Conventional Construction Methods Research Articles

Research on Construction Technology of Embankment Widening of Waterside Cantilever High Retaining Wall

In the project of the fill section widening of the cantilever high retaining wall of the old embankment, the construction of the embankment widening is carried out under the condition of allowing cars to drive through. As the stability of the old embankment and the normal and safe car driving shall be guaranteed, the cantilever reinforcement high retaining wall can’t be dismantled once for all or completely during the widening process, and the conventional construction of excavating the steps for joining the new and old embankments. This paper aims to solve the defects of the conventional construction method by introducing a newly-developed construction technology of embankment widening of waterside cantilever high retaining wall, which can effectively solve the anti-floating problem of the light-weight embankment, prevent the differential deformation at the joint of the wall bottom plate and the reinforced concrete continuous slab of the cantilever retaining wall, and improve the bearing capacity of the embankment.

A Novel Graph Construction Method Based on Locality Sensitive Histogram for Locality Preserving Projections

This paper presents a novel construction method of neighbor graph based on locality sensitive histogram for Locality Preserving Projections (LPP), which is called LSH Graph Construction. Unlike the conventional construction method of neighbor graph that vectorizes the original data set to compute the k-nearest neighbor graph, the LSH graph construction method which we proposed is acting on 2D image matrixes directly. Firstly, we compute each sample’s locality sensitive histogram, so that each sample can be easily divided into multiple overlapping regions. Then we construct the samples’ neighbor graph basing on corresponding region-to-region matching. Our proposed LSH Graph Construction method have the following two advantage: it can preserve samples’ intrinsic structural information and is insensitive to illumination and pose variation in some extent. We apply LSH Graph Construction into the famous dimensionality algorithm: LPP to develope a new algorithm called LSHG-LPP. Experiments on two wellknown face databases (Yale and ORL face databases) demonstrate that the proposed method outperforms LPP.

A new accelerated-replacement method and full-scale test of a new superstructure for existing OSPG railway bridges

Existing open-steel-plate-girder (OSPG) railway bridges in Korea are so old that they can no longer provide the desired ride quality when trains pass over them due to loss of integrity. In addition, existing bridges do not have ballast, thus impacts from passing trains are delivered directly to piers and abutments. The damage that accumulated is one of the main causes of cracks in pier concrete. To cure this problem, replacement of the existing bridges is required. However, since they are still in service, conventional construction methods cannot be used for their replacement. A new method is necessary to quickly replace the existing bridges in a way that does not disturb the existing train schedule. In this study, a new accelerated-replacement method is proposed using a newly developed crane-vehicle which possesses cranes able to lift a replacement bridge, and which is able to travel on existing train tracks. This study also addresses the design and manufacture of a new bridge deck appropriate for accelerated-replacement construction. Finite element analyses and experimental tests were conducted to estimate the performance of the new bridge deck. The analyses included a static load case and dynamic analysis at various train speeds. The experimental tests included static loading and modal tests to capture the fundamental natural frequency and damping ratio of the bridge deck, and a dynamic amplification test. The results of this study can be used for practical replacement of aged existing open-steel-plate-girder bridges and to improve the integrity and ride quality of railway bridges in Korea.

Probability weighted indices for improved ecosystem report card scoring

This paper outlines a new method for computing an ecosystem index using probability weighted moments (PWMs) in place of conventional moments. Conventional methods of index construction are based on a scaled measure of the discrepancy between the sample mean and a guideline or reference value and as such tend to reflect only gross movements in distributional location. PWMs on the other hand allow for a more targeted assessment through the incorporation of a weighting function specified by the analyst. We refer to the resulting index as a probability weighted index or PWI. Although all data are used in the computation of the PWI, they do not necessarily contribute equally to the final result as is the case with conventional moments. Computational formulae and associated R code are provided, which allow the PWIs and their standard errors to be unbiasedly estimated from empirical data. Copyright © 2014 John Wiley & Sons, Ltd.

