Assessment of innovative solutions for non-load bearing masonry enclosures

This paper presents some of the results of the research project “Masonry Enclosures” developed in the framework of the transnational access (TA) to LNEC’s triaxial shake table within the FP7 project SERIES.

Seismic vulnerability of existing masonry buildings: Nonlinear parametric analysis

Existing masonry structures are usually associated to a high seismic vulnerability, mainly due to the properties of the materials, weak connections between floors and load-bearing walls, high mass of the masonry walls and flexibility of the floors. For these reasons, the seismic performance of existing masonry structures has received much attention in the last decades. This study presents the parametric analysis taking into account the deviations on features of the gaioleiro buildings - Portuguese building typology. The main objective of the parametric analysis is to compare the seismic performance of the structure as a function of the variations of its properties with respect to the response of a reference model. The parametric analysis was carried out for two types of structural analysis, namely for the non-linear dynamic analysis with time integration and for the pushover analysis with distribution of forces proportional to the inertial forces of the structure. The Young's modulus of the masonry walls, Young's modulus of the timber floors, the compressive and tensile non-linear properties (strength and fracture energy) were the properties considered in both type of analysis. Additionally, in the dynamic analysis, the influences of the vis-cous damping and of the vertical component of the earthquake were evaluated. A pushover analysis proportional to the modal displacement of the first mode in each direction was also carried out. The results shows that the Young's modulus of the masonry walls, the Young's modulus of the timber floors and the compressive non-linear properties are the pa-rameters that most influence the seismic performance of this type of tall and weak existing masonry structures. Furthermore, it is concluded that that the stiffness of the floors influences significantly the strength capacity and the collapse mecha-nism of the numerical model. Thus, a study on the strengthening of the floors was also carried out. The increase of the thickness of the timber floors was the strengthening technique that presented the best seismic performance, in which the reduction of the out-of-plane displacements of the masonry walls is highlighted.

Masonry components

Masonry is a non-homogeneous material, composed of units and mortar, which can be of different types, with distinct mechanical properties. The design of both masonry units and mortar is based on the role of the walls in the building. Load-bearing walls relate to structural elements that bear mainly vertical loads, but can serve also to resist to horizontal loads. When a structural masonry building is submitted to in-plane and out-of-plane loadings induced by an earthquake for example, the masonry walls are the structural elements that ensure the global stability of the building. This means that the walls should have adequate mechanical properties that enable them to resist to different combinations of compressive, shear and tensile stresses.The boundary conditions influence the resisting mechanisms of the structural walls under in-plane loading and in a buildings the connection at the intersection walls are of paramount importance for the out-of-plane resisting mechanism. However, it is well established that the masonry mechanical properties are also relevant for the global mechanical performance of the structural masonry walls. Masonry units for load-bearing walls are usually laid so that their perforations are vertically oriented, whereas for partition walls, brick units with horizontal perforation are mostly adopted.

MODELING OF SOIL LOAD-BEARING CAPACITY AS A FUNCTION OF SOIL MECHANICAL RESISTANCE TO PENETRATION

Estimation of soil load-bearing capacity from mathematical models that relate preconsolidation pressure (σp) to mechanical resistance to penetration (PR) and gravimetric soil water content (U) is important for defining strategies to prevent compaction of agricultural soils. Our objective was therefore to model the σp and compression index (CI) according to the PR (with an impact penetrometer in the field and a static penetrometer inserted at a constant rate in the laboratory) and U in a Rhodic Eutrudox. The experiment consisted of six treatments: no-tillage system (NT); NT with chiseling; and NT with additional compaction by combine traffic (passing 4, 8, 10, and 20 times). Soil bulk density, total porosity, PR (in field and laboratory measurements), U, σp, and CI values were determined in the 5.5-10.5 cm and 13.5-18.5 cm layers. Preconsolidation pressure (σp) and CI were modeled according to PR in different U. The σp increased and the CI decreased linearly with increases in the PR values. The correlations between σp and PR and PR and CI are influenced by U. From these correlations, the soil load-bearing capacity and compaction susceptibility can be estimated by PR readings evaluated in different U.

