Construction Cost Research Articles

Capacity planning of storage batteries for remote island microgrids with physical energy storage with CO2 phase changes

Energy storage devices based on the CO2 thermal cycle (CTC) lose competitiveness in cold regions because of the decreased energy volume density and charge–discharge efficiency at low ambient temperatures. The CO2 hybrid thermal cycle (CHS) combines the CTC with the CO2 hydrate thermal cycle (CHT) to maintain a high energy volume density and charge–discharge efficiency regardless of the ambient temperature. The CHS-based energy storage system has been shown to have an energy volume density of 80–140 kWh/m3 and charge–discharge efficiency of 60 %–106 %. However, the economic feasibility of this system has not been considered. In this study, a numerical analysis was performed on the practical application and economic feasibility of CHS-based energy storage for the 100 % renewable energy microgrid of a pair of remote islands. In a case analysis of CHS installation in a microgrid for a remote island with 100 % renewable energy, the construction cost of CHS was 2/3 of that of pumped storage; the equipment cost reduction of CHS strongly depends on the type and amount of renewable energy to be interconnected, and therefore, the overall optimization of the power system is necessary.

Effect of granite powder on the strength, durability and sustainability of soil treated using steel slag or cement

Granite powder, a byproduct of granite quarrying, enhances the long-term strength of cement-treated soil due to its pozzolanic reactivity. However, its effects on early strength and seawater durability, as well as its influence on slag-treated soils, remain unexplored. We studied cement-treated and slag-treated soil composites with 0% and 30% granite powder, using 8% cement or 30% steel slag per dry soil mass. We performed vane shear and unconfined compressive strength (UCS) tests at 1, 3, 6, 12hours, and 1, 3, 7, 28, 63, 91, 119 days. After 28 days of air curing, samples endured seawater exposure at 30°C for 0, 28, 63, and 91 days, followed by UCS and XRF calcium composition tests. Seawater samples were also analyzed for calcium and magnesium concentrations using a photometer. Despite similar dry unit weights, slag-treated soil initially exhibited lower strength than cement-treated soil. However, granite powder enabled slag-treated samples to reach comparable strength levels to those of cement-treated soil. Its pozzolanic reactivity facilitated self-repair in samples affected by seawater-induced calcium depletion, while also reducing emissions, resource consumption, and construction costs associated with treated soil materials.

Justification of the safe parameters of recreational zones during the reclamation of watered residual quarry spaces

Purpose. To determine the safe parameters of the recreational zones created in the residual space of the quarry taking into account the physical and mechanical properties of waste rocks in a watered state. Methodology. The Bishop Simplified Method is used to determine the influence of the irrigation level of the residual quarry space on the stability of the embankment from different types of mining rocks when creating a recreational area during reclamation works. Findings. The safe parameters of recreational areas during their construction in the watered residual space of the quarry were established taking into account the physical and mechanical properties of embankments made of sand, loam, and crushed rock by determining the stability of their slopes. The obtained results are necessary for the implementation of project works on the development of technological schemes for the reclamation of the residual spaces of construction materials quarry for the recreational direction of post-mining. Originality. The influence of the height of the rock embankment formation on the stable angle of inclination of the watered slope was established, which allowed determining that with an increase in the aggregates embankment height from 20 to 80 m, the safe angle of the slope will decrease from 46 to 26°. It was determined that the lowest FOS indicator is 0.57 when using sand rocks for an embankment height of 80 m at a water content of 40 %. It was established that with partial flooding of the rock embankment by 45–50 % for sandy, loamy and rocky rocks, there is a significant decrease in the coefficient of the reserve of stability by 1.4–1.5 times, in contrast to the absence of water or complete flooding, which confirms the negative impact of partial flooding of embankments and reducing the stability of their slopes. Practical value. It was determined that when forming an embankment 20 m high from loamy rocks, the volume of reclamation works will be 1.34 times less compared to sandy rocks, but 1.02 times larger than rocky rocks. When the height of the embankment increases to 80 m, the volume of reclamation works when replacing loam with sand will increase to 1.87 and 1.12 times when using crushed stone. However, taking into account the market value of materials, when using loam, the cost of construction will decrease by 2.5 times compared to sandy rocks and 3.2 times – to crushed stone, with an embankment height of 20 m. When the embankment height increases to 80 m, the cost of materials will increase by 3.5 and 3.8 times when loamy rocks are replaced by sand or crushed stone, respectively.

