Major Construction Activities Research Articles

Decomposing and mapping different scales of land subsidence over Shanghai with X- and C-Band SAR data stacks

ABSTRACT Land subsidence can be observed with time-series of Interferometric Synthetic Aperture Radar (InSAR) data. However, existing approaches only reveal subsidence signals that are multi-scale mixed, which is not conducive to the systematic analysis of subsidence of different mechanisms. A deformation signal decomposition (DSD) method based on spectral analysis is used to decompose the deformation extracted by time-series InSAR into three classes of deformation signals. They refer to large-scale deformation related to geological settings, medium-scale deformation caused more by group excavation, and small-scale deformation along linear infrastructures. TerraSAR-X datasets for Shanghai spanning April 2013 to September 2020, and Sentinel-1A datasets spanning January 2016 to September 2020 are used in this study. The results were cross-verified between the TerraSAR-X and Sentinel-1A datasets, and validated against levelling measurements. Subsidence signals caused by different mechanisms were automatically decomposed, which facilitates a systematic analysis for targeted diagnosis of land subsidence signals. A detailed analysis was conducted jointly at three scales of surface displacement, geological conditions, major construction activities, and subsidence mechanisms. It indicated that construction activities were the leading cause of land subsidence, and suggests that local authorities that wish to mitigate surface subsidence may benefit from primarily considering this process.

Quantifying sedimentation patterns of small landslide‐dammed lakes in the central Oregon Coast Range

AbstractUnderstanding sedimentation patterns in small coastal watersheds due to landscape perturbations is critical for connecting hillslope and fluvial processes, in addition to managing aquatic habitats for anadromous fish and other aquatic species in the Oregon Coast Range (OCR). Changes in sedimentation patterns spanning the last 250 years are preserved in two landslide‐dammed lakes in small watersheds (< 10 km2) underlain by the Tyee Formation in the central OCR. Dendrochronology of drowned Douglas‐fir stumps in both lakes provided precise timing of the damming and formation of the lakes, with Klickitat Lake forming in winter ad 1751/52 and Wasson Lake in winter ad 1819/20. Perturbations from wildfires, logging and road development, and previously underappreciated snow events affect sedimentation rates in the lakes to different degrees, and are identified in the sediment record using cesium‐137 (137Cs), high‐resolution charcoal stratigraphy, local fire records, and aerial photography. Each lake has variable sedimentation accumulation rates (0.05–4.4 cm yr−1) and mass accumulation rates (0.02–1.42 g cm−2 yr−1). Sedimentation rates remained low from the landslide‐damming events until the mid‐19th century, when they increased following stand‐replacing wildfires. Aside from a sediment remobilization triggered by human modification of the landslide dam at Klickitat Lake around 1960, the largest peaks in mass accumulation rates in the mid‐20th century at both lakes in the early 1950s precede major road construction and logging activity in the watersheds. Subsequent sedimentation rates are lower, but variable, and possible effects of logging and road development might be exacerbated by abnormal precipitation and heavy snow events. A comparison of previous studies of landslide‐dammed lakes in larger watershed of the OCR are consistent with our findings of increased sedimentation in the mid‐20th century, as well as higher sedimentation rates in the debris‐flow dominated southern Tyee Formation than in the lower‐relief northern Tyee Formation.

A multi-time scale vibration surveillance system for third-party threats on urban pipeline

Third-party interference caused by construction activities have seriously jeopardized the security of underground pipelines. Following the process of signal collection—feature extraction and selection—multi-time scale identifying— combining results by voting, this paper proposes a multi-time scale surveillance system for interference prevention of thirdparty threats on the nearby pipeline by using ground vibration monitors. The system focuses on the two major urban construction activities induced by excavator breaking hammers and road cutters, and presents excellent performance under the noise of traffic and pedestrian. Three features including the short-time zero-crossing rate, subset differential parameter and the Mel frequency cepstrum coefficients are selected by the analysis of the maximal information coefficient and feature importance for identifying the patterns of different third-party activities. The crucial part of the surveillance system consists of the two random forest-based classifiers trained by 0.5 s samples and 8 s samples respectively, and the alarm depends on the voting of the two classifiers, which brings the perspectives on different time scales for decision making. In the test, 96.14% of the threat vibration signals can be detected, while only 0.45% of the environmental noise signals cause false alarms.

