design will be significantly impacted by requirements to 

 transfer horizontal seismic and wind loads at the 

 foundation level and to provide overall stability of each 

 point of foundation support. These considerations should 

 be studied by the structural consultant early in the 

 design. 



Walkway 



Based on the plans provided by CBT, the proposed walkway 

 from the office structure to the pier structure will exist 

 one level below grade with the bottom at approximately El. 

 100.0. This level is within the intertidal zone range in 

 Boston Harbor, and is about 11 ft. below the 100 year 

 storm tide level. Therefore the walkway must be designed 

 with consideration for waterproofing, uplift loading due 

 to bouyant forces, hydrostatic and wave loading. The 

 walkway will also be subject to constructibility 

 difficulties similar to those outlined for the southern 

 foundation wall of the proposed underground garage. 



Therefore, unless the present walkway location is 

 essential to project development, it is suggested that the 

 walkway be relocated above grade and designed to bear on 

 pile foundations, similar to the pier structure. 



4-04. PROPOSED SITE DEVELOPMENT 



During definitive planning for the various structures and site 

 development, existing site and subsurface conditions must be 

 considered. The site is generally comprised of filled, 

 reclaimed land, with compressible organic soils underlying. 

 Granite block seawalls provide shore protection at the water's 

 edge. Within the site area structures exist which will require 

 demolition, timber piles and previously existing utilities will 

 be encountered during excavation. In consideration of these 

 site characteristics, the following preliminary criteria are 

 recommended: 



A. Site Utilities and Pavements . The site, being underlain 

 by a deposit of miscellaneous fill and organic soils, is 

 potentially susceptible to significant ground movements 

 and large differential surface settlements if additional 

 surface loading occurs by raising grades or adding 

 structural loads. If extensive filling is proposed within 

 the area of the site, settlement may be anticipated and 

 soil support of utilities may require surcharging or over 

 excavation of organic soils. Further evaluation of design 

 details for utilities and pavements in fill areas will be 

 required. 



-16- 



Aex 



OC 37 



