04-0440U4

CONTRACTOR'S INQUIRY RESPONSES NO. 2,

MAY 13, 1998


MORE INQUIRIES (#3).

51)Reference Sheet 131- Elevation- Upper Right Interior Cell. There is a hidden line shown here. This hidden line also seems to appear in section A-A. The scope of what this is very unclear. Please provide additional detail as to what this is.

These details indicate an existing electrical conduit as shown in the as-built drawings.

52)Please provide top of pier elevations or some other information that will give us pier height information for Piers 4-12. As previously discussed, this information is vital in preparing our bid and needed as soon as possible.

Your attention is directed to the footing and bearing detail plan sheets in the as-built drawings.

53)Reference Specification Section 10-1.01, paragraph 13. Can the work of drill & bond and coring on the pier walls begin prior to completion of foundation retrofit work?

Your attention is directed to Contract Addendums No. 1 and No. 3. Alternative construction methods are subject to the approval of the Engineer after the bid opening.

54)Please indicate if the gussets shown on Sheet 55 of 190 are found on both sides-top & bottom.

Your attention is directed to the note "Gusset plate, both sides (typ)" on contract plan sheet 55 of 190.

55)Throughout the drawings, many details show the replacement of existing bolts. Please verify that the new bolts being called for are the same size as the bolts they are replacing (reaming or drilling will not be required to perform the bolt replacement)

Your attention is directed to special provision section 10-1.36 "STEEL STRUCTURES", sub-section "REPLACE FASTENERS" and Contract Addendum No. 3 dated January 12, 1998.

56)Detail 1 on Sheet 56 of 190 shows the plan view for the bolt layout at the floor-beam connection and shear lock. Please indicate if the bolt pattern is the same on both sides- top gusset plate and bottom gusset plate. View C-C shows no bolting to the underside of the floor beam.

Section C-C is not intended to show the bolt pattern. See Detail 1 for the bolt pattern on both top and bottom gussets. Additionally, your attention is directed to special provision section 10-1.36 "STEEL STRUCTURES", sub-section "REPLACE FASTENERS" and Contract Addendum No. 3 dated January 12, 1998.

57)Sheet 47 of 190 shows two retrofit locations scheduled for the type 3 construction, while Sheet 50 of 190 calls for the Type 3 retrofit at Pier 4 only. Please clarify.

Your attention is directed to Contract Addendum No. 2 dated January 9, 1998.

58)In order to prevent the inflow of soft materials above the rock into the 72" casing during the operation of seating the 72"casing into rock, it would seem better to drive the 72"casing rather than drill below it. If the driving became difficult, then it would be appropriate to drill below the casing, or use other methods, to facilitate its installation. The last paragraph on page 90 of the special provisions does not allow this. Can this provision be modified?

No. SEE ADDENDUM No. 5 FOR NEW REVISIONS TO THESE SPECIFICATIONS.

59)Working Drawings, page 97 requires "details and methods for locating the center of the existing concrete filled caissons, for monitoring, controlling, and verifying the alignment of the drilling or coring operations through the center of the existing caissons". Does Caltrans know of any method that would satisfy these requirements?

See list of companies with this technology on Contractor's Inquiry Responses No. 1. SEE ADDENDUM No. 5 FOR NEW REVISIONS TO SPECIFICATIONS.

60)Specification pages 98 and 99 regarding 17-inch diameter drilling. It is stated that "equipment used to drill or core through concrete filled caissons shall be capable of cutting through existing bar reinforcing steel." Further it is stated that "Percussion type drills shall not be used". We anticipate subcontractors may exclude drilling through steel from their price. Will Caltrans reconsider equipment requirements and allow the use of percussion down the hole hammers to lessen the risk of drilling through rebar spiders, or a bid item to deal with it?

No. Bid what is in the contract plans and specifications. SEE ADDENDUM No. 5 FOR NEW REVISIONS TO SPECIFICATIONS.

