Volume 8Enero - Diciembre 2018

Alejandro Navas Carro, Ana María Campos Rojas (Author)

Influence of Lime in Bond Masonry Mortar

• PDF (Spanish)

In this research it was studied the mortars for block pasting, fabricated in situ and the effects in their physical and mechanical characteristics by adding lime to the mix. For this, were made mortars type M and type S with and without lime, using the volumetric proportions that the Seismic Code of Costa Rica 2010 (CSCR 2010) says. It was used quarry sand and industrial sand like fine aggregate, separately. Testing compressive strength was conducted in mortar cubes at 7 and 28 days, also percentage of water retention, air content and workability were tested. Also, masonry prisms and “crosses” were made for compressive strength and bond test, respectively. All this, to determine if the use of lime produced in this country improves the properties of the bond masonry mortar, because this could reactivate in Costa Rica the use of lime in the Industrial construction.

Tests were made with 3 different limes, and the results change depends on the lime used. But in general, the lime improves some properties like water retention, workability and bond, and in some cases increases prisms resistance. Conversely, compressive strength in mortar cubes decreases and the air content wasn’t affected.

Sergio Lobo Aguilar, Richard E. Christenson (Author)

A SimplifiePesaje simplificado de vehículos en movimiento basado en mediciones de deformaciones unitarias cortantes para puentes en serviciod Shear-Strain Based Bridge Weigh-In-Motion Method For In-Service Highway Bridges

• PDF (Spanish)

Bridge Weigh-In-Motion (BWIM) has been demonstrated to be reliable for obtaining critical information about the characteristics of trucks that travel over the highways. Continued improvements provides greater opportunity for increased use of BWIM. Traditional BWIM systems based on measuring the bending strain of the bridge have various challenges which has led to a class of BWIM methodologies that employ the use of shear strain in determining the gross vehicle weight (GVW) of crossing trucks. However, the known techniques of these shear-strain BWIM methods assume or measure the shear influence line for the calculation of the GVW. In this paper, an alternative shear-strain based BWIM technique is proposed. The method presented here is independent of the influence line, does not require a measurement of the speed of the truck, and is based on the difference in magnitude observed at the discontinuity of the shear strain record as a truck crosses over the sensor location on the bridge. A series of field tests is presented that demonstrate this shear-strain based BWIM method has error levels consistent with other more complex BWIM methods and as such has great potential to be used for determining the GVWs of trucks that travel on simple or multispan bridges in a consistent and reliable manner.

Jorge Omar Cruz Toribio, José Wilfredo Gutierrez Lazares (Author)

Pavement Surface Evaluation of Urban Roads using an Unmanned Aerial Vehicle (UAV)

• PDF (Spanish)

This research paper presents an alternative methodology for the surface evaluation of pavements on urban roads, using georeferenced images obtained by an unmanned aerial vehicle (UAV) that are processed by generating an orthophoto and a high-resolution 3D digital model. The analysis of the generated products allows the total inspection of the pavement in a safe way, identifying the type of deterioration, its severity and its damaged density, as parameters and inputs to use the Pavement Condition Index (PCI) Method. The results obtained in a test track show that the VANT method collects data in a safer way, allows more informative plans with reliable values and avoids accidents of the technical staff in comparison with the traditional method. This research innovates an alternative procedure to evaluate pavements periodically in order to establish strategies for maintenance and rehabilitation of urban roads. 

Sergio Gabriel Álvarez González (Author)

Comparison between Techniques of Computational Modeling of Wall-Type Buildings

• PDF (Spanish)

This paper compares the application of different computational modeling techniques of wall-type buildings; specifically, the following modeling methodologies were studied:

1. Modeling through frame type elements with rectangular cross-section
2. Modeling through frame type elements with irregular cross-section
3. Modeling through shell type elements

In order to apply each modeling techniques to different buildings, the structural analysis software called ETABS was used. In which a spectral dynamic analysis of each one of these models was carried out, with which a results matrix was created that allowed comparing and discussing the different global structural responses that can be obtained for the same building when a linear analysis is carried out using different modeling techniques. From this comparison, it is concluded that in general, the models composed of frame type elements with a rectangular cross-section and the models made with area type elements show similar behaviors, so that wall-type buildings of up to 30 levels could be modeled with both methodologies without significant differences in structural responses (periods, seismic forces at the base of the structure and drifts). On the other hand, models made with frame type elements with irregular cross-section presented significant differences for these same responses.