Least Limiting Water Range and Load Bearing Capacity of Soil under Types of Tractor-Trailers for Mechanical Harvesting of Green Sugarcane

ABSTRACT The expansion of the sugarcane industry in Brazil has intensified the mechanization of agriculture and caused effects on the soil physical quality. The purpose of this study was to evaluate the limiting water range and soil bearing capacity of a Latossolo Vermelho distroférrico típico (Rhodic Hapludox) under the influence of different tractor-trailers used in mechanical sugarcane harvesting. The experiment was arranged in a randomized block design with five replications. The treatments consisted of green sugarcane harvesting with: harvester without trailer (T1); harvester with two trailers with a capacity of 10 Mg each (T2); harvester with trailer with a capacity of 20 Mg (T3) and harvester and truck with trailer with a capacity of 20 Mg (10 Mg per compartment) (T4). The least limiting water range and soil bearing capacity were evaluated. The transport equipment to remove the harvested sugarcane from the field (trailer) at harvest decreased the least limiting water range, reducing the structural soil quality. The truck trailer caused the greatest impact on the soil physical properties studied. The soil load bearing capacity was unaffected by the treatments, since the pressure of the harvester (T1) exceeded the pre-consolidation pressure of the soil.

Hypothalamic energy metabolism is impaired by doxorubicin independently of inflammation in non-tumour-bearing rats

We sought to explore the effects of doxorubicin on inflammatory profiles and energy metabolism in the hypothalamus of rats. To investigate these effects, we formed two groups: a control (C) group and a Doxorubicin (DOXO) group. Sixteen rats were randomly assigned to either the control (C) or DOXO groups. The hypothalamus was collected. The levels of interleukin (IL)-1β, IL-6, IL-10, TNF-α and energy metabolism (malate dehydrogenase, complex I and III activities) were analysed in the hypothalamus. The DOXO group exhibited a decreased body weight (p < 0.01). Hypothalamic malate dehydrogenase activity was reduced when compared with control (p < 0.05). In addition, pro-inflammatory cytokine levels were unchanged. Therefore, our results demonstrate that doxorubicin leads to an impairment of \hypothalamic energy metabolism, but do not affect the inflammatory pathway. Copyright © 2015 John Wiley & Sons, Ltd. Conflict of Interest Significance paragraph The hypothalamus is a central organ that regulates a great number of functions, such as food intake, temperature and energy expenditure, among others. Doxorubicin can lead to deep anorexia and metabolic chaos; thus, we observed the effect of this chemotherapeutic drug on the inflammation and metabolism in rats after the administration of doxorubicin in order to understand the central effect in the hypothalamus. Drug treatment by doxorubicin is used as a cancer therapy; however the use of this drug may cause harmful alterations to the metabolism. Thus, further investigations are needed on the impact of drug therapy over the long term.

Tailoring surface nanostructures on polyaryletherketones for load-bearing implants

High-performance thermoplastics including polyetheretherketone (PEEK) are key biomaterials for load-bearing implants. Plasma treatment of implants surfaces has been shown to chemically activate its surface, which is a prerequisite to achieve proper cell attachment. Oxygen plasma treatment of PEEK films results in very reproducible surface nanostructures and has been reported in the literature. Our goal is to apply the plasma treatment to another promising polymer, polyetherketoneketone (PEKK), and compare its characteristics to the ones of PEEK. Oxygen plasma treatments of plasma powers between 25 and 150 W were applied on 60 μm-thick PEKK and 100 μm-thick PEEK films. Analysis of the nanostructures by atomic force microscopy showed that the roughness increased and island density decreased with plasma power for both PEKK and PEEK films correlating with contact angle values without affecting bulk properties of the used films. Thermal analysis of the plasma-treated films shows that the plasma treatment does not change the bulk properties of the PEKK and PEEK films.