61)The section "drilled shafts" on page 91 of the special provisions allows the use of casing to prevent the caving at the interface of the existing caissons and the bedrock. If casing is used then it would be necessary to reduce the hole size below 17" in the rock in order for the drill bit to pass through the casing. Is this acceptable?

Bid what is in the contract plans and specifications.

62)Section A-A Sheet 114 shows top and bottom steel to remain. Section A-A Sheet 116 does not show how the top steel is to be incorporated into the new footing concrete. Please advise?

Bid what is in the contract plans and specifications. The stated reinforcement is not intended to be spliced or extended. SEE ADDENDUM No. 5 FOR NEW REVISIONS TO SPECIFICATIONS.

63)The structural plans (i.e. Sheet 116, HS Threaded Bar Detail) indicate coupler locations are subject to the approval of the Engineer. Can you provide more information to the locations allowed at this time due to the fact that the cofferdam size, as stated on Special Provision p. 83 depends on the location of the couplers?

Your attention is directed to contract plan sheet 140 of 190. Bid what is in the contract plans and specifications. SEE ADDENDUM No. 5 FOR NEW REVISIONS TO SPECIFICACIONS.

64)Please provide shop drawings of the existing Pier and Footing formwork that may be in place per Special Provision section 10-1.19E.

As-built plans and shop drawings are available for viewing through District 4, contact Duty Senior at (510)286-5549.

65)Reference Section C-C Sheet 132- the exterior pier corners- dimension 4'-0" max. & varies. It appears in the elevation that this is also true for the 2'-8' dimension and the interior 2' and 3' dimensions. Please confirm.

Your attention is directed to Addendum No. 2 dated January 9, 1998.

66)Reference Section M-M Sheet 133. The Drill and Bond call outs reference Note 3. What is this to be?

Your attention is directed to Addendum No. 2 dated January 9, 1998.

67)Reference special provision Section 10-1.32 "DRILL AND BOND DOWELS" which states "Drilling and bonding of dowels or high strength threaded rods with couplers shall conform to the details shown on the plans, the provisions in Section 83-2.02D(1), "General," of the Standard Specification and these special provisions." Section 83-2.02D(1) is a concrete barrier specification and requires that dowels be bonded in holes 1/2" larger than the nominal dowel diameter with magnesium phosphate concrete. Is the intent that all drill and bond dowels and high strength threaded rods for the project conform to this specification instead of Section 51-1.13 which specifies 1/4" larger holes and cement grout?

The provisions in Section 10-1.32 "DRILL AND BOND DOWELS" of the special provisions are correct.

68)With reference to drawing 41 of 76, detail 3 and section C-C... The existing bottom chord at panel point LO is a welded box end section. The existing shop drawings show no hand holes or access openings to allow for the installation of the horizontal stiffeners or 5x4x1/2" angles.

The As-built drawings indicates"Perforations 10"X18" at 3'-0" centers." These perforations are obvious from a field review.

69)Additionally, the size of the box section does not allow sufficient clearance for bolt tightening. Please clarify this detail.

The clearance is adequate.

70)With reference to drawing 89 of 190, the jacking points shown in stage 2 and stage 3, projected down to the bearing pedestal, interfere with the new bearing bolt circle. The projected jacking point falls only 5-1/2" from the edge of the pedestal (and could possibly be only 3" with a 30°F temperature change). Using the stated allowable bearing pressure of 1,500 psi (note 8, sheet 81 of 190) and the specified developed loads ((DL+LL)x1.5) which are in the order of 3,200 kip, a bearing area of 2,133 in (insert squared) is required. In addition to there being only 1,152 in (insert squared) available on the jacking pedestal, (sheet 93 of 190) the 1,000 ton jack required to accomplish this task has a diameter of 36" which puts it well within the bolt pattern and isolator bearing.Please confirm the validity of your prescribed details with respect to the bearing/jacking pedestals with consideration to accommodating the factored loads and allowable bearing pressure on new concrete.

