Journal of Construction Engineering http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Feasibility of Using Palmyrah Strips as Reinforcing Material in Cost Effective Houses Mon, 14 Apr 2014 08:24:05 +0000 http://www.hindawi.com/journals/jcen/2014/589646/ Construction of cost effective houses is a dilemma among the impoverished population in developing countries. The ever increasing price of traditional building materials results in high capital investments for residential buildings. Palmyrah is a significant economic resource, widely spread all over the northeast region of Sri Lanka. This research explores the technical feasibility of using heartwood of Palmyrah as a reinforcing member in lightly loaded concrete elements. Initially, mechanical properties of Palmyrah were examined through static bending, tensile, and compressive tests. Percentages of water absorption, dimensional stability, and anchorage bond strength were investigated to envisage the suitability of Palmyrah as reinforcement. Next, several short span slabs and beams reinforced with Palmyrah strips were subjected to tests. It was observed that Palmyrah reinforcement enhanced the moment capacity of the slabs and beams compared to unreinforced sections. Experimental failure loads of slabs and beams were higher than theoretically predicted values with Palmyrah reinforcement. Further, Palmyrah reinforced beams and slabs underwent flexural failures. Thus, it is concluded that heartwood of Palmyrah has the potential to be used as reinforcement in lightly loaded slabs and beams. Further research is recommended to investigate the durability and serviceability issues. K. Baskaran, H. E. Mallikarachchi, M. J. P. L. M. Jayasekara, and G. A. T. Madushanka Copyright © 2014 K. Baskaran et al. All rights reserved. An Artificial Intelligence Approach for Groutability Estimation Based on Autotuning Support Vector Machine Thu, 10 Apr 2014 09:43:06 +0000 http://www.hindawi.com/journals/jcen/2014/109184/ Permeation grouting is a commonly used approach for soil improvement in construction engineering. Thus, predicting the results of grouting activities is a crucial task that needs to be carried out in the planning phase of any grouting project. In this research, a novel artificial intelligence approach—autotuning support vector machine—is proposed to forecast the result of grouting activities that employ microfine cement grouts. In the new model, the support vector machine (SVM) algorithm is utilized to classify grouting activities into two classes: success and  failure. Meanwhile, the differential evolution (DE) optimization algorithm is employed to identify the optimal tuning parameters of the SVM algorithm, namely, the penalty parameter and the kernel function parameter. The integration of the SVM and DE algorithms allows the newly established method to operate automatically without human prior knowledge or tedious processes for parameter setting. An experiment using a set of in situ data samples demonstrates that the newly established method can produce an outstanding prediction performance. Hong-Hai Tran and Nhat-Duc Hoang Copyright © 2014 Hong-Hai Tran and Nhat-Duc Hoang. All rights reserved. Magnitude of Construction Cost and Schedule Overruns in Public Work Projects Wed, 18 Dec 2013 18:34:23 +0000 http://www.hindawi.com/journals/jcen/2013/935978/ This study analyzed 363 Clark County Department of Public Works (CCDPW) projects to determine construction cost and schedule overruns in various types and sizes of the projects. The sample projects were constructed from 1991 to 2008, with a total construction cost of $1.85 billion, equivalent to 2012 cost. A one-factor ANOVA test was conducted to determine whether construction cost and schedule overruns significantly varied based on types and sizes of the projects. The study showed that large, long-duration projects had significantly higher cost and schedule overruns than smaller, short-duration projects. Pramen P. Shrestha, Leslie A. Burns, and David R. Shields Copyright © 2013 Pramen P. Shrestha et al. All rights reserved. Effect of Turf Roof Slabs on Indoor Thermal Performance in Tropical Climates: A Life Cycle Cost Approach Thu, 07 Nov 2013 12:01:54 +0000 http://www.hindawi.com/journals/jcen/2013/845158/ Urbanization related to population growth is one of the burning issues that the world is facing today. Parallel to this, there is visible evidence of a possible energy crisis in the near future. Thus, scientists have paid attention to sustainable development methods, and in the field of building construction also, several innovations have been proposed. For example, green roof concept is one of such which is considered a viable method mainly to reduce urban heat island effect, to regain lost land spaces in cities, and to increase aesthetics in cities. The present study was aimed at investigating the impact of green roofs on indoor temperature of buildings, the effect of different types of roofs on the air conditioning loads, and the life cycle cost of buildings with different types of roofing. The study was conducted in several phases: initial small-scale models to determine the heat flow characteristics of roof top soil layers with different thicknesses, a large-scale model applying the findings of the small-scale models to determine temperature fluctuations within a building with other common roofing systems, a computer simulation to investigate air conditioning loads in a typical building with cement fiber sheets and green roof slabs, a comparative