Sustainable bridge engineering: Cost reduction and durability enhancement in developing nations

This paper explores innovative approaches to sustainable bridge engineering, focusing on cost reduction and durability enhancement in developing nations. Drawing from my successful projects in Uganda and Guinea, where I reduced construction costs by 30% without compromising structural integrity, I will present detailed case studies that highlight the effective application of sustainable materials and techniques. In Uganda, through the use of locally sourced materials and optimized construction processes, I achieved significant cost savings while ensuring long-term durability in rural infrastructure. Similarly, in Guinea, I implemented advanced engineering practices that prioritized resource efficiency, leading to a reduction in project expenses and a strengthened bridge lifespan. The case studies demonstrate how sustainable engineering practices can be tailored to local conditions and still meet global standards for resilient infrastructure. By emphasizing cost-effective materials such as recycled aggregates and low-carbon concrete, and employing techniques such as modular construction and innovative foundation designs, my work offers a blueprint for reducing expenses while enhancing the longevity of infrastructure. The strategies I employed in Uganda and Guinea are adaptable to other developing nations and can be applied globally, including in the U.S., to build durable and sustainable bridges that address both budgetary constraints and environmental considerations. This paper aligns with the broader goals of sustainable infrastructure development by contributing to the global discourse on resource-efficient engineering solutions. The findings support national and international objectives to enhance infrastructure resilience while minimizing environmental impact and construction costs.

Comprehensive Analysis of Implementing Robotics in the Indian Construction Industry

Implementing robotics in the Indian construction industry presents a significant opportunity to address longstanding challenges such as labour shortages, project delays, safety concerns, and quality inconsistencies. As India's urbanization accelerates, the demand for faster, safer, and more efficient construction processes is growing. This comprehensive analysis explores the potential benefits, obstacles, and strategies associated with adopting robotics in India’s construction sector. Key drivers include increasing automation trends, government initiatives like "Make in India," and the global shift toward smart infrastructure. However, challenges such as high initial investment, a fragmented industry structure, and the need for skilled operators and technicians could hinder widespread adoption. The analysis also highlights the role of robotics in enhancing productivity, reducing construction costs, and improving worker safety through a cost-benefit analysis, ultimately paving the way for more sustainable and advanced construction methodologies in India.

Dynamic location model for designated COVID-19 hospitals in China.

In order to effectively cope with the situation caused by the COVID-19 pandemic, cases should be concentrated in designated medical institutions with full capability to deal with patients infected by this virus. We studied the location of such hospitals dividing the patients into two categories: ordinary and severe. Genetic algorithms were constructed to achieve a three-phase dynamic approach for the location of hospitals designated to receive and treat COVID-19 cases based on the goal of minimizing the cost of construction and operation isolation wards as well as the transportation costs involved. A dynamic location model was established with the decision variables of the corresponding 'chromosome' of the genetic algorithms designed so that this goal could be reached. In the static location model, 15 hospitals were required throughout the treatment cycle, whereas the dynamic location model found a requirement of only 11 hospitals. It further showed that hospital construction costs can be reduced by approximately 13.7% and operational costs by approximately 26.7%. A comparison of the genetic algorithm and the Gurobi optimizer gave the genetic algorithm several advantages, such as great convergence and high operational efficiency.

Mechanical Analysis and Optimization of Concrete Structures Based on Advanced Finite Element Method

