Abstract: Assessment of the residual strength of reinforced concrete buildings subjected to fire is a problem that requires fast and sufficiently reliable resolution, necessary for the action of firefighters, forensic fire investigation, and structural assessment of post-fire condition of the building to take place. In all cases safety and integrity of firefighters and researchers can be at risk, and it is necessary to have rapidly and sufficiently reliable information in order to choose whether to enter freely, to enter with caution, or simply do not enter to the burned structure. This required prompt assessment gives no time or background to develop mathematical models of the structure and damage propagation. This work presents an experimental methodology for a fast assessment of post-fire residual strength of reinforced concrete frame buildings based on the high correlation between the loss of strength and non-destructive test results of frame concrete elements subjected to fire action. (C) 2019 Elsevier Ltd. All rights reserved.

Abstract: This paper presents a strategy for modelling dynamic soil-structure interaction (DSSI) using the spectral element method (SEM) with a Discontinuous Galerkin approach, calibrated by micro-vibrations. The proposed methodology allows not only to adjust the vibration frequencies of the structure but also the observed vibration modes. First, models of two structural shear wall buildings with basements in medium dense sandy soils are developed to estimate empirical modal characteristics and calibrate the structural subdomain and low-strain site properties. Convenient 3D arrays of multiple seismic sensors are used to obtain the environmental vibrations measurements. Afterwards, an optimization process is conducted to calibrate volumetric models of structures. This optimization is performed by preserving the most relevant modal frequencies and shapes to achieve an equivalent dynamic response. Finally, structural models are placed into a neighbouring soil model (soil subdomain), approximating nonlinear soil behaviour by an equivalent linear strategy. Using this complete soil-structure interaction model, relevant engineering performance parameters are assessed via simulations of buildings subjected to a plane wave excitation. The results show the significant effect DSSI have in shear-wall buildings with basements and the importance of considering the flexibility of the foundation in the interpretation of the results. In general, results indicate that DSSI effects are strongly dependent on the input frequency content, which might cause a reduction of the inter-story drifts. Furthermore, a significant period lengthening of the studied structures up to 47% is found, as well as a considerable decrease in story shear up to 220% and a maximum lateral roof displacement reduction of 34% when compared against fixed base referential responses.

Abstract: Chile presents a social housing deficit that needs to be addressed with solutions that increase habitability and environmental benefits. This paper addresses the benefits of implementing earthbag buildings as an option to mitigate the existing social housing deficit in Chile. A literature review presents details on the use of earthbag buildings around the world, and motivations and obstacles for implementing earthbag buildings in Chile. In particular, a case study was simulated to compare an earthbag social house to a reinforced brick masonry social house in terms of environmental and economic performances such as CO2 emissions, energy and costs. It is concluded that both alternatives generate similar CO2 emissions, but the earthbag social house can save up to 20% of energy during its life cycle. In economic terms, the earthbag social house generates savings of 50% and 38% for initial investment and life cycle cost, respectively, compared to the reinforced brick masonry social house. The implementation of earthbag social housing projects would be encouraged by the development of a Chilean building code for earthbag design that provides guidance on the safe use of this technique in a seismic country.

Abstract: In Chile, office buildings are typically reinforced concrete (RC) structures whose lateral load-resisting system comprises core structural walls and perimeter moment frames (i.e., dual wall-frame system). In the last 20 years, nearly 800 new dual wall-frame buildings have been built in the country and roughly 70% of them have less than ten stories. Although the seismic performance of these structures was deemed satisfactory in previous earthquakes, their actual collapse potential is indeed unknown. In this study, the collapse performance of Chilean code-conforming mid-rise RC buildings is assessed considering different hazard levels (i.e., high and moderate seismic activity) and different soil types (i.e., stiff and moderately stiff). Following the FEMA P-58 methodology, 3D nonlinear models of four representative structural archetypes were subjected to sets of Chilean subduction ground motions. Incremental dynamic analysis was used to develop collapse fragilities. The results indicate that the archetypes comply with the 'life safety' risk level defined in ASCE 7, which is consistent with the observed seismic behavior in recent mega-earthquakes in Chile. However, the collapse risk is not uniform. Differences in collapse probabilities are significant, which might indicate that revisions to the current Chilean seismic design code might be necessary.

