The URL can be used to link to this page

Home My WebLink About1983-08-02; City Council; 7457; Notice of Completion of Longard Tuben w > 0 cc e 2 NOTICE OF COMPLETION TlTLe FOR AB# 74' 3- 7 MTQ. 8/2/83 LONGARD TUBE DEPT. ENG DEW. HD..~. us CITY MOR,&% CITY AllY RECOMMENDED ACTION: I Accept the construction of the Longard Tube as complete and withhold release of bonds. ITEM EXPLANATION: Construction of the Longard Tube has been completed as verified by the City's Consultant, James Dunham. The property owners have Submitted a letter of approval. On December 16, 1982, the City entered into an agreement with the property owners to administer a contract for the installation of the Longard Tube. The completion of this contract fulfills that agreement. A legal Stop Notice has been filed by a subcontractor which requires the amount ($5,193) claimed by the subcontractor be withheld from the final payment. The Labor and Materials Bond will be retained until the claim is settled. The Stop Notice does not affect the City in any other way. I I FISCAL IMPACT: I The Contract amount was $115,797.60. The Contractor has been paid $77,198.60 and is due the final payment upon filing the Notice of Completion, less the amount of the claim. Funds are available in Account No. 30-18-90-3133 to pay the full amount of the contract. EXHIBITS: 1. Letter of Approval, dated July 22, 1983. 2. Letter of Inspection by Consultant, James Dunham 3. Notice of Completion I . 1. .. c each TErracQ Inn THE INN ON THE BEACH 2775 Ocean Street Carlsbad, Calif orn la 92008 (619) 729-5951 City of Carlsbad ' Engineering Department Carl sbad. July 22nd I983 Attention Bob h'ojick Reference to the Longard Tube installation. The participating property owners have been contacted and also given a copy of the report from James Dunhan our consultant for this project. This is to advise that all the owners are satisfied with the installation and it meets with their approval. As a matter of record though, it is understood when the tubes become exposed again t?-ds winter all the missed surfeces will be coated with the special epoxy. This was verbally agreed by Mr Neil Weis in my office. CALL TOLL FREE 1-800-528-7234, In Arizonia 1-800-352-1222, In Phoenix 956-7600 (1 -I. .d EXHIBIT 1 HARBORS. SHORE PROTECTION FLOOD CONTROL ,<. f 3342 BRADBURY RD. e40 LOS ALAMITOS, CA -720 (2 13) 430-2391 Engineering Department City of Carlsbad 1200 Elm Ave, Carlsbad, CA 92008 Gent lema : JAMES W. DUNHAM P.E. CALIFORNIA LICENSE NO. C 1 0.93 1 June 10, 1983 p?; J - r.JLu, " 4-~ -- I J ... / As the consultant to the City of Carlsbad on the installa- tion of a series of Longard Tubes along approximately 1200 feet of the City's shorefront, I inspected the work from time to time as it progressed, making 6 visits to the site in May and June, Because of the narrowness of the beach, the contractor could work only during the ueek or so of neap tides that occurred during the early part of each month. The double 40-inch tube at the south end was installed first, and because of the high elevation of the hardpan layer in that area it had to be placed about 2 feet higher than the 69-inch tubes to the north. Although it should function eves better than the lower-level tubss, it is more susceptible to dislodgeaent by high wzives. On the other hand such dislodgement is not as likely to damage the 40-inch tubes as their weight per linear foot is less, and the tensfon in the cloth is not as great as in the large tubes, The inner liner of the top tube was torn in one area by a broken bottle that got into the slurry and passed out the far end of the tube, The damaged section of tube was removed and the ends tied off on each side of the gap. The gap was then sealed off by another section of single 40-inch tube, placed in lap position behind it. Considarable difficulty resulted from the high percentage of cobbles in the sand used to fill the &-inch tubes, Atteapts to screen tkre cobbles out in the hopper only succeeded in clogging the screen so that the slurry would not fall into the hydraulic eductor, Tne tu3es were finally filled after repeated shutdowns and unblocking of the eductor, but the surface cloth was left humpy and a bit irregular, However, this should not Drevent the tubes fron breakir?g the waves and trapping sand, The contractor elected to install the first 100 meter length of 69-inch tube at the north end next. this area, allowing the tube to be placed in a trench with the bottom at about mean sea level as desired. A supply of sand that was relatively cobble-free was found for this tube, and the work progressed with fewer interruptions. I instructed the contractor The hardpan is lower in EXHIBIT 2 3 -12 . to place the tube about 10 feet farther seaward than he had in- tended, positioning it about 30 feet from the Beach Terrace seawall, This was Tnore difficult for him, because it left less room for a protective sand cofferdam to hold back t'ne sea,. However, the re- sult will provide a wider berm of trapped sand on which breaking waves will expend their energy when the sand fronting the tube goes out again next winter, The tube was filled just before the next series of high tides, and further work was deferred until the neap tides of June. The last two sections of 69-inch tube were placed early in June, A good supply of relatively cobble-free sand had drifted onto the beach since the May effort. Only one incident disruptad the June installations when the loading end of the last tube failed to drop to a lower level as expected, and the slurry impact on the trenched-in tube %o the north tore the inner liner, necessitating another break in tube continuity with a lap splice of extra tube. The contractor had devised an ingenious coupling which would have permitted successive sections of 69-inch tube to be joined end-to-end, Technical difficulties developed as he attempted to make the first coupling, and time did not pennit him to make the necessary adjustznent to perfect the coupling system, As a result, the successive sections of tube were lapped instead of butt-ended, Adequate lengths of tube were available for this purpose, however, and the result should be equally effective in providing continu- ous protection wi"&out gaps. The work was cornpleted June 7, 1993. All exDosed areas of tubing were treated with a sand-epoxy coat- ing. Iiowever, relatively little surface was exposed by this tine, as the sand level cn the beach was rising rapidly, Hhen the tubes become exposed again next winter, it would be desirabLe to coat the missed areas to prevent abrasion and tearing of the cloth by debris impact and vandals, Although no guarantee can be given as to the longevity of the tubes in the severe environment of the Pacific coast during winter storms, the low tube positioning at Carlsbad should provide optimum resistance to displacement by high waves consistent with adequate wave breaking and protection of the shoreline, It was initially intended to provide a filter-cloth apron fronting the tubes in areas where they could not be trenched all the way down to hardpan, However, recent demonstrations in other areas showed that such aprons were virtually useless during severe wave action and actually hastened tube deterioration by violent flapping of dislodged segments of cloth under high wave turbulence, For this season, I directad the contractor not to use the aprons, but to place the tubes as nearly as possible directly on the underlying hardpan, It is my opinion that the contractor complied as nearly as possible with all of my iastructions, and that the tubes should function as intended, It is understood that the Engineering Depart- ment will survey the actual tube locations and repeat the surveys next winter to detect any movement vertically or horizontally, If any serious displacements are detected, either the con-tractar or I should be contacted to determine wbether corrective action is necessary9 Very trul gt~urs, -22 F Jazes He Dunham cc: Longard Pacific