This article explores the mechanical analysis and optimization problems of concrete structures based on the Advanced Finite Element Method. By integrating advanced numerical techniques with practical engineering cases, this study aims to improve the safety and economy of concrete structure design. Firstly, the paper outlines the limitations of traditional finite element methods in concrete structure analysis, such as insufficient computational accuracy and low computational efficiency. Subsequently, by introducing AFEM, we significantly improved the accuracy and efficiency of the analysis. For example, when simulating a complex bridge structure, AFEM not only reduces the calculation time by about 25%, but also improves the accuracy of stress distribution prediction by more than 10%. In the optimization stage, we utilized the analysis results of AFEM and optimized the material consumption, cross-sectional dimensions, and reinforcement parameters of concrete structures through multi-objective optimization algorithms. A comprehensive data analysis underscores that the optimized concrete structure triumphantly meets all safety performance criteria while achieving a remarkable 12% reduction in material usage. This substantial material savings translates into a substantial 8% decrease in overall construction costs, significantly bolstering the project’s economic feasibility. Moreover, these cost savings not only amplify the project’s profitability but also play a pivotal role in enhancing the structure’s longevity and durability, thereby contributing to its sustainable performance over its entire service life. Furthermore, we delved into the capability of AFEM in simulating intricate phenomena such as the nonlinear behavior of concrete materials, crack propagation patterns, and the intricate interactions between steel reinforcements and concrete. These complex mechanical behaviors are crucial for the safety and stability of structures, and AFEM provides more comprehensive and accurate references for structural design by accurately simulating these behaviors. This article conducts in-depth research on the mechanical analysis and optimization of concrete structures based on AFEM, and demonstrates the significant advantages of AFEM in improving structural safety and economy through specific data. These research results not only provide new theoretical support and practical tools for concrete structure design, but also provide valuable references for future research and application in related fields.

Utility Cut Impact Assessment and Fee Development Using Pavement Management System

The purpose of this study is to estimate any damage caused by utility cuts to pavements and develop a fee schedule to recover the costs associated with such damage using the City of Pacifica, CA, U.S.’s pavement management system (PMS). To accomplish this, the study looked at the functional deterioration of pavements resulting from utility cuts. The City of Pacifica’s PMS containing a vast dataset of pavement distress spanning 15 years, comprising thousands of data points encompassing various pavement ages and conditions, was analyzed to assess the impact of utility cuts. The findings from this study include: 1) Pavements with cuts of any size deteriorate more than pavements without cuts across all age groups with one exception for older residentials with small cuts; 2) On average, pavement condition index drops by 30% if the cut area is greater than 10% of the section area; and 3) Utility cuts inflict greater damage on newer pavements (<10 years old) compared with older ones (≥10 years old). Consequently, new pavements experience an average percent reduction of approximately 33% in their remaining service life, while older pavements suffer a reduction of about 17%. The statistical analyses indicate that utility cuts caused significant damage, and supported a tiered utility cut fee structure based on functional classification, age of pavement, and size of the cut. The resulting fee schedule is based on 2021 material and construction cost estimates; consequently, implementation including an annual adjustment for inflation is recommended. Example fee calculations are provided.

Construction Cost-Influencing Factors: Insights from a Survey of Engineers in Saudi Arabia

Cost overruns represent a continuous challenge within the construction industry, frequently affecting the success of projects. This study explores the factors influencing cost during the construction phase in Saudi Arabia, utilizing data from a survey of 1076 engineers working in the Saudi construction industry. The results identify a number of cost-related factors, including inadequate project management, poor cost estimation, and design errors. Interestingly, some factors, such as currency exchange rate fluctuations and social and cultural influences, were found to have a limited impact on construction costs. Furthermore, the study highlights the role of experience and education level in shaping engineers’ perceptions of these cost factors. The study employs statistical analysis, including Pearson’s chi-squared test, to demonstrate associations between demographics, project characteristics, and cost-influencing factors. The findings suggest the need for refined project management practices, enhanced technical training, and the implementation of digital technologies such as Construction 4.0 to mitigate cost-related risks. This research provides significant insights for construction professionals and policymakers seeking to enhance cost management within the Saudi construction sector, thereby contributing to the ongoing development initiatives aligned with Saudi Arabia’s Vision 2030.

Leaf architecture and functional traits for 122 species at the University of California Botanical Garden at Berkeley.

The dataset contains leaf venation architecture and functional traits for a phylogenetically diverse set of 122 plant species (including ferns, basal angiosperms, monocots, basal eudicots, asterids, and rosids) collected from the living collections of the University of California Botanical Garden at Berkeley (37.87° N, 122.23° W; CA, USA) from February to September 2021. The sampled species originated from all continents, except Antarctica, and are distributed in different growth forms (aquatic, herb, climbing, tree, shrub). The functional dataset comprises 31 traits (mechanical, hydraulic, anatomical, physiological, economical, and chemical) and describes six main leaf functional axes (hydraulic conductance, resistance and resilience to damages caused by drought and herbivory, mechanical support, and construction cost). It also describes how architecture features vary across venation networks. Our trait dataset is suitable for (1) functional and architectural characterization of plant species; (2) identification of venation architecture-function trade-offs; (3) investigation of evolutionary trends in leaf venation networks; and (4) mechanistic modeling of leaf function. Data are made available under the Open Data Commons Attribution License.

