Performance of an 11 m high block-faced geogrid wall designed using the K-stiffness method

2014 ◽  
Vol 51 (1) ◽  
pp. 16-29 ◽  
Author(s):  
Tony M. Allen ◽  
Richard J. Bathurst

An 11 m high dry-stacked masonry concrete block wall reinforced with a high-density polyethylene (HDPE) geogrid was designed, instrumented, and monitored for a period of 2 years as part of a highway-widening project southeast of Seattle, Washington, in the USA. An extensive materials-testing program was conducted to characterize the geogrid and backfill soil properties. The empirical-based K-stiffness method was used to design the wall, and this approach resulted in a 35% reduction in total required reinforcement strength compared with the American Association of State Highway and Transportation Officials / Federal Highway Administration (AASHTO/FHWA) simplified method. The cost savings more than compensated for the cost of the instrumentation program. Geogrid strains were measured using strain gauges and extensometers, and the walls were surveyed to monitor facing deformations. The stiffness of the geogrid materials was computed from the results of laboratory in-isolation constant-load (creep) tests. The time- and strain-dependent stiffness values, in combination with measured strains, were used to compute measured reinforcement loads at the reinforcement connections and at locations within the reinforced soil backfill. The measured loads were compared with class A, B, and C1 predictions using the AASHTO/FHWA simplified and K-stiffness methods. These comparisons demonstrate that the simplified method significantly overestimated reinforcement loads, whereas the K-stiffness method provided estimates that were judged to be in better agreement with the measured results. The paper also quantifies the influence of construction procedures on reinforcement strains and load, shows that long-term creep of the reinforcement after 2 years after construction is negligible, and identifies lessons learned.

2014 ◽  
Author(s):  
Jeff Cowan

California experienced a 300% increase in loss of propulsion (LOP) incidents since its distillate fuel regulation came into effect in 2009. The compression ignition (Diesel) engines aboard modern cargo ships over 10,000 gross tons use 3.0% sulfur Heavy Fuel Oil (HFO). This fuel must be heated to flow through the fuel lines because at normal ambient temperature HFO has the consistency of tar. Distillate fuel in contrast does not require the high temperatures, and the thermodynamics of cooling metal, gaskets and seals resulted in leaks, along with filter clogging from engine buildup scrubbing. In addition, the cost savings of using HFO are significant over the use of distillate fuel which is typically around US$300 more per ton.


1994 ◽  
Vol 31 (4) ◽  
pp. 564-569 ◽  
Author(s):  
R.J. Fannin

Field data are reported that describe the load–strain–time relationship of geogrid reinforcement in a reinforced soil structure. The data are for a period exceeding 5 years and reveal a continued strain in the reinforcement, which occurs at nearly constant load. The response to loading is attributed to creep of the polymeric material. A comparison of the field data with laboratory isochronous load–strain curves, from rapid loading creep tests performed at a temperature similar to the mean annual temperature in the backfill soil, shows the curves describe very well the magnitude of creep strains observed in the field. Implications of the load–strain–time performance data are assessed with reference to the use in design of a tensile strength established from the rapid-loading creep test and wide-width strip test. The need to clarify, in design of polymeric reinforced soil structures, between a safe and allowable tensile strength is emphasized. Key words : reinforced soil, geogrid, creep, tensile strength, strain.


2021 ◽  
pp. 1-14
Author(s):  
Ashutosh Dikshit ◽  
Amrendra Kumar ◽  
Glenn Woiceshyn

Summary Interest is high in a method to reliably run single-trip completions without involving complex/expensive technologies (Robertson et al. 2019). The reward for such a design would be reduced rig time, safety risks, and completion costs. As described herein, a unique pressure-activated sliding side door (PSSD) valve was developed and field tested to open without intervention after completion is circulated to total depth (TD) and a liner hanger and openhole isolation packers are set. A field-provensliding-sleeve door (SSD) valve that required shifting via a shifting tool run on coiled tubing, slickline (SL), or wireline was upgraded to open automatically after relieving tubing pressure once packers (and/or a liner hanger) are set. This PSSD technology, which is integrable to almost any type of sand control screen, is equipped with a backup contingency should the primary mechanism fail to open. Once opened, the installed PSSDs can be shifted mechanically with unlimited frequency. The two- or three-position valve can be integrated with inflow control devices (ICDs) (includes autonomous ICDs/autonomous inflow control valves) and allows mechanical shifting at any time after installation to close, stimulate or adjust ICD settings. After a computer-aided design stage to achieve all the operational/mechanical requirements, prototypes were built and tested, followed by field installations. The design stage provided some challenges even though the pressure-activation feature was being added to a mature/proven SSD technology. Prototype testing in a full-scale vertical test well proved valuable because it revealed failure modes that could not have appeared in the smaller-scale laboratory test facilities. Lessons learned from the first field trial helped improve onsite handling procedures. The production logging tool run on first installation confirmed the PSSDs with ICDs opened as designed. The second field installation involved a different size and configuration, in which PSSDs with ICDs performed as designed. The unique two- or three-position PSSD accommodates any type of sand control or debris screen and any type of ICD for production/injection. The PSSD allows the flexibility to change ICD size easily at the wellsite. Therefore, this technology can be used in carbonate as well as sandstone wells. Wells that normally could not justify the expense of existing single-trip completion technologies can now benefit from the cost savings of single-trip completions, including ones that require ICD and stimulation options.


