Project-specific Conditions Research Articles

Scalability and Replicability Analysis in Smart Grid Demonstration Projects: Lessons Learned and Future Needs

This paper compares various approaches to the scalability and replicability analysis (SRA) of smart grid pilot projects, highlighting the need for a comprehensive SRA methodology as called for by the European Commission and International Energy Agency. This study addresses the need for a standardized SRA methodology and explores how three EU-funded projects—Platone, EUniversal, and IElectrix—adapted the general guidelines developed by the BRIDGE initiative. These guidelines provide recommendations for developing a comprehensive large-scale deployment analysis. The results show that while the guidelines are usable and flexible, project-specific conditions and data availability limitations—particularly in regulatory and technical analysis—can pose challenges. Some key recommendations to overcome these and facilitate future applications are identified. These include defining SRA methodologies and securing data-sharing agreements early. The lack of standardized approaches for presenting SRA results hampers cross-project comparison. Thus, creating an open-use case repository and updating the BRIDGE guidelines with more detailed examples, benchmarks, and reference networks is recommended. Additionally, linking SRA with cost–benefit analysis (CBA) is suggested in order to evaluate the commercial viability of smart grid solutions. The paper concludes that while the BRIDGE guidelines have proven to be fit for purpose, further developments are needed to facilitate their practical application in real-world projects.

Installation of geosynthetic interlayers during overlay construction: Case study of Texas State Highway 21

Geosynthetic interlayers in the form of geotextiles, geogrids, and geocomposites have been used to minimize reflective cracks and enhance overlay performance through functions such as stress relief, reinforcement and moisture barrier. However, proper geosynthetic installation and asphalt overlay construction practices are essential to the adequate performance of geosynthetic-reinforced asphalt overlays. In this study, various factors determining the successful construction of a geosynthetic-reinforced asphalt overlay are discussed in light of experiences during the construction of experimental test sections constructed in Texas State Highway 21. The project included nine different types of geosynthetic interlayers including four polymeric geogrid composites, three fiberglass geogrid composites, one fiberglass grid, and a fiberglass paving mat. The experimental test section included both sensor- and non-instrumented sections. The constructability evaluation of such experimental sections revealed that the primary factors influencing tack coat type and application rates include the pre-existing surface condition, geosynthetic type and their asphalt retention capacities. The geosynthetic installation procedures adopted in the experimental sections were proficient and comprised a specialized installation equipment that is capable of pre-tensioning the geosynthetics during the installation to minimize wrinkles and irregularities. Additionally, particularly high temperature of the pre-existing asphalt surface resulted in blistering of geotextile backing and subsequently leading into an excessive bleeding of tack coat through the geosynthetic apertures that resulted in tracking of construction equipment wheels. Recommendations on efficient geosynthetic installation and overlay construction techniques include adopting the tack coat type and application rates based on project-specific conditions, and using such tack coat to determine the asphalt retention capacity of the geosynthetic interlayer to be used in the project. Additional recommendations include minimizing the movement of construction vehicles on top of the geosynthetic interlayer, and adopting asphalt sanding technique to restore the friction between the paver and surface to minimize possible damage to the geosynthetic interlayer.

Numerical simulation of risk mitigation strategies for early-age thermal cracking and DEF in concrete

Early-age thermal cracking and delayed ettringite formation (DEF) are short-term and long-term major issues to the durability of mass concrete and require a high level of consideration in the development of a suitable concrete mix design in placement and curing strategies, particularly in mixes of high cement content. Where DEF risk proves to be significant, contractors are required to adopt risk mitigation strategies including lowering concrete’s temperature during placement by adding cool water or ice, for example, to the mix, embedding cooling pipes in the cast element and/or sequential placement of the concrete. These strategies can be implemented at different levels, as needed, to minimise the risk of cracking and DEF. Determining the most suitable and cost-efficient risk mitigation strategy, however, together with its implementation, is a complex task that requires consideration of each complex strategy under project-specific conditions. While a significant research effort has been invested to develop an improved understanding of the effectiveness of different early age thermal cracking and DEF risk mitigation strategies, the lack of reliable models capable of simulating and comparing the effectiveness of all scenarios remains elusive and considerably limits the ability of the practitioners in identifying the optimal approach. This paper presents a Multiphysics model developed to predict the effect of early-age thermal cracking and DEF risk mitigation scenarios. The model is validated using four real-life project Case Studies and is demonstrated to provide reliable results. In addition, the paper studies the comparative effectiveness of key risk mitigation strategies and the important parameters influencing their effectiveness.