Your attention is directed to Section 1-1.19C "RAISE BRIDGE", sub-section "GENERAL" of the special provisions. Specifically review paragraphs 5 and 10 in the above mentioned section. Any portion of the pier top (not only the leveled portion of the bearing pedestal) may be used to support jacking loads and meet the maximum bearing pressure requirements, subject to the approval of the Engineer. The contractor is responsible for design of jacking assemblies and temporary supports. Permanent or temporary alterations of the structure in connection with jacking and the jacking assemblies are permitted, subject to the approval of the Engineer. SEE ADDENDUM No. 5 FOR NEW REVISIONS TO SPECIFICATIONS.

71)Reference : "Description of work and construction sequence" Plan Sheet 120 of 190. Can the work in the later sequence steps occur prior to the completion of the earlier step?

Your attention is directed to Contract Addendum No. 1 dated December 23, 1997.

72)In regards to curing concrete, Section 90-7.01D of the Standard Specifications titled "Forms- In- Place Method" states that "forms shall be left in place for a minimum period of seven days after the concrete has been placed, except that for members over 20 inches in the least dimension the forms shall remain in place for a minimum period of 5 days." Is the minimum member dimension defined as the sum of existing and new concrete where new concrete is cast against existing concrete?

Per the provisions in Section 90-7.01D "Forms-In-Place-Method", the "20 inches in least dimension" applies to all new concrete sections only.

73)A substantial amount of work for the project is to take place inside of the pier cells below sea level. The Plans and Specifications do not address the current condition of the existing piers. Will the existing piers be water tight? If not, how much water infiltration can be expected?

Bid the contract plans and special provisions.

74)Regarding plan sheet #81 of 190 - Temporary Support Notes; There seems to be a discrepancy as to how the required jacking force can be provided and still remain below the maximum bearing pressure of 1,500 psi. Please see the table below.

Your attention is directed to Section 1-1.19C "RAISE BRIDGE", sub-section "GENERAL" of the special provisions. Specifically review paragraphs 5 and 10 in the above mentioned section. Any portion of the pier top (not only the leveled portion of the bearing pedestal) may be used to support jacking loads and meet the maximum bearing pressure requirements, subject to the approval of the Engineer. The contractor is responsible for design of jacking assemblies and temporary supports. Permanent or temporary alterations of the structure in connection with jacking and the jacking assemblies are permitted, subject to the approval of the Engineer. SEE ADDENDUM No. 5 FOR NEW REVISIONS TO SPECIFICATIONS.

75)We may be misinterpreting the loads and the application of the loads to the jacking points. We assumed the loads presented in the table provided on sheet #81 of 190 are to be applied at each jacking location. This assumption is what is driving the higher bearing stress discussed above. Please verify that we are using the forces correctly.

Your calculation approach is generally correct. Notes 1 and 8 on sheet 81 of 190 describe specific requirements for jacking process, and bearing pressure. No construction loads were included in your calculations of the loads (see note 1, sheet 81 of 190). SEE ADDENDUM No. 5 FOR NEW REVISIONS TO SPECIFICATIONS.

76)On contract plan sheet 72 of 190, section A-A: Note the 7/8" bolts that are called out to be removed. The head of the bolt appears to be cast in the deck. Is the intended construction to involve removal of the existing concrete deck to gain access to remove the existing bolts?

Your attention is directed to Contract Addendum No. 3 dated January 12, 1998.

77)With reference to clause 10-1.01 of the Special Provisions wherein it is stated that "Prior to beginning bearing replacement at any pier from Piers 3 through 13, inclusive, all pier work, except associated bearing replacement work, shall be completed, and all associated new concrete shall have obtained 100 percent of its specified strength..." Please clarify if this means that bearing replacement cannot begin until all pier work on all eleven piers has been completed, or can replacement of the bearings on a specific pier begin when the work on that specific pier only has been completed?

Bearing replacement can proceed on an individual pier after the substructure work on that pier is complete.

