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6.1.A. - Page 28 <br /> be selected to try ta avoid underground u�ifities; and E�e sloped to avoid the need <br /> far temporary 5horinc�. <br /> • Consult�nt will ir�spect the tap one foot (or so) of uncovered piles at the edges; <br /> and examine the surFace soil samples f ground w�ter conditions. If fe�sible and <br /> located close enough to the edge� without requiring excessive excavatian, the <br /> first interior piles may also be exposed. <br /> � The excavatians will then be replaced. Using Redwood City standards, <br /> Consu�tant can provide a recarnmended approach for excavaticrn ar�d suitable <br /> soil replacement /��mpaction and repair a# the surface. The 7ikely replacement <br /> material wili be � cantrolled low strength mater��l (controlled der�sity fill}. <br /> + Consultant will reviewv the borings made during original constructian to estabiish <br /> sflil laye�in� and bounds far soil properkies. This will be suppl�mented by a <br /> geaphysical test (non-destructive) at each sit� to establish slaw-strain shear <br /> wave speeds for the site. <br /> • Consultant w�ll perform tank —�ile soil-structure interaction analy�es to estahlish <br /> the dynamic response of the tanks uncfer three s�ismic grQUnd mations (Loma <br /> Prieta, 475-year �nd 213 x 2,475 year) far the two tank sites. <br /> • Consu[t�nt will evaluate the likely ductility demands in the pile f pi�e-c�p <br /> eonnectivns under the Loma Pr�eta and the design basis ground motions. <br /> • Cansu�tant will develop recommend�tions as to #he seismic performanee of eacf� <br /> tank �nder desigr�-b�sis earti�q�akes, and any upgrades 1 operatior�al changes <br /> �hat are suitable. The upgrades might include: do nothing; �t�uctural <br /> improvement (new caissans) ta strengthen the overall tank-pife sys�em; lower <br /> wat�r ap�6a�ing levels to reduce seism�c forces; soil remediation. <br /> f Consultant wilM write a report that includes all fi�rdir�gs and recommendat�ons. <br /> Consultant wifl 5ubmit the report as draft, meet with Redwood Gity ad obtain <br /> camments, and is�ue as final. <br /> 5hould the recommendations inclucie seismic up�rades, Consult�nt can t��n pravide <br /> Redwoo� City with the desi�n s�rvices to implement t}�ese �pgrades. The cost of th�se <br /> serwices is not included in the iaa�e scc�pe af fhis propo��l. Deper�ding an th� f�ndings, <br /> the upgrades could range from operational only (install suitabfe ir�strumantatir�n and <br /> cont�ols to limit operationai water he�ghts}; or structurai (new caissor�s}; requiring fram <br /> between 2 to 10 sheets per tank. <br /> Task 5 Bid Pe�iod' Services (Optional) <br /> Consultant shalf assi�t Redwood �ity staff with the applicatian processes ta cabtain <br /> pe�mits as needed. '� <br /> For each p�ckage to be separately f�id (assumed 3) Con�ult�nt shall att�nd a pre-bid I � <br /> conferenc� for potential bidders and respond to questions and requ�st� for informatian <br /> frvm Cmntr�ctars during the bid p�riod. Consultant shall natify Reciwood �ity af any <br /> patentially si��ificant questic�ns and requests for information. <br /> ATTYlAGR12472.001fG8� ENGINEERING Page 24 af 3Q <br /> Q�E•n1 r�nr�7 <br />