A summary is presented with the main historical background in the analysis of the composite slabs with steel sheets subjected to flexion, as well as of the main methods of design, instrumentation and tests accepted by different International Standards. They fundamental parameters that influence the structural behaviour of the composite slabs are analyzed, and with a numeric study an analytical optimization method of the embossments system, is proposed and implemented in a spread sheet is possible to estimate the shear resistance of open web sheets and by comparing them, is possible to determine the better embossments system to include in a open web sheet with such method. Applying the proposed method a technologically possible embossments system can be obtained with a minimum cost for an industrial line of open web sheets.
Rev. ing. constr. [online]. 2007, vol.22, n.3, pp. 145-156. ISSN 0718-5073. http://dx.doi.org/10.4067/S0718-50732007000300001.
Since the publication of White Paper #7 "Phase Scheduling" (Ballard, 2000), work on many projects has been planned with this technique by teams of varying configuration. Many teams have adapted their own approach to developing a "phase schedule", in some cases called a "reverse phase schedule" or a "pull phase schedule". During these planning sessions, ideas have been put in practice that improve on the original scheme and increase the benefits of producing a phase schedule. Perhaps the most significant being the conversations that the teams pursue during the exercise. This paper will briefly describe the authors' current approach to and practices for preparing phase schedules and how this has become, in actuality, phase planning. It will then describe how phase planning produces the project schedule as traditionally understood, and more importantly designs the network of commitments necessary to deliver each project milestone, and how understanding and using the network of commitments improves project performance
Rev. ing. constr. [online]. 2007, vol.22, n.3, pp. 157-162. ISSN 0718-5073. http://dx.doi.org/10.4067/S0718-50732007000300002.
Na2Si04 behavior as a mineralizer agent on organic fibers composites with Type I Portland Cement matrix is possible to observe it through a Scanning Electron Microscope (SEM). The purpose of this research was to study the role of this agent on this material's durability due to the chemical incompatibility between calcium hydroxide Ca(OH)2 and the fiber reinforcement from the mahogany (Swietenia Macrophylla), from composites of three different ages and two different fiber volumetric fraction as well. The tests were made in three different zones: matrix, reinforcement and transition zone, using a SEM, whereas the chemical composition was scanned out with an Energy Disperse X-Ray Spectrometer (EDS); through the first equipment the contrast between the different phases was observed; with the second one, the chemical composition of the regions of interest was analyzed. The results showed usefulness of the agent in improving the material durability, as well as the benefits of the use of SEM to visualize the microstructural behavior
Rev. ing. constr. [online]. 2007, vol.22, n.3, pp. 165-172. ISSN 0718-5073. http://dx.doi.org/10.4067/S0718-50732007000300003.
In a long descending slopes heavy vehicles might lose control and runaway downgrade. To mitigate the potential damage, exist several systems that permits heavy vehicles leave the lane and stop. These systems are known as Arrestor Bed (AB). Design Standards consider the geometric criteria proposed by AASHTO (2001) standards. AASHTO recommend a constant value of the design speed for AB. Also, recommends general criteria to evaluate the need and location of an AB. The standards does no proposed analytic procedures to the designer assess the need and location of an AB. In this work, a methodology of analysis and design of AB is proposed. The methodology applies analytic criteria to evaluate the need and the location of an AB based on the brake temperature profile of trucks developed by Bowman (1989). Also, an energetic based method to estimate speed profile and design speed is proposed. The method consider the slope and the length of the slope. The proposed methodology allows to the designer to solve the main questions in the design of AB: ¿It is necessary an AB? ¿Where to locate it? ¿What is the design speed?. To illustrate the proposed methodology an AB at present in operation was analyzed. It was determined that is necessary to relocate de AB, to design an impact attenuator, and to post a limit speed for heavy vehicles in the downgrade lane
Rev. ing. constr. [online]. 2007, vol.22, n.3, pp. 175-184. ISSN 0718-5073. http://dx.doi.org/10.4067/S0718-50732007000300004.
The results of a study that assesses the effect of adding small amounts of calcium carbonate as fluxing agent on fired Clay bricks are presented. The paper aims to improve the energy demand of fire clay bricks manufacture through the reduction of firing temperature and process duration. The paper shows that additions in the range of 2-5 % (wt) of clay improves compressive strength of bricks fired at temperature around 900 °C and sintering times between 1-3 hours. This effect would be caused by modifications of the mineralogical transformations through which clay minerals undergo in the presence of calcite. which reduces sintering temperature in clays containing mainly montmorillonite. This paper presents a broad study of the changes of phisico-chemical-mechanical properties at both macroscale and microscale levels. The results show a consistent increase in compressive strength, associated with the formation of the phase anorthite within the reaction products. These results were tested in real prototypes, where the compressive strength of the manufactured bricks increased by 40-50%, while the energy demand decreased by 30-50%
Rev. ing. constr. [online]. 2007, vol.22, n.3, pp. 187-196. ISSN 0718-5073. http://dx.doi.org/10.4067/S0718-50732007000300005.
Since the nineties, housing construction companies began to incorporate the quality management and have developed quality management systems (QMS), using the directives given by the ISO 9000 standards. Construction companies have invested a big amount of resources -especially economic and human resources - in the development of their QMSs; this has been done in order to increase the level of satisfaction of their customers through the improvement of the quality of their constructive processes and the quality of the houses they build. Then, it is very important to construction companies to know if this investment has been as profitable as they hoped. A study was performed to determine the impact of QMSs on the performance of ISO 9001:2000 certified housing construction companies regarding the level of application of quality management’s principles without considering the impact that can generate the implementation of other standards such as environmental management and risk prevention. The measuring instrument consisted of a survey applied as a personal interview, which was answered by 118 individuals from 11 Chilean housing construction companies; out of a total universe of 34 ISO 9001:2000 certified housing construction companies. These people gave their perceptions over the accomplishment of quality management’s principles in their companies. The main conclusion of this study indicates that people perceive that quality management’s principles are applied in an unsatisfactory way.
Rev. ing. constr. [online]. 2007, vol.22, n.3, pp. 197-213. ISSN 0718-5073. http://dx.doi.org/10.4067/S0718-50732007000300006.
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