Особенности исторического развития городской среды г. Алжира в период 1830-1962 гг.

The article examines the main stages of the historical and urban development of the city of Algiers, particularly its growth and urban changes during the period from 1830 to 1962. Starting from the early 1830-s., Algiers became the scene of major construction activities carried out in accordance with the French idea of the development of the city which was to become the capital of the French colony.There were two directions of development, namely, construction on the territory of the «White City» (Kasbah) and construction outside the Ottoman fortifications, on free land areas. Construction activities on the territory of the old city led to irreparable losses of the urban environment. During this period, the historical part of Algiers underwent profound social, economic, cultural and spatial changes. The new districts were built in accordance with the style trends existing in this period in Europe.

Assessment of Insurance Company’s Roles in Ethiopian Construction Industries

Presently, Ethiopia has relatively an extensive program of infrastructure development and it is growing faster. The construction of new infrastructures, high rising buildings, energy and water work projects, airfields etc. are among the major construction activities. Construction insurance plays an increasingly important role in guaranteeing the success of projects. However, insurance sometimes does not receive the attention for it. Construction risks are uncertain events or conditions that may have an adverse effect on the construction projects. Due to this, this research amid to assesses the insurance practice, the problems and challenges encountered while implementing in Ethiopian construction industries. Questioners were designed and both cense and judgmental sampling techniques were applied. The study finds out most of the contractors are willing to buy insurances for their vehicles and plants and has no awareness about other types of construction insurances like third party and contractor’s all risk insurance coverage. On the other hand, insufficient documentation and low level of awareness of customers towards the benefit of insurance, financial and professional shortages are challenges that insurance companies faced. As a result, Ethiopian government should create awareness about insurance and formulate enforcing law that enables using of insurances for all construction works. Keywords: - construction, contractors, insurance, risk, role DOI: 10.7176/CER/12-3-03 Publication date: March 31 st 2020

Impact of Land-Use Changes on Spatiotemporal Suspended Sediment Dynamics within a Peri-Urban Catchment

Understanding sediment dynamics in peri-urban catchments constitutes a research challenge because of the spatiotemporal complexity and variability of land-uses involved. This study investigates differences in the concentration of total sediments (TSC) and suspended sediments (SSC) in the small peri-urban Mediterranean Ribeira dos Covões catchment (40% urban area) in central Portugal. Suspended sediment responses at the catchment outlet (E) and in three upstream sub-catchments, during periods of urbanization (2011–2013) and stabilizing land-use (2017–2018) are compared for storm-event datasets encompassing similar ranges of rainstorm sizes and antecedent rainfall condition. The Quinta sub-catchment, with the lowest urban area (22%) but subject to major construction activities affecting 17% of its area, led to highest TSC and SSC during urbanization (attaining 4320 mg/L and 4184 mg/L, respectively), and a median reduction of 38% and 69%, respectively, during stabilization. Espírito Santo sub-catchment, with highest urban area (49%) and minor construction activities, displayed similar median TSC in both periods (258–240 mg/L) but highest SSC reduction (76%), highlighting the impact of the anthropogenic disturbance mainly on fine-particle sediments and a good connectivity with the stream. Porto Bordalo sub-catchment, with 39% urban area and subject to the construction of a four-line road covering 1.5% of its area, showed the lowest TSC and SSC concentrations and the lowest median reductions in both periods (31% and 64%, correspondingly), mainly because of the impact of an unplanned retention basin established with soil from the construction site. Overall, median TSC and SSC reduced 14% and 59% at E, from urbanization to stabilization. Information about sediment dynamics should guide stakeholders in establishing strategies to reduce sediment loads and mitigate the impacts on urban aquatic ecosystems.