Stresses in simple framed structures : a text book to accompany exercises in the computation of the axial stresses in the members of load-bearing frames /

"List of treatises on stresses": p. 190.

Structural behaviour and design of load-bearing falsework

Tne object of this research was to investigate the behaviour of birdcage scaffolding as used in falsework structures, assess the suitability of existing design methods and make recommendations for a set of design rules. Since excessive deflection is as undesirable in a structure as total collapse, the project was divided into two sections. These were to determine the ultimate vertical and horizontal load-carrying capacity and also the deflection characteristics of any falsework. So theoretical analyses were developed to ascertain the ability of both the individual standards to resist vertical load, and of the bracing to resist horizontal load.Furthermore a model was evolved which would predict the horizontal deflection of a scaffold under load using strain energy methods. These models were checked by three series of experiments. The first was on individual standards under vertical load only. The second series was carried out on full scale falsework structures loading vertically and horizontally to failure. Finally experiments were conducted on scaffold couplers to provide additional verification of the method of predicting deflections. This thesis gives the history of the project and an introduction into the field of scaffolding. It details both the experiments conducted and the theories developed and the correlation between theory and experiment. Finally it makes recommendations for a design method to be employed by scaffolding designers.

Nonlinear modelling of non-structural masonry walls under a low-intensity earthquake motion: calibration through a parametric study

This thesis aims to understand the behavior of a low-rise unreinforced masonry building (URM), the typical residential house in the Netherlands, when subjected to low-intensity earthquakes. In fact, in the last decades, the Groningen region was hit by several shallow earthquakes caused by the extraction of natural gas. In particular, the focus is addressed to the internal non-structural walls and to their interaction with the structural parts of the building. A simple and cost-efficient 2D FEM model is developed, focused on the interfaces representing mortar layers that are present between the non-structural walls and the rest of the structure. As a reference for geometries and materials, it has been taken into consideration a prototype that was built in full-scale at the EUCENTRE laboratory of Pavia (Italy). Firstly, a quasi-static analysis is performed by gradually applying a prescribed displacement on the roof floor of the structure. Sensitivity analyses are conducted on some key parameters characterizing mortar. This analysis allows for the calibration of their values and the evaluation of the reliability of the model. Successively, a transient analysis is performed to effectively subject the model to a seismic action and hence also evaluate the mechanical response of the building over time. Moreover, it was possible to compare the results of this analysis with the displacements recorded in the experimental tests by creating a model representing the entire considered structure. As a result, some conditions for the model calibration are defined. The reliability of the model is then confirmed by both the reasonable results obtained from the sensitivity analysis and the compatibility of the values obtained for the top displacement of the roof floor of the experimental test, and the same value acquired from the structural model.

Condicionantes de la adherencia y anclaje en el refuerzo de muros de fábrica con elementos de fibras