2014 ◽  
Vol 222 (1) ◽  
pp. 37-48 ◽  
Author(s):  
Stephanie Romney ◽  
Nathaniel Israel ◽  
Danijela Zlatevski

The present study examines the effect of agency-level implementation variation on the cost-effectiveness of an evidence-based parent training program (Positive Parenting Program: “Triple P”). Staff from six community-based agencies participated in a five-day training to prepare them to deliver a 12-week Triple P parent training group to caregivers. Prior to the training, administrators and staff from four of the agencies completed a site readiness process intended to prepare them for the implementation demands of successfully delivering the group, while the other two agencies did not complete the process. Following the delivery of each agency’s first Triple P group, the graduation rate and average cost per class graduate were calculated. The average cost-per-graduate was over seven times higher for the two agencies that had not completed the readiness process than for the four completing agencies ($7,811 vs. $1,052). The contrast in costs was due to high participant attrition in the Triple P groups delivered by the two agencies that did not complete the readiness process. The odds of Triple P participants graduating were 12.2 times greater for those in groups run by sites that had completed the readiness process. This differential attrition was not accounted for by between-group differences in participant characteristics at pretest. While the natural design of this study limits the ability to empirically test all alternative explanations, these findings indicate a striking cost savings for sites completing the readiness process and support the thoughtful application of readiness procedures in the early stages of an implementation initiative.


2017 ◽  
Vol 7 (1) ◽  
pp. 43-52
Author(s):  
Mochamad Tamim Ma’ruf

One-solving methods and techniques necessary to avoid inefficiencies and not economic costs as well as reduce the cost of housing construction is the method of Value Engineering. Value engineering is a method and cost control techniques to analyze a function to its value at the lowest cost alternative (most economical) without reducing the quality desired.At the writing of this study used a comparison method by comparing the initial design to the design proposal of the author. In the housing projects Upgrading Tirto Penataran Asri type 70, the application of Value Engineering conducted on the job a couple walls and roofs pair by replacing some work items with a more economical alternative but does not change the original function and high aesthetic level and still qualify safe. For that performed the step of determining a work item, the alternative stage, the analysis stage, and the stage of recommendations to get a Value Engineering application and cost savings against the wall a couple of work items and partner roof.The proposed design as compared to the initial design. Work items discussed was the work of a couple wall having analyzed obtained savings of Rp. 2,747,643.56 and the work of the roof pair obtained savings of Rp. 2,363,446.80. Thus the total overall savings gained is Rp 5,111,090.36 or savings of 0048%.


2020 ◽  
Vol 15 ◽  
Author(s):  
Billu Payal ◽  
Anoop Kumar ◽  
Harsh Saxena

Background: Asthma and Chronic Obstructive Pulmonary Diseases (COPD) are well known respiratory diseases affecting millions of peoples in India. In the market, various branded generics, as well as generic drugs, are available for their treatment and how much cost will be saved by utilizing generic medicine is still unclear among physicians. Thus, the main aim of the current investigation was to perform cost-minimization analysis of generic versus branded generic (high and low expensive) drugs and branded generic (high expensive) versus branded generic (least expensive) used in the Department of Pulmonary Medicine of Era Medical University, Lucknow for the treatment of asthma and COPD. Methodology: The current index of medical stores (CIMS) was referred for the cost of branded drugs whereas the cost of generic drugs was taken from Jan Aushadi scheme of India 2016. The percentage of cost variation particularly to Asthma and COPD regimens on substituting available generic drugs was calculated using standard formula and costs were presented in Indian Rupees (as of 2019). Results: The maximum cost variation was found between the respules budesonide high expensive branded generic versus least expensive branded generic drugs and generic versus high expensive branded generic. In combination, the maximum cost variation was observed in the montelukast and levocetirizine combination. Conclusion: In conclusion, this study inferred that substituting generic antiasthmatics and COPD drugs can bring potential cost savings in patients.


2011 ◽  
Vol 14 (2) ◽  
Author(s):  
Thomas G Koch

Current estimates of obesity costs ignore the impact of future weight loss and gain, and may either over or underestimate economic consequences of weight loss. In light of this, I construct static and dynamic measures of medical costs associated with body mass index (BMI), to be balanced against the cost of one-time interventions. This study finds that ignoring the implications of weight loss and gain over time overstates the medical-cost savings of such interventions by an order of magnitude. When the relationship between spending and age is allowed to vary, weight-loss attempts appear to be cost-effective starting and ending with middle age. Some interventions recently proven to decrease weight may also be cost-effective.


