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.

Concessional agreements have been to many developing countries the keystone to reach development. Since the middle twentieth century up to now roads, water - wastewater systems, electricity’s generation and distribution have been operated under arrangements that foster the private sector participation. Concessional agreements seem to be an advantageous feature of project finance for a country as a whole and perhaps that is why governments have mostly opted for this option. The foregoing sum up to developing world problems, as lack of own recourses to build, operate or maintain infrastructure and inexperience of public sector in these affairs, have arisen the utilization of concessional agreements. Developing countries use to follow the models pre-established by developed countries embracing either slightly or substantial changes in the schemes. Concessions have not been the exception. The questions then, rise from two sides. From the developed countries view it is appropriate to inquire: Did concessional agreements contributed to third world countries development? Are they still been utilized? If so, what made them work? What failed? On the other hand we should ask ourselves: Have developing countries followed carefully the third world concessional schemes? Have they settled new schemes? What were developing countries’ purposes when establishing concessional agreement schemes as public policies? Have those schemes worked or not? What is the landscape in a developed country such as Germmany and in a developing country such as Colombia? A concessional agreement as a project finance´s feature depends heavily on its preparation. Structuring phase plays a major role to reach success. Project finance is a matter of risk. Implementation of concessional agreements is as well a matter of risk. Parties assume their own project responsibility and therefore they relay in the project risks allocation. Risks allocation is the first mitigation measure. A proper structuration supposes an accurate allocation of risks and a better performance of each party. This research as of an appraisal between the role of infrastructure concessions in developed and developing countries, and has as a purpose to make a comparison between both schemes regarding the management of infrastructure concessions in their structuring phase paying special attention in the risks allocation and mitigation. The foregoing study would focus in Germany and Colombia´s scenarios principally, but using as reference other cases in specific issues, if necessary.

Impreso en el que Jenaro Balderrama se defiende de las acusaciones formuladas en su contra en una hoja suelta, y según las cuales, lo acusan de posesionarse de forma ilegal de una propiedad, además de cometer estafa y alteración de documentos oficiales. El documento conserva la ortografía de la época.

Al Eminentisimo Señor Don José Eusebio Otálora, por la Gracia de Dios Presidente de los Estados Unidos de Colombia, &c.

Documento en el que José María Chicaiza declara que el impreso publicado en días anteriores en el que se afirmaba su decisión de retractarse de sus opiniones políticas, es falso. El documento conserva la ortografía de la época

Documento escrito por los hermanos Luis María, Pedro y Zoilo Silvestre, con el fin de aclarar y defenderse de las acusaciones que se formulan en su contra, según las cuales, uno de ellos ha robado unos papeles. A juicio de los Silvestre, esta situación que daña su buen nombre, por lo que publiacan el impreso para darlo a conocer a la opinión pública. El documento conserva la ortografía de la época.

Copia del discurso que pronunció el general Rogerio López, luego de una batalla que tuvo lugar en el marco de la Guerra civil de 1884, en la que se dirige a los soldados que estaban cargo suyo.

Discurso del gobernador de Cundinamarca, en el que informa acerca de la determinación de declarar estado de conmoción en el estado soberano, como medida preventiva por la expansión de la guerra civil de 1884.

Copia de la alocución que pronunció el gobernador de Cundinamarca, Daniel Aldana, luego de los sucesos de alteración del orden público que tuvieron lugar en dicha población en 1882.

Copia de la alocución de Julián Trujillo en la que felicita a las tropas del ejército del sur, en el Cauca, por su patriotismo; e informa a los ciudadanos de Antioquia que asumió el cargo de jefe civil y militar del estado.