Abstract: This article investigates the feasibility of achieving higher performance from ground-source heat-pumps (GSHP) in space heating mode through the use of solar thermal collectors. A novel simulation tool for solar-assisted ground-source heat-pumps (SGSHP) is presented with an analysis of the influence of solar collectors on the improvement of heat pump performance. Solar radiation and climate temperature data of 19 European cities were used to perform simulations of SGSHP and GSHP systems considering a typical residential house. Overall performance coefficients (COPsys) varied from northern to southern locations between 4.4 and 5.8 for SGSHP and between 4.3 and 5.1 for GSHP. Results show that solar collectors coupling has more impact on performance improvement in regions that benefit from higher irradiance. However, greater running cost savings are achieved in milder climate conditions. Both heat-pump systems are able to effectively contribute to carbon footprint reductions for residential buildings, especially in countries where fossil fuels are the primary source of electricity generation. SGSHP payback periods are found between 8.5 and 23 years from northern to southern localities, making such heating system an economic heating option. SGSHPs are best suited for high irradiance and cool climate locations such as the mountainous regions in southern Europe. (C) 2015 Elsevier Ltd. All rights reserved.

Abstract: This research compares the building energy consumption and the photovoltaic economic analysis between residential buildings in Santiago de Chile and Santo Domingo of the Dominican Republic. The methodology considered thermal simulation, sizing of a solar PV system, an economic analysis and CO2 emissions given the solar resources of both countries. A scenario where the constructive systems are switched between the countries was also analyzed. A comparison of the energy performances of the houses exposed to other climate conditions. Results show that housing in Santiago de Chile required less energy than housing in Santo Domingo due to the fact that the thermal transmittance of the enclosures of the Chilean housing has better thermal behavior, compared to the materials of the Dominican housing. Dominican houses need a higher amount of electricity for air cooling due to the high temperatures in the tropic. Meanwhile, Chilean countries requires a higher amount of gas for heating purposes. The Dominican Republic lacks thermal regulation for construction material, and applying Chilean standards in Dominican houses, helped to lower the yearly electricity demand by 19%. Dominican constructions materials improvement could have an important impact in the country's overall goal to lower CO2 emission and in-house energy savings. The economic analysis showed that the Dominican Republic renewable energies incentives contribute to the development of very attractive PV projects, meanwhile in Chile, the use of net metering instead of net billing could increase by 11 times the net present value of PV projects.

Abstract: To reduce the energy consumption in buildings, there is a demand for tools that identify significant parameters of energy performance. The work presents the development and validation of a simulation model, called MEEDI, and graphical figures for the parametric sensitivity investigation of energy performance in different climates in Chile. The MEEDI is based on the ISO 13790 monthly calculation method of building energy use with two improved procedures for the calculation of the heat transfer through the floor and the solar heat gains. The graphical figures illustrate the effects of climate conditions, envelope components and window size and orientation on the energy consumption. The MEEDI program can contribute to find the best solution to increase energy efficiency in residential buildings. It can be adapted for various parameters, making it useful for future projects. The economic viability of specific measures for building envelope materials was analysed. Payback periods range from 5 to 27 years depending on the location and energy scenario. The study illustrates how building design decisions can have a significant impact on final energy performance. With simple envelope components modification, valuable energy gains and carbon emission reductions can be achieved in a cost-effective manner in Chile.

Abstract: When modeling RC shear wall buildings for seismic analysis there is little consensus in the literature on the appropriate value of the wall effective shear stiffness (GA(eff)) and the slab effective bending stiffness (EIeff). A probabilistic analysis based on fragility curves is a robust technique to assess the influence of these parameters on the expected seismic performance, but such studies are scarce because they require computationally expensive analysis such as Incremental Dynamic Analysis (IDA). In this paper, fragility curves are developed following the recently introduced SPO2FRAG procedure, a simplified methodology that does not require IDA but the computationally more affordable incremental static (pushover) analysis. The fragility curves provided by SPO2FRAG are used to evaluate the influence of the values of GA(eff) and EIeff on the analytical seismic response of full 3D nonlinear models of two actual (and representative) residential wall buildings of 17 and 26 stories located in Santiago (Chile). The accuracy of SPO2FRAG is also evaluated through comparisons with empirical fragilities.