Es cada vez más frecuente la rehabilitación de patrimonio construido, tanto de obras deterioradas como para la adecuación de obras existentes a nuevos usos o solicitaciones. Se ha considerado el estudio del refuerzo de obras de fábrica ya que constituyen un importante número dentro del patrimonio tanto de edificación como de obra civil (sistemas de muros de carga o en estructuras principales porticadas de acero u hormigón empleándose las fábricas como cerramiento o distribución con elementos autoportantes). A la hora de reparar o reforzar una estructura es importante realizar un análisis de las deficiencias, caracterización mecánica del elemento y solicitaciones presentes o posibles; en el apartado 1.3 del presente trabajo se refieren acciones de rehabilitación cuando lo que se precisa no es refuerzo estructural, así como las técnicas tradicionales más habituales para refuerzo de fábricas que suelen clasificarse según se trate de refuerzos exteriores o interiores. En los últimos años se ha adoptado el sistema de refuerzo de FRP, tecnología con origen en los refuerzos de hormigón tanto de elementos a flexión como de soportes. Estos refuerzos pueden ser de láminas adheridas a la fábrica soporte (SM), o de barras incluidas en rozas lineales (NSM). La elección de un sistema u otro depende de la necesidad de refuerzo y tipo de solicitación predominante, del acceso para colocación y de la exigencia de impacto visual. Una de las mayores limitaciones de los sistemas de refuerzo por FRP es que no suele movilizarse la resistencia del material de refuerzo, produciéndose previamente fallo en la interfase con el soporte con el consecuente despegue o deslaminación; dichos fallos pueden tener un origen local y propagarse a partir de una discontinuidad, por lo que es preciso un tratamiento cuidadoso de la superficie soporte, o bien como consecuencia de una insuficiente longitud de anclaje para la transferencia de los esfuerzos en la interfase. Se considera imprescindible una caracterización mecánica del elemento a reforzar. Es por ello que el trabajo presenta en el capítulo 2 métodos de cálculo de la fábrica soporte de distintas normativas y también una formulación alternativa que tiene en cuenta la fábrica histórica ya que su caracterización suele ser más complicada por la heterogeneidad y falta de clasificación de sus materiales, especialmente de los morteros. Una vez conocidos los parámetros resistentes de la fábrica soporte es posible diseñar el refuerzo; hasta la fecha existe escasa normativa de refuerzos de FRP para muros de fábrica, consistente en un protocolo propuesto por la ACI 440 7R-10 que carece de mejoras por tipo de anclaje y aporta valores muy conservadores de la eficacia del refuerzo. Como se ha indicado, la problemática principal de los refuerzos de FRP en muros es el modo de fallo que impide un aprovechamiento óptimo de las propiedades del material. Recientemente se están realizando estudios con distintos métodos de anclaje para estos refuerzos, con lo que se incremente la capacidad última y se mantenga el soporte ligado al refuerzo tras la rotura. Junto con sistemas de anclajes por prolongación del refuerzo (tanto para láminas como para barras) se han ensayado anclajes con llaves de cortante, barras embebidas, o anclajes mecánicos de acero o incluso de FRP. Este texto resume, en el capítulo 4, algunas de las campañas experimentales llevadas a cabo entre los años 2000 y 2013 con distintos anclajes. Se observan los parámetros fundamentales para medir la eficacia del anclajes como son: el modo de fallo, el incremento de resistencia, y los desplazamientos que permite observar la ductilidad del refuerzo; estos datos se analizan en función de la variación de: tipo de refuerzo incluyéndose el tipo de fibra y sistema de colocación, y tipo de anclaje. Existen también parámetros de diseño de los propios anclajes. En el caso de barras embebidas se resumen en diámetro y material de la barra, acabado superficial, dimensiones y forma de la roza, tipo de adhesivo. En el caso de anclajes de FRP tipo pasador la caracterización incluye: tipo de fibra, sistema de fabricación del anclajes y diámetro del mismo, radio de expansión del abanico, espaciamiento longitudinal de anclajes, número de filas de anclajes, número de láminas del refuerzo, longitud adherida tras el anclaje; es compleja la sistematización de resultados de los autores de las campañas expuestas ya que algunos de estos parámetros varían impidiendo la comparación. El capítulo 5 presenta los ensayos empleados para estas campañas de anclajes, distinguiéndose entre ensayos de modo I, tipo tracción directa o arrancamiento, que servirían para sistemas NSM o para cuantificar la resistencia individual de anclajes tipo pasador; ensayos de modo II, tipo corte simple, que se asemeja más a las condiciones de trabajo de los refuerzos. El presente texto se realiza con objeto de abrir una posible investigación sobre los anclajes tipo pasador, considerándose que junto con los sistemas de barra embebida son los que permiten una mayor versatilidad de diseño para los refuerzos de FRP y siendo su eficacia aún difícil de aislar por el número de parámetros de diseño. Rehabilitation of built heritage is becoming increasingly frequent, including repair of damaged works and conditioning for a new use or higher loads. In this work it has been considered the study of masonry wall reinforcement, as most buildings and civil works have load bearing walls or at least infilled masonry walls in concrete and steel structures. Before repairing or reinforcing an structure, it is important to analyse its deficiencies, its mechanical properties and both existing and potential loads; chapter 1, section 4 includes the most common rehabilitation methods when structural reinforcement is not needed, as well as traditional reinforcement techniques (internal and external reinforcement) In the last years the FRP reinforcement system has been adopted for masonry walls. FRP materials for reinforcement were initially used for concrete pillars and beams. FRP reinforcement includes two main techniques: surface mounted laminates (SM) and near surface mounted bars (NSM); one of them may be more accurate according to the need for reinforcement and main load, accessibility for installation and aesthetic requirements. One of the main constraints of FRP systems is not reaching maximum load for material due to premature debonding failure, which can be caused by surface irregularities so surface preparation is necessary. But debonding (or delamination for SM techniques) can also be a consequence of insufficient anchorage length or stress concentration. In order to provide an accurate mechanical characterisation of walls, chapter 2 summarises the calculation methods included in guidelines as well as alternative formulations for old masonry walls as historic wall properties are more complicated to obtain due to heterogeneity and data gaps (specially for mortars). The next step is designing reinforcement system; to date there are scarce regulations for walls reinforcement with FRP: ACI 440 7R-10 includes a protocol without considering the potential benefits provided by anchorage devices and with conservative values for reinforcement efficiency. As noted above, the main problem of FRP masonry walls reinforcement is failure mode. Recently, some authors have performed studies with different anchorage systems, finding that these systems are able to delay or prevent debonding . Studies include the following anchorage systems: Overlap, embedded bars, shear keys, shear restraint and fiber anchors. Chapter 4 briefly describes several experimental works between years 2000 and 2013, concerning different anchorage systems. The main parameters that measure the anchorage efficiency are: failure mode, failure load increase, displacements (in order to evaluate the ductility of the system); all these data points strongly depend on: reinforcement system, FRP fibers, anchorage system, and also on the specific anchorage parameters. Specific anchorage parameters are a function of the anchorage system used. The embedded bar system have design variables which can be identified as: bar diameter and material, surface finish, groove dimensions, and adhesive. In FRP anchorages (spikes) a complete design characterisation should include: type of fiber, manufacturing process, diameter, fan orientation, anchor splay width, anchor longitudinal spacing and number or rows, number or FRP sheet plies, bonded length beyond anchorage devices,...the parameters considered differ from some authors to others, so the comparison of results is quite complicated. Chapter 5 includes the most common tests used in experimental investigations on bond-behaviour and anchorage characterisation: direct shear tests (with variations single-shear and double-shear), pullout tests and bending tests. Each of them may be used according to the data needed. The purpose of this text is to promote further investigation of anchor spikes, accepting that both FRP anchors and embedded bars are the most versatile anchorage systems of FRP reinforcement and considering that to date its efficiency cannot be evaluated as there are too many design uncertainties.

Estudio de las propiedades de las fábricas históricas de adobe como soporte a intervenciones de rehabilitación

El extenso legado edificado que constituyen las construcciones históricas de fábrica de adobe distribuidas por toda la península encuentra en la región de Aveiro (Portugal) su máxima expresión, tanto desde el punto de vista cuantitativo, un 30% de los edificios existentes en la región, como tipológico, compuesto por un amplio conjunto de diferentes construcciones (edificios residenciales, edificios militares, iglesias, escuelas, teatros, naves industriales, etc.), muchos de los cuales de reconocido valor histórico, arquitectónico y patrimonial. Tras la gradual desaparición del empleo de la fábrica de adobe como técnica constructiva, durante la segunda mitad del siglo XX, la necesaria conservación y/o rehabilitación de los edificios remanentes no se ha tenido en cuenta. Como consecuencia de esta actitud generalizada de pasividad continuada, se verifica el estado actual de deterioro y de daño acusado que presentan una gran parte de estas construcciones, del cual ha resultado el panorama presente de abandono y ruina en el que se encuentran muchas de ellas. Por regla general, la solución adoptada para afrontar el estado actual de los edificios en estas condiciones suele ser la demolición. No obstante lo anterior, en los últimos años, se viene produciendo en el seno de los diferentes agentes que intervienen en la toma de decisiones sobre estos edificios un interés creciente en su preservación, promoviendo la rehabilitación de los mismos. Empieza de este modo a cobrar importancia la necesidad de desarrollar estrategias de intervención que posibiliten alargar la vida útil de estas estructuras, permitiendo, por un lado, establecer metodologías de análisis de sus condiciones de seguridad, que posibiliten determinar las medidas de actuación necesarias para el aseguramiento de las mismas frente a las acciones existentes y, en su caso, a la incorporación de nuevas solicitaciones debidas a cambios de uso o ampliaciones, así como, dando respuesta a los principales mecanismo de daño a los que se encuentran sujetas. Tratándose de estructuras que fueron construidas utilizando técnicas y materiales escasamente estudiados y entre tanto abandonados, se hace también necesario, y con carácter previo a lo anterior, acometer un estudio e investigación multidisciplinares que permitan su caracterización y comprensión, y la par establecer un diagnóstico sobre los principales agentes y procesos patológicos que promueven el deterioro de las mismas. En este contexto, el estudio llevado a cabo tuvo como objetivos ampliar el conocimiento e investigación acerca de las propiedades y parámetros resistentes de las fábricas históricas de adobe, así como, analizar los principales mecanismos de daño asociados a las mismas, a la luz del el estado actual de estas construcciones, y su repercusión en el comportamiento resistente de las fábricas –con especial énfasis para la influencia del agua–. De este modo, se pretendió construir una base de resultados que, por un lado, pueda servir de soporte a intervenciones de rehabilitación y/o consolidación de estas estructuras – permitiendo de forma ágil y a partir de datos y recursos de cálculo expeditos la evaluación de los niveles de seguridad en las fábricas–, y por otro, el estudio de soluciones de mejora o corrección de deficiencias en su comportamiento estructural. The vast edified legacy composed of the historical adobe load-bearing walls which can be found spread all over the Iberian peninsula has, in the region of Aveiro (Portugal), its maximum expression, both from a quantitative point of view (around 30% of the local construction) and a typological point of view, including a considerable number of different types of constructions (residential buildings, military buildings, churches, industrial buildings, etc.), most of which have a recognized high historical, architectural and patrimonial value. The conservation and/or rehabilitation of many of these edifications has been neglected, since its gradual abandonment as constructive technique during the second half of the 20th century. As a consequence of this posture of general passivity, it is nowadays visible the state of pronounced damage manifested by great part of these constructions, which has been leading to their abandonment and state of ruin. In most cases, the option for demolition has been the solution found to face the actual state of these constructions. However, in recent years, a growing interest in the preservation and maintenance of the adobe constructions has become visible by the envolved parties, with the obvious consequence of rehabilitation. By so, it becomes mandatory to develop strategies of intervention that, through rehabilitation, are able to extend the useful life of the existing structures, allowing on one hand, to establish methodologies to analyze their safety state and determine the actions needed to ensure their protection against existing pressures and, when applicable, the occurrence of new demands due to changes of use or extensions, and on the other hand, to give response to the main damage mechanisms to which these structures are exposed. Because these structures were built using not very well know techniques and materials, which have been, in the meantime, abandoned, it is now crucial that these are object of a previous phase of study and multidisciplinary investigation, essential not only to their characterization and comprehension, but also to the diagnosis of the main pathological processes that affect them. In this context, the present study had as main goal to develop the analysis and knowledge regarding the properties and resistant parameters of the adobe masonry as well as bringing to the light of day the actual state of the existing adobe constructions, making evident the main damage mechanisms by which they are affected and analyzing, through their occurrence, the vulnerability of the mentioned properties and resistant parameters. By so, it was objective of the present study the development of a result database which on one hand, supports the execution of rehabilitation interventions and/or strengthening of these constructions and, on other hand, allows the development of improvement solutions in the mechanical characteristics of the adobe masonry which permit corrections of deficiencies in their structural behavior with a special emphasis on the influence of water. Thus, a database of results was developed. Its goal is, on one hand, to support the rehabilitation or consolidation interventions on these structures - allowing for a quick analysis of the safety state of the adobe walls from expedite data and calculus resources and, on the other hand, to study improvement or correction solutions of their structural behavior.