Optimization Process Maximizes Financial, Environmental Benefits in LNG Breakwater

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper OTC 31284, “Greater Tortue Ahmeyim Project for BP In Mauritania and Senegal: Breakwater Design and Local Content Optimizations,” by Alexis Replumaz, Yann Julien, and Damien Bellengier, Eiffage Génie Civil Marine, prepared for the 2021 Offshore Technology Conference, originally scheduled to be held in Houston, 4–7 May. The paper has not been peer reviewed. Copyright 2021 Offshore Technology Conference. Reproduced by permission. During summer 2017, the authors’ company was invited by BP to bid for the construction of a concrete caisson breakwater protecting an offshore liquefied natural gas (LNG) floating terminal at a water depth of 33 m on the Mauritanian/Senegalese maritime border. As a result of subsequent front-end engineering design (FEED) studies, including 3D model testing, the company was able to reduce the amount of concrete required by 40% compared with the initial design, leading to financial and environmental benefits. Introduction The BP Tortue development comprises a subsea production system tied back to a pretreatment floating, production, storage, and offloading (FPSO) unit, which transfers gas to a near-shore hub for LNG production and export. Phase 1 will provide sales gas production and domestic supply and will generate approximately 2.5 mtpa of LNG to Mauritania and Senegal. The Phase 1 FPSO, in 100–130 m of water, will process inlet gas from the subsea wells located across several drill centers by separating condensate from the gas stream and exporting conditioned gas to a hub, where LNG processing and export will occur. The hub, 10 km from shore, comprises a breakwater to protect marine operations, including LNG processing and carrier loading. A single floating LNG vessel will condition the gas for LNG export. Hub construction began early in 2019 and should be completed in 2021 for a first-gas target in 2022. The breakwater design was conceived during the bidding stage of the project at the end of 2017 by proposing an alternative design for the breakwater adapted to project-specific conditions and regional facilities. The design has been improved continuously and optimized during the FEED stage based on a collaborative approach between the client and the contractor. Client Preliminary Design Optimizations During pre-FEED and bidding stages, the client performed an intensive geotechnical campaign based on several shallow and deep boreholes and a large-area geophysical survey. In water depths greater than 18 m along the maritime boundary between Mauritania and Senegal, a significant layer of soft soil exists, except around the outcrop located on the west side (10–11 km offshore in approximately 33 m of water). Although rock quantities could be slightly higher in the western location, the reduction of the dredging quantities and the reduction of the effect on the nearby coastal community of Saint Louis (lighting, noise, and vessel traffic) led to selection of this location for the hub terminal. The initial breakwater type was a rubble-mound structure. However, a composite breakwater (caisson on berm foundation) allowed for optimization of dredging and rock quantities. The change in breakwater type allowed a rock-quantity drop from 5.8 million to 1.1 million m3.

Evaluation of Bleeding Resistance in Chip Seal and Asphalt Emulsion Residue Rheology

Chip seal bleeding is influenced by many factors, including design inputs, material properties, and project-specific conditions. It reduces the surface texture of the pavement and thus compromises the safety of the traveling public. Even though factors that bring about premature bleeding are known, currently, no laboratory test methods for evaluating bleeding in chip seals have been specified. The objective of this paper is to present the results of an investigation of the influence factors of asphalt emulsion residue properties measured by the ASTM D7405 multiple stress creep and recovery (MSCR) test, as well as other factors related to chip seal bleeding resistance as measured by the modified loaded wheel test (MLWT). In this study, the MSCR test was used as a tool for evaluating the performance of asphalt emulsions because it has been identified as a potential test related to bleeding in the field. In addition, MLWT was selected as a tool for evaluating chip seal bleeding performance in the laboratory. The results of the MLWT showed that the emulsion application rate (EAR), aggregate gradation, and emulsion properties were significant factors affecting bleeding. The MSCR test was found to be a promising tool for the performance evaluation of asphalt emulsion residue, as the test was able to differentiate between emulsion chemistries and modifications in terms of sensitivity to both temperature and stress. In relation to chip seal bleeding resistance, only the creep compliance (Jnr) obtained from the MSCR test results was identified as a significant property affecting potential for bleeding.