Dynamic Optimization of Exclusive Bus Lane Location Considering Reliability: A Case Study of Beijing

For metropolises like Beijing, heavy congestions cause transit passengers’ unreliable travel time, including in vehicle time and waiting time. Comparing with other managerial measures, designing a lane for bus use only is an effective method to improve travel reliability, for it can eliminate the influence on bus-driving conditions. This paper proposes a reliable and practical method to determine exclusive bus lanes (EBL). A reliability-based optimization model is established, in which the tradeoff among bus and private car passengers’ travel time, reliability, and EBL construction cost are considered. Based on the actual network, a user equilibrium demand assignment model is applied to estimate the dynamic bus flow distribution. Since the model is nonlinear, a two-step method is proposed where tangent lines are introduced to constitute an envelope curve to linearize the model. This work conducts the statistical modeling and fitting analysis with actual bus trajectory data, collected on EBL in Beijing during peak hours. Passenger travel time distributions are fitted to estimate the statistical passenger travel time; Lognormal distribution and Gaussian distribution are the best fit. The optimization results indicate that the passenger travel time reliability can be improved by 5.5% by the optimized EBL location scheme. This study will provide a theoretical basis and methodological support for improving the service level of the public transportation system in large cities through the scientific planning of exclusive bus lanes.

Experimental evaluation on dynamic performance of medium–low-speed maglev vehicle running on low-positioned subgrade

ABSTRACT As a novel urban rail transit system with relatively low construction costs, medium–low-speed maglev transportation is currently experiencing rapid development in China. However, there have been rare studies on the experiments of medium–low-speed maglev vehicle passing curves and low-positioned subgrade. Therefore, this paper systematically conducts on-site dynamic tests on the Qingyuan Maglev Tourism Line. The experiment provides a detailed analysis of the dynamic characteristics of the vehicle system and subgrade under varying speeds up to 132 km/h. The study explores the impacts of operating speed, track layout, and type of girder structure. The results indicate that a significant increase in operating speed and the application of emergency braking intensify the dynamic response of the vehicle system. When passing through the R700m curve and low-positioned subgrade sections at different speeds, the primary vibration frequency of the sprung structure is below 2.5 hz, while the unsprung structure shows a wide frequency distribution. The peak frequencies of the vibration for the low-positioned subgrade are mainly distributed in the 60–140 hz range, and the vibration response of the girder remains at a low level. The Sperling index values, levitation gap, and lateral offset of the levitation electromagnet of the testing vehicle do not exceed 2.5, 4 mm, and 10 mm, respectively, indicating excellent ride comfort and stable levitation performance. The results of this test study provide a reliable assessment of the safety of the vehicle and subgrade system and would help precise modelling of vehicle and subgrade system in the future.

Stakeholders’ perceptions of and willingness to pay for circular economy in the construction sector

Adopting Circular Economy practices in the construction industry can help reduce greenhouse gas emissions. However, many barriers exist to adoption, and current perceptions of and willingness to pay for circularity have yet to be quantified. This study seeks to understand the various perceptions of circularity in the construction industry, characterize uncertainties and risks, and identify economic incentives and opportunities that could accelerate circular adoption via an industry survey of three stakeholder groups. 58 stakeholders filled out part of the survey, and 42 stakeholders completed the majority of questions. Real estate developers are willing to pay an average premium of 10% for construction costs if there’s a minimum embodied carbon reduction of 53%. Design and construction professionals and material suppliers were also surveyed. Reasons for adopting circular practices were primarily driven by client, design team, and net zero goals. The results of this survey begin to characterize the economic landscape of what is needed for a circular transition in the built environment.