Use of Wicking Fabric to Help Prevent Frost Boils in Alaskan Pavements

AbstractBeaver Slide is on the Dalton Highway near 177.8 km (110.5 mi), and it is downhill when heading north. The road gradient is approximately 11% and the road prism is on a side hill. Each year, there are soft spots that usually appear in late April and remain all summer, which are also called “frost boils” by engineers at the Alaska Department of Transportation and Public Facilities (AKDOT&PF). The frost boils have resulted in extremely unsafe driving conditions and frequent accidents. Past repair efforts indicate conventional road construction methods do not work. A new type of geosynthetic wicking fabric has been recently developed that has a high specific surface area (consequently high wettability and high capillary action) and high directional permittivity. Preliminary laboratory tests indicate it has great promise as a cost-effective means to solve the frost heave-related problems on northern road systems. This study verifies the effectiveness of the wicking fabric to mitigate frost boils in Al...

Case Study of Innovative Top-Down Construction Method with Channel-Type Excavation

AbstractAlthough the conventional top-down construction method is widely used in deep excavation, it has the drawback of low efficiency attributable to the long hauling distance and the possibility of the occurrence of excessive excavation deformation and construction risk. This paper introduces a case of deep metro station excavation at West Shanghai Railway Station. The top-down construction method must be used because the excavation is located under a running high-speed railway, and an innovative excavation scheme is proposed to improve construction efficiency and to control excavation deformation. In this method, an operation channel for earth hauling is first excavated in the middle of the excavation. With the available operation channel, the soil on both sides of the channel is excavated simultaneously in a segment pattern, and the required strut systems are subsequently constructed. Both the excavated soil and the construction materials are transported through the channel. This channel-type constru...

Graphical modeling method application in construction of petrochemical plant block-diagram

The article represents a block diagram executed by a new method. A traditional block diagram has quite a few drawbacks: place and location of blocks are not clearly defined; orientation and direction of lines are not determined by their configuration and material flow properties; communications within the plant structure form an intricate network of lines; it is difficult to trace some connections as well as to extract information contained in the diagram; the system of relationships is impossible to visually identify. Thus, the conventional methods of block diagram construction create cumbersome and uninformative graphical representations of production. The new method involves graphical modeling. Optimization of petrochemical production graphical representation is carried out on the example of a plant which is a structural unit of the largest petrochemical complex in Russia. An analysis of petrochemical production structure was carried out, its results are presented. The plant has two productions: production of ethylene, propylene and liquid pyrolysis products containing a significant amount of aromatic hydrocarbons; plastics production. The plant production cycle is divided into petrochemical process blocks. Each production consists of several process blocks. A linear network with process blocks is constructed. Elements and their connecting bonds are arranged in a certain order. The plant block diagram is constructed by connecting all the blocks of single processes. This graphical model of a plant block diagram is more descriptive and easier to use for system analysis; it forms unified graphical representation of a petrochemical plant. Due to the graphical modeling method system, petrochemical production block diagrams are represented in a significantly simplified form, convenient for analysis, storage, processing and using the information contained in graphic models of petrochemical processes.

Investigation of Industrialised Building System Performance in Comparison to Conventional Construction Method

Conventional construction methods are still widely practised, although many researches have indicated that this method is less effective compared to the IBS construction method. The existence of the IBS has added to the many techniques within the construction industry. This study is aimed at making comparisons between the two construction approaches. Case studies were conducted at four sites in the state of Penang, Malaysia. Two projects were IBS-based while the remaining two deployed the conventional method of construction. Based on an analysis of the results, it can be concluded that the IBS approach has more to offer compared to the conventional method. Among these advantages are shorter construction periods, reduced overall costs, less labour needs, better site conditions and the production of higher quality components.

Mathematical Model for Optimization of Construction Contracting in Housing Development Project

This article presented a method for solving a construction planning problem in a housing development project using a mathematical model which is an integer linear programming for dividing house construction jobs to three contractors in a project case study. 169 units of the house in the project would be constructed by the three contractors in conventional construction method and precast method. The results found application of the mathematical model was applicable. The mathematical models were formulated, minimum construction cost of the project was 417.69 million baht (M$13.92), and within the total project duration of 72 months. Conclusions and recommendations were discussed in this research.