analysis of the effect of traditional type roofs and green roofs on the air conditioning loads, and finally an analysis to predict the influence of traditional type roofs and green roofs on life cycle cost of the buildings. The main findings of the study were that green roofs are able to reduce the indoor temperature of buildings and are able to achieve better heat transfer through the roof, and, thus a lower cooling load is necessary for air conditioning and has the possibility of reducing life cycle cost of a building. R. U. Halwatura Copyright © 2013 R. U. Halwatura. All rights reserved. Building Sustainability Assessment throughout Multicriteria Decision Making Mon, 30 Sep 2013 14:32:42 +0000 http://www.hindawi.com/journals/jcen/2013/578671/ Opinion and choice strongly influence sustainability concepts. The building construction industry, in particular property developers, has been charged with promoting excess environmental impacts ranging from overuse of resources to pollution generation. This paper presents an application of sustainability concepts to building projects, as well as to the development of practices, methodology, and tools for evaluating existing buildings. This study will detail how current systems to evaluate building performance operate and how to improve them. This approach utilizes the analytic hierarchy process (AHP). AHP is a multicriteria method that evaluates the relative importance of criteria, subcriteria, and families of indicators, used in the proposed system of technical characteristics applied to the local culture. At the same time, AHP makes visible the critical factors involved in evaluation of sustainability of these buildings. A result of the application of this type of modeling is a system for sustainability assessment and evaluation of environmental aspects and socioeconomic perspectives of existing buildings in the state of Rio de Janeiro, Brazil. Lúcio VillarinhoRosa and Assed Naked Haddad Copyright © 2013 Lúcio VillarinhoRosa and Assed Naked Haddad. All rights reserved. A Study of Concrete Made with Fine and Coarse Aggregates Recycled from Fresh Concrete Waste Mon, 26 Aug 2013 11:28:43 +0000 http://www.hindawi.com/journals/jcen/2013/317182/ This paper deals with the possibility of using fresh concrete waste as recycled aggregates in concrete. An experimental program based on two variables (proportion of fine aggregates replacement and proportion of coarse aggregates replacement) was implemented. The proportions of replacement were 0%, 50%, and 100% by mass of aggregates. Several mechanical properties were tested as compressive and tensile strengths. The results show a good correlation between aggregates replacement percentage and concrete properties. Concerning mechanical properties, a gradual decrease in compressive, splitting, and flexural strengthn with the increase in recycled aggregate percentage is shown. Mamery Sérifou, Z. M. Sbartaï, S. Yotte, M. O. Boffoué, E. Emeruwa, and F. Bos Copyright © 2013 Mamery Sérifou et al. All rights reserved. Improving the Collaboration between Main Contractors and Subcontractors within Traditional Construction Procurement Mon, 15 Jul 2013 13:30:57 +0000 http://www.hindawi.com/journals/jcen/2013/281236/ The inability of subcontractors/specialist contractors to contribute meaningfully to the construction process under the traditional construction procurement hampers the possibilities of improving value on projects and their integration with the rest of the supply chain. In particular, the main contractors and subcontractors in traditional construction procurement projects pursue their self-interests to such an extent that collaborative working has been impossible to achieve. In this research, qualitative and quantitative approaches were used to collect data to explore the problems at the root of the main contractor-subcontractor relationship. Intending to derive innovative ideas to reinvent the delivery process of traditional construction procurement, the principles of integrated project delivery (IPD) and the last planner system (LPS) were studied to seek useful ideas that can be employed to improve collaboration between main contractors and subcontractors. A high point of contention is the debate on the managerial competence of subcontractors; nevertheless, hope is expressed at the possibility of improving collaboration between the main contractor and subcontractor within traditional construction procurement work environment. Obafemi A. Akintan and Roy Morledge Copyright © 2013 Obafemi A. Akintan and Roy Morledge. All rights reserved. Improvement of Bearing Capacity of Shallow Foundation on Geogrid Reinforced Silty Clay and Sand Wed, 19 Jun 2013 18:25:30 +0000 http://www.hindawi.com/journals/jcen/2013/293809/ The present study investigates the improvement in the bearing capacity of silty clay soil with thin sand layer on top and placing geogrids at different depths. Model tests were performed for a rectangular footing resting on top of the soil to establish the load versus settlement curves of unreinforced and reinforced soil system. The test results focus on the improvement in bearing capacity of silty clay and sand on unreinforced and reinforced soil system in non-dimensional form, that is, BCR. The results show that bearing capacity increases significantly with the increased number of geogrid layers. The bearing capacity for the soil increases with an average of 16.67% using one geogrid layer at interface of soils with equal to 0.667 and the bearing capacity increases with