Sand ◽  
Bearing Plate ◽  
Contact Points ◽  
Falling Weight ◽  
The Impact

The present article includes an experimental study of the behavior of dry and saturated dense sandy soil under the action of a single impulsive load. Dry and saturated dense sand models were tested under impact loads. Different falling masses from different heights were conducted using the falling weight deflectometer (FWD) to provide the single pulse energy. The responses of dense soils were evaluated at surface of soil under impact load. These responses include; displacements, velocities, and accelerations that are developed due to the impact acting at top and the displacement at different depths within the soil using the falling weight deflectometer (FWD) and accelerometers (ARH-500A waterproof, and low capacity acceleration transducer) that are embedded in the soil in addition to soil pressure gauges and then recorded using the multi-recorder TMR-200. Based on the experimental test results, it was found that as the sand becomes saturated, the amplitude of the force-time history decreases by about 10-22% since the voids are filled with water which lead to less contact points between particles. Moreover, the resulting vertical displacement due to impact increases by about 20-60% as compared to the case of dry sand at a depth B (where B is the diameter of the bearing plate) from the bearing plate. Such a behavior is related to two compressive waves through the saturated medium; the fluid wave and the soil skeleton wave with a coupled motion of those two waves hence, makes the displacement to be larger in the saturated soil. The horizontal displacement within the soil medium at a distance B away from the edge of the footing are less than the displacements in dry state. The excess pore water pressure increases by about 40% as the amplitude of the impact force increases due to the increase of the contact pressure.

scholarly journals Cost-Effective Alternatives to Conventional Charpy Tests for Measuring the Impact Toughness of Very-High-Toughness Steels

2017 ◽  
Author(s):  
Enrico Lucon
Keyword(s):  
Electrical Discharge Machining ◽  
Test Procedure ◽  
Cost Effective ◽  
Moderate Increase ◽  
Type Specimens ◽  
Charpy Test ◽  
Line Pipe ◽  
High Toughness ◽  
The Impact ◽  
Very High

For modern plate steels exhibiting high toughness and ductility, the conventional Charpy test is ostensibly stretched beyond its limits of applicability. Impact tests yield absorbed energy values in excess of 300 J – 400 J, which are associated with limited material fracture and mostly derive from plastic deformation of the specimen (bending), friction and vibrations of the swinging hammer. It would be therefore very desirable to measure the actual fracture toughness of very-high-toughness steels by means of an alternative specimen and/or methodology, entailing just a moderate increase of cost and test complexity with respect to Charpy testing. The investigation presented here was aimed at establishing a reasonable, yet cost-effective test procedure utilizing Charpy-type specimens for measuring the dynamic toughness of high-toughness steels, such as line pipe steels. Promising results have been obtained from notches cut by Electrical-Discharge Machining (EDM) using a thin wire of 0.1 mm diameter, as compared to specimens where an actual crack was generated and propagated by fatigue at the root of the machined notch.

Regulatory and sustainability initiatives lead to improved polyaminopolyamide epichlorohydrin (PAE) wet-strength resins and paper products

TAPPI Journal ◽  
2018 ◽  
Vol 17 (09) ◽  
pp. 519-532 ◽  
Author(s):  
Mark Crisp ◽  
Richard Riehle
Keyword(s):  
Health And Safety ◽  
Cost Effective ◽  
Worker Safety ◽  
Regulatory Requirements ◽  
Wet Strength ◽  
The Past ◽  
Consumer Safety ◽  
Federal Institute ◽  
Sustainability Initiatives ◽  
The Impact

Polyaminopolyamide-epichlorohydrin (PAE) resins are the predominant commercial products used to manufacture wet-strengthened paper products for grades requiring wet-strength permanence. Since their development in the late 1950s, the first generation (G1) resins have proven to be one of the most cost-effective technologies available to provide wet strength to paper. Throughout the past three decades, regulatory directives and sustainability initiatives from various organizations have driven the development of cleaner and safer PAE resins and paper products. Early efforts in this area focused on improving worker safety and reducing the impact of PAE resins on the environment. These efforts led to the development of resins containing significantly reduced levels of 1,3-dichloro-2-propanol (1,3-DCP) and 3-monochloropropane-1,2-diol (3-MCPD), potentially carcinogenic byproducts formed during the manufacturing process of PAE resins. As the levels of these byproducts decreased, the environmental, health, and safety (EH&S) profile of PAE resins and paper products improved. Recent initiatives from major retailers are focusing on product ingredient transparency and quality, thus encouraging the development of safer product formulations while maintaining performance. PAE resin research over the past 20 years has been directed toward regulatory requirements to improve consumer safety and minimize exposure to potentially carcinogenic materials found in various paper products. One of the best known regulatory requirements is the recommendations of the German Federal Institute for Risk Assessment (BfR), which defines the levels of 1,3-DCP and 3-MCPD that can be extracted by water from various food contact grades of paper. These criteria led to the development of third generation (G3) products that contain very low levels of 1,3-DCP (typically <10 parts per million in the as-received/delivered resin). This paper outlines the PAE resin chemical contributors to adsorbable organic halogens and 3-MCPD in paper and provides recommendations for the use of each PAE resin product generation (G1, G1.5, G2, G2.5, and G3).

