Design and Performance Verifcation of Ultra-High Performance Concrete Piles for Deep Foundations Final Report, November 2008

The strategic plan for bridge engineering issued by AASHTO in 2005 identified extending the service life and optimizing structural systems of bridges in the United States as two grand challenges in bridge engineering, with the objective of producing safer bridges that have a minimum service life of 75 years and reduced maintenance cost. Material deterioration was identified as one of the primary challenges to achieving the objective of extended life. In substructural applications (e.g., deep foundations), construction materials such as timber, steel, and concrete are subjected to deterioration due to environmental impacts. Using innovative and new materials for foundation applications makes the AASHTO objective of 75 years service life achievable. Ultra High Performance Concrete (UHPC) with compressive strength of 180 MPa (26,000 psi) and excellent durability has been used in superstructure applications but not in geotechnical and foundation applications. This study explores the use of precast, prestressed UHPC piles in future foundations of bridges and other structures. An H-shaped UHPC section, which is 10-in. (250-mm) deep with weight similar to that of an HP10×57 steel pile, was designed to improve constructability and reduce cost. In this project, instrumented UHPC piles were cast and laboratory and field tests were conducted. Laboratory tests were used to verify the moment-curvature response of UHPC pile section. In the field, two UHPC piles have been successfully driven in glacial till clay soil and load tested under vertical and lateral loads. This report provides a complete set of results for the field investigation conducted on UHPC H-shaped piles. Test results, durability, drivability, and other material advantages over normal concrete and steel indicate that UHPC piles are a viable alternative to achieve the goals of AASHTO strategic plan.

Development of LRFD Procedures for Bridge Pile Foundations in Iowa Final Report, June 2010

For well over 100 years, the Working Stress Design (WSD) approach has been the traditional basis for geotechnical design with regard to settlements or failure conditions. However, considerable effort has been put forth over the past couple of decades in relation to the adoption of the Load and Resistance Factor Design (LRFD) approach into geotechnical design. With the goal of producing engineered designs with consistent levels of reliability, the Federal Highway Administration (FHWA) issued a policy memorandum on June 28, 2000, requiring all new bridges initiated after October 1, 2007, to be designed according to the LRFD approach. Likewise, regionally calibrated LRFD resistance factors were permitted by the American Association of State Highway and Transportation Officials (AASHTO) to improve the economy of bridge foundation elements. Thus, projects TR-573, TR-583 and TR-584 were undertaken by a research team at Iowa State University’s Bridge Engineering Center with the goal of developing resistance factors for pile design using available pile static load test data. To accomplish this goal, the available data were first analyzed for reliability and then placed in a newly designed relational database management system termed PIle LOad Tests (PILOT), to which this first volume of the final report for project TR-573 is dedicated. PILOT is an amalgamated, electronic source of information consisting of both static and dynamic data for pile load tests conducted in the State of Iowa. The database, which includes historical data on pile load tests dating back to 1966, is intended for use in the establishment of LRFD resistance factors for design and construction control of driven pile foundations in Iowa. Although a considerable amount of geotechnical and pile load test data is available in literature as well as in various State Department of Transportation files, PILOT is one of the first regional databases to be exclusively used in the development of LRFD resistance factors for the design and construction control of driven pile foundations. Currently providing an electronically organized assimilation of geotechnical and pile load test data for 274 piles of various types (e.g., steel H-shaped, timber, pipe, Monotube, and concrete), PILOT (http://srg.cce.iastate.edu/lrfd/) is on par with such familiar national databases used in the calibration of LRFD resistance factors for pile foundations as the FHWA’s Deep Foundation Load Test Database. By narrowing geographical boundaries while maintaining a high number of pile load tests, PILOT exemplifies a model for effective regional LRFD calibration procedures.

Innovative Solutions for Slope Stability Reinforcement and Characterization: Vol. I, TR-489, 2005

Soil slope instability concerning highway infrastructure is an ongoing problem in Iowa, as slope failures endanger public safety and continue to result in costly repair work. Characterization of slope failures is complicated, because the factors affecting slope stability can be difficult to discern and measure, particularly soil shear strength parameters. While in the past extensive research has been conducted on slope stability investigations and analysis, this research consists of field investigations addressing both the characterization and reinforcement of such slope failures. The current research focuses on applying an infrequently-used testing technique comprised of the Borehole Shear Test (BST). This in-situ test rapidly provides effective (i.e., drained) shear strength parameter values of soil. Using the BST device, fifteen Iowa slopes (fourteen failures and one proposed slope) were investigated and documented. Particular attention was paid to highly weathered shale and glacial till soil deposits, which have both been associated with slope failures in the southern Iowa drift region. Conventional laboratory tests including direct shear tests, triaxial compression tests, and ring shear tests were also performed on undisturbed and reconstituted soil samples to supplement BST results. The shear strength measurements were incorporated into complete evaluations of slope stability using both limit equilibrium and probabilistic analyses. The research methods and findings of these investigations are summarized in Volume 1 of this report. Research details of the independent characterization and reinforcement investigations are provided in Volumes 2 and 3, respectively. Combined, the field investigations offer guidance on identifying the factors that affect slope stability at a particular location and also on designing slope reinforcement using pile elements for cases where remedial measures are necessary. The research findings are expected to benefit civil and geotechnical engineers of government transportation agencies, consultants, and contractors dealing with slope stability, slope remediation, and geotechnical testing in Iowa.

Debris flows as a factor of hillslope evolution controlled by a continuous or a pulse process?