an average of 33.33% while using one geogrid in middle of sand layer with equal to 0.33. The improvement in bearing capacity for sand underlain silty clay maintaining and equal to 0.33; for two, three and four number geogrid layer were 44.44%, 61.11%, 72.22%, respectively. The finding of this research work may be useful to improve the bearing capacity of soil for shallow foundation and pavement design for similar type of soil available elsewhere. P. K. Kolay, S. Kumar, and D. Tiwari Copyright © 2013 P. K. Kolay et al. All rights reserved. Estimating Strain Changes in Concrete during Curing Using Regression and Artificial Neural Network Sun, 21 Apr 2013 15:36:53 +0000 http://www.hindawi.com/journals/jcen/2013/380693/ Due to the cement hydration heat, concrete deforms during curing. These deformations may lead to cracks in the concrete. Therefore, a method which estimates the strain during curing is very valuable. In this research, two methods of multivariable regression and neural network were studied with the aim of estimating strain changes in concrete. For this purpose, laboratory cylindrical specimens were prepared under controlled situation at first and then vibration wire strain gauges equipped with thermistors were placed inside each sample to measure the deformations. Two different groups of input data were used in which variables included time, environment temperature, concrete temperature, water-to-cement ratio, aggregate content, height, and specimen diameter. CEM I, 42.5 R was utilized in set (I) and strain changes have been measured in six concrete specimens. In set (II) CEM II, 52.5 R was employed and strain changes were measured in three different specimens in which the diameter was held constant. The best multivariate regression equations calculated the determined coefficients at 0.804 and 0.82 for sets (I) and (II), whereas the artificial neural networks predicted the strain with higher of 1 and 0.996. Results show that the neural network method can be utilized as an efficient tool for estimating concrete strain during curing. Kaveh Ahangari, Zahra Najafi, Seyed Jamal Sheikh Zakariaee, and Alireza Arab Copyright © 2013 Kaveh Ahangari et al. All rights reserved. Seismic Analysis of Deep Water Pile Foundation Based on Three-Dimensional Potential-Based Fluid Elements Thu, 11 Apr 2013 10:22:24 +0000 http://www.hindawi.com/journals/jcen/2013/874180/ This paper investigates the use of three-dimensional (3D) potential-based fluid elements for seismic analyses of deep water pile foundation. The mathematical derivations of the potential-based formulations are presented for reference. The potential-based modeling technique is studied and validated through experimental data and analytical solutions. Earthquake time history analyses for a 9-pile foundation in dry and different water environments are conducted, respectively. The seismic responses are discussed to investigate the complex effect of earthquake-induced fluid-structure interaction. Through the analyses, the potential-based fluid and interface elements are shown to perform adequately for the seismic analyses of pile foundation-water systems, and some interesting conclusions and recommendations are drawn. Kai Wei and Wancheng Yuan Copyright © 2013 Kai Wei and Wancheng Yuan. All rights reserved. Review of Nondestructive Testing Methods for Condition Monitoring of Concrete Structures Thu, 04 Apr 2013 08:20:17 +0000 http://www.hindawi.com/journals/jcen/2013/834572/ The deterioration of concrete structures in the last few decades calls for effective methods for condition evaluation and maintenance. This resulted in development of several nondestructive testing (NDT) techniques for monitoring civil infrastructures. NDT methods have been used for more than three decades for monitoring concrete structures; now it has been recognized that NDT plays an important role in the condition monitoring of existing RC structures. NDT methods are known to be better to assess and evaluate the condition of RC structures practically. This paper reviewed several available NDT methods developed and used in the last few decades. Sanjeev Kumar Verma, Sudhir Singh Bhadauria, and Saleem Akhtar Copyright © 2013 Sanjeev Kumar Verma et al. All rights reserved. Thermal Behavior of Green Roofs Applied to Tropical Climate Thu, 10 Jan 2013 08:02:06 +0000 http://www.hindawi.com/journals/jcen/2013/940386/ The main goal of this paper is to present results on an experimental field about the green roofs thermal behavior, compared to other traditional roof covering systems. On the one hand, it intends to describe shortly the constructive system of a green roof with a lightweight building system, which has a sustainable building materials character and, on the other, it worries with the water reuse and with the run-off delay. The main methodological procedure adopted to study the thermal behavior of green roof was installing thermocouples to collect surface temperatures and indoor air, later comparing them with existing prototypes in an experimental plot. The thermal behavior analysis of cover systems was assessed by a representative episode of the climate fact, based on the dynamic climate approach. The experimental results from internal air temperature measurements show that the green roofs applied to warm and dry climates also provide an interesting time lag with surface and internal air temperature reduction. Grace Tibério Cardoso and Francisco Vecchia Copyright © 2013 Grace Tibério Cardoso and Francisco Vecchia. All rights reserved.