Project Discrepancies in Roadway Construction and Preservation: A Statistical Analysis of Public–Private Partnership Contract Types in the US

At the planning stage of a roadway construction or preservation project, public agencies face a crucial challenge; to adopt and implement the appropriate contractual framework that can minimize the anticipated project discrepancies, on the basis of project-specific conditions. Focusing on Public-Private Partnerships (PPP), a deeper understanding of the factors that affect each type of discrepancy can assist public agencies in thoroughly evaluating and comparing PPP options. This paper seeks to provide an empirical but comprehensive analysis on PPP-specific project discrepancies, by identifying influential factors that significantly affect cost savings, cost overrun, change orders, and time delays in roadway projects. Using data from 645 PPP projects implemented in the USA between 1996 and 2011, seven popular PPP contracting approaches in the USA were considered in the analysis, and a number of random parameters linear and non-linear statistical models were estimated by PPP approach. The results demonstrate that PPP-specific attributes such as project cost, size, types of constituent activities, and expected duration, have mixed effects on the occurrence and the magnitude of each type of discrepancy.

Design concepts for spillage recovery in a molten salt central receiver

This work evaluates concepts of hybridizing the molten salt central receiver design to recover spilled energy in an effort to reduce the electricity cost. The hybridization is done using existing technologies requiring marginal improvements. A simplified assessment is done to arrive at a target cost of two spillage recovery system without changing the prevailing levelized cost of electricity (LCoE) from the reference solar power plant. The target cost of the spillage recovery system using feedwater heater panels is $49M, whereas for concentrated photovoltaic modules, it is $40M. Integrating such systems with the tower type receiver below the target price is expected to reduce the LCoE of the plant. However, project specific conditions and requirements may also play an important role and should be taken into consideration with a more detailed overall plant level study to determine the feasibility of the hybridization concepts in a specific project.

Multi-causal pathways of public opposition to dam projects in Asia: A fuzzy set qualitative comparative analysis (fsQCA)

Scholars overwhelmingly adopt the case study method when analyzing causal conditions inducing anti-dam-protests. We have carried out the first medium-N-study on this topic analyzing public opposition to 12 dam projects in Asia. For this purpose, we employ a fuzzy-set Qualitative Comparative Analysis (QCA) which is based on a thorough review of scholarly writings and press reports on the dam projects at question as well as an online survey and semi-structured interviews. We identify two causal recipes sufficient for the emergence of significant anti-dam-protests. First, lacking social safeguards in combination with the presence of political opportunity structures and higher levels of development are sufficient for significant anti-dam-protests to emerge. Second, lacking social safeguards in combination with rampant corruption and environmental risk induce these protests. Current scholarly literature particuarly emphasizes political opportunity structures and development as causal conditions inducing significant protests. Our findings build on this literature to highlight the importance of project-specific conditions.

Big and Clean - A Novel Design for LNG Plants

This article, written by Technology Editor Dennis Denney, contains highlights of paper IPTC 11637, "Big and Clean - A Novel Design for LNG Plants," by Barend Johan Jan Pek, Kaart Sander, and Elion Wiveka, Shell, prepared for the 2007 International Petroleum Technology Conference, Dubai, 4-6 December. The paper has not been peer reviewed. The demand for clean and afford-able energy translates into a large demand for liquefied-natural-gas (LNG) production capacity. To meet this increase in production capacity, increasingly larger processing-train sizes have become the trend. A mega-train design is presented for production of more than 10 Mt/a. Much of the LNG expansion is taking place in the Middle East. A typical feed-gas composition from this region was selected as the basis for integration of gas conditioning (treating), natural-gas-liquid (NGL) extraction, liquefaction process, and utility facilities. Introduction The demand for natural gas is forecast to grow by 3%/yr over the next 15 years, with demand for LNG growing by 8–10%/yr. For several years, many projects have been under way, resulting in a constrained contractor market, a worldwide heavy demand for raw materials, and issues regarding logistics of work force and products. These challenges lead to large trains, particularly where large resources are involved, as in the Middle East, Russia, and Australia. An increasingly important challenge is the need to minimize CO2-emission rates. High efficiency is a crucial enabler. Higher efficiency increases the amount of LNG that can be produced for the selected power turbines and compressors that make up a large part of the capital costs. Therefore, the focus is extended to the use of exhaust heat. The full-length paper presents a train design for LNG production at a rate of 11 Mt/a. The design is based on Shell's Parallel Mixed Refrigerant (PMR) Process, which uses propane refrigerant in the precool cycle. Depending on project-specific conditions, such as climate and market opportunities, other designs may be more suitable. The double-mixed-refrigerant process was selected for the Sakhalin LNG project currently under construction (Fig. 1). The PMR concept is scalable from 11 to 6 Mt/a by changing helper-motor size or changing to smaller gas turbines. Improved fuel efficiency by use of waste-heat recovery is applicable to several designs, thus minimizing CO2 emissions. Design Premises Plantwide integration of heat generation and demand is provided by steam. The full use of waste heat from the gas-turbine exhausts enables a step change in plant efficiency with respect to conventional LNG-plant designs and can help to reduce the specific CO2 emissions. This design uses air cooling. Dedicated attention to hot-air recirculation and plot-plan optimization provides a robust design. Should cooling water be available for a once-through or recirculating cooling system, this can be incorporated and will further improve fuel efficiency and, depending on cooling-water-supply complexity, also the specific cost.

