The interest in the application of “lean” concepts in the construction industry is growing, but gaps are still found in the implementation of the concepts

and tools into different processes involved in construction; such as, on site production and assembly of precast elements. This research aims to seek

improvement opportunities on site production and assembly management of concrete precast elements using lean thinking principles and tools as references.

For this purpose, a Stream Value Map was design, using as generic process the production and assembly of the Tilt-Up system, base on projects followed

by the authors and recommendations of the system practitioners. Next, a Future State Map was drawn, identifying changes in the process management,

incorporation lean concepts. The results show that the SVM is a reliable tool for the diagnosis of losses, and the correct allocation of lean tools to improve

the process as a whole. Finally, the possible improvements were identified, followed by the necessary lean tools for the implementation.

This investigation presents the results of the inspection performed on the Pajaritos Bridge as part of the activities for the Mexican bridge infrastructure

evaluation project denominated National Plan for Bridge Corrosion Evaluation. This plan considers the evaluation of structural integrity of approximately

10000 bridges in the federal highway network. In this evaluation the following activities were performed: 1) A thoroughly visual examination; 2) A detailed

inspection in two steps: a) Photographic and damage surveys; b) Mechanical, chemical and electrochemical testing; 3) A structural survey; 4) Results analysis

and recommendations. It was found that the bridge deck was in need of major repairs and the bridge required the implementation of a cathodic protection

system. All of the above made the bridge rehabilitation financially unfecesible, so it was recommended to tear down the bridge and to rebuild a new one.

It was recommended that the new bridge design was based on durability requirements.

Construction industry has a multiplier effect on the economy of each country. Within the construction industry, residential building is the most important:

e.g., in Spain, there were 687,000 new residential units built in 2004, which represent 33% of production in construction industry; these figures correspond

to 6% of the Gross National Product. The reasons for this boom are: low interest rates, increase of family incomes, demand from immigrants, changes in

family structure, perception of housing as an attractive investment alternative, and demand for tourist housing. In Spain, housing prices increased more

than in any other country of the European Union during last years. Our work analyzed statistically this evolution and its causes. Thirty three variables were

used and a correlation matrix was obtained. It was found that the main explanatory variables were: population growth, income levels, interest rates, and

the progressive involvement of the country in the European Union. Spain belongs to the Euro zone, which implies a tendency to standardize the economy

of the eleven countries that embrace it; the average income per capita of the Euro zone is higher than that of Spain, thus a smooth leveling is unavoidable,

even in the housing market. This economic globalization influences the housing prices evolution through financial markets, migratory and tourist movements,

and urban growth.

Recycled aggregates, such as the ones used in making the sub-base and base layers of roads and the ones used as replacement of natural aggregates in

concrete production, may give an important contribution towards decreasing the negative consequences that production and dumping of construction and

demolition waste nowadays impose on the environment. Within the research work being carried on at Instituto Superior Técnico (IST) in Lisbon, the results

of an experimental research project are presented in this article. Its main purpose was to demonstrate the technical sustainability of multiple recycling of

coarse stone aggregates originally obtained from the demolition of existing concrete elements to make new concrete with no further consumption of any

coarse natural aggregates. The results, in terms of compression strength and workability, show that concrete produced after multiple recycling of aggregates

has approximately the same characteristics as the one obtained after only one cycle, thus proving that the process can be reproduced with no further

limitations.

This paper analyzes the role of construction site supervisors, including foremen and general foremen, as front-line managers. The role is treated as a critical

labor function and a source of value-added for construction management. An original model based on the labor competency management framework is

proposed for training, developing and certifying construction supervisors in Chile and other developing countries. This model was developed from the

findings of a case study in which the competency framework was applied to a specific construction company. The main conclusion of this work is that the

application of the competency approach might help to greatly improve the human resource management function in construction companies as well as

the site performance of their personnel. The application of this model may help to improve the human resource function in construction companies, as

well the performance on their projects. New applications of this model allow for its adjustment and validation.

Technological innovations in the industry of chemical admixtures for construction materials as concrete, specifically of the superplasticizers, make possible

the development at the end of the eighties, of a revolutionary concrete capable of auto consolidating, being commonly designated as Self-consolidating

Concrete – SCC. The characteristic of the self compacting concrete is its ability to fill completely and without segregation the shape of formwork and get

consolidation without need to apply vibration energy. In this research different procedures of mixtures design and existing equipments to evaluate self

compacting concrete mixtures were analyzed. The obtained results allow to propose an effective evaluation and control criteria of the requirements of auto

consolidation of self compacting concrete mixtures. This research is aimed to develop a design methodology for self compacting concrete mixtures following

a sequential design procedure. First, to obtain an optimum dosage of chemical admixture to saturate the cement paste, then, to evaluate concrete mixtures

with different proportions of coarse and fine aggregates, and finally, testing and measuring the different basic properties of the SCC in plastic state.