2021 ◽  
Vol 6 (1) ◽  
pp. e000561
Author(s):  
Ving Fai Chan ◽  
Fatma Omar ◽  
Elodie Yard ◽  
Eden Mashayo ◽  
Damaris Mulewa ◽  
...  

ObjectiveTo review and compare the cost-effectiveness of the integrated model (IM) and vertical model (VM) of school eye health programme in Zanzibar.Methods and analysisThis 6-month implementation research was conducted in four districts in Zanzibar. Nine and ten schools were recruited into the IM and VM, respectively. In the VM, teachers conducted eye health screening and education only while these eye health components were added to the existing school feeding programme (IM). The number of children aged 6–13 years old screened and identified was collected monthly. A review of project account records was conducted with 19 key informants. The actual costs were calculated for each cost categories, and costs per child screened and cost per child identified were compared between the two models.ResultsScreening coverage was 96% and 90% in the IM and VM with 297 children (69.5%) from the IM and 130 children (30.5%) from VM failed eye health screening. The 6-month eye health screening cost for VM and IM was US$6 728 and US$7 355. The cost per child screened for IM and VM was US$1.23 and US$1.31, and the cost per child identified was US$24.76 and US$51.75, respectively.ConclusionBoth models achieved high coverage of eye health screening with the IM being a more cost-effective school eye health delivery screening compared with VM with great opportunities for cost savings.


Author(s):  
Boris Claros ◽  
Beau Burdett ◽  
Madhav Chitturi ◽  
Andrea Bill ◽  
David A. Noyce

Roundabout implementations at traditional intersections have been shown to be effective at reducing severe crashes. Roundabouts have also been implemented at interchange ramp terminals; however, limited research is available. In this study, 25 roundabout ramp terminal implementations were evaluated. The methodological approach consisted of Empirical Bayes for safety effectiveness and crash cost changes, crash type weighted distribution, crash rate analysis of bypass configuration, and cost of implementation. Roundabouts were effective at reducing fatal and injury crashes when replacing existing interchange diamond ramp terminals: 65% reduction for roundabouts replacing stop-controlled ramp terminals and 41% reduction for roundabouts replacing signal-controlled ramp terminals. Observed crash type weighted distributions are provided to visualize the frequency and location of crashes within roundabout ramp terminals for design considerations. Exit ramp and outside crossroad approaches with right-turn bypass showed significantly lower crash rates than designs without bypass. The crash cost analysis showed that roundabouts replacing diamond ramp terminals yielded crash cost savings of between $95,000 and $253,000 per site per year (69% to 54% decrease in crash costs). Considering crash costs savings only, the cost of implementation should be less than $1.9 million for a roundabout replacing a stop-controlled ramp terminal and less than $5.1 million for a roundabout replacing a signal-controlled ramp terminal to accomplish benefit-cost ratios greater than one for a service life cycle of 20 years. Costs are in 2019 dollars.


2010 ◽  
Vol 26 (2) ◽  
pp. 170-174 ◽  
Author(s):  
Shin Yuh Ang ◽  
Rachel Woo Yin Tan ◽  
Mariko Siyue Koh ◽  
Jeremy Lim

Objectives: Endobronchial ultrasound (EBUS), encompassing endobronchial ultrasound transbronchial needle aspiration (EBUS-TBNA) and Endobronchial ultrasound transbronchial lung biopsy (EBUS-TBLB) has been proven to be a useful modality in the staging and diagnosis of lung cancer. However, there are limited publications on the cost-effectiveness of EBUS and no economic evaluations relevant to the Singapore setting. An economic evaluation using our hospital's data was used to assess the cost implications of EBUS substituting where clinically appropriate: transthoracic needle aspiration; (TTNA), fluoroscopy-guided transbronchial lung biopsy (TBLB), and mediastinoscopy in the diagnosis and staging of lung cancer.Methods: Relationship between the clinical and economic implications of alternative modalities was modeled using data inputs that were relevant to the Singapore setting. Two decision analytic models were constructed to evaluate the cost of EBUS compared with TTNA, TBLB, and staging mediastinoscopy. Only direct costs were imputed.Results: In the base–case analysis, TTNA was the most economical strategy (SGD3,335 = US$2,403) where clinically suitable for the diagnosis of lung cancer as compared to the other options: TBLB (SGD4,499) and EBUS-TBLB (SGD4,857). On the other hand, EBUS-TBNA resulted in expected cost savings of SGD1,214 per positive staging of lung cancer as compared to mediastinoscopy.Conclusions: The use of EBUS-TBNA could result in cost savings of SGD1,214 per positive staging of lung cancer as compared to mediastinoscopy. Whereas TTNA was the most economical intervention for the diagnosis of lung cancer as compared to the other options, its main limitation lies in its suitability only for peripheral lung lesions and high complication rate.


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