Contractor Inquiry Responses, California Toll Bridge Seismic Retrofit


04-043824

CONTRACTOR'S INQUIRY RESPONSES NO. 1,

OCTOBER 2, 1998



1) CALTRANS TOLL BRIDGE PROGRAM ADDRESS

The Caltrans District 4 Office is located at 111 Grand Avenue, Oakland, CA 94612. The mailing address is P.O. Box 23660, Oakland, CA 94623-0660. The Toll Bridge Duty Senior telephone number is (510) 286-5549, and the fax number for Contractor's inquiries submittals is (510) 286-4563

1) Would contract plan electronic files be available to contractor?

Contract plan electronic files will not be available to Contractors.

2) Coastwise trade determination for qualified barges.

"A non-coastwise qualified barge may be used as a moored stationary work platform within the territorial waters of the United States without violating the coastwise laws, provided that it transport neither passengers nor merchandise while under tow between coastwise points." Contractors have to get all the appropriate permits from the US Coast Guard.

3) Does the worker's compensation insurance for this project fall under the jurisdiction of the United States Longshore and Harbor Worker Act/or the Jones Act?

The Jones Act (46 U.S.C. & 13 et seq.) applies to seamen and shipping and does not relate to construction workers on the bridge. The Longshore and Harbor Workers' Compensation Act (33 U.S.C. & 901 et seq.) applies to employees engaged in maritime employment. A federal court decision of the Fourth Circuit Court of Appeals has held that a construction worker employment in building a bridge over navigable water, designed to benefit both traffic and navigation, is engaged in maritime employment under the Longshore and Harbor Workers' Compensation Act. (LeMelle v. B.F. Diamond Const. Co.)(1982) (674 Fed2.d 296). Under California law (Lab. Code & 3700), every employer is responsible for being insured against liability to pay workers' compensation. That responsibility is incorporated into the Department of Transportation's (Department) construction contracts under the provisions of the Standard Specifications Section 7-1.01(A)(6) that requires the construction contractor to certify compliance with Labor Code Section 3700.

4) Reference page 98 in Section 10-1.19, "Piling," of the special provisions. "Steel shells for cast-in-place concrete piling and 14-inch diameter steel pipe piles to be installed through precast pile cap assemblies may conflict with existing battered steel piles. The Contractor shall field locate the existing battered piles ..." Regarding specified method of locating possibly conflicting existing steel piles accurately with respect to downward batter angle and horizontal skew angle by locating a minimum of two points along the existing piles separated by a minimum horizontal distance of 5 feet. The deeper point of the two will be in the order of 30 feet below seabed. The seabed can be up to 60 feet below sea level. The orientation of the H piles will be uncertain, and at any point in the ground the H pile can change direction. Under these circumstances we would doubt that many H piles can be found and when found that the two points do reliably predict the location of the pile at deeper levels. Please specify a realistic method for locating H piles.

The special provisions clearly state that the Contractor shall determine the method of locating existing piles. Therefore, the bidder should bid as shown in the contract plans and specifications.

5) On sheet 24 of 512 the bolt symbology legend is displayed. The symbol for existing fastener to remain in place is a circle with a cross hair. On page 249 of 512 the same symbol is displayed with the comment, "remove existing rivets typ." Which is correct?

The symbols on sheet 24 of 512 are correct. The note "remove existing rivets typ" on sheet 249 of 512 is also correct. However this note refers to the existing rivets that are not being replaced by bolts but are interfering with the new cover plates or batten plates. The heads of these rivets should be removed at these locations. If an optional splice on the EBF frame is deemed unnecessary, can it be deleted?

6) If an optional splice on the EBF frame is deemed unnecessary, can it be deleted?

Yes, optional splices can be deleted. The EBF members can only be spliced at the locations shown. The Contractor cannot move the locations of the splices-even the optional splices.

7) Special Provisions Section 10-1.41, Column Restrainer Brackets, requires that all brackets shall be cleaned and painted in accordance with the provisions in Sections 59-2, "Painting Structural Steel," and 91, "Paint," of the Standard Specifications and the following: (Spec Provision 10-1.41, par. 7, indented text). However, the restrainer brackets for the 10 ft. diameter columns are to be fully encased in concrete. Is it necessary to paint these concrete encased brackets?

Yes, the brackets should be painted as specified.

8) Referring to Special Provisions Section 10-1.35, Steel Structures, Measurement and Payment on page 153. The payment reduction penalties for fabrication sited in excess of 300 or 3,000 air line miles from both Sacramento and Los Angeles appear to be excessive based upon the estimated steel quantities on this project. Please review and give economic consideration to the $0.020 and $0.036 per pound bid item reduction penalties for CalTrans shop inspection expenses.

No, the payment reduction penalties due to shop inspection as specified in the special provisions will not be revised.

9) In reviewing the special provisions Section 10-1.13, "Maintaining Traffic," the 2nd. paragraph states "No work that would require a lane or shoulder closure shall be performed. "We are interested in bidding the Ready-Mix Concrete for this project and would like to clarify if concrete trucks can be staged on the roadway to supply concrete for the cast in steel shell piles and structural concrete requirements of this project.

No lane and shoulder closures will be permitted as per Section 10-1.13, "Maintaining Traffic." Therefore, concrete trucks will not be allowed to stage on the roadway to supply concrete.

10) Reference note 2 on page 161 of 512 of contract plans.

a) Where can we find the dimensions of the existing Armor rock that was placed around the piers in 1987?

b) What is the grading of this rock and can it be reused?

a) The approximate limits of existing armor rock that was placed in 1987 can be found on As-built plans for the 04-002434 contract. It should be noted that between the time of original construction and the 1987 placement of armor rock there were other contracts under which course backfill, armor rock, and/or revetment rock was placed at piers.

b) For contract 04-002434, the grading is 1/4 ton size with Method B Placement. Rock that is obtained during the pier excavations that conforms to the provisions in Section 72-2, "Rock Slope Protection," of the Standard Specifications and the special provisions may be reused. Information concerning size and/or grading of the course backfill, armor rock, and revetment rock is being forwarded to the Toll Bridge Duty Senior, telephone number (510) 286-5549 at 111 Grand Avenue Oakland, California 94601.

11) The Fender Plans (sheets 455 and 463) show existing rock backfill at Piers 33,34,35, and 47. A reference is given to a Drawing No. C-1034-2 "Rockfill At Piers," 1967. Sheet No. 161 refers to 11 piers that have existing armor rock placed in 1987.

a) Are these 15 piers the only ones that have existing armor rock and/or rock backfill?

b) Is armor rock and rock backfill the same thing?

c) Is the excavation and removal of existing armor rock and rock backfill to be paid under dredging item (which is removal and disposal of bay sediments)?

d) If the rock cannot be reused, can the Contractor move the rock out of the way of the new work without having to remove it from the site?

a) No, there is a rock type backfill at all piers.

b) No, they are not the same thing.

c) Measurement and payment for the removal and disposal of existing armor rock and rock backfill shall adhere to the provisions in Section 10-1.15, "Earthwork," and Section 10-1.15A, "Dredging," of the special provisions.

d) Lateral displacement of bay sediments material, including rock and rock backfill, will not be allowed.

12) a) What are the allowable construction loads that can be placed on top of the existing piers?

b) What are the allowable construction loads that can be placed on the existing spandrels?

a & b) The Contractor may use the existing structure for temporary support, work platforms, load test frames, and for anchoring and supporting erection equipment. The Contractor shall verify by calculation the adequacy of the existing structure for the temporary loads that the Contractor proposes to impose on the existing structure. The allowable loads that can be sustained by the existing piers will depend on the orientation, method of application, and the position of the Contractor's proposed temporary loads.

13) Are the HS Bars shown in drawing section G-G on Sheet 81 required for panel "A" where there is no "B" or "C" panel above?

When there are no "B" or "C" panels above panel "A" the HS bars shown in Section G-G on sheet 81 that connect panels "B" or "C" to panel "A" may be ommitted. HS bars are required for connecting panels "D" and "F" to panel "A" as shown on Section D-D on sheet 80.

14) The EBF steel in most cases can be installed in much larger sizes and weights if the STATE allows the Contractor to temporarily brace the existing tower legs so that all transverse steel, "K-frames," can be removed. What is the intent of the designer on this issue? Will the STATE allow a temporary bracing scheme that opens up the area between the tower legs for EBF installation? If not all levels, how many of the levels can be removed at once?

It is the responsibility of the Contractor to provide a temporary bracing system that maintains the stability and load carrying capacity of the existing structure during removal of portions of the existing steel towers, as per Section 10-1.14B, "Temporary Bracing System," of the special provisions.

15) Refer to Section 10-1.29, "Core Concrete," of the special provisions. Will the Contractor be required to submit concrete cores for inspection to the Engineer? If the submittal of cores for inspection will be required, at what intervals along the centerline of the core will core samples have to be taken and how long will each sample have to be?

The Contractor is not required to submit concrete core samples for inspection. However, the Engineer shall have access to the work, and the work shall be subject to inspection in accordance with the provisions in Section 5-1.08, "Inspection," of the Standard Specifications.

16) Who will be responsible for handling and disposing the concrete cores after inspection by the Engineer?

Concrete cores shall become the property of the Contractor and shall be disposed of outside the highway right of way in accordance with the provisions in Section 7-1.13, "Disposal of Material Outside the Highway Right of Way," of the Standard Specifications.

17) The only splice information concerning the box columns for the main span bents is indicated on sheet 313 of 512, "Box Column Connection Details." This sheet shows shop welding. How are the columns to be field spliced? If a CJP weld without steel backing is required please show the joint.

Field welding is not allowed. Steel backing bars are not allowed. If access for backgauging is not available and a welding process that would allow the CJP weld to be made without a backup bar or backgauging is not available, then a ceramic backing as shown on the plans should be used.

18) Is the bathemetry sonar soundings used to produce the subsurface elevation contours on Foundation Plan sheets 1 through 14, drawing sheets 43 through 56 of 512, available to planholders in either electronic, tabulated, or drawing format?

No, they are not available.

19)Sheet 159 of 512. The micropile elevations show shear rings cut into bell foundations spaced at 2 1/2 inches on center. Do you anticipate spalling of the concrete between the the rings? Can the rings be made larger and spaced further apart?

Only minor spalling at the outside corner of the groove is expected. The grooves shall be a minimum 1/2" deep. The height of the grooves may vary from 3/4" to 1 1/4" maximum. The spacing of the grooves is 2 1/2" as shown.

20)Sheets 78 and 79 of 512 shows the detail for the precast jacket panel bolted connection layout. If rebar is encountered while coring the existing diaphram walls or spandrels will coring through the existing rebar be acceptable? If not, how does the jacket get modified to suit a revised core hole layout?

Reinforcement encountered during coring of the concrete will not require repair.

21)Refer to page 131 of special provisions Section 10-1.25, "Concrete Jacket Assembly." It states "The joints shall be surface dry and the ambient temperature shall be 50 degrees F or above when the adhesive is applied unless otherwise approved by the Engineer." It appears these joints will be made underwater and in that case, these "dry" conditions cannot be met. Can the epoxy joint be made underwater?

The panel heights of the precast jackets were chosen to allow the epoxy joints to be made above water. Lower panels may need to be lowered and submerged prior to joining the upper panels. A successive joining-then-lowering operation is anticipated. An alternative construction method that allows the joints to be made underwater will be considered by the Engineer during contract administration. Alternative construction methods are subject to approval by the Engineer.

22)Sheet 158 of 512 shows a butt welded continuous #8 hoop for the main socket reinforcement. Can this reinforcing detail be changed to a continuous #8 spiral?

No, bundled, butt welded continuous #8 hoops are required.

23)Special Provisions Section 10-1.41, Column Restrainer Brackets, requires that all brackets shall be cleaned and painted in accordance with the provisions in Sections 59-2, "Painting Structural Steel," and 91, "Paint," of the Standard Specifications and the following: (Spec Provision 10-1.41, par. 7, indented text). However, the restrainer brackets for the 10 ft. diameter columns are to be fully encased in concrete. Is it necessary to paint these concrete encased brackets?

Yes, the brackets should be painted as specified.

24)Referring to Special Provisions Section 10-1.35, Steel Structures, Measurement and Payment on page 153. The payment reduction penalties for fabrication sited in excess of 300 or 3,000 air line miles from both Sacramento and Los Angeles appear to be excessive based upon the estimated steel quantities on this project. Please review and give economic consideration to the $0.020 and $0.036 per pound bid item reduction penalties for CalTrans shop inspection expenses.

No, the payment reduction penalties due to shop inspection as specified in the special provisions will not be revised.

25)What is the intent of cleaning on this project, Mechanical or Non Mechanical?
Typical requirements on prior jobs which we have done for US Navy, US Corp of Engineers, and various other Ports requiring underwater cleaning have requirements of either mechanical or nonmechanical. Typical requirements are as follows:
a. Mechanical, roughening of the existing surface to 1/4" amplitude.
b. Non Mechanical, removal of all soft organic material and loose debris from the exposed surfaces. All growth is removed with exception of firmly attached calcereous shells less than 1/4" in thickness. The removal of calcareous shells and basil plates less than 1/4" may create spalling of the existing concrete surface.

The concrete surfaces of bell foundations, shafts and diaphragms should be free of marine growth and fouling prior to the installation and grouting of the retrofit elements. Fan jet nozzles on 10,000 psi high pressure water jets have been found to be effective for this type of removal. Mechanical equipment may also be used.




Caltrans Toll Bridge Program always welcome any comments or suggestions.

Author:Yader A. Bermudez
Email:Bernie_Edrada@dot.ca.gov