540 research outputs found
A Framework for Smart Building Technologies Implementation in the Ghanaian Construction Industry: A PLS-SEM Approach
This study sought to identify the dimensions and the significant critical factors capable of enhancing Smart Building Technologies' (SBTs') implementation for smart building projects in developing countries. A desk literature review is first conducted to identify and categorize the potential factors. It is further analyzed using partial least square structural equation modelling (PLS-SEM) based on 227 valid data from experts in Ghana. The study revealed four underlying dimensions (i.e., âprocesses and control'[PC], âpeople and skills'[PS], âmethods and techniques'[MT], and âknowledge sharing'[KS]) consisting 14 significant critical factors capable of enhancing SBTs implementation for smart building projects, with the top three comprising âappropriate procedures/practices for managing smart building projects (MT3)', âappropriate tools/techniques to guide smart building projects to their delivery (MT2)', and âskills and experience required to pick project team members for smart building projects (PS1)â. Further analysis with PLS-SEM revealed a significant positive effect of the four underlying dimensions and their positive interrelationships toward framework development. Besides the unique contribution of this study to the knowledge body, it also provides project managers and a construction design team with a structured knowledge of the skills, expertise, attitudes, decision-making, processes, control mechanisms, and effective delivery of smart building projects in developing countries
Risk of excavators overturning: determining horizontal centrifugal force when slewing freely suspended loads
Purpose: Tracked hydraulic excavators are versatile and ubiquitous items of off-highway plant and machinery that are utilised throughout the construction industry. Each year a significant number of excavators overturn whilst conducting a lifting operation, causing damage to property, personnel injury or even fatality. The reasons for the overturn are myriad, including: operational or environmental conditions; machine operator acts or omissions; and/ or inadequate site supervision. Furthermore, the safe working load (SWL) figure obtained from manufacturer guidance and utilised in lift plans is based upon undertaking a static load only. This research seeks to determine whether the SWL is still safe to be used in a lift plan when slewing a freely suspended (dynamic) load, and if not, whether this may be a further contributory factor to overturn incidents.
Approach: Previous research has developed a number of machine stability test regimes but these were largely subjective, impractical to replicate and failed to accurately measure the âdynamicâ horizontal centrifugal force resulting from slewing the load. This research contributes towards resolving the stability problem by critically evaluating existing governing standards and legislation, investigating case studies of excavator overturn and simulating the dynamic effects of an excavator when slewing a freely suspended load at high rotations per minute (rpm). To achieve this, both the static load and horizontal centrifugal force from slewing this load were calculated for six randomly selected cases of an excavator, with different arm geometry configurations.
Findings: The results from the six cases are presented and a worked example of one is detailed to demonstrate how the results were derived. The findings reveal that the SWL quoted on an excavatorâs lift rating chart considerably underestimates the extra forces experienced by the machine when an additional dynamic load is added to the static load whilst lifting and slewing a freely suspended load.
Originality: This work presents the first attempt to accurately model excavator stability by taking consideration of the dynamic forces caused by slewing a freely suspended load and will lead to changes in the way that industry develops and manages lift plans. Future research proposes to: vary the weight of load, arm geometry and rpm to predict machine stability characteristics under various operational conditions; and exploit this modelling data to populate pre-programmed sensor based technology to monitor stability in real time and automatically restrict lift mode operations
Characterizing the Hydrology of Shallow Floodplain Lakes in the Slave River Delta, NWT, Canada, Using Water Isotope Tracers
The relative importance of major hydrological processes on thaw season 2003 lakewater balances in the Slave River Delta, NWT, Canada, is characterized using water isotope tracers and total suspended sediment (TSS) analyses. A suite of 41 lakes from three previously recognized biogeographical zonesâouter delta, mid-delta, and apexâwere sampled immediately following the spring melt, during summer, and in the fall of 2003. Oxygen and hydrogen isotope compositions were evaluated in the context of an isotopic framework calculated from 2003 hydroclimatic data. Our analysis reveals that flooding from the Slave River and Great Slave Lake dominated early spring lakewater balances in outer and most mid-delta lakes, as also indicated by elevated TSS concentrations (\u3e0.01 g L-1). In contrast, the input of snowmelt was strongest on all apex and some mid-delta lakes. After the spring melt, all delta lakes underwent heavy-isotope enrichment due to evaporation, although lakes flooded by the Slave River and Great Slave Lake during the spring freshet continued to be more depleted isotopically than those dominated by snowmelt input. The isotopic signatures of lakes with direct connections to the Slave River or Great Slave Lake varied throughout the season in response to the nature of the connection. Our findings provide the basis for identifying three groups of lakes based on the major factors that control their water balances: (1) flood-dominated (n=10), (2) evaporation-dominated (n=25), and (3) exchange-dominated (n=6) lakes. Differentiation of the hydrological processes that influence Slave River Delta lakewater balances is essential for ongoing hydroecological and paleohydrological studies, and ultimately, for teasing apart the relative influences of variations in local climate and Slave River hydrology
Climate-driven Shifts in Quantity and Seasonality of River Discharge over the past 1000 Years from the Hydrographic Apex of North America
Runoff generated from high elevations is the primary source of freshwater for western North America, yet this critical resource is managed on the basis of short instrumental records that capture an insufficient range of climatic conditions. Here we probe the effects of climate change over the past ~1000 years on river discharge in the upper Mackenzie River system based on paleoenvironmental information from the Peace-Athabasca Delta. The delta landscape responds to hydroclimatic changes with marked variability, while Lake Athabasca level appears to directly monitor overall water availability. The latter fluctuated systematically over the past millennium, with the highest levels occurring in concert with maximum glacier extent during the Little Ice Age, and the lowest during the 11th century, prior to medieval glacier expansion. Recent climate-driven hydrological change appears to be on a trajectory to even lower levels as high-elevation snow and glacier meltwater contributions both continue to decline
Short run causal relationship between foreign direct investment (FDI) and infrastructure development
Purpose â Foreign direct investment (FDI) ïŹows for infrastructure development have grown in volume to become more widely dispersed among home (outward investor) and host (recipient) countries. This paper aims to explore the short-run causal relationship between FDI and infrastructure development in the developing country of Ghana.