Review of soil compaction: History and recent developments

Abstract Compaction of soils is a major construction activity in civil engineering, and particularly in the transport industry. This paper presents a brief historical account of soil compaction development with special emphasis on transport geotechnics. Proctor’s curves and California Bearing Ratio (CBR) are reviewed and the associated state-of-the-art field specifications are discussed. The properties of compacted soil and the typical behaviours of compacted fill under in-service conditions are discussed. Intelligent compaction is being increasingly adopted with a view to increased uniformity in compaction, lack of which is a major cause of premature pavement failure. However, it needs further advancement to make it more intelligent. The current state of the ability to predict compacted soil behaviour is reviewed and the limitations are identified. Of more recent developments, interpretation of compacted soil behaviour with a three-dimensional state boundary surface is highlighted, and simplified behaviour can be interpreted and used in routine practice. Areas that need further advancements in theory and practice are highlighted.

Developing cost model for preliminary estimate of road projects in Nigeria

This paper was aimed at developing cost models to predict the preliminary estimate of road projects in Nigeria at the early state using parametric estimating techniques. To achieve this, there is need to identify both the quantitative and qualitative factors that affects the construction cost of road projects. The used procedure resulted in the formulation of linear and multiple regression models which provide a means of determining the cost of road functional activities as a function of projects characteristics. The models developed were for seven major construction activities based on 50 sets of data collected from road projects executed within between 2010 and 2015 in South Western Nigeria. The addition of all elements will give the probable cost of the road project. The coefficient of determination r2 for the developed models ranged from 0.85 to 0.99 indicating that the predicted values from a forecast models fit with the real-life data.

AN ANALYSIS OF ACCIDENT TRENDS AND MODELING OF SAFETY INDICES IN AN INDIAN CONSTRUCTION ORGANIZATION

Construction industry has been recognized as a hazardous industry in many countries due to distinct nature of execution of works.The accident rate in construction sector is high all over the world due to dynamic nature of work activities. Occurrence of accidents and its severity in construction industry is several times higher than the manufacturing industries. The study was limited to a major construction organization in India to examine the trends in construction accidents for the period 2008-2014. In India, safety performance is gauged basing on safety indices; frequency, severity and incidence rates. It is not practicable to take decisions or to implement safety strategies on the basis of indices. The data used for this study was collected from a leading construction organization involved in execution of major construction activities all over India and abroad. The multiple regression method was adopted to model the pattern of safety indices wise .The pattern showed that significant relationships exist between the three safety indices and the related independent variables.

Quantified Impact Analysis of Construction Delay Factors on Steel Staircase Systems

Construction projects have become so large, complicated and incredibly high-tech that process management is currently considered one of the most important issues. Unlike typical manufacturing industries, most major construction activities are performed in the open air and thus are exposed to various environmental factors. Many studies have been conducted with the goal of establishing efficient techniques and tools for overcoming these limitations. Productivity analysis and prediction, one of the related research subjects, must be considered when evaluating approaches to reducing construction duration and costs. The aim of this research is to present a quantified impact analysis of construction delay factors on construction productivity of a steel staircase system, which has been widely applied to high rise building construction. It is also expected to improve the process by managing the factors, ultimately achieving an improvement in construction productivity. To achieve the research objectives, this paper analyzed different delay factors affecting construction duration by means of multiple regression analysis focusing on steel staircase systems, which have critical effects on the preceding and subsequent processes in structure construction. Statistical analysis on the multiple linear regression model indicated that the environment, labor and material delay factors were statistically significant, with 0.293, 0.491, and 0.203 as the respective quantified impacts on productivity.

Daily Work Reports–Based Production Rate Estimation for Highway Projects

AbstractProduction rate estimation of major construction activities in a project play an important role in the planning of resources, tracking project progress, and determining contract time of construction projects as these activities typically fall in the critical path of the project schedule. This paper discusses the possiblity that readily available data from highway agencies such as Daily Work Reports (DWRs), soil data, average traffic information, and weather information can be successfully used to identify and assess significant factors that must be considered in estimating the production rates of major highway activities and to develop production rate estimation models. Common production rate estimation methods such as expert opinion, engineering judgment, and production rate charts may lead to erratic production rate estimation by comparing the production rates calculated and estimated through different methods. Actual project data–based production rate estimation might be the most reliable metho...

