3000 ROCKEFELLER AVE PARKING GARAGE 2018-01-02 MF Import

`''it'di\Oi�,:.:°�'i� ��'':.livC. (UQC, 1997). The UBC requires that the seismicity of thc region be considered in building dcsign by rcquinng that stn�ctures bc designcd for ea�Yhquake ground motions with a 10 percent chancc of being cxceeded in 50 ycars (475-ycar recw-rencc). Accordingly, the UBC indicatcs that the project site is located in Scismic Zonc 3(pcak ground acccleration on rock of approximately 0.3g). Morc recent regional ground motion swdics conducted by thc Unitcd States Gcological Survcy (USGS) indicatc that thc pcak ground acccicration (PGA) for a 475- ycar recurrence in the vicinity of the site for "soft" rock condiiions �vould be approximately 0.33g. In addition to scismiciq�, thc UI3C :�Iso rcquires th:ll U1L flSE100$L' O� II1C $11V5Uf�acc soils at thc sitc bc considcrcd in dcvcloping dcsign carthquakc oround motions. Thc soil profilc cocfficicnt (5-factor) is used to represent thc soil conditions at thc sita Bccause thc projcct site is gencrally undcrlain by dcnsc to ��cry dcnsc and hard soiis, which arc anticipatcd to cxtcnd to a dcpth of sc��eral hundred feet, ��c rccommcnd that thc soils at this site be ch:iracterized as a UBC Soil Profilc Ty�C Sp TIIC COITCS�OII(II11�' SCISIIIIC COC��ICICIIIS C� 811(I C, h:i��c ��alucs of 0.33 :md 0.4i, respcctivcly. A scismic zonc factor, Z, of 0.30 is rccommendcd. ]0.3 I:artliyu.�kc-induced Gcologic llaz:�rds In gcncral, cailliquakc-induccd gcologic hazards may in�ludc liqucfaction, latcral sprc�ding, slopc inslahilily, and ground surG•�cc fa�ilt rupturc. In our opinion, thc potential for liqucfaction and latcral sprcading is not significant bcc;wsc of thc dcnsc/hard nature of thc on-sitc soils. Thc ground surfacc at the sitc slopcs gently down to thc nonhcast, thereforc, the potenti:d for significant carthyuakc-induccd slopc instability is ulso lo��. In our opinion, thc potential for ground surfacc fault nipturc at thc sitc is low bccausc thc ncarest known fault is in thc northwcst- southcast h'ending Southcrn \1'hidbc� Islan� I�:wlt zonc, loratcd approxim:uelp 5 to o miles southwcst of thc silc. IU.�I I�ooting I�oundalions �'Ve recommcnd that spread footing foundations bc used to support the proposed Administration Building Garagc. Based on our borings, native, vcry densc and hard, glacially-overtidden soil would Uc encountered at thc lowest floor clevations (73.5 to 53.5 (ecp. For footings bearing in the ��ery dense or haid, native soil, we recommend a m.��imum allo��able bearing capacity of 16 kips per squarc foot (ksn; this allu�e:�blc ��aluc corresponds to an ultimate bcaring capocity of 32 ks( in �,I;iri:�l soil. 'I�hc allo��'ablc �:iluc c:m hc incrcascd by one-third to account for �+�ind and :1.1-U��nu.lr�p-0tl.�.p IA�1 �U 21-1-0964�1-005