78)The elevations and table shown on contract plan sheet 47 of 190. Define a "location" for Type II retrofits as 1 (one) panel [i.e. L1-L2, L2-L3, etc.] ... On contract plan 49 of 190, the detail entitled "Retrofit Location at Expansion Hinge" defines a "location" as spanning 2 (two) panels [i.e. L1-L3], please clarify.

Your attention is directed to Contract Addendum No. 2 dated January 9, 1998.

79)Plan sheet 114 of 190 calls for phased demolition and construction of the Pier 3 & 13 footings. How are the joints between the new and the "to be demolished" concrete to be constructed? How are the rebar details to be handled? Please provide details for this situation, as well as for the similar situation at Piers 4-12 (please reference plan sheet 118 of 190).

It is anticipated that reinforcement couplers will be used to facilitate staging. For piers 4 through 12, refer to contract plan sheet 139 of 190. SEE ADDENDUM No. 5 FOR NEW REVISIONS TO SPECIFICATIONS.

80)After reviewing the construction drawings and specifications, we have come up short the 3,030,000 lbs shown for Bid Item 62, Furnish Structural Steel (Bridge). We are somewhat uncertain exactly what steel materials have been included in the above mentioned weight. Please help us by providing a rough outline of what has been included in the structural steel and the approximate weights.

Your attention is directed to Section 10-1.36 "STEEL STRUCTURES", sub-sections "GENERAL" AND "MEASUREMENT AND PAYMENT" of the special provisions. Additionally review special provision section 10-1.39 "MISCELLANEOUS METAL (BRIDGE).

81)Is the weight of any alternate design shown on the plans included in the bid item amount?

No.

82)Are the jacking shoes at Piers 7 through Pier 12 shown on Sheet 90 of 190 considered permanent items of structural steel?

Yes. SEE ADDENDUM No. 5 FOR NEW REVISIONS TO SPECIFICATIONS.

83)Spec page 108, 10-1.25 para 20: Can additional holes other than those shown on plans be cored for concrete placement? There are not sufficient holes shown, for the placement of concrete in the interior pier walls.

Bid what is in the contract plans and specifications. Alternative construction methods are subject to approval of the Engineer after the bid opening.

84)LOADTEST, Inc. Pricing shown in the table on page 87 of the special provisions is only good to January 1, 1998. Will Caltrans have LOADTEST, Inc. Extend their pricing to 30 days after actual bid date?

Your attention is directed to Contract Addendum No. 1 dated December 23, 1997. SEE ADDENDUM No. 5 FOR NEW REVISIONS TO SPECIFICATIONS.

85)Spec. P. 94, right column, 2nd paragraph. What would the Engineer consider an adequate repair or replacement in the event the caisson concrete is rejected?

Bid what is in the contract plans and specifications. Repair or replacement would require the same structural properties as that indicated by the contract plans and specifications.

86)Can the construction joints required in the footings at pier 3 & 13 at the center line of the bridge per note 4 on drawing sheet 114 be moved slightly to accommodate the type B tiedown anchor formed hole placement shown on the plan view on sheet 115 at these locations? Additionally, what type of coupler is allowed at this location for the reinforcement?

Yes, minor adjustments of the construction joint locations are acceptable, however revised locations will have to be approved by the Engineer after the bid opening.

87)Please indicate how the vertical reinforcing shown "clouded" in the attached section L-L of drawing 139 of 190 is spliced. The existing slab conflicts with the vertical bars because of construction sequencing.

Your attention is directed to contract plan sheet 118 of 190 for bridge removal and staging. Additionally splicing shall conform to the splicing requirements elsewhere in this contract.

88)Please clarify the note shown at the bottom of Detail 12 on Sheet 97 of 190. Are the 1-inch diameter rods to be cast in concrete and bolted to the existing L8 x 6 x 7/16 only?