Landscape scale ecological monitoring as part of an EIA of major construction activities: experience at the Turkish section of the BTC crude oil pipeline project

Ecological monitoring is a complementary component of the overall environmental management and monitoring program of any Environmental Impact Assessment (EIA) report. The monitoring method should be developed for each project phase and allow for periodic reporting and assessment of compliance with the environmental conditions and requirements of the EIA. Also, this method should incorporate a variance request program since site-specific conditions can affect construction on a daily basis and require time-critical application of alternative construction scenarios or environmental management methods integrated with alternative mitigation measures. Finally, taking full advantage of the latest information and communication technologies can enhance the quality of, and public involvement in, the environmental management program. In this paper, a landscape-scale ecological monitoring method for major construction projects is described using, as a basis, 20 months of experience on the Baku-Tbilisi-Ceyhan (BTC) Crude Oil Pipeline Project, covering Turkish Sections Lot B and Lot C. This analysis presents suggestions for improving ecological monitoring for major construction activities.

Risk Assessment in Construction

This study is concerned with the assessment of risk for major construction activities. Risk has been defined as a measure of the probability, the severity, and the exposure of all hazards of an activity. A risk assessor model (RAM) was developed and computerized to determine the risk associated with a particular activity and the justification factor for a proposed remedy. Knowing the value of risk would help contractors identify the high risk of major construction activities and would enable them to allocate safety precautions in a more efficient manner.

A Case Study of the Behaviour of a Vertical Seawall

Reclamation is a major construction activity in Singapore, and this often entails the construction of a vertical seawall to contain the reclamation. In Singapore a frequently used technique is the use of L-Blocks. However, there are concerns about the movement and tilt of such relatively light blocks. An ongoing reclamation in the northeast of Singapore makes use of nearly 5.6km of such wall. As a requirement, prior to commencement of construction, a finite element study was carried out to analyze the possible movement and tilting of the blocks as well as the long-term settlement of the seabed. Instrumentation clusters were then installed to provide valuable data to validate the accuracy of the design and also allow lessons to be learned from the difference between prediction and measurement. This paper is a report of the comparison between prediction and performance that was carried out at this site. As is the case in many actual constructions projects, the effect of certain activities unanticipated in the design caused the measured value to differ significantly from prediction. When these are factored out, it is evident that the finite element analysis can produce reasonable trend, though not the magnitude. However, the results thus far suggest that two simple steps can greatly improve performance, namely a more accurate soil profiling and accounting for the higher stiffness of stiffer strata due to non-linearity at small strain.

The National Ignition Facility

The National Ignition Facility (NIF) is the largest construction project ever undertaken at Lawrence Livermore National Laboratory (LLNL). The NIF consists of 192 40 cm square laser beams and a 10 m diameter target chamber. The NIF is being designed and built by an LLNL led team from Los Alamos National Laboratory, Sandia National Laboratories, the University of Rochester and LLNL. Physical construction began in 1997. The Laser and Target Area Building and the Optics Assembly Building were the first major construction activities, and despite several unforeseen obstacles, the buildings are now 92% complete and have been built on time and within cost. Prototype component development and testing has proceeded in parallel. Optics vendors have installed full scale production lines and have performed prototype production runs. The assembly and integration of the beampath infrastructure have been reconsidered and a new approach has been developed. The article discusses the status of the NIF project and the plans for completion.

The National Ignition Facility Project: An Update

The National Ignition Facility (NIF) consists of 192 forty-centimeter-square laser beams and a 10-m-diameter target chamber. Physical construction began in 1997. The Laser and Target Area Building and the Optics Assembly Building were the first major construction activities, and despite several unforeseen obstacles, the buildings are now 92% complete and have been done on time and within cost. Prototype component development and testing has proceeded in parallel. Optics vendors have installed full-scale production lines and have done prototype production runs. The assembly and integration of the beampath infrastructure has been reconsidered and a new approach has been developed. This paper will discuss the status of the NIF project and the plans for completion. It will also include summary information on Laser MegaJoule (LMJ) provided by M. Andre, LMJ Project Director.

