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Home My WebLink About05/21/1991, 6 - PLANS AND SPECIFICATIONS FOR CRACK REPAIR PROJECT FOR PALM STREET AND MARSH STREET PARKING STRUCTURES, CITY PLAN NO. R-39D Original Agenda report-"- mm 5/7/91 meeting. / MffT1NG DATE ' city of san gats owpo COUNCIL AGENDA REPORT IT6vl NUMBER. FROM: David F. Romero, Public Works Director SUBJECT: Plans and specifications for crack repair project for Palm Street and Marsh Street parking structures, City Plan No. R-39D CAO RECOMMENDATION: By motion, approve the plans and specifications for crack repair for the Palm Street and Marsh Street parking structures and authorize solicitation of bids and awarding of contract if lowest responsible bid is within Engineer's estimate BACKGROUND: At its meeting of March 19, 1991, the City Council considered plans and specifications for sealing a number of cracks in the walls of the two parking structures. Council was concerned that these cracks represented some level of failure of the parking structure, or improper workmanship, and requested that staff obtain additional information justifying the need for this work. Attached are letters from Conrad and Associates, the original design consultant; Fred Schott and Associates, a local structural engineering firm hired to investigate the cracks on the Marsh Street structure; and Applied Engineering, a local engineering firm hired to investigate the Palm Street structure. All three of the consultants recommend epoxy injection of the cracks so as to prevent corrosion of the reinforcing steel. All three indicated that these are primarily surface cracks and not structural in nature. Conrad indicates that these cracks are not uncommon in this type of structure. None of the consultants indicate, nor does the staff believe, that the cracks are a result of improper workmanship. Even if improper workmanship could be proven, the contractor guarantee is for one year and it is now more than two years since the Palm Street structure was accepted. 94% of the crack sealing will take place at the Palm Street structure. DISCUSSION: Staff believes that this kind of cracking is inherent with this design of structure and that it still must be protected or face the risk of ultimate failure of the parking structure due to corrosion. ALTERNATIVES: 1. The project could be delayed until a later date, with a probable increase in cost and probable corrosion damage to the steel. 2. The project could be reduced by eliminating the Marsh Street structure from the contract, since these cracks are very, very minor and are generally closed during the warmer weather thus minimizing the rain water penetration to the steel. ,��r��'�►fullllllllll� ��ll city of San tins OBlspo 1 1111 .0 COUNCIL AGENDA REPORT Crack Sealing Page Two 3. Conduct work with City forces. If the contract approach is not approved, staff will have to attempt the epoxy injection with its own forces. Staff would rent equipment and materials locally and attempt to do the job. However, we are not expert in this type of operation and are not likely to do as good a job as a contractor specializing in this work. 4. Do nothing. Staff does not feel that the option of doing nothing is a viable one, since the structures would ultimately be subject to failure because of lack of proper maintenance. FISCAL IMPACT: The Engineer's estimate for the project is $42,000. This is a new project and monies have not been allocated for this repair work in the current budget. Funds will have to be allocated from the undesignated fund balance of the parking program. As reflected in the recent mid- year budget review, adequate balances are projected at year end to fund this project. However, the long-term financial status of the parking system continues to be a concern, and any unprogrammed outlay reduces the funds available for future capital purchases, such as acquisition of a third parking site. i i I Attachments: Council Agenda Report, 3/19/81 Conrad letter, April 10, 1991 Fred Schott letter, September 28, 1990 Applied Engineering letter, November 9, 1990 Page from specifications I NOTE: Plans and Specifications are on file in the City Clerk's Office. i i i I I crackseal/dfr#28 p�l��►B��Ilulllllllll`�IIUIII "J r ME ING DATE: �p�ml Cl o san �Uis oB�spo � / s- � COUNCIL AGENDA REPORT ITEM NUMBER: FROM: Dave Romero Wayne Peterson Prepared by: Reith Opalewski Public Works City Engineer Parking Manager SUW: Plans and Specifications for Crack Repair Project for Palm Street and Marsh Street Parking Structures. CAO RECOMMENDATION: By motion, approve the plans and specifications for crack repair for the Palm Street and Marsh Street Parking Structures and authorize soliciting of bids and awarding of contract if lowest responsible bid is within Engineer's estimate. BACKGROUND: Since the completion of the Palm Street Parking Structure in March 1988, there have been a number of structural cracks in the walls and floors. This is common with structures of this construction. These cracks are easily penetrated by water which is causing deterioration of the concrete and metal reinforcement in the walls and floors. If allowed to continue unchecked, this water penetration could cause serious damage and costly reconstruction to the structure. There have been similar cracks in the floor area of the new Marsh Street facility, but to a lesser degree. DISCUSSION: Through an