Desempeño a largo plazo de secciones de pavimentos existentes de concreto con cemento tipo Portland – estudio de caso

RESUMEN: La presente investigación presenta el desempeño de diecisiete pavimentos rígidos hechos de Concreto con Cemento Portland (PCC) localizados en el Estado de Ohio, USA. La metodología de ensayos con el Deflectómetro de Impacto (FWD) se usó en un total de 58 km de secciones de pavimentos PCC para evaluar la condición estructural del pavimento. Cada sección se clasifica como excelente, buena, regular o deficiente basado en los parámetros de deflexiones normalizadas obtenidas de los ensayos FWD, deformabilidad, transferencia de carga y relación de soporte de las juntas. El desempeño global de las secciones analizadas está entre bueno y excelente. La metodología de ensayo de campo, junto con los análisis de datos del desempeño presentados en esta publicación, son una herramienta valiosa para evaluar la condición estructural actual de pavimentos y como resultado proponer planes de rehabilitación a corto o mediano plazo que garanticen el buen funcionamiento del pavimento.ABSTARCT: This paper presents the performance of seventeen rigid pavements made of Portland Cement Concrete (PCC) located in the State of Ohio, USA. The Falling Weight Deflectometer (FWD) testing method was used in a total of 58 km of PCC pavement sections to assess the pavement structural condition. Each section is classified as excellent, good, fair, or poor based on the normalized deflections obtained from FWD tests, spreadability, load transfer, and joint support ratio parameters. The overall performance of the analyzed sections is from good to excellent. The field testing methodology along with the performance data analyses presented in this publication are a valuable tool to evaluate the actual structural condition of pavements and as a result short or medium term rehabilitation programs can be issued to ensure the serviceability of the pavement

Desempeño a largo plazo de secciones de pavimentos existentes de concreto asfáltico

RESUMEN: Los pavimentos de carreteras están diseñados para soportar las cargas proyectadas del tr·Æ co y a la vez proporcionar alta calidad para los niveles de servicio. Las grandes cargas que los pavimentos experimentan durante su existencia en conjunto con las condiciones variables de clima y humedad aceleran el proceso de deterioro y podrían causar fallas prematuras a los pavimentos. En esta investigación se realiza un estudio de patología para evaluar el desempeño actual de varios concretos asfálticos. La condición estructural de secciones de concreto asfáltico, localizados en el Estado de Ohio, Estados Unidos, se realizan por medio del método de ensayo del DeØ ectómetro de Impacto (FWD). La interpretación de los ensayos con FWD permite la evaluación de potenciales rehabilitaciones a corto y mediano plazo. La metodología de análisis e interpretación de resultados presentados en este artículo para el caso de los 110 km de pavimento de concreto asfáltico en el Estado de Ohio, se muestra como una técnica valiosa en el caso colombiano para determinar, con mediciones reales de campo, la condición y potencial rehabilitación del sistema de infraestructura que se requiere para garantizar el desarrollo económico sostenible del país.ABSTRACT: Highway pavements are designed to withstand the projected trafÆ c loads while providing a high quality level of service. The large loads that pavements experience during the design life in conjunction with variable climate and moisture conditions accelerate the deterioration process and might cause premature failure of the pavements. In this research, a forensic study to assess the current performance of several asphalt concrete (AC) pavements is conducted. The structural condition of the AC sections, located in the State of Ohio, United States, was determined by means of the Falling Weight DeØ ectometer (FWD) testing method. The evaluation and interpretation of the FWD tests permit the assessment of potential short or medium-term rehabilitation projects. The methodology of analysis and data interpretation presented in this paper for the case of 110 km of asphalt concrete pavement in the State of Ohio, stands as a valuable technique in Colombia to determine, with actual Æ eld measurements, the condition and potential rehabilitation of the infrastructure system that is required to guarantee the sustainable economic development of the country

Performance, instrumentation and numerical simulation of one museum park west excavation = Desempeño, instrumentación y modelación numérica de la excavación del edificio “One museum park west”

The excavation for the 53-story reinforced concrete One Museum Park West building (OMPW) in Chicago was constructed using combined support systems. The building was supported by caissons and a perimeter wall formed by secant piles which transitioned to tangent piles below the bottom of the cut. After installing the perimeter wall and deep foundations for the building, the excavation for the reinforced concrete central core was supported by a circular cofferdam made of sheet piles and steel ring beams. This excavation was made using conventional bottom-up excavation techniques. The excavation for the rest of the building was made using a top-down method and was laterally braced with reinforced concrete floor slabs structurally connected to the secant pile walls and the reinforced concrete core. Field performance data during construction of the OMPW basements were collected with settlement points, inclinometers and strain gages installed in the concrete basement slabs. Significant settlements were observed adjacent to the excavation during wall and deep foundation installation, central core construction and top-down excavation. The influence of concrete material time-dependence of the floor slabs on the performance during top-down excavation is evaluated and a method for the separation of temperature-related strains from the excavation-induced strains in the concrete is described. The construction of the basements is simulated with a 3D numerical structural model to study the influence of the concrete material time-dependence of the floor slabs in the excavation-induced movements resulting from top-down construction. Computed strains in the floor slabs are compared with the observed performance data collected from the strain gages. For use in numerical simulation of the entire excavation process, hypoplasticity constitutive parameters for clays (HC model) at the element test level were calibrated with tests conducted on high quality block samples obtained from the excavation of Block 37 project in Chicago. They included oedometer tests, bender element measurements, and triaxial tests following different stress probes, and were further refined with seismic cone penetration results.  The entire OMPW excavation is simulated with the calibrated parameters with a fully coupled-flow deformation, three-dimensional finite element model. Influence of the construction of secant pile walls, concrete material time-dependence, and nonlinear concrete behavior of the perimeter pile walls on the performance of the OMPW excavation is determined. Conclusions about top-down construction are drawn in light of the measured and simulated performance of the OMPW excavation