Sustainable Housing Construction to Reduce Greenhouse Gas Emissions

Global warming is a reality due to the curent level of greenhouse gas emissions globally. Housing construction should take into account factors which contribute to global warming while making the construction affordable in view of the greenhouse gas emissions and the continually increasing energy costs. It is important that housing construction overcomes the irrationality of the current conventional construction method which is not only expensive but has poor thermal performance and ignores the significant environmental impact of high embodied energy of the building process which contributes to the greenhouse gas emissions. Because of this there is a need for developing improved low cost sustainable building techniques. This paper presents an innovative rammed earth core concrete jacket walling system that can provide significant improvements in environmental impact, comfort and cost of both building the house and the cost of operational energy. The construction uses mainly local natural materials with very little high energy processing there by reducing the embodied energy of the construction. Not only using local materials in this construction but also only basic building skills are required for construction workers and therefore the system is ideally suited to rural areas and has potential application to developing countries. This method of construction has better performance in case of earth quakes which saves many lives. The paper presents a discussion of the efficiency of such high thermal mass solutions and describes the construction process.

Jacking Force Controlling Technique of PC Beam Flexible Piers Based on Multiple Points Pushing Method

With the advantages such as shortening the construction period, not affecting the relative navigation and effectively reducing the construction cost, jacking construction technology has been widely applied, as the construction method compared with other conventional construction method is more complicated, it is necessary to discuss the control technology of jacking force during the construction process.

Comparative study of greenhouse gas emissions between off-site prefabrication and conventional construction methods: Two case studies of residential projects

Greenhouse gas (GHG) emissions in the construction stage will be more relatively significant over time. Different construction methods influence GHG emissions in the construction phase. This study investigates the differences of GHG emissions between prefabrication and conventional construction methods. This study sets a calculation boundary and five emission sources for the semi-prefabricated construction process: embodied emissions of building materials, transportation of building materials, transportation of construction waste and soil, transportation of prefabricated components, operation of equipment, and construction techniques. A quantitative model is then established using a process-based method. A semi-prefabrication project and a conventional construction project in China are employed for preliminary examination of the differences in GHG emissions. Results show that the semi-prefabrication method produces less GHG emissions per square meter compared with the conventional construction, with the former producing 336kg/m2 and the latter generating 368kg/m2. The largest proportion of total GHG emissions comes from the embodied emissions of building materials, accounting for approximately 85%. Four elements that positively contribute to reduced emissions are the embodied GHG emissions of building materials, transportation of building materials, resource consumption of equipment and techniques, and transportation of waste and soil, accounting for 86.5%, 18.3%, 10.3%, and 0.2%, respectively, of reduced emissions; one a negative effect on reduced emissions is the transportation of prefabricated components, which offsets 15.3% of the total emissions reduction. Thus, adopting prefabricated construction methods contribute to significant environmental benefits on GHG emissions in this initial study.

Quantitative Insight into Rational Tornado Design Wind Speeds for Residential Wood-Frame Structures Using Fragility Approach

Tornadoes are an extremely devastating natural hazard that have significant consequences but are currently not considered in the structural design codes due to their low probability of occurrence. These low-occurrence high-consequence events have been studied but not to the extent of other natural hazards. This paper presents the results of a study whose objective was to provide quantitative insight into a rational design wind speed for tornadoes considering the current state-of-practice in construction methods. Five archetype buildings were selected to be representative of the typical residential structure design space in tornado-prone regions of the United States. Wind analysis was performed using the ASCE standard loading in combination with modification factors for tornadic winds developed from the available literature. Fragilities were developed for the main components along the vertical load path that included roof sheathing and roof-to-wall connection. Then, system fragilities for the combined load path of these two potential failure modes were formulated as a series system. The results of the fragility analysis were compared with the Enhanced Fujita (EF) scale ratings for residential construction and were then used to identify which critical component had a greater effect on system performance. Finally, it was concluded that, if proper foundation anchorage is provided, it is possible to design a residential wood-frame structure for winds from an EF1 tornado, possibly an EF2, but not an EF3, using conventional construction methods including hurricane clips.