A Numerical Analysis of the Role of Pile Foundations in Shaft Sinking Using the Vertical Shaft Sinking Machine (VSM)

The use of the Vertical Shaft Sinking Machine (VSM) for shaft construction marks a significant advancement in modern technology and is recognized as one of the leading techniques in the field. However, much of the existing research focuses on mechanical and technical challenges, often overlooking the effects on surrounding soil and the structural integrity of shafts. This study demonstrates that increasing pile diameter by 20% improves load-bearing capacity by 15% and reduces soil settlement by 12%, though these improvements come with higher construction costs. Additionally, larger diameters improve lateral stability, but excessively long piles lead to diminishing returns. To address the limited research on reinforcement design in soft soils, a series of numerical models were employed to investigate the effects of pile spacing, length, and diameter on surrounding soil behavior. This in-depth analysis aims to provide a scientific foundation for optimizing VSM technology in caisson pile foundations, particularly in soft-soil conditions.

Seismic isolation strategy via controlled soft first story with innovative multi-stage yielding damper: Experimental and numerical insights

While the presence of a soft story within a building is typically discouraged in structural engineering due to potential vulnerabilities, this research proposes a strategy that incorporates seismic isolation concepts by integrating a soft first story within the structural framework. This approach challenges traditional reluctance by demonstrating the potential benefits of such a configuration. The primary objectives are twofold: firstly, to diminish seismic responses and enhance structural resilience when subjected to earthquake forces, and secondly, to reduce construction costs as compared to conventional passive control methods. The seismic responses assessed and compared in this study encompass story displacements, story drifts, floor accelerations and base shear of the structure. Furthermore, an investigation is conducted into a replaceable or repairable shear fuse that serves as a controller in the Controlled Soft First Story (CSFS) strategy, namely, an innovative Multi-stage Steel Yielding Damper (MSYD). Notably, the numerical analysis of the introduced damper has been carried out, followed by rigorous validation testing under experimental conditions. This study elucidates the implementation of this strategy within the structural framework. The overarching principle behind employing the CSFS results in outcomes akin to those achieved with base isolation techniques. However, it distinguishes itself by significantly mitigating the construction costs around 70% associated with this system when juxtaposed with traditional base isolation systems.

An event tree-based distance transform algorithm for simultaneously determining mountain railway alignments and station locations

The concurrent optimization of railway alignments and station locations (RA&SL) is a complex task, especially for the main railway lines in mountainous regions. The intricate coupling constraints between RA and SL are very challenging for the conventional RA&SL search methods, which consider limited solution types to generate an optimized RA&SL solution. To solve this problem, an event tree-based distance transform (ET-DT) algorithm is proposed. The study area is first divided into grid cells, followed by a preprocessing step to identify infeasible areas for station locations. Next, an event tree (ET) is constructed to represent all the possible solution types during the RA&SL design process. Afterward, in the ET-DT method, a total of eight types of RA&SL search operators are integrated to generate diverse RA&SL alternatives. Ultimately, the proposed method is applied to a realistic case with significantly-undulating terrain. Results show that ET-DT generates 2.8 times more solutions than a contemporary DT-based method (PreDT) and further improves solution quality through an 8.7% reduction in construction cost compared to the best manually-designed alignment, while PreDT only achieves a 5.7% reduction.

Predicting Subsurface Drainage Requirement for Different Soil Desalinization Goals in Coastal Reclamation Areas

ABSTRACTBuilding subsurface drainage systems for more efficient salt leaching with the natural rainfall or artificial irrigation is a widely accepted practice for saline soils reclamation, but the high initial cost of the system construction often limits its adoption, and the uncertainty in drainage intensity requirement to meet desired desalinization goals for field crop production challenges the system design. In this paper, we proposed a soil desalinization model based on the field hydrology model‐DRAINMOD, predicted number of years required to lower soil salinity to a threshold level under different subsurface drainage conditions, and estimated the net return from different subsurface drainage system layout based on a case study in a coastal reclamation area in eastern China. The results showed that, DRAINMOD accurately predicted water table fluctuations in artificially drained fields: the root mean square error to standard deviation ratio (RSR) was 0.4 and 0.54, and the Nash Sutcliffe efficiency (NSE) was 0.84 and 0.68, respectively, during the model calibration and validation periods. The DRAINMOD based soil desalinization model predicted a negative relationship between subsurface drainage intensity and the soil desalinization period, that is, improving drainage condition shortened the time requirement for soil desalinization. For the study area, the model's predictions showed that installing subsurface drainage at 20 m spacing and 1.2 m deep lowered soil salinity to the slightly saline level in less than 7 years under the rainfall leaching only, and such system layout produced the maximum economic return based on the local agricultural practice. The results indicate that, early investment in adequate subsurface drainage systems is beneficial for field crop production in the salt impacted farmland areas. Findings from this research may provide technical references for saline soil reclamation or land improvement in both rain fed and irrigated agricultural areas.

