Dr. Nuñez-Castellanos, Eduardo

BIM models are seldom used for the energy certification of buildings. This paper discusses the advantages of linking two important fields: building information modeling (BIM) and building environmental assessment methods (BEAM), presented as a rating system and a proposal for the Chilean context. The state of the art in both fields around the world is discussed, with an in-depth examination of current BIM software and related applications, followed by a discussion about previous research on integrating them. A lack of interoperability and data losses between BIM and BEM were found. A new tool is presented that addresses these challenges to ensure accurate rating system data, and this new framework is based on database exchange and takes crucial information from BIM to BEAM platforms. The development of the method includes BIM programming (API), database links, and spreadsheets for a Chilean building energy certification through a new tool, also applicable to multiclimactic zones. This new semi-automatic tool allows architects to model their design in a BIM platform and use this information as input for the energy certification process. The potential and risks of this method are discussed. Several improvements and enhancements of the energy certification process were found when incorporating this new framework in comparison to current methodologies.

In this research the seismic performance of eccentrically braced frames (EBF) with short links using Chilean earthquakes is studied. The study includes nonlinear static and dynamic analyses, calibration of numerical link models with experimental studies, and over 15,000 models analyzed. Results show that higher ductility and deformation are obtained in most archetypes, while models with 8 stories exhibit more stiffness and less ductile behavior. Furthermore, the strength capacity and ductility increase with the increment of the seismic zone and soft type of soil. Moreover, the research provides a table with the seismic design parameters for each archetype group comparing these values with Chilean seismic specifications. Finally, the study concludes that structures designed with more strength and stiffness have a lower collapse probability under extreme events. This research provides valuable information for structural design and includes fragility curves and a discussion of results that can be applied to structural design.

Concrete strength assessment is an important topic in evaluating existing structures. Formerly, only destructive tests were employed, limiting the number of tests due to their complexity and cost. Nowadays, the application of non-destructive tests has been booming to determine material strength, offering a more accessible and cheaper strategy than its counterpart. Non-destructive strategies are based on two steps: (1) the identification of the correlation between the concrete strength and another parameter that is easy to measure in situ, and (2) the use of this easy-to-measure parameter to infer the concrete strength in any desired element of the structure. The most common parameter adopted for this purpose is the Ultrasonic Pulse Velocity (UPV). However, the correlation between concrete strength and UPV must be determined via destructive experiments. From the research perspective, attention has focused on determining the correlation coefficient and the range of credibility for estimating the inferred concrete strength. Despite it, this strategy has remained elusive in the fundamental understanding and accounting of the joint dispersion of the concrete strength and the UPV. The present work addresses this knowledge gap by proposing a new correlation method based on probability interpretations to infer the compressive concrete strength from in-situ UPV measurements and including the dispersion evidenced in UPV measurements in both steps mentioned. The results demonstrated that it is possible to determine the confidence interval for the concrete compressive strength given a certain percentile of the UPV measured in situ. Finally, the application of the proposed method is illustrated through a case study, which is representative of different building pathologies. This novel proposal is a foundation to deal with the uncertainties involved in non-destructive tests, inspiring future advances in this field.

The behavior of the web panel zone has a direct effect on the cyclic performance of steel moment connections. While the mechanisms of web panel zone failure are known under cyclic load, little is known about the behavior of the web panel zone under bidirectional loads in bolted connections. Using experimental tests and calibrated numerical models, this research evaluated the web panel zone behavior under unidirectional and bidirectional cyclic loads. The results showed that bidirectional load can modify the stress and strain distribution in the web panel zone. Moreover, the increasing of the width-to-thickness ratio of the column influences the failure mechanism of the joint configuration and increases the plastic incursion in the column. These data demonstrate that bidirectional effects improve the web panel zone performance under cyclic loads.

The Soil–Structure Interaction (SSI) effect has been widely evidenced during several earthquakes around the world. In the Venezuelan context, the seismic event in Caracas in 1967 showed the significant consequences of designing buildings without considering the SSI effect. Nevertheless, limited research on the seismic performance of concrete moment frames (commonly used as structural systems in office and residential buildings in Venezuela and Latin America) considering the SSI effects has been developed, although there have been continuous updates to the Venezuelan Seismic Code. In this research, the influence of the SSI on the seismic performance of RC moment frame buildings designed according to the New Venezuelan Seismic Code was studied. An extensive numerical study of 3D buildings using concrete moment frames supported by mat foundations on sandy and clayey soils was performed. The response spectrum method, non-linear static analysis, and non-linear dynamic analysis were used to assess the seismic response of the archetypes studied. The results show that SSI effects can have a significant impact on the seismic response of RC moment frame buildings, increasing the interstory drift ratio and decreasing the shear forces. As is shown in fragility curves, the probability of collapse increases for cases with flexible bases in comparison to the cases of models with fixed bases. Additionally, in the 24-story archetype, the fixed-base model reached a maximum probability of collapse. Finally, a new proposal for the reduction of the strength-reduction factor (R) must be incorporated into the Venezuelan Seismic Code to improve the safety of the structures. Limitations in the use of RC moment frames must be incorporated for high-rise buildings since, as the present work demonstrates, for high-period structures, the normative provisions are not reached.