Other Than a Citizen: Vernacular Poetics in Postwar America

Few symbols of 1950s-1960s America remain as central to our contemporary conception of Cold War culture as the iconic ranch-style suburban home. While the house took center stage in the Nixon/Khrushchev kitchen debates as a symbol of modern efficiency and capitalist values, its popularity depended largely upon its obvious appropriation of vernacular architecture from the 19th century, those California haciendas and Texas dogtrots that dotted the American west. Contractors like William Levitt modernized the historical common houses, hermetically sealing their porous construction, all while using the ranch-style roots of the dwelling to galvanize a myth of an indigenous American culture. At a moment of intense occupational bureaucracy, political uncertainty and atomized social life, the rancher gave a self-identifying white consumer base reason to believe they could master their own plot in the expansive frontier. Only one example of America’s mid-century love affair with commodified vernacular forms, the ranch-style home represents a broad effort on the part of corporate and governmental interest groups to transform the vernacular into a style that expresses a distinctly homogenous vision of American culture. “Other than a Citizen” begins with an anatomy of that transformation, and then turns to the work of four poets who sought to reclaim the vernacular from that process of standardization and use it to countermand the containment-era strategies of Cold War America.

In four chapters, I trace references to common speech and verbal expressivity in the poetry and poetic theory of Charles Olson, Robert Duncan, LeRoi Jones/Amiri Baraka and Gwendolyn Brooks, against the historical backdrop of the Free-Speech Movement and the rise of mass-culture. When poets frame nonliterary speech within the literary page, they encounter the inability of writing to capture the vital ephemerality of verbal expression. Rather than treat this limitation as an impediment, the writers in my study use the poem to dramatize the fugitivity of speech, emphasizing it as a disruptive counterpoint to the technologies of capture. Where critics such as Houston Baker interpret the vernacular strictly in terms of resistance, I take a cue from the poets and argue that the vernacular, rooted etymologically at the intersection of domestic security and enslaved margin, represents a gestalt form, capable at once of establishing centralized power and sparking minor protest. My argument also expands upon Michael North’s exploration of the influence of minstrelsy and regionalism on the development of modernist literary technique in The Dialect of Modernism. As he focuses on writers from the early 20th century, I account for the next generation, whose America was not a culturally inferior collection of immigrants but an imperial power, replete with economic, political and artistic dominance. Instead of settling for an essentially American idiom, the poets in my study saw in the vernacular not phonetic misspellings, slang terminology and fragmented syntax, but the potential to provoke and thereby frame a more ethical mode of social life, straining against the regimentation of citizenship.

My attention to the vernacular argues for an alignment among writers who have been segregated by the assumption that race and aesthetics are mutually exclusive categories. In reading these writers alongside one another, “Other than a Citizen” shows how the avant-garde concepts of projective poetics and composition by field develop out of an interest in black expressivity. Conversely, I trace black radicalism and its emphasis on sociality back to the communalism practiced at the experimental arts college in Black Mountain, North Carolina, where Olson and Duncan taught. In pressing for this connection, my work reveals the racial politics embedded within the speech-based aesthetics of the postwar era, while foregrounding the aesthetic dimension of militant protest.

Not unlike today, the popular rhetoric of the Cold War insists that to be a citizen involves defending one’s status as a rightful member of an exclusionary nation. To be other than a citizen, as the poets in my study make clear, begins with eschewing the false certainty that accompanies categorical nominalization. In promoting a model of mutually dependent participation, these poets lay the groundwork for an alternative model of civic belonging, where volition and reciprocity replace compliance and self-sufficiency. In reading their lines, we become all the more aware of the cracks that run the length of our load-bearing walls.