The primary method of public sector project delivery in the United States (U.S.) has traditionally been design-bid-build delivery. The public sector has historically separated design and construction contracts. In the 1990s, the U.S. public sector began to experiment with design-build project delivery, which combines design and construction in one contract. In 1997, a decision support system was developed to provide a formal selection model for public sector design-build projects. The model supports public owners in determining which projects are appropriate for design-build delivery. This initial model was static in nature and was based on a regression analysis of 104 projects. The analysis resulted in a predictive model with five performance criteria: overall satisfaction; administrative burden; conformance to expectations; schedule variance; and budget variance. Since 1997, the number of design-build projects has increased dramatically and public sector design-build methods have evolved. The original model can be improved with new data and a new framework to provide for an adaptive model as the industry continues to evolve. This paper presents a formalized application and use of learning capabilities to supplement the original static model. This model adjusts parameters and functions using artificial intelligence as the main knowledge engine. This approach can be adapted to many applications of decision support in the design and construction industry.

Rev. ing. constr. [online]. 2010, vol.25, n.1, pp. 5-20. ISSN 0718-5073.  http://dx.doi.org/10.4067/S0718-50732010000100001

The Project “MAR VASTO” (“Risk Management in Valparaíso”), http://www.marvasto.bologna.enea.it) has been financed by BID (“Banco Interamericano de Desarrollo”). It started in March 2007 and ended in October 2008. It has been managed by ENEA (Italian Agency for New Technologies, Energy and Sustainable Economic Development). The project saw the participation of Italian (Universities of Ferrara, Padua and Trieste) and Chilean (University Federico Santa Maria, in Valparaiso, and University of Chile, in Santiago) partners, and the support of local stakeholders. Being the city declared patrimony of the humanity by, UNESCO in 2003, the following main outcomes have been achieved: to evaluate the impact of main hazards (earthquake, tsunami, fire, and landslide); to provide a vulnerability analysis for three historical churches San Francisco, Las Hermanas de la Divina Providencia, La Matríz, comprised of various materials (masonry, concrete, wood, and adobe) and located in different city areas); to carry out an architectural and vulnerability analysis for a pilot building stock in the Cerro Cordillera historic area; to suggest guidelines for future urban planning; and to develop a GIS digital data base (well organized, user-friendly and easy to be implemented in the future), providing hazard maps and scenarios. The paper summarizes some final results, taking into account the in situ work of missions at Valparaíso (May and October-December 2007) and the “MAR VASTO” public final conference (September 2008), where all the above said activities have been presented.

Rev. ing. constr. [online]. 2010, vol.25, n.1, pp. 21-62. ISSN 0718-5073.  http://dx.doi.org/10.4067/S0718-50732010000100002

This document contains a methodology to assess the level of damage that buildings with reinforced concrete wall structural system may reach. The model estimates a vulnerability rate calculated in function of structure characteristics that most influent a seismic behaviour, and relates this value to a damage rate, which, in turn, depends on the action of seismic movements. The model estimates different levels of vulnerability and, consequently, defines different damages produced the same action. The vulnerability / damage ratio is materialized to vulnerability function in a continuous manner. The model was constructed on a sample of real and hypothetical buildings representing the most relevant characteristics of this type of buildings in Colombia.

Rev. ing. constr. [online]. 2010, vol.25, n.1, pp. 63-82. ISSN 0718-5073.  http://dx.doi.org/10.4067/S0718-50732010000100003

Laboratory tests were used to evaluate the effect on the mechanical properties of a hot asphalt mix (MDC-2 as per INVIAS, 2007 specifications) due to the addition by wet way of a residue of low density polyethylene (LDPE). The strength under monotonic load, resilient modulus, rutting and fatigue strength were evaluated. Asphalt cement (AC) AC 80-100 was used from Colombia. The results show that the monotonic and cyclic mechanical strength evaluated were higher for the mixes modified with LDPE compared with mixtures with asphalts without additives. However, the mixes modified with LDPE undergo less fatigue strength. Additionally, characterization tests were conducted on asphalt cement with and without additive. The LDPE produces higher penetration resistance and viscosity, and lower thermal flow susceptibility.

Rev. ing. constr. [online]. 2010, vol.25, n.1, pp. 83-94. ISSN 0718-5073.  http://dx.doi.org/10.4067/S0718-50732010000100004

Presented of illustrated form the application of the method of distribution of  orizontal:PPG modified. The method is applied at a building of six levels, whose lateral stabilizers are integrated for shear walls and frames distributed in plant of asymmetric form. The shear walls are from rectangular section and section canal, so that this building proves to be sufficiently simple in its structural conception. This makes possible that the analysis of the distribution of lateral forces may take effect utilizing the models and the methodology of calculation of the mentioned method. At a later time establish its numerical results of the plane and space behaviour of stabilizers in terms of forces and displacements, to evaluating the influence of the effect of the moment flexotorsor in the shear walls of section canal. Finally compare these results with the obtained ones belonging to space analysis of the building utilizing the method of the finite elements supported by the computer midways, becoming established the advantages of the method modified PPG.

Rev. ing. constr. [online]. 2010, vol.25, n.1, pp. 95-120. ISSN 0718-5073.  http://dx.doi.org/10.4067/S0718-50732010000100005

This paper presents the simulation of discreet events as a tool for the planning and the analysis of construction projects based on a case study of the constructive process of a reinforced con-crete structure that includes the foundation, pedestals, beams, a slab and columns. Initially a field work was carried out to register duration, resources and delays for each activity. Based on this information a simulation model in the software Arena was developed. The sequence of the activities, probability dis-tribution functions defined for the processes and the resources used were included for each activity. The model works through an interface with Microsoft Excel and macros developed in Visual BASIC, through which the user can easily introduce the input data. The simulation controls the duration of ac-tivities, use of resources and consumption of materials. This integration of tools allows simulating dif-ferent project scenarios permitting to analyze improvement opportunities assigning different attributes to the variables that affect the project such as activities begin date, availability of resources and materi-als, among others.

Rev. ing. constr. [online]. 2010, vol.25, n.1, pp. 121-141. ISSN 0718-5073.  http://dx.doi.org/10.4067/S0718-50732010000100006