36E77618R0052-00006002.pdf

Y:\171\171-005 Iowa City VA Additions\DOCUMENTS\ADM'S\ADM-00006-open\171-005_VAIC Addendum No. 00006.doc 1

ADDENDUM NO. 00006 KENNETH HAHN ARCHITECTS

Architecture/Planning/ to the Interior Design/Engineering Specifications and Drawings 1343 South 75th Street Omaha, Nebraska 68124

24 APRIL 2018

KHA Project No. 171-005

IOWA CITY VA HEALTH CARE SYSTEM

CORRECT LIFE SAFETY DEFICIENCIES

Iowa City, Iowa

VA Project: 636A8-16-006

NOTICE TO BIDDERS: The Specification and Drawings for the above-referenced project are hereby amended as follows:

SPECIFICATIONS – VOLUME 1

ITEM NO. S-01, SECTION 31 63 26, DRILLED CAISSONS

A. Paragraph 1.5c, Classification of Excavation:

a. Revise 220 kN and 50,000 pounds to 44.5 kN and 10,000 pounds.

B. Paragraph 1.8, Submittals:

a. Delete sections D and G

b. Delete “observe load test” and “test results required for pile load tests” from section G

C. Paragraph 2.1, Materials:

a. Delete from section G “The Contractor shall design shells to withstand drilling forces and earth pressures and reinforce the bottom cutting edge as required for proper drilling and sealing of the shells into the rock. The cutting edge shall be capable of coring through at least 3000 mm (10 ft) of broken or solid rock. A minimum of 2% out of roundness of the diameter shall be considered in the design of the shell. All seams shall be welded and watertight.” Replace with “Contractor to supply water tight steel casing of sufficient length and thickness to withstand drilling forces and earth and water pressures.”

D. Paragraph 3.3, Placing Concrete

a. Revise section B to read “Place concrete using a down pipe to direct flow of concrete. Except in presence of water, concrete may fall freely the full shaft height provided the concrete does not hit the sides of the caisson.

DRAWINGS – VOLUME 1

ITEM NO. D-01, SHEET S1 – Structural General Notes A. Note F11 shall be revised to read “Drilled piers have been designed for an allowable end bearing of

80,000 psf on moderately weathered limestone bedrock. Assume tip elevation of 660 feet for bidding purposes”

B. Delete note F13 C. Note F15 shall be revised as follows: “Drilled pier concrete shall be placed using a sealed tremie as approved and directed by the Geotechnical engineer in the case of a wet shaft. If shaft is dry, concrete may fall freely the full shaft length.”