No. Both of the 1-inch diameter rods are intended to be attached, one end on the new angle (which is part of Contract No. 04-044024) and one end to the existing angle. Your attention is directed to special provision section 10-1.06 "COOPERATION" for this contract.

89)The Engineers Estimate does not indicate bid item 34 as a final pay item, however Special Provisions p. 110, section 10-1.25 last paragraph indicates that the limits of payment will not change. Please clarify.

The provisions following MEASUREMENT AND PAYMENT in Section 10-1.25 "CONCRETE STRUCTURES" are correct.

90)Regarding temporary jacking shoe and gusset plates, How must the holes drilled for temporary gusset plates be filled after the gusset is removed?

Your attention is directed to special provisions Section 10-1.19C "RAISE BRIDGE. SEE ADDENDUM No. 5 FOR NEW REVISIONS TO SPECIFICATIONS.

91)Is A36 material acceptable for the circular shear ring bars on sheet 27 of 190?

Your attention is directed to to Section 10-1.21 "PILING - CAISSON - Materials." "Shear ring bars shall conform to ASTM Designation: A 709, Grade 36."

92)Reference Addendum 1, Page 1, Paragraph 6, beginning with, "On Project Plan Sheet 120, Notes 1-6 under "description of work...". Can Note 4 wall strengthening be completed prior to or during Item #3?

Alternative construction methods are subject to approval of the Engineer after the bid opening.

93)Reference Specification 5-1.23 RELATIONS WITH U.S. COAST GUARD which states "The Contractor shall not moor their vessel(s) to the bridge structure." It will be necessary to tie off material barges at each pier. Does this specification preclude material barges from being tied off to the fender systems or footings of the piers?

Your attention is directed Section 5-1.33 "LOADS ON STRUCTURES" in the special provisions. SEE ADDENDUM No. 5 FOR NEW REVISIONS TO SPECIFICATIONS.

94)Reference Specification 10-1.26 FURNISH SEISMIC ISOLATOR BEARING. A proprietary supplier of the bearing has been specified by Caltrans. However, the Contractor is held responsible for satisfying the acceptance criteria of the prototype and proof testing, including any delays caused by the failure of the bearing to meet the specifications. It is impossible for the Contractor to determine the cost associated with the risk of the failure of the bearing(s) to meet the acceptance criteria. Please include provisions in the specifications that relieve the Contractor of this risk.

Bid the contract plans and specifications. SEE ADDENDUM No. 5 FOR NEW REVISIONS TO SPECIFICATIONS.

95)Reference Specification 13A-2 RAILROAD PROTECTIVE INSURANCE which states ³The approximate ratio of the estimated cost of the work over or under or within 50 feet of Railroad¹s tracks to the overall estimated cost is 0.50. Approximate daily train traffic is 60 passenger trains and 5 freight trains.² Upon inspection of the site, it appears that this frequency of train traffic applies to the railroad bridge across the Carquinez Strait. None of the work under this contract is within 50 feet of the tracks on the railroad bridge. However, the work at Pier 3 is within 50 feet of the railroad tracks along Bayshore Road. Is Railroad Protective Insurance required under this contract? If so, please clarify the requirements.

Yes. Bid it in accordance to Section 13A-2, "Railroad Protective Insurance."

96)With reference to 2nd paragraph of clause entitled"Epoxy - Coated Reinforcement" on page 130 of the Special Provisions which states: "All reinforcing steel bars, including dowels, which are placed in holes drilled into or cored through the exterior surfaces of the existing structure, shall be epoxy coated." Please confirm / clarify if it is the intent of this contract that only reinforcing steel placed in holes cored through the exterior surfaces of the existing structure be epoxy coated and hence, all other reinforcing steel shall not be epoxy coated.

Your attention is directed to special provisions Section 10-1.35 "REINFORCEMENT", sub-section "EPOXY-COATED REINFORCEMENT." The second paragraph identifies the minimum limits of epoxy coated reinforcement placed in cored holes through exterior walls of the existing structure.

