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r <br /> I <br /> NORTH WALL APPARENT THICKNESS AND REINFORCING IS <br /> PROVIDED AS AN ATTACHMENT TO ADDENDUM 3. <br /> Q14. Sheet Si Section F states that the ultimate bond stress for the micropiles is to <br /> be 27psi. In our experience, the stated value is extremely conservative and will <br /> result in micropile lengths that are extremely long with very high deflections. Is <br /> it acceptable for the micropile designer to select an ultimate bond stress for the <br /> micropile design? <br /> RESPONSE: THE PILE SYSTEM IS A PERFORMANCE BASED DESIGN. <br /> THE BONDING CRITERIA IS PROVIDED FOR THE DESIGNER TO <br /> DETERMINE THE REQUIRED BONDING LENGTH. THE CONTRACTOR IS <br /> ' ULTIMATELY RESPONSIBLE TO PROVIDE A PILE SYSTEM THAT MEETS <br /> THE LOAD AND CREEP REQUIREMENTS OF THE SPECIFICATION. IF <br /> THE CONTRACTOR CHOOSES TO USE A HIGHER SKIN FRICTION AND, <br /> WHEN TESTED, IT DOES NOT MEET THE ACCEPTANCE CRITERIA, <br /> THEN A NEW DESIGN AND VERIFICATION TEST WILL NEED TO BE <br /> PERFORMED AT THE EXPENSE OF THE CONTRACTOR. <br /> Q15. What is the deflection criteria for the micropiles? <br /> RESPONSE: SEE SPECIFICATION 31 61 00.3.03 F AND L FOR <br /> ACCEPTANCE CRITERIA. <br /> Q16. The geotechnical report that was provided doesn't provide micropile design <br /> information, however it seems like they must be involved because the <br /> structural drawings provide some specific geotechnical design criteria for the <br /> micropiles. Has Terracon has issued supplementary info regarding the pile <br /> design criteria, including verifying the pile design requirements such as skin <br /> friction, minimum cased length if required, minimum embedment depth, <br /> downdrag if required, testing requirements if varied from what in the spec, and <br /> any other relevant information? The spec seems to state there is <br /> supplemental pile information available. <br /> RESPONSE:A SUPPLEMENTAL GEOTECHNICAL REPORT PERTAINING <br /> TO THE MICROPILE DESIGN HAS BEEN PROVIDED AS PART OF <br /> ADDENDUM 3. <br /> Q17. The drawings list the required pile capacity in ultimate values (276 kips) that I <br /> assume already has an unknown factor of safety applied, but we need to know <br /> the required allowable capacity so we can apply the appropriate factor of <br /> safety. Pile designs should be provided in allowable values so a 2.0 factor of <br /> safety can be applied to the geotechnical design criteria per the spec. <br /> RESPONSE: LOADING AND SKIN FRICTION ARE BOTH PRESENTED AS <br /> ULTIMATE NUMBERS SO AN ADDITIONAL FACTOR OF SAFETY HAS <br /> ALREADY BEEN INCORPORATED. <br /> 1 <br /> Addendum 3 to Evergreen Pump Station Modifications(WO#UP3747-3) Page 15/17 <br /> rCITY OF EVERETT • 3200 Cedar Street • Everett, WA 98201 • (425)257-8800 • Fax(425)257-8882 <br />