WSP USA, formerly WSP|Parsons Brinckerhoff and Parsons Brinckerhoff, is a multinational engineering and design firm with approximately 14,000 employees. The firm operates in the fields of strategic consulting, planning, engineering, construction management, energy, infrastructure and community planning. In 2013, the company was named the tenth largest U.S.-based engineering/design firm by Engineering News Record. In 2020, it was ranked #7 of the Top 500 Design Firms and #2 of the Top 100 Pure Designers by the same magazine.On October 31, 2014, Parsons Brinckerhoff became a wholly owned independent subsidiary of WSP Global, a Canadian-based professional services firm. Parsons Brinckerhoff was renamed to WSP|Parsons Brinckerhoff, then to WSP USA in 2017. Together with WSP Global, WSP USA is one of the largest professional services firms in the world, with approximately 31,500 employees in 500 offices serving 39 countries.
This paper presents the broad spectrum of considerations in the planning and design phases for utilization of space above the Central Artery/Tunnel (CA/T) project in Boston. The issues include land planning and zoning, utilities, traffic management, structural design, geotechnical features and environmental commitments. Specifically this paper focuses on the structural design considerations and other details for the deepest section of the CA/T which begins at Kneeland Street and ends at Congress Street. This section of the CA/T project supports the Massachusetts Bay Transit Authority's (MBTA's) South Boston Pier Transitway tunnel for electrically operated buses. The Transitway tunnel crosses the Red Line subway at the South Station, thus forming three tier tunnels at Summer Street intersection.
Considerations important to design of cast-in-place concrete liners for repository shafts are discussed. Requirements for repository shaft liners and design criteria appropriate to those requirements are presented. Types of loads acting on a liner and modes of deformation are discussed. Methods are proposed for calculating load magnitudes and liner stresses and for evaluating liner performance. 14 refs., 3 figs.
Al explicitar el interés que le genera cómo la “nueva interpretación de la historia se traslada desde el museo o la colección privada al paisaje rural más extenso y al paisaje urbano,” John Brinckerhoff Jackson recuerda que tan pronto como terminó la Guerra Civil en los EEUU “hubo un deseo generalizado de declarar el campo de batalla de Gettysburg como monumento. Esto fue algo inédito: un enorme paisaje poblado de miles de acres de campo, caminos y granjas convirtiéndose en monumento de un evento que había ocurrido allí.” Se refiere al sitio histórico de Gettysburg, donde en 1863 se libró la mayor batalla de la Guerra Civil de EEUU y donde Lincoln pronunció un famoso discurso conocido como el Gettysburg Address.
Translating burial and exhumation histories from the petrological and geochronological record of high-pressure assemblages in subduction channels is key to understanding subduction channel processes. Convective return flow, either serpentinite or sediment hosted, has been suggested as a potential mechanism to retrieve rocks from significant depths and exhume them. Numerical modelling predicts that during convective flow, subducted material can be cycled within a serpentinite-filled subduction channel. Geochronological and petrological evidences for such cycling during subduction are preserved in lawsonite eclogite from serpentinite melange in the Southern New England Orogen, eastern Australia. Ar–Ar, Rb–Sr phengite and U–Pb titanite geochronology, supported by phase equilibrium forward modelling and mineral zoning, suggest Cambro–Ordovician eclogite underwent two stages of burial separated by a stage of partial exhumation. The initial subduction of the eclogite at ca. 490 Ma formed porphyroblastic prograde-zoned garnet and lawsonite at approximate P–T conditions of at least 2.9 GPa and 600 °C. Partial exhumation to at least 2.0 GPa and 500 °C is recorded by garnet dissolution. Reburial of the eclogite resulted in growth of new Mg-rich garnet rims, growth of new prograde-zoned phengite and recrystallization of titanite at P–T conditions of approximately 2.7 GPa and 590 °C. U–Pb titanite, and Ar–Ar and Rb–Sr phengite ages constrain the timing of reburial to ca. 450 Ma. This was followed by a second exhumation event at approximately 1.9 GPa and 520 °C. These conditions fall along a cold approximate geotherm of 230 °C/GPa. The inferred changes in pressure suggest the lawsonite eclogite underwent depth cycling within the subduction channel. Geochronological data indicate that partial exhumation and reburial occurred over ca. 50 M y., providing some estimation on the timescales of material convective cycling in the subduction channel.
This paper describes the modelling of the behaviour of a large precast concrete segmental arch structure during construction over a main line railway. The main aim of the modelling was to accurately predict the deflections of the segmental arch during construction and to set trigger levels to prevent another failure similar to that which occurred at Gerrards Cross, UK. The failure at Gerrards Cross, reported in 2005, demonstrated the importance of controlling the backfill and carefully controlling and monitoring the deflections of the arch during construction. To enable accurate predictions, finite-difference analysis of the precast segmental structure was utilised, which takes account of the soil–structure interaction effects covering structure and soil stiffness. Many sensitivity analyses were necessary to predict lower and upper bounds using predominant parameters that influenced the behaviour and included the movement of the arches on the piled foundations. Observations taken on site of movements of the arch during construction showed that actual deflections matched the predicted movements to a very high degree.