Flood effectiveness observations imply that two families of processes describe the formation of debris flow volume. One is related to the rainfall?erosion relationship, and can be seen as a gradual process, and one is related to additional geological/geotechnical events, those named hereafter extraordinary events. In order to discuss the hypothesis of coexistence of two modes of volume formation, some methodologies are applied. Firstly, classical approaches consisting in relating volume to catchments characteristics are considered. These approaches raise questions about the quality of the data rather than providing answers concerning the controlling processes. Secondly, we consider statistical approaches (cumulative number of events distribution and cluster analysis) and these suggest the possibility of having two distinct families of processes. However the quantitative evaluation of the threshold differs from the one that could be obtained from the first approach, but they all agree in the sense of the coexistence of two families of events. Thirdly, a conceptual model is built exploring how and why debris flow volume in alpine catchments changes with time. Depending on the initial condition (sediment production), the model shows that large debris flows (i.e. with important volume) are observed in the beginning period, before a steady-state is reached. During this second period debris flow volume such as is observed in the beginning period is not observed again. Integrating the results of the three approaches, two case studies are presented showing: (1) the possibility to observe in a catchment large volumes that will never happen again due to a drastic decrease in the sediment availability, supporting its difference from gradual erosion processes; (2) that following a rejuvenation of the sediment storage (by a rock avalanche) the magnitude?frequency relationship of a torrent can be differentiated into two phases, the beginning one with large and frequent debris flow and a later one with debris flow less intense and frequent, supporting the results of the conceptual model. Although the results obtained cannot identify a clear threshold between the two families of processes, they show that some debris flows can be seen as pulse of sediment differing from that expected from gradual erosion.

La cartografía colonial española durante la Segunda República (1931-1936)

La Segunda República dedicó cuantiosos recursos, económicos y humanos, a la cartografía de las posesiones coloniales. Los sucesivos gobiernos republicanos mantuvieron una fuerte continuidad, organizativa y funcional, en el ámbito de la cartografía colonial, sin que se detecte ningún cambio significativo respecto a los planes trazados en etapas anteriores. La actividad cartográfica continuó centrada en el territorio de Marruecos, y fue protagonizada por una unidad dependiente del Ministerio de la Guerra, la Comisión Geográfica de Marruecos y Límites. En este trabajo, que se apoya en fuentes primarias, se ofrece una descripción del marco institucional de la cartografía colonial durante el período republicano, se identifica a sus artífices, y se da cuenta de los levantamientos cartográficos realizados.

La cartografía del Estado Mayor del Ejército de Tierra republicano durante la Guerra Civil española. El archivo del general Vicente Rojo

En los últimos años, se ha llevado a cabo un considerable esfuerzo de análisis y catalogación de la ingente cantidad de mapas militares, planos, croquis y vistas panorámicas realizados durante la Guerra Civil española, pero aún quedan múltiples aspectos por investigar. En este artículo, analizamos la formación cartográfica del general Vicente Rojo -el jefe del Estado Mayor del Ejército de Tierra republicano-, las relaciones de Rojo con la cartografía durante la Guerra Civil y la cartografía militar contenida en su archivo personal, que se custodia en el Archivo Histórico Nacional de Madrid. Dicha cartografía posee un gran valor cartográfico y militar, porque fue utilizada por el Estado Mayor del Ejército de Tierra republicano durante el período en que Rojo estuvo al frente del mismo, y porque contiene una serie de documentos cartográficos manuscritos inéditos de gran importancia para comprender el desarrollo de algunas de las operaciones bélicas principales.

El mapa topográfico del Protectorado de Marruecos en su contexto político e institucional (1923-1940)

Durante los años veinte, tras una profunda reorganización de los servicios cartográficos del Estado, la dictadura de Primo de Rivera encargó al Depósito de la Guerra la formación de un mapa topográfico del Protectorado español de Marruecos a escala 1:50. 000. El levantamiento de la carta marroquí se realizó simultáneamente a otras operaciones cartográficas en las islas Canarias, el norte de África y la Península. Este artículo estudia la formación del mapa de Marruecos, prestando especial atención a su contexto geopolítico e institucional. La carta marroquí abrió una nueva etapa en la militarización de la cartografía topográfica española. La consulta de fuentes archivísticas ha permitido reconstruir la trayectoria profesional de sus artífices.

Notes sobre subjectivitat i experiència

The aim of this paper is to underline the fact that, in most contemporary philosophical debates (and somehow, issues in feminist theory are not an exception), a well-known term is playing an important role: experience. We need a cartography of the uses of experience, if we want to know what we are talking about and also if we intend to analyze and to rethink the last 25 years of ¿women studies¿, ¿gender studies¿ or ¿subaltern studies¿.

Monitoring and failure mechanism interpretation of an unstable slope in Southern Switzerland based on terrestrial laser scanner

We present the application of terrestrial laser scanning (TLS) for the monitoring and characterization of an active landslide area in Val Canaria (Ticino, Southern Swiss Alps). At catchment scale, the study area is affected by a large Deep Seated Gravitational Slope Deformation (DSGSD) area presenting, in the lower boundary, several retrogressive landslides active since the 1990s. Due to its frequent landslide events this area was periodically monitored by TLS since 2006. Periodic acquisitions provided new information on 3D displacements at the bottom of slope and the detection of centimetre to decimetre level scale changes (e.g. rockfall and pre-failure deformations). In October 2009, a major slope collapse occured at the bottom of the most unstable area. Based on the comparison between TLS data before and after the collapse, we carried out a detailed failure mechanism analysis and volume calculation.