Steel requirements for current and future Canadian gas pipeline systems

Canada has significant future natural gas reserve potential, particularly in the frontier areas of the Canadian Arctic. To utilize these energy resources, as well as those in Alaska, USA, will require major pipeline construction activity throughout the 1980s and 1990s. The first major natural gas pipeline, the Alaska Highway Gas Pipeline Project, is now under construction using high-strength (Grade 483), high-pressure line pipe. For future pipelines, the use of even higher strength line pipe materials (Grade 690) offers potential savings of the order of 25% in the cost of transporting gas. While materials at this strength level are currently feasible, further research is required to ensure their reliability in pipeline applications.

Synchrotron Radiation Sources

As a result of the exponential growth of the utilization of synchrotron radiation for research in the domain of the material sciences, atomic and molecular physics, biology and technology, a major construction activity has been generated towards new dedicated electron storage rings, designed optimally for synchrotron radiation applications, also, expansion programs are underway at the existing facilities, such as DORIS, SPEAR, and VEPP. In this report the basic properties of synchrotron radiation will be discussed, a short overview will be given of the existing and new facilities, some aspects of the optimization of a structure for a synchrotron radiation source will be discussed and the addition of wigglers and undulators for spectrum enhancement will be described. Finally, some parameters of an optimized synchrotron radiation source will be given.

Harmony in science: Superconductivity and high energy physics

Thirty-one days after the disclosure of high field superconductivity in Nb 3 Sn, the bubble chamber group at the Lawrence Berkeley Laboratory began a program to apply this discovery to high energy physics. On that day in 1961 a very special relationship was born which, as subsequent events were to show, proved to be one of the most fruitful associations in modern science. Given the well-known high technology content and innovative approach to problem solving associated with high energy physics, it is hardly surprising that significant developments in applied superconductivity took place in accelerator laboratories. Particle physics requires a bewildering array of technologically sophisticated equipment: from the instant when particles are injected into the accelerator through the acceleration process, beam extraction, separation, and steering to the instant of collision and analysis of the interaction products, superconducting devices play a most important role. We examine each step in this process and not only describe how the latest advances in superconductivity have been applied but also discuss why these developments necessarily took place. It is remarkable that, in spite of considerable fiscal restraint, high energy physics is entering a period of major construction activity. Thus if history repeats itself we are about to witness a flood of innovations each intended to alleviate some problem brought on by increasingly expensive power and rising production costs, not to mention the constant clamor for higher accelerator energies and greater resolution of the detection equipment.

Navajo Graves: Some Preliminary Considerations for Recording and Classifying Reservation Burials

Southwestern anthropologists have been slow to discuss and describe historic Indian burials. This has been especially true for the Navajo Indian Reservation, that region commonly referred to as the Four Corners Country, where the four states of Arizona, Utah, Colorado, and New Mexico share common borders. In the vast realm of ethnographic literature on the Navajos, there heretofore appeared only three papers devoted exclusively to death and burial practices among these people (Shufeldt 1891:303-306; Haile 1917:29-34; Ward and Brugge 1975:31-42). There have been several reasons for this situation. First, little has been written ethnographically because of the extreme reluctance on the part of most native informants to discuss the subject. It has long been known, among anthropologists and many other outsiders, that traditional Navajos possess a great fear of the dead. This point has been well documented in lone sentences and single paragraphs scattered throughout the literature. A second reason has been the fear of tribal reprisal, which in recent years has become a great barrier to productive archaeological research on Navajo period remains. Tribal permits have been withheld, or not renewed, and many researchers fearing loss of all archaeological privileges have chosen to avoid Navajo sites in favor of prehistoric ones. Finally, in advance of major construction or mining activity, many individuals are exhumed each year. Graves are opened and the entire contents removed and transported for reburial. If allowed to remain in place, these burials would be totally destroyed. For this reason, at the request of some family member(s), an archaeologist is called in and the deceased exhumed.