Experimental and Numerical Study for the Shaping Formation of SCST Structures by Cable-tensioning

This paper discusses the behaviour characteristics of the shaping formation of Single-Chorded Space Truss (SCST) structures by means of cable-tensioning of bottom chords. The innovative technique is fast and economical and issued in many types of space structures. The small-scale test models presented herein consist of uniform pyramids with multi-directional ball type joints which are erected into their final shape by cable-tensioning. Since the joint behaviour is very significant in studying the shaping of SCST structures, basic tests for beam and pyramidal units were performed. The feasibility of the proposed cable-tensioning technique and the reliability of the established geometric model were confirmed by finite element analysis. The proposed cable-tensioning technique indicates that the behaviour characteristic of joints is very important in the shaping formation of SCST structures. More specifically in situations where heavy cranes are inaccessible, the cable-tensioning construction technique has proven to be an easy and reasonable method compared to conventional construction methods that typically include heavy cranes and scaffolding.

Measuring Socio-economic Status in the Millennium Villages: The Role of Asset Index Choice

How are poverty analyses and poverty traps assessments affected by the choice among conventional methods of asset index construction? To address this question, this article uses panel data from four sites in the Millennium Villages Project (MVP) in Malawi, Tanzania, Mali and Ghana to study the relationship between eight asset indices and the sensitivity of findings related to poverty rates, poverty transitions and poverty traps to the index used. We find that although estimations of poverty rates and transitions are largely consistent across indices, evidence of poverty traps can be conditional on which asset index is used. The asset indices studied include structural income, principal components, factor analysis and a reduced set of assets reflecting the portfolio assessed in the Demographic Health Survey (DHS) data.

Quartet-Net: A Quartet-Based Method to Reconstruct Phylogenetic Networks

Phylogenetic networks can model reticulate evolutionary events such as hybridization, recombination, and horizontal gene transfer. However, reconstructing such networks is not trivial. Popular character-based methods are computationally inefficient, whereas distance-based methods cannot guarantee reconstruction accuracy because pairwise genetic distances only reflect partial information about a reticulate phylogeny. To balance accuracy and computational efficiency, here we introduce a quartet-based method to construct a phylogenetic network from a multiple sequence alignment. Unlike distances that only reflect the relationship between a pair of taxa, quartets contain information on the relationships among four taxa; these quartets provide adequate capacity to infer a more accurate phylogenetic network. In applications to simulated and biological data sets, we demonstrate that this novel method is robust and effective in reconstructing reticulate evolutionary events and it has the potential to infer more accurate phylogenetic distances than other conventional phylogenetic network construction methods such as Neighbor-Joining, Neighbor-Net, and Split Decomposition. This method can be used in constructing phylogenetic networks from simple evolutionary events involving a few reticulate events to complex evolutionary histories involving a large number of reticulate events. A software called "Quartet-Net" is implemented and available at http://sysbio.cvm.msstate.edu/QuartetNet/.

A Simple and Robust Vector-Based shRNA Expression System Used for RNA Interference

BackgroundRNA interference (RNAi) mediated by small interfering RNAs (siRNAs) or short hairpin RNAs (shRNAs) has become a powerful genetic tool for conducting functional studies. Previously, vector-based shRNA-expression strategies capable of inducing RNAi in viable cells have been developed, however, these vector systems have some disadvantages, either because they were error-prone or cost prohibitive.ResultsIn this report we described the development of a simple, robust shRNA expression system utilizing 1 long oligonucleotide or 2 short oligonucleotides for half the cost of conventional shRNA construction methods and with a>95% cloning success rate. The shRNA loop sequence and stem structure were also compared and carefully selected for better RNAi efficiency. Furthermore, an easier strategy was developed based on isocaudomers which permit rapid combination of the most efficient promoter-shRNA cassettes. Finally, using this method, the conservative target sites for hepatitis B virus (HBV) knockdown were systemically screened and HBV antigen expression shown to be successfully suppressed in the presence of connected multiple shRNAs both in vitro and in vivo.ConclusionThis novel design describes an inexpensive and effective way to clone and express single or multiple shRNAs from the same vector with the capacity for potent and effective silencing of target genes.

