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HomeMy WebLinkAboutSecond Slab Evaluation~M :BEE LI~E SERV ICES • 06/19/~00G l b:~9 9729500605 FAX ND. :972 429 6643 TRIPLEl£T Jun. 20 2006 09 :31AM P2 PAGE ~2/65 --------------~---------------Mc CRORY ENGINEERING, INC. June6, 2006 Triple Net Properties, LLC Attri: Mr. Paul Albert 8360 LBJ Freeway, Suite 100 Dallas, TX 75243 Wolf Pen Plua Shoppma Cmter Second Slab Evalaatioa Revlalon 5121/06 SCOPE JUN 2 2 2006 COLLEGE STATION ENGINEERING As a result of a full inspection of the shopping center with two site visits, McCrory Engineering returned to take topographical ~ents of the int.erior slab. In addition, in order to prove or dib'prove movement of the perimeter wnll and main foundation, rooftop topographical re~inas were taken of the top of the tilt-wall panels. '--~~~~~~~R_O_O_F_P_ER.lME~~TE~R_E_LE~V_A_T_IO_N_S~~~~~~~-j The laser level was sm up in the center of the roof of the Ooode Department Store. Elevation reiulings w~ taken of the top of the tilt-wall panels. The top of the panels~ wve"m:l with metal flashins, which was not at~ys flllt against the concrete. Some elevation variatioM WC1'C attributed to this. Readings were taken at approxima1cly 15-ft intervals, starting above the front entrance, moving counterclockwise around the parapet. Readings were repeated every 24-ft in ~ clockwise direction to verify the first elevations readings. Thus, each area could be averaged to arrive at actual elevations. The elevation data was converted to inches above an arbitrary zero point. The data was tnul5fetred to a plan view drawing of the interior slab, columns, and perimeter wall. Tbe relative elevations of the top of the wall are circled in order to keep them separate form the interior elevation readings. 9894 Bis•onnet,J')tr: 740, Houston, 'hx.1 77036 'Jil (713) "34-!000 Fax (7l3) 484-SOOS ...-· EmAfl: dm<?C!rory@mc:C("OryHg..coin ~RGM :BEE LINE SERV ICES FRX NO. :972 429 6643 Jun. 20 2006 09:32RM P3 06/19/2006 16:29 97~9500605 TRIPLEl'ET PAGE 03/fji-:> INTERIOR SLAB SlJRF ACE ELEVATIONS In July of 2005, finished slab elevations were taken by Strong Surveying. On May 2, 1he same spots were measured to study possible elevation changes, and to establish a pattern of slab movement. The rcBulta of these new readings are shown on the plan view attached. Readings were found to be within %-inc::h of the readings taken in July of last year. The interior area of the main slab was consistently measured at 7.Ct'O or +~-inch. At "l'PfOximately 19-ft closer to the outer wall, the slab bad elevated an average of 1-112-inch. At the edge of the main slab, Swft from the outer wall, the average elevation had doubled. The slab then slopes backs approximately 1 ·inch at the outer wall. The main slab heave has the greatest infillf'llce at the south end, or highest grade point. Even on the east back the slab heave decreases to the nonh, as the influence of water has less and less affect. TM water influence cawdng the heaving picks up again on the east back of the Ro$S store, a lower slab. This heave also plays out when moving to the north. A section view of the pour strip. with its attachment to the wall panel and to tbe main slab, is shown on a section view taken from the original struchu'a1 drawing S4.l. The pour mp is attached to the tilt-wall by a series of reinforcing bars scrt on 12~inchc~ spacing. The pour strip is attached to the main slab with reinforcing rods set on 30..inoh centers. The reinforcing will follow the main slab up or down, but is pinned at the outer wall. The pour slab is able to swivel at both the outer wall 8i1d the main alsb. EXTERIOR REP AIRS The east back of Ross store is wet with asphalt sloping towards the building reta.inet wall. Rather than cutting down the asphalt, chains can be cut into the asphalt to direct water to the eMt avvay from the buildlllg. The best chain for this service is an open drain with grate covelr. This can be kept clean and well drained. Inspection indicated that water has been seeping from under the retaining wall. This water can be removed, and its effect minitniz.ed, by inst.alling drain holes at grade level so that trapped water can be continually removed from under the slab. A strainer must be installed in the drain to restrict soil erosion while allowing water to pass through. Page 2of5 1 FROM :'BEE LI NE SERVICES FRX NO. :972 429 6643 aG/1912006 16:20 972B5eese5 TRIPLEl'ET INTERIOR SLAB REPAIR Jun. 20 2006 09:32RM P4 f-'AC:.ili ~4/ E1b Tripi. Net Properties Wolf Pen Plaza June 6, