To consider a wall as a city element, a city addition, a wall proportioned to the scale of a city where the wall ls proposed not as a building, but rather as a community of buildings whose presence demands that their external possibilities are as significant as their internal obligations, a wall whose position brings order to the means of movement vital to the life of the city. / M. Arch.

There is an undefinable order in the universe. In our solar system, nine planets revolve around one sun. The earths’ orbit around the sun takes 365 days. The moons’ orbit about the earth take 30 days. The earths’ revolution about its own axis takes 24 hours. The sun rises in the east and sets in the west. This is how man begins to define his portion of the universe, to distinguish limits. There is much more to explore, learn and explain. As humans we subconsciously desire a harmony and balance around us. Order. It is a physical, tangible presence that we can see, label and understand, which is evident throughout the human existence. We have a need to define, regulate and establish rules, to create order. Order permeates our lives on a daily basis. This thesis seeks to give order to a structure, a House. It is the study of grids, columns and walls in relation to the structure that it supports. A sixteen square grid is a constant of this project. It is the controlling element that gives rise to the placement of the walls and columns. Walls and columns are placed with in the house according to an order that is defined by the grid. Materials are also used to distinguish boundaries of the grid establishing its influence throughout the house. / Master of Architecture

Washington D.C., along with similar historically significant cities, boasts architectural treasures. Understanding how our above-ground archeology, which represents the passage of time and suggests urban development, will continue to influence our architecture today, is the essential core of this thesis. 14th Street is one of the crucial entrance corridors of the city, existing as a vertical way-finder for modern day travelers coming in and out of the District. Brick rowhouses line this valuable street, providing multi-use functions that have evolved over the past century. Unfortunately, most of these urban gems have lost their place to the City's superblock high rises. The program of this thesis serves the Corcoran School of Art + Design with a new central campus location in D.C. while reusing an existing block of parti walls, excavated from rowhouses of the past. The modern need of maximizing space is thoughtfully merged with the intentional reuse of historic structures. / Master of Architecture

This thesis presents a numerical study of the influence of varying story strength on the seismic performance of multi-story wood-frame shear wall buildings. In the prior FEMA P695 studies of these buildings, the non-simulated collapse limit-state was exceeded primarily in the first story. This observation raised interest in quantifying the influence of varying strength from story to story on seismic response. In this study, four distributions of strength are used as bounding cases. The Parabolic strength distribution (1) results from the ELF vertical force distribution method in ASCE 7 that assigns forces to each level based on weight and story height. The Triangular strength distribution (2) results from an assumed vertical force distribution that assigns lateral forces based on the seismic weight at each level. The Constant strength distribution (3) results from an assumed vertical force distribution that assigns a concentrated lateral force at the uppermost level based on the total seismic weight of all levels. The Baseline distribution (4) reflects a realistic vertical strength distribution resulting from the ELF vertical force distribution method. The FEMA P695 methodology, which quantifies seismic performance via adjusted collapse margin ratios, is employed in this study. The analytical models include P-Delta effects and utilize the 10-parameter hysteresis CASHEW model. It is observed that the Parabolic strength distribution allows for dissipation of energy over the height of the building, has less collapse risk than other strength distributions studied, and reduces occurrence of concentrated deformations in a single story from the onset of applied lateral force. / MS / Multi-story wood-frame buildings are becoming increasingly common, especially in areas like the western United States. Past earthquakes have shown that multi-story wood-frame buildings that have a soft and weak first story relative to upper stories are vulnerable to collapsing on the first story. This vulnerability has raised interest in understanding how the relative strength of each story of a wood building affects its performance in an earthquake. This thesis studies four strength distribution cases. The first three cases are called the Parabolic, Triangular and Constant strength distributions named after the shape of the building’s story to story strength profile. For example, the Triangular case has the least amount of strength on the top story, which increases linearly in the lower stories down to the first story, which has the greatest strength. The fourth case, called the Baseline case, is based on actual building designs. All four strength distribution cases have the same first story strength. Two evaluation methods are used to test the strength distribution cases. The first, known as a pushover analysis, applies lateral forces to the building until the roof reaches a specified displacement. The second, called an incremental dynamic analysis, subjects the building to increasingly intense earthquakes until a certain amount of displacement is reached in any story. The results of these analyses showed that the Parabolic strength distribution most effectively used the strength available in every story of the building to delay the onset of collapse and to distribute the location of the collapse story.

The safety of gravity earth retaining structures is usually evaluated with regard to: (1) overturning about the toe, (2) sliding along the base and (3) bearing failure of the foundation. Conventional equilibrium methods are utilized in these analyses, which are performed using assumed earth loads based on simplified earth pressure theories. Recent finite element studies performed on gravity retaining walls founded on rock revealed that the use of conventional methods may lead to overly conservative results. The effects of soil-structure interaction result in a greater degree of wall stability than conventional approaches would indicate. This research examines the behavior of gravity earth retaining structures founded on soil. Two methods of analyses were used in these studies : (1) the Following Load method, which does net account for soil-structure interaction effects, and (2) the Backfill Placement method, which does account for soil-structure interaction effects. A procedure called the “Alpha Method” for 2D soil elements was developed for the purpose of improving the post-failure stress-strain behavior of the backfill and foundation soils and incorporated in the finite element program (SOILSTRUCT) utilized in the analyses. A series of analyses demonstrated the effectiveness of the Alpha Method in controlling overshoot and providing good estimates of collapse loads on wall-foundation systems. Following Load analyses indicated that walls on soil become unstable by bearing capacity rather than overturning or sliding. These results also provided the basis for modifications to Vesic’s bearing capacity theory, which extended the applicability of the theory to the conditions encountered in retaining wall problems. The Backfill Placement analyses showed that there are significant differences in behavior between walls founded on rock and walls founded on soil. These analyses also led to new insight into the factors that affect the shear forces within the backfill and which contributes to the stability of the wall. / Ph. D.

The objective of this study was to investigate the accuracy of the procedures employed in the conventional equilibrium method of analysis of gravity-earth-retaining structures founded on rock, using the finite element method of analysis. This study was initiated because a number of existing large retaining structures at various navigation lock sites in the United States that show no signs of instability or substandard performance have been found not to meet the criteria currently used for design of new structures. The results of following load analyses show that when the loss of contact along the base of a wall is modeled in the finite element analysis, the calculated values of effective base contact area and maximum contact pressure are somewhat larger than those calculated using conventional equilibrium analyses. The values of the mobilized base friction angle calculated using both methods are in precise agreement. Comparisons between the results of backfill placement analyses using the finite element method and the conventional equilibrium analyses indicate that conventional analyses are very conservative. The finite element analyses indicate that the backfill exerts downward shear loads on the backs of retaining walls. These shear forces have a very important stabilizing effect on the walls. Expressed in terms of a vertical shear stress coefficient (Kᵥ - r_xy/σᵥ), this shear loading was found to range in value from 0.09 to 0.21, depending on the geometrical features and the values of the material parameters involved in the problem. Another important factor not considered in the conventional equilibrium method is that the displacements of the wall have a significant influence on the distribution of both the stabilizing and destabilizing forces exerted on the wall. In general, as the wall moves away from the backfill, the lateral forces exerted on the wall by the backfill decrease, and the lateral forces exerted on the front of the wall by the toe fill increase. / Ph. D.

A higher level of complexity is possible by combining more than one idea as long as the order of the elements is readable in each built condition. Order is possible at any level of complexity. The more complex the greater the need of order. Order can be the relationship of a limited set of elements that inform and reform each other. / Master of Architecture

wilderness and urban texture Since the earliest beginnings of civilization, mankind has strived to form urban space by limiting its outlines and bringing a system of order to the wilderness of nature. Thus street and place mark the public space clearly bound by built mass, the enclosure of the more private space. In many modern cities of the United States the urban counterpart of street and place the continuous building mass is largely missing. Colin Rowe describes this phenomena as the unpleasant condition of urban texture of the modern city. If we want to fix that urban wilderness of the American City, we have to redraw its outlines and redefine its spaces. / Master of Architecture

Yes / Since 2010 the Stonehenge Hidden Landscapes Project (SHLP) has undertaken extensive archaeological prospection across much of the landscape surrounding Stonehenge. These remote sensing and geophysical surveys have revealed a significant number of new sites and landscape features whilst providing new information on many previously known monuments. The project goal to integrate multimethod mapping over large areas of the landscape has also provided opportunities to re-interpret the landscape context of individual monuments and, in the case of the major henge at Durrington Walls, to generate novel insights into the structure and sequence of a monument which has attracted considerable research attention over many decades. This paper outlines the recent work of the SHLP and the results of survey at Durrington Walls that shed new light on this enigmatic monument including a site ‘hidden’ within the monument.

The major goal of this study was to achieve sustained cultivation of virulent T. pallidum in vitro. The putatuive binding of host proteins to the outer membrane (OM) of intact, virulent T. pallidum subsp. pallidum has been investigated. A major breakthrough was the development of a filtration assay, usinglow protein-binding membrane filters, for the measurement of substances bound to or incorporated into th eOM of T. pallidum. This avoided the conventional manipulations which can damage the fragile OM of T. pallidum. Using this filtration assay, studies on the binding of host serum proteins demonstrated that intact treponemes did not bind host proteins as previously reported. It also indicated that previous studies were probably performed with damaged by this research. The studies on the binding of polyclonal and monoclonal antibodies to intact and detergent treated treponemes provided evidence of the low level binding of antibody to intact treponemes which was greatly enhanced but the removal of the outer membrane with 0.1% Triton X. This research research corroborated that of others which suggests that the outer membrane of T. pallidum contains very little protein or surface exposed antigen.