Exploring the Benefits of Early Contractor Involvement (ECI) and the Mechanism for Automated 5D BIM Quantification Process in Offsite Modular Construction

2016 ◽  
Author(s):  
Tochukwu Moses ◽  
David Heesom ◽  
David Oloke ◽  
Martin Crouch
Keyword(s):  
Effective Means ◽  
Cost Effective ◽  
Modular Construction ◽  
Automated Quantification ◽  
Building Information ◽  
Project Risks ◽  
Value Add ◽  
The Uk ◽  
The Impact ◽  
Level 2

The UK Construction Industry through its Government Construction Strategy has recently been mandated to implement Level 2 Building Information Modelling (BIM) on public sector projects. This move, along with other initiatives is key to driving a requirement for 25% cost reduction (establishing the most cost-effective means) on. Other key deliverables within the strategy include reduction in overall project time, early contractor involvement, improved sustainability and enhanced product quality. Collaboration and integrated project delivery is central to the level 2 implementation strategy yet the key protocols or standards relative to cost within BIM processes is not well defined. As offsite construction becomes more prolific within the UK construction sector, this construction approach coupled with BIM, particularly 5D automated quantification process, and early contractor involvement provides significant opportunities for the sector to meet government targets. Early contractor involvement is supported by both the industry and the successive Governments as a credible means to avoid and manage project risks, encourage innovation and value add, making cost and project time predictable, and improving outcomes. The contractor is seen as an expert in construction and could be counter intuitive to exclude such valuable expertise from the pre-construction phase especially with the BIM intent of äóÖbuild it twiceäó», once virtually and once physically. In particular when offsite construction is used, the contractoräó»s construction expertise should be leveraged for the virtual build in BIM-designed projects to ensure a fully streamlined process. Building in a layer of automated costing through 5D BIM will bring about a more robust method of quantification and can help to deliver the 25% reduction in overall cost of a project. Using a literature review and a case study, this paper will look into the benefits of Early Contractor Involvement (ECI) and the impact of 5D BIM on the offsite construction process.

HBOT Application at Cases of Gingival Inflammation

2019 ◽  
Author(s):  
Ilma Robo
Keyword(s):  
Root Resorption ◽  
Periodontal Diseases ◽  
Therapeutic Effects ◽  
Clinical Effects ◽  
Gingival Inflammation ◽  
Beneficial Effects ◽  
New Therapeutic Approaches ◽  
Short Period ◽  
Mechanical Therapy ◽  
The Impact

The treatment of periodontal diseases, mainly of their origin, with the most common clinical manifestation in form of gingival inflammation, is manifold and powerful, including: mechanical therapy, antibiotic, antiseptic and various approaches to treatment, which are recommended to be used within a short period of time. New therapeutic approaches have been proven as alternative treatment to conventional therapy, or in combination with conventional therapies, to reduce the number of periodontopathic pathogens in gingival sulcus. HBOT has a detrimental effect on periodontal microorganisms, as well as beneficial effects on the healing of periodontal tissue, increasing oxygen pressure in gingival pockets. Our study is aimed at reviewing the current published literature on hyperbaric oxygen therapy and focuses on role of HBOT as a therapeutic measure for the individual with periodontal disease in general and for the impact on the recovery of gingival inflammation. HBOT and periodontal treatment together, reduce up to 99% of the gram-negative anaerobic load of subgingival flora. HBOT, significantly reduces subgingival anaerobic flora. Clinical effects in 2-year follow-up of treated patients are sensitive. Reduction of gingival hemorrhage indexes, depth of peritoneum, plaque index, occurs in cases of combination of HBOT and detraction. Reduced load persists up to 2 months after therapy. The significant increase in connective tissue removal starts at the end of 2nd week, to achieve the maximum in week 3-6 of application. HBOT used for re-implantation, stimulates the healing of periodontal membrane, pulp, prevents root resorption, healing of periodontal lining tissues. HBOT, significantly reduces the hemorrhage index with 1.2 value difference, 0.7mm probe depth, reduces gingival fluid by 2. HGH exposure is increased by gingival blood flow, with a difference of 2 in measured value. The therapeutic effects of HBOT in the value of the evaluation index can be saved up to 1-year post treatment.

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