97)Ref. Plan Sheet No. 60, "Hinge Bottom Lateral Retrofit Details No. 3": As presently shown, shear lock assemblies can not be installed without removing one of the existing bottom struts. Please advise.

The existing gusset plates for the left strut member shown on "Detail 5 top view", and "Bottom Gusset-Top View" are to be removed and replaced. The referenced strut member may be temporarily removed to allow for placement of shear lock assemblies, and reinstalled upon completion of work. Construction methods and alternatives are subject to the approval of the Engineer.

98)Ref. Plan Sheet No. 65, "Hinge Truss Retrofit Details No. 2": Please confirm the existing 8" diameter pins require removal to allow removal and replacement of existing pin plates.

Yes the existing 8" dia pin may be removed to provide access for removal and replacement of the pin plates. Construction methods and alternatives are subject to the approval of the Engineer.

99)I have found a major discrepancy in the core concrete quantities on the Benicia Bridge Retrofit, contract no. 04-0440U4. The most significant differences are in items no. 42, 44, and 49. Please verify that your quantities are correct.

Items 42 & 44 - On sheet 123 of 190, "HS threaded bar detail", the location of coupler at the interface of 3" diameter and 1-7/8" diameter cored holes is governed by clearance within the adjacent existing voided cells for the horizontal bars, and by clearance at the top of existing concrete filled cells for the vertical bars. Item 49 - Refer to sheets 116, 123 thru 125, 134 of 190 for the majority of the 1-1/2" diameter cored holes. Note that the quantity of the cored holes shown on sheet 134 of 190 depends on the height of the lower portions in piers 3 and 13 which are different. Refer to sheet 131 of 190 for the said height dimensions. Bid it as you see it.

100)On contract plan sheets 82 and 92 of 190: Please confirm jacking brackets, shoes and gussets are to be paid for as Furnish Structural Steel (Bridge) and Erect Structural Steel (Bridge).

Yes, the said items are to be paid as Furnish Structural Steel (Bridge) and Erect Structural Steel (Bridge).

101)We have completed our takeoffs on Bid Items #39, 41, 42, 43, 44, 45, 46, 49, 50, and 51 and have come up with quantities significantly different than the bid quantities. We also have contacted subcontractors for these items that have encountered the same problems. Please advise?

Your attention is directed to Addendum No. 3 and the following contract plan sheets of 190:

Item 39: contract plan sheets 72,125 and 133.

Items 41 & 46: contract plan sheets 116 and 140.

Items 42 & 44: contract plan sheet 123.

Item 43: contract plan sheet 139.

Item 45: contract plan sheet 136.

Item 49: contract plan sheets 116, 123, 125,131 and 134.

Item 50: contract plan sheets 123.

Item 51: contract plan sheets 116, 123, 124, 125 and 126.

Additionally: Items 42 & 44 - On sheet 123 of 190, "HS threaded bar detail", the location of coupler at the interface of 3" diameter and 1-7/8" diameter cored holes is governeed by clearance within the adjacent existing voided cells for the horizontal bars, and by clearance at the top of existing concrete filled cells for the vertical bars. Bid it as you see it.

Item 49 - Refer to sheets 116, 123 thru 125, 134 of 190 for the majority of the 1-1/2" diameter cored holes. Note that the quantity of the cored holes shown on sheet 134 of 190 depends on the height of the lower portions in piers 3 and 13 which are different. Refer to sheet 131 of 190 for the said height dimensions. Bid it as you see it.

102)SECTION 10-1.19 of the special provisions makes the contractor responsible for making arrangements for transportation and disposal of the paint debris and is silent on who will sign the required manifest. We request clarification that the State will be designated as the "Generator", responsible party, or owner" of any pre-existing hazardous or contaminated material.

The Engineer is responsible for signing the manifests.


MORE INQUIRIES (#3).



For comments and questions regarding this web site, contact the webmaster at DTB_Webmaster_Dist04@dot.ca.gov.