Design/methodology/approach â A two-stage least squares estimation method was adopted where FDI was endogenized, and all variables were in constant prices. Stationarity tests were performed on the annualized log difference of variables using augmented DickeyâFuller test(ADF).
Findings â Results reveal a positive and signiïŹcant relationship between FDI and infrastructure but a negative and signiïŹcant relationship between FDI and GDP and FDI and openness. GDP growth also has a long-run negative relationship with FDI inïŹows.
Originality/value â The paperâs contribution to knowledge is two-fold. First, it examines the short run effect of FDI upon the Ghanaian economy and how market shocks to FDI and infrastructure development can be ameliorated. Second, it illustrates that government policymakers should prioritize development that requires FDI and ensure that the local market is not excessively open to foreign exploitation. Future work is required to further investigate international capital ïŹow and its impact upon other developing nations
Real-Time structural health monitoring for concrete beams: a cost-effective 'Industry 4.0' Solution using Piezo Sensors
Purpose: This research paper adopts the fundamental tenets of advanced technologies in industry 4.0 to monitor the structural health of concrete beam members using cost effective non-destructive technologies. In so doing, the work illustrates how a coalescence of low-cost digital technologies can seamlessly integrate to solve practical construction problems.
Methodology: A mixed philosophies epistemological design is adopted to implement the empirical quantitative analysis of âreal-timeâ data collected via sensor-based technologies streamed through a Raspberry Pi and uploaded onto a cloud-based system. Data was analysed using a hybrid approach that combined both vibration characteristic based method and linear variable differential transducers (LVDT).
Findings: The research utilises a novel digital research approach for accurately detecting and recording the localisation of structural cracks in concrete beams. This nondestructive low-cost approach was shown to perform with a high degree of accuracy and precision, as verified by the LVDT measurements. This research is testament to the fact that as technological advancements progress at an exponential rate, the cost of implementation continues to reduce to produce higher accuracy âmass-marketâ solutions for industry practitioners.
Originality: Accurate structural health monitoring of concrete structures necessitates expensive equipment, complex signal processing and skilled operator. The concrete industry is in dire need of a simple but reliable technique that can reduce the testing time, cost and complexity of maintenance of structures. This was the first experiment of its kind that seeks to develop an unconventional approach to solve the maintenance problem associated with concrete structures. This study merges industry 4.0 digital technologies with a novel low-cost and automated hybrid analysis for real-time structural health monitoring of concrete beams by fusing several multidisciplinary approaches in one integral technological configuration
Coupling climate and economic models in a cost-benefit framework: a convex optimization approach
In this paper we present a general method, based on a convex optimisation technique, that facilitates the coupling of climate and economic models in a cost-benefit framework. As a demonstration of the method, we couple an economic growth model Ă la Ramsey adapted from DICE-99 with an efficient intermediate complexity climate model, C-GOLDSTEIN, which has highly simplified physics, but fully 3-D ocean dynamics. As in DICE-99 we assume that an economic cost is associated with global temperature change: this change is obtained from the climate model which is driven by the GHG concentrations computed from the economic growth path. The work extends a previous paper in which these models were coupled in cost-effectiveness mode. Here we consider the more intricate cost-benefit coupling in which the climate impact is not fixed a priori. We implement the coupled model using an oracle-based optimisation technique. Each model is contained in an oracle which supplies model output and information on its sensitivity to a master program. The algorithm Proximal-ACCPM guarantees the convergence of the procedure under sufficient convexity assumptions. Our results demonstrate the possibility of a consistent, cost-benefit, climate-damage optimisation analysis with a 3-D climate model
An investigation into the construction industryâs view on fire prevention in high-rise buildings post Grenfell
Purpose
The purpose of this paper is to explore contemporary attitudes amongst UK construction professionals regards fire safety post the Grenfell Tower disaster. Specifically, the research examines practitionerâs perceptions of fire safety design, material specification, construction and maintenance of high-rise blocks throughout a buildingâs whole life cycle.
Design/methodology/approach
A multi-methodology approach was adopted that utilises a mix of research methods. Extant literature and media content is used as a secondary data source, providing a more insightful interpretivist analysis â the results of which guided the development of the surveyâs main question set. Primary survey data are sourced from structured interviews and questionnaires completed by participating industry professionals and built environment undergraduate students using non-representative sampling methods. In addition, a Grenfell Tower special advisory panel member was interviewed to add further validity to the overall findings.
Findings
The quantitative findings present evidence to suggest that the Grenfell disaster (and media storm that has surrounded this event) has raised the general level of fire safety knowledge and competency amongst construction professionals. However, qualitative feedback from the special advisory panel member suggests specific fire prevention knowledge remains elusive within both industry and taught programmes at Higher Education Institutes. As a consequence, changes in the taught curriculum are proposed together with an extension of the role of facilities managers in practice to cover fire safety in greater depth.
Originality/value
This paper provides thoughtful insights into the contemporary discourse on fire safety within the UK construction industry. The research also provides critical suggestions to both industry and policy makers which seek to prevent a repeat tragedy occurring again
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