Management of Edentulous Resorbed Mandibular Residual Ridge in Malaysian Geriatric Patients: 2-Year Clinical Study

ABSTRACT Objectives A combination of the neutral zone and the polished surface impression techniques is a useful method to reserve the functional and physiological forms of the underlying mandibular residual ridge by enhancing both retention and stability in Malaysian geriatric patients (2-year clinical study). Materials and methods A total of 25 Malaysian geriatric patients have participated in the current study. Two sets of dentures were served to the patients. The first set was constructed according the conventional method of complete denture construction whereas the second set was constructed by using neutral zone and polished surface impression techniques. Results The patients were followed up for 2 years and the obtained results showed that all patients have stopped using the conventional dentures and continued with the test dentures. The comparative analysis exhibited significant difference (p < 0.05) in favor of test dentures. Conclusion Combination of the neutral zone and the polished surface techniques can impart a physiological reservation to the underlying residual ridge without changes. Statement of problem It is common for completely edentulous geriatric patients to have resorbed mandibular residual ridge because of the process of aging. Some surgical interactions are contraindicated for this age group of patients, so, neutral zone technique and/or polished surface impression verified effective in improving stability for lower complete dentures. In spite of the fact that the above mentioned methods often used to enhance stability of complete denture, most of the studies were relying on only one of those methods to improve stability rather than retention. Researcher hypothesis stated that a combination of the neutral zone and the polished surface impression techniques should be performed together to enhance both stability and retention and henceforth reservation of the residual ridge under mandibular complete dentures issued to the patients with a constant follow-up for two consecutive years. How to cite this article Mustafa AA. Management of Edentulous Resorbed Mandibular Residual Ridge in Malaysian Geriatric Patients: 2-Year Clinical Study. Int J Prosthodont Restor Dent 2013;3(2):83-86.

Locally Weighted Multi-atlas Construction.

In image-based medical research, atlases are widely used in many tasks, for example, spatial normalization and segmentation. If atlases are regarded as representative patterns for a population of images, then multiple atlases are required for a heterogeneous population. In conventional atlas construction methods, the "unit" of representative patterns is images. Every input image is associated with its most similar atlas. As the number of subjects increases, the heterogeneity increases accordingly, and a big number of atlases may be needed. In this paper, we explore using region-wise, instead of image-wise, patterns to represent a population. Different parts of an input image is fuzzily associated with different atlases according to voxel-level association weights. In this way, regional structure patterns from different atlases can be combined together. Based on this model, we design a variational framework for multi-atlas construction. In the application to two T1-weighted MRI data sets, the method shows promising performance, in comparison with a conventional unbiased atlas construction method.

The Construction Technology of Segmented Parallel Operations in Main Shaft No. 2, Wutong Coal Mine

The construction of main shaft No.2 in Wutong coal mine is the key project of energy expansion and technological innovation. It started in December 2008 and jointed commissioning in the end of July 2010.Engineering capacity,a tight schedule and the difficulty of construction are the tough points. So if according with conventional construction methods,the project would have difficulty in completing on schedule.After repeated demonstration ,the researches of Wutong coal mine break the routine. The construction technology of segmented parallel operations is adopted to accelerate the construction schedule.This technology not only makes main shaft No.2 in advance of two months to complete construction and installation works, but also achieves difficult precisely through in both upper and lower segments.Totally plane error is only 80mm in through point.The project hits a good example for future wellbore rapid construction.