The design of a model predictive control strategy and performance analysis for pumped storage units and super capacitors in power systems

IntroductionSuper capacitors were regarded as one of the most effective frequency regulation technologies in power systems. The major issue of applying super capacitors for frequency regulation is the limited energy capacity and the high construction costs. The pumped storage units have been developed and applied in power systems for decades, whereas it was rarely operated to regulate the system frequency due to the operation limitations. The pumped storage units could be operated as a hydro generator under the generation mode and provide effective frequency regulation service with the conventional automatic generation control (AGC) system while its output power was constant under the pumping mode.MethodIn this paper, the pumped storage unit was controlled to participate in frequency regulation under the generation mode with super capacitors. Considering the AGC system could not consider the state of charging (SOC) of super capacitors for frequency regulation, an optimization model was proposed to determine the operation points for super capacitors and pumped storage units under a model predictive control (MPC) strategy to regulate the system frequency for power systems.Results and DiscussionBased on the various operation scenarios, the effectiveness and costs of pumped storage units and super capacitors to provide frequency regulation services were discussed. It was indicated that pumped storage units and super capacitors were effective technologies for power systems.

Natural and synthetic fiber reinforced recycled aggregate concrete subjected to standard fire temperature

The increasing scarcity of natural materials and rising construction costs have prompted the need for alternative materials that can match the performance of conventional aggregates. This study explores the use of recycled aggregate concrete (RAC) as a sustainable alternative, supplemented with natural and synthetic fibers to overcome the inherent strength limitations caused by the residual cement paste on the aggregate surface. To enhance the mechanical and thermal stability of RAC, steel, polypropylene, and coconut fibers were incorporated. The rheological, hardened, and post-fire properties of fiber-reinforced RAC were thoroughly investigated. After 28 days, the porosity of RAC with fiber reinforcement was observed to be less than 2 %. The concrete was also exposed to elevated temperatures as per ISO 834 guidelines to assess its thermal performance. Key parameters such as mass loss, crack width, porosity, and strength degradation were analyzed. Image analysis was used to track surface modifications and measure surface porosity after heating. Among the fiber types, steel fiber reinforced concrete exhibited superior mechanical and thermal performance, followed by coconut fiber reinforced concrete, making coconut fibers a viable natural alternative to synthetic fibers. RAC without fibers displayed the highest porosity (20 % and 32 %) after exposure to 821 °C and 1029 °C, respectively. Strength degradation ranged from 40 to 50 % after heating to 821 °C, increasing to 74–80 % at 1029 °C, irrespective of fiber type. This research highlights the potential of fiber-reinforced RAC for structural applications, offering a sustainable solution with comparable strength and durability to conventional concrete.

An evaluation of square footing response on lime-treated geotextile-reinforced silty sand: contrasting experimental and computational approaches

Improving soil strength and reducing the anticipated settlement and construction cost is a great paradox for civil as well as geotechnical engineers. In this paper, these aspects and other suitable types of ground improvement are discussed based on the principles of using geosynthetics for soil reinforcement. A series of load-settlement tests were also performed to compare strength and settlement of the silty sand reinforced with lime and one layer of geotextile. The study finds the maximum insertions of geotextile at 0.2D (3.0 cm) beneath the square footing base, and the lime percentage of 5.0% increases the UBC substantially. The UBC of lime-treated and geotextile-reinforced silty sand was to an optimum of 1,360 kN/m2 that has shown an enhancement of 258% compared to that of untreated and unreinforced silty sand that is approximately 380 kN/m2. Furthermore, comparative analysis between two ANN models was performed to provide improved estimate of the UBC, namely artificial neural network (ANN) and extreme learning machine (ELM). The developed computational models were then compared with experiment data, which proved that such models are more economical and effective than the expensive and time consuming conventional techniques. Consequently, based on the results, it was further validated that ELM possesses better generalization capability compared to ANN for predictive efficiency and thereby proves the efficiency of the model in estimating the ultimate bearing capacity of square footings incorporated with geotextile and lime-treated silty sand. This places the ELM model as a useful tool in the initial conceptual as well as the design for improvement steps of soil reinforcement.