Tunnel Safety Concept Koralm Tunnel

AbstractThe 32.8 km long Koralm tunnel requires specific measures to guarantee a sufficient safety level. The methodology applied to define safety measures for this very long tunnel is on the one hand based on a set of guidelines and on the other hand based on the specific boundary conditions of this tunnel. These projectspecific conditions are considered by establishing customized safety targets. All aspects of safety are summarized in a specific tunnel safety concept.As a result of an investigation into the construction and operating phase, the tunnel system was determined to consist of two single‐track tunnels, an emergency station, cross‐passages every 500 m and no crossover. The emergency station in the centre of the tunnel, which incorporates various considerations, was designed to accommodate staggered platforms and a combined refuge room with a length of 800 m. The physical structures of the emergency station (distance of escape tunnels, door configurations) were checked by application of an evacuation simulation. With a view to the incident management strategy to be adopted, characteristic operating scenarios were analysed to realistically reflect the sequence of events in case of an emergency.

Productivity Aspects of Urban Freeway Rehabilitation with Accelerated Construction

Over the last 5years the California Department of Transportation (Caltrans) has completed three experimental long-life urban freeway rehabilitation projects by utilizing a fast-track (accelerated) construction approach of around-the-clock operations under extended closure. This paper presents the fast-track rehabilitation approaches and the as-built production rates of major rehabilitation operations monitored at the three experimental projects. The monitoring results show that the contractor’s production rates varied considerably depending upon the construction logistics, material delivery and hauling methods, lane-closure tactics, and/or pavement designs being implemented. A higher production rate and a noticeable “learning-curve effect” were observed when full-width rehabilitation was compared with partial-width rehabilitation, when continuous lane reconstruction was compared with random slab replacements, and when full roadbed closures were compared with partial lane closures. Findings in this study suggest that Caltrans should evaluate project-specific conditions and constraints, which might restrict use of a preferred rehabilitation scheme, by taking production rate variances into account when establishing schedule baselines of construction staging plans and incentive/disincentive contracts for urban freeway rehabilitation projects.

JUDGMENT-BASED CROSS-IMPACT METHOD FOR PREDICTING COST VARIANCE FOR HIGHLY UNCERTAIN PROJECTS

Construction projects are very sensitive to project-specific conditions. Any possible combination of risk factors can significantly affect the success of a project's performance. Risk analysis has been used to predict the impact of various uncertainties that are inherent in construction projects. However, one key problem with present-day risk analysis methods is that they are basically mathematical or probability-oriented approaches which are not easy to adopt in real business because they easily become complex to capture the relations between the complex variables. This paper presents the use of a judgment-based method called Cross Impact Analysis (CIA) to model the cost risks of a construction project in a highly uncertain environment and to predict their impact on cost variance in the early stage of a bidding process. Then, a case study is performed to demonstrate the approach, which allows complex risk analysis to be performed simply by common users in capturing the risk variables' relations, while maintaining an acceptable accuracy limit.

Cold Cap Grout Formulation for Waste Containment at DOE Site, Hanford, Washington

ABSTRACTWES developed a grout to be used as a cold (non-radioactive) cap or void-fill material between the solidified low-level waste and the cover blocks of near-surface disposal vaults at the U.S. Department of Energy (DOE) Hanford Facility. The project consisted of formulation and evaluation of candidate grout, followed by a physical scale-model test to verify grout performance under project-specific conditions and provide data to verify numerical models of stresses and isotherms inside the Hanford demonstration vault. Evaluation of unhardened grout included segregation, bleed, flow, and working time. For hardened grout, strength, volume stability, thermal heat rise, and geochemical compatibility with surrogate wasteform grout were examined.The grout was formulated to accommodate unique environmental boundary conditions (vault temperature = 45 °C) and exacting regulatory requirements (mandating less than 0.1% shrinkage with no expansion and no bleeding); and to remain pumpable for a minimum 2 hr. A grout consisting of API Class H cement, an ASTM C 618 Class F fly ash, sodium bentonite clay, and a natural sand from the Hanford area met all performance requirements in laboratory studies.