epoxy injection system the floors and walls of both structures can be sealed to prevent further water damage. Approximately 3100 linear feet will have to sealed in the Palm Structure and 200 linear feet in the Marsh Structure. This application process in the most cost-effective and can be done with a minimum of disruption to the operations of each structure. The life expectancy of this project is unknown because of the nature of post-tension concrete contruction. Periodic inspections will be required to determine if additional repairs are needed. CONCURRENCES: The Engineering and Parking Divisions concur with the recommendation to epoxy seal the walls and floors. FISCAL II4PACT: The Engineer's estimate for the project is $42, 000. This is a new project and monies have not been allocated for this repair work in CTL / Of San L ,.,S OBISPO COUNCIL AGENDA REPORT Council Agenda Report Page Two the current budget. Funds will have to be allocated from the undesignated fund balance of the parking program. As reflected in the recent mid-year budget review, adequate balances are projected at year end to fund this project. However, the long-term financial status of the parking system continues to be a concern, and any unprogrammed outlay reduces the funds available for future capital purchases, such as acquisition of a third parking site. ALTERNATIVES: 1. Delay the project to a later date j 2. Reduce the scope of the project i 3. Cancel the project PROS AND CONS I It is possible to postpone the project, especially in light of our limited rainfall. However, any additional moisture from condensation or light rain will only accelerate the concrete deterioration. The longer we wait, the more costly for future repairs. Repairing only part of the cracks or completing only one structure would be less expensive in the short-term, but more costly in the long-term since the bidding and contract process j would have to be repeated. Cancelling the project would be short sighted and only cause more serious problems in the future. Approved: I City Administrative Officer I tt ey I .. I City Finance Director ! Public Works Director I (l/ — 1 Conrad Associates 5990 Sepulveda Wd.,Suite 200 P.O.Box 514 Nkn Nuys,CA 91408-0514 (818)901-0853 Apr i 1 10, 1991 (800)4Conrod In sa ffi m Caffom (800)533-7049 In caffgnla (818)901-7504 FAX David F. Romero, Director Public Works Department Raymondlraya 955 Morro Street P1e*11811 San Luis Obispo, CA 93401 J.Renard 1ef 6mcUmre VIMaaeloUK Dennis Slmonlan,AIA Afcht d Re: Palm Street Parking Structure and Antonio S.Wlsoni Marsh Street Parking Structure A00*ft S.E. Dear Mr. Romero: We received your letter dated March 26, 1991 in regards to epoxy injection for crack repair. The undersigned paid a visit to the structures on April 4 , 1991 and walked through the two parking structures with Tom Gingg to see the cracks referred to in your letter. In the Palm Street parking structure the cracks in the concrete walls and slabs appear to be of the same size and location as observed about a year ago. These cracks are caused by shortening (creep and shrinkage) of the postensioned floor system and are not uncommon in this type of structure. Since it was a very warm day it was practically impossible to find the slab cracks (which were leaking according to Tom Gingg) in the Marsh Street structure. Even though the above captioned cracks do not impair the structural safety of the structure, the cra�k ��sealed bby en�oxy injection to preventa f,rt,r� rnrrc�d;nQ o�obm of,, e__reinforcing steel and lengthening the useful life of the structures. We hope this information is sufficient for your needs at this time. If you have any questions please call. Sincerely, CONRAD ASSOCIATES Antonio S. Luisoni S.E. Associate APR A DMSION OF CONRAD BUILDING SMMS.INC. Fred H. Schott 81 Associates, Inc. CIVIL&STRUCTURAL ENGINEERING•LAND PLANNING R E C E I V E D SEP 2 8 1990 Se tember 27 , 1990 ENGINEERING DIVISION P cm of SAN LUIS OSISM Mr. Wayne Peterson San Luis Obispo City Engineer 955 Morro Street San Luis Obispo, CA 93401 Subject: Slab Cracking in the Northerly half of the Parking Structure Slab at the roof level Dear Wayne: Per your request we have made a site inspection, reviewed the original concrete mix designs prepared by Kaiser (#56055 & 6084 dated 5/26/89) and the revised and apparently approved mix design by Pacific Geoscience (Job No. PT-5420-W01 dated Sept. 7 , 1989) . We have also reviewed the General Structural Notes and specification requirements for concrete in the Construction documents as well as made a cursory examination of the structural plans and details as they might relate to slab cracking. The original (Kaiser) mix designs would have resulted in substantially greater shrinkage than the Pacific Geoscience mix design. While the mix design used is considerably finer than a mix designed to minimize shrinkage, it was obviously satisfactory in most of the structure. Most of the visible cracks in the northerly half of the roof slab run parallel to the beams (perpendicular to the direction of span for the slabs) . Some of these cracks do not extend through the slab while others do. There are a few cracks on the underside of the slab in the most northerly bay which are perpendicular to the beams (parallel to the slab span) . Our professional judgement is that the partial depth cracks in the top of the Slab are nl a-Etic _hri.