BOSTON i^UBLIC LIBRARY /M-/ r, ^(/ - GEOTECHNICAL DATA REPORT BRA PARCEL A BOSTON, MASSACHUSETTS m ^m ^^^« i^> PREPARED FOR: Chinese Economic Development Corporation 65 Harrison Avenue Boston, Massachusetts PREPARED BY: GZA GeoEnvironmental, Inc. Newton Upper Falls, Massachusetts August 1991 File No. 12547 GZA Copyright® 1991 GeoEnvironmental, Inc. GZA Engineersand GeoF.nvironmental, Inc. Scientists August 2, 1991 File No. 12547-C,PC Chinese Economic Development Corporation 65 Harrison Avenue Boston, Massachusetts 02111 Attention: Mr. Frank Chen, Executive Director oz\ Re: Geotechnical Data Report BRA A Parcel Boston, Massachusetts Dear Mr. Chen: 320NeedhamStreet NewtonUpperFalls Following the completion of subsurface explorations and geotechnical laboratory M6a1s7s-a9c6h9u-s0e0t5t0s02164 testing, GZA GeoEnvironmental, Inc. is pleased to present this geotechnical data FAX517-965-7769 report summarizing our findings. These data include a location plan of the proposed Parcel A development, locations ofthe borings, profiles of the subsurface explorations interpreted from the boring data which are more fully described on the enclosed individual boring logs, and the results of laboratory testing performed on selected undisturbed samples of the underlying clay deposits. A In addition to the enclosed data specific to the Parcel site, also contained are the results ofthe subsurface explorations and laboratorytesting completed for the adjacent Parcel B site for Asian Community Development Corporation (ACDC). The borings indicate the subsurface profile consists of miscellaneous fill, overlying compressible silty clay soils, overlying a thin glacial till, overlying argillite bedrock. The primary foundation engineering consideration is whether or not deep foundations should be used. This is a function of estimated total settlement due to compression of clay soils under the imposed structural loads from the proposed structures. Secondly, consideration must be given for the potential differential settlement between structures ASubsidiaryofGZA of differing foundation loads. Finally, consideration must be given to the potential GTeecohEnnovliorgioensm,enintca.l costs relative to disposal of the on-site fills, which is somewhat dependant on the number of basement levels and the foundation scheme ultimately selected. Three foundation systems are presently under consideration; a mat foundation bearing on the upper stiff clay deposit, caissons bearing within the clay, and deep end bearing piles bearing on the glacial till and/or bedrock. Each of these likely foundation schemes will be more fully discussed in a forthcoming foundation design summary report. This report will present a comparative cost analysis of the various alternates along with excavation and disposal cost estimates. GZA Copyright® 1991 GeoEnvironmental, Inc. AnEqudIOpportunityEmployerM/F/V/H CEDC August 2, 1991 File No. 12547 Page 2 In the meantime, should you have any questions with regard to the data contained herein, please do not hesitate to contact the undesigned. Very truly yours, oz\ GZKGEOENVIRONMENTAL, INC. K. Franklin M. Grynke Senior Project Manager C m<D ^ Walter Jaworsjci Senior PrmGii FMG:idm