ISSN: 0718-5073

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Home > Archives > Vol 18, No 1 (2003)

Table of Contents

Original Research

USING PRODUCTIVITY OF LABORUM INFORMATION AND COMPUTER SIMULATIONS IN THE CLASSROOM Page 14-21 Julio Baeza Pereyra, Romel Solís Carcaño, Carlos Arcudia-Abad Abstract  PDF (285KB)  PDF (285KB) Abstract At the School of Engineering of the Autonomous University of Yucatan, the use of computers in teaching to undergraduatestudents is mostly oriented to budgeting and to structural analysis tasks. Also the curricula does not emphasizes aspects offield productivity data acquisition, nor the observation of the construction field dynamics. This paper presents the structureof a degree level course designed specifically to teach civil engineering students on how to combine the concepts ofproductivity recording and computer simulation. The main goal of this course is that the students get the knowledge on howto use the currently available tools and methods for making realistic estimation of field work duration and cost. This courseis divided in four parts. In the first part, the students learn how to use the simulation system and its probabilistic CPM Add-On. In the second part, the students are introduced to the basic fundamentals of the Factors Model. In the third part of thecourse the students are asked to get involved in the observation of field construction processes. In the last part, the studentsare asked to analyze the field data, and to build simulation models. Courses similar to the one presented in this paperemphasize the need to link the theoretical concepts, with the reality of the construction field.

AN ASSESMENT OF THE ACCURACY OF QUANTITY SURVEYORS’ PRELIMINARY COST ESTIMATES IN NIGERIA Page 33-38 Henry Agboola Odeyinka, Ade Yusif Abstract  PDF (197KB)  PDF (197KB) Abstract Accuracy of quantity surveyors’ preliminary cost estimates was evaluated through a questionnaire surveyadministered on quantity surveying firms in Nigeria. A total of 24 quantity surveying firms were surveyed and data on 40completed and on-going projects collected to quantitatively measure the degree of accuracy of quantity surveyors’preliminary cost estimates. The survey also evaluated preliminary cost estimating procedures employed generally. Withinthe limitation of the sample data analysed, it was concluded that quantity surveyors’ preliminary cost estimates in Nigeriawere not significantly biased. However, the consistency of the estimates was found to be unsatisfactory and as such, anissue that needs to be addressed. Using analysis of variance (ANOVA), the paper also concluded that estimating accuracyimproved with increasing contract size. However, for very large contracts, this was found to be contrary; the reasonsadduced being time lag between preliminary cost estimate and invitation of tenders and political factors that are commonwith such projects.

A CONSTITUTIVE MODEL TOWARDS THE FATIGUE CHARACTERIZATION OF ASPHALT CONCRETE Page 04-12 Nelson Galé, Alex Visser Abstract  PDF (258KB)  PDF (258KB) Abstract A constitutive model was used to evaluate the fatigue performance of asphalt concrete, consideringdamage evolution. The aim of the paper is to present a methodology capable of predicting fatigue life in asphalt concretemore realistically and comparable with field fatigue life. Firstly, the correspondence principle was verified, which is basedon the calculation of pseudo deformations and the relaxation curve as a function of time. In turn, this relaxation curve waspredicted through the creep test. Consequently, the master creep compliance curve and the master relaxation curve wereobtained using the Prony series and the theory of viscoelasticity. Then, the constitutive model for uniaxial stress-strainbehaviour was presented and it was shown that the model provides a satisfactory characterization of the mechanicalbehaviour of asphalt concrete under uniaxial loading. The theoretical model was used to predict fatigue performance inasphalt concrete by means of a fatigue curve, which present a smaller slope compared to the conventional curves. Withinthe range of tensile strains analyzed, this curve presents higher values of number of repetitions to failure, indicating a betterfatigue resistance.

CUSTOMER SERVICING IN THE BRAZILIAN HOUSE-BUILDING INDUSTRY Page 23-32 Carlos Formoso, Margaret Jobim Abstract  PDF (771KB)  PDF (771KB) Abstract Despite the growing awareness of the strategic importance of consumer satisfaction, most house building companiesdo not manage the customer servicing process in a systematic way. This paper describes a model for the customerservicing process that was developed for small sized companies involved in developing and building housing projects.The model integrates the main functions involved in customer servicing throughout the project life cycle, from the stageof project inception to the delivery and the operation of the building. The research involved five case studies carriedout in the South of Brazil. The main functions involved in the model are discussed, emphasising the task of measuringcustomer satisfaction. Some of the tools and procedures devised for systematic data collection are briefly described. Atthe end, a short discussion on possible ways to further improve customer servicing in the building industry ispresented.

INFLUENCE OF FINES ON SELF COMPACTING CONCRETE PROPERTIES Page 40-46 Carlos Aguilar R., Hugo Barrera V. Abstract  PDF (260KB)  PDF (260KB) Abstract The main objective of the investigation was to study the influence of different types and amount of fines on the selfcompactingbehavior and mechanical properties of this concrete type. It was analyzed 6 types of fine in different amount,two with cement properties. Also, the admixture amount was analyzed in order to optimizing the mix proportions.To characterize each concrete type was carried out a complete analysis of concrete making materials andnormalized tests of fresh concrete, air content and fresh density. Moreover, the tests recommended in the technicalliterature to determine the self-compacting properties was realized i.e. slump flow test and L box. The compression concretestrength was measured in cubic specimens at 3, 7 and 28 days.It was conclude that the main characteristics of fine that influence the self-compacting concrete properties are thefines specific surface and fine shape. Therefore, the quantity of fine that should be incorporated into the concrete dependson the magnitude of these properties.

RATIONAL METHODOLOGY FOR ESTIMATE DAMAGES IN NEW ROADWAYS AND REHABILITATION OF FLEXIBLE PAVEMENT Page 48-59 Fredy Reyes, César González, Diana Vega Abstract  PDF (689KB)  PDF (689KB) Abstract By resorting to rational methodology it is possible to predict any future distress affecting roadways with asphaltmixtures, permitting the planning of a maintenance policy. This policy is based on: a more exact knowledge of all thefactors affecting the roadway, both at its initial stage and over years; a systematic measurement of different characteristicpercentages during its use and throughout its lifetime; the definition of priority classification criteria; prioritizing them withrespect to any intervention. To prepare this systematic maintenance plan using the numerical modelling of Rationalmethodology, the following data are needed: a knowledge of mathematical modelling of pavement and the materials, basedon elastic modules and fatigue methods; visual auscultation of the roadway to quantify the degradations or the use ofGERPHO, the analysis of the pavement’s traffic load, based on determining its aggressiveness and its equivalence to anumber of axles of reference; and the structural diagramming of the pavement so as to calculate the theoretical risk it isexposed to considering its future traffic load.