^.kage C�.1.ck '::i,i1c the full dept-h .^..^..'�..$ :an y— y.. s. .. ..• draping shrinkage cracks emanating from the plastic shrinkage cracks. It is quite probable that this particular pour was made on a relatively dry, windy and probably warm day. None of acks aDDear to be s+rt•.. *�*��l—�a >,_g___and should not af_ ec. th<e_structgrjpLlpe�f,ormance__of th lab : n the near future Unfortunately_thr- full_depth.._cracka.._. wiJ.l allm rainwater to__penetrate_t-o_.the.-.slab_.r..einfor.c n.g steel resulting ir_ fu ter .rus.zn - _g_of the__.teinfor-cing._and ..4palling_of _the...adjacent concrete. Tl�oncrete should__be sealed. to prev_en _._.Lhis__..fut.u>te _deter crati.on. Evox% grout of� a crjzks u installation of a_surface membrane _ will accom lish that erbd. we would recommend the latter course since one would seal the entire surface--not just the larger cracks. This surface membrane must have sufficient flexibility and elasticity to bridge over any and all cracks. SAN LUIS OBISPO OFFICE (805)544-7276 SANTA MARIA OFFICE (805)925-3433 200 Suburban Rood.Suite A 9 San Luis Obispo.California 93401 222 west Carmen Lone.Suite 104 • Santa Marla.California 93454 'iptember 27 , 1990 Wayne Peterson Page 2 The cracks in the bottom surface of the end bay appear to reflect the prestressing strands and probably resulted from movement of the strands during concrete placement in the adjacent bay while the concrete was only partially hardened. Again these cracks do not appear to be structural in nature and should not affect the performance of the slab. The reinforcing steel in the slab is parallel to the cracks and may or may not be subjected to moisture in the cracks. It would probably be wise to seal by epoxy grouting or caulking. A second note of concern relates to the lateral force resisting system in the structure. The project structural calculations (sheets R1 through R47) do not cover lateral forces and a review of the plans does not reveal any obvious comprehensive and integrated lateral force resisting system. We suggest that you obtain copies of the lateral force system calculations and check the plans to insure that the calculation results have been incorporated into the plans and details. If you have any further questions in this matter please do not hesitate to contact us. . Sincerely yours, Fred H. Schott FHS:nsb i APPLIED O ENGINEERING P.O. Box 4445 708 Fiero Lane, Unit 12 San Luis Obispo, California 93403 David M. Carter P.E. 805/544-5684 Jeffrey CTParker P.E. November 9, 1990 C E i V a o City of San Luis Obispo NO VI Engineering/Parking 3 1990 955 Morro street �''a Esn�,u,�0er� San Luis Obispo, California 93401 Attention: Wayne Peterson Subject: 290087 -- Palm Street Parking Garage Evaluation of Concrete Cracking Dear Wayne: in accordance with your request, we observed existing cracking of concrete shear walls at the subject project with you on September 4, 1990. Generally the cracks observed were diagonal cracks extending from the top outer ends of shear walls to the interior lower edge of the shear walls. These cracks appear at lines of resistance where shear walls occur at opposite ends of the building such as at the north and west wall. For the purpose of this reportsouth an, Palm Street is walls which occur eapproximately rmidlengthth and uof. thethTha buildingd heast ave sustained no discernable damage. The west wall is continuous across the west end of the building, but is divided into 3 effective walls by control joints. virtually all of the cracking in the west wall occurs in the two end sections. The north wall occurs in two sections at opposite ends of the building, and the cracks are most severe near the ends of the building. in addition, the cracking was noted to be more severe at the lower levels. There is a pour strip extending across the structure at approximately midlength. This effectively uncouples the shear i walls along the north side from the effects of elastic shortening. The cracks appear to be a little more severe at the west end shear walls where there is no such pour strip to mitigate the effects of elastic shortening. The floor slabs are prestressed and are subject to the volumetric changes associated with prestressing. The walls are not prestressed, and undergo no such volumetric changes . The floor slabs' are cast into the walls. i Wayne Peterson November 9, 1990 page 2 It is our opinion that the cracks in the shear walls are due to a combination of stresses caused by elastic shortening of the floor slabs due to prestressing, and creep in the floor slabs due to the sustained compression from prestressing. Essentially, top ends of the shear walls together b rigid in compariare being pulled floor slabs, and the bottoms of the shear walls are relatively _ son. The diagonal cracks described above are the result. The west end wall is being stressed by the slab from both elastic shortening and the continuing action of creep in the slab. The north end wall is being stressed by the slab primarily from creep in the slab due to the sustained compression from prestressing, and not from Since the length of the slab is subsoritantiallynal more shortening. width, the effects of only the Gree more than the direction have an effect similar to the sum of elasticthe shortening and creep in the transverse direction. The total effects of creep can be in the range of double that due to the initial elastic shortening. Based upon the a age of the structure, we estimate that between 70% and 85%oOfmthe effects of. creep have been experienced to date. We have reviewed the material we received which was Sup contain calculations showing the magnitude of stress intheeshear walls. This documentation operation of the programs used�toained calculateythe xshear swalls, and "ad no actual calculations for the specific ro 'ect. of the do not know the level of stress in the shear walls. Th However, we must assume they are fairly highly stressed, and cannot accomodate the partial loss of the concrete component of shear resistance due to the cracking. We recommend that epoxy who has Tis may a accomplished b iniactinn he fi=n—moo Leit_he previouslyY the injection . sub-contractor parkin Performed similar work on the Marsh Street g structure for which we assume exist. Alternately, it may be accomplished fiwithonmaterials available locally. We have investigated an injection system by Anchor-it, and have specifications Prepared the attached guideline to describe groposed materials and procedures for the Anchor-it system. These materials are available locally through Cuesta Equipment, but the process requires some training. Therefore, the procedure must be supervised by a contractor or manufacturer's representative experienced in this type of work . You should be aware that since not all of the creep has occurred as described above, it is possible that additional cracking will occur after the current cracks are repaired. We- do the_t _you wait to E�air the cracks since the ema�n ercof�the creep w'IT't`ake a number of years to occur, and if the cracks become contaminated, any injection may be an ineffective repair. We suggest that you repair the current cracks, and resolve problems of any further cracking if and when they occur. �j Wayne Peterson November 9, 1990 page 3 It is the intent of the procedures described above to return the shear walls to as near their new condition as possible. It will restore the monolithic structure of the walls. It will not increase their load carrying capability above that originally available, nor will it necessarily preclude future cracking. Therefore,' we cannot be responsible for the original design of the structure. This responsibility remains with the original design Engineer. We hope this information is sufficient for your needs at this time. If you have any questions, please call. Sincerely yours, afE3S/ MU pyq�r,- v Z. David M. Cart r No. 1955 . SE1955/9-30-93 z SER 3O1998 .= ,� Jlq UCN�P —� Of CALF i iii► SECTION 5. LEGAL RELATIONS AND RESPONSIBILITIES TO THE PUBLIC. .S Y. Relief from Maintenance and Responsibility. Upon the request of the Contractor, the City of San Luis Obispo may relieve him of the duty of r maintaining and protecting certain portions of the work that have been completed in all respects in accordance with the requirements of the Contract and to the satisfaction of the Engineer, and thereafter except with his consent, the Contractor will not be required to do further work thereon. In addition, such action by the City will relieve the Contractor of responsibility for injury or damage to said completed portions of the work resulting from use by public traffic or from the action of the elements or from any other cause, but not from injury or damage resulting from the Contractor's own operations or from his negligence. However, nothing in this Article "W" providing for relief from maintenance and responsibility will be construed as relieving the Contractor of full responsibility for making good the defective work or materials found at any time before the formal written acceptance of the entire contract by the City of San Luis Obispo. Z. Personal Liability. Neither the City Council, the City Engineer, nor any other officer or authorized assistant or agent shall be personally responsible for any liability arising under the Contract. A-A. Responsibility for Damage. The City of San Luis Obispo, the City Council, the City Engineer, or his authorized assistants or agents, shall not be answerable or accountable in any manner for any loss or damage that may happen to the work or any part thereof, or for loss or damage to any material or equipment used in performing the work. B-B. Responsibility of the City. The City of San Luis Obispo shall not be held responsible for the care or protection of any material or parts of the work prior to final acceptance of the work, except as expressly provided in these specifications. C-C. Guarantee. The Contractor shall be responsible for faulty materials or vnr4n�nah+n and shall remedy any defects resulting therefrom appearing within one year from the completion of the project and shall pay for any damage to other work resulting therefor. �q,,M jT ; D-D. Acceptance of Contract. when the Engineer has made the final inspection and has determined that the contract has been completed in all respects in accordance with the plans and specifications, he will recommend that the City of San Luis Obispo formally accept the Contract. Unless conditions to the acceptance are imposed by the City of San Luis Obispo, immediately after acceptance by the City, the Contractor shall be relieved of the duty of maintaining and protecting the work as a whole, and he will not be required to perform any further work thereon, except as provided in Article "C-C", Guarantee, in this Section of the specifications. • 5-e