Análisis no lineal de la estructura del Hospital Darío Machuca Palacios del cantón La Troncal en Ecuador

The hospital "Darío Machuca Palacios" is located in La Troncal (Cañar-Ecuador). In the nonlinear dynamic analysis of this hospital was determined inconsistencies in its design, such as non-compliance with maximum permissible drifts established by the Ecuadorian Construction Standard (NEC, as per its Spanish acronym), demonstrating vulnerability and possible collapse of the hospital. Considering that it is an essential building according to the NEC of seismic danger, it needs to be maintained in correct post-earthquake operation. For this reason the behavior of the structure with seismic isolation systems at their base was simulated, offering results that analyzed in depth could determine that this measure of seismic protection is adequate.Keywords: nonlinear dynamic analysis, essential building, seismic isolation systems

Effect of substitution of aggregates by thermally treated foundry sand on physical properties of mortars

In the present work, the effect produced by the substitution of the aggregate by waste foundry sand (WFS) on physical properties of mortars was studied, the aggregate was replaced by waste foundry sand (WFS), washed waste foundry sand (WFSL) and thermally treated waste foundry sand (WFST) in certain replacement percentages (15%, 20%, 25%). WFS and its clay obtained by washing (montmorillonite) were characterized physically, mineralogically and thermally, the mortars with WFS and WFSL were evaluated through tests of resistance to compression and capillary suction. The application of a heat treatment to WFS was evaluated by the performance of mortars with thermally treated WFS (WFST) evaluated by means of tests of resistance to compression and capillary suction. The pozzolanic activity and the consumption of calcium hydroxide were also evaluated, in cement pastes containing clay recovered from the WFS wash (Raw Clay) and pastes that also contains clay recovered from the WFS wash, but this clay was applied the heat treatment (Treated Clay) through the thermogravimetric and Frattini test. It was found that the performance of mortars containing WFS and WFSL was satisfactory because WFS and WFSL performed filling spaces and voids, which in turn caused a decrease in the porosity of the mortars causing an improvement in compressive strength. While for the mortars containing WFST the heat treatment had an effect and active on the clay, but this was opaque since the treatment also caused a change in the size of pores, increasing the volume of larger pores in the clay, so which this effect caused the fall in the values of physical properties (compressive strength, capillary suction) in mortars containing WFST.En la presente investigación se estudió el efecto que produce la sustitución del agregado por arena de fundición desechada (WFS) sobre propiedades físicas de morteros, se sustituyó el agregado por arena de fundición desechada (WFS) en su estado natural, arena de fundición lavada (WFSL) y arena de fundición tratada térmicamente (WFST) en porcentajes de sustitución (15, 20 y 25). Se caracterizó física, química, mineralógicamente la WFS y su arcilla obtenida del lavado (Montmorillonita), se evaluaron morteros con WFS, WFSL y WFST mediante ensayos de resistencia a la compresión y succión capilar. Se evaluó la aplicación de un tratamiento térmico a WFS mediante el desempeño de morteros con WFS tratada térmicamente (WFST) evaluados por medio de ensayos de resistencia a la compresión y succión capilar. Se evaluó la actividad puzolánica con base en el consumo de hidróxido de calcio mediante el ensayo termogravimetrico y Frattini, en pastas de cemento que contenian arcilla recuperada del lavado de WFS (Arcilla Cruda) y pastas que también contiene arcilla recuperada del lavado de WFS, pero a esta arcilla se le aplicó el tratamiento térmico (Arcilla Tratada). Se encontró que el desempeño físico de morteros que contiene WFS y WFSL fue satisfactorio debido a que WFS y WFSL actúa rellenando espacios vacíos esto a su vez provoca una disminución en la porosidad de los morteros ocasionando una mejoría en la resistencia a la compresión. Mientras que para los morteros que contienen WFST tiene una gran demanda de agua lo cual ocasiona un aumento de la ITZ a más de esto, el tratamiento térmico tuvo efecto y activó a la arcilla, pero esto se vio opacado ya que el tratamiento también provocó un cambio en el tamaño de poros, incrementando el volumen de poros mayores en la arcilla, por lo cual estos efectos de gran demanda de agua y aumento de volumen de poros, ocasionaron la caída de los valores de propiedades físicas (resistencia a la compresión, succión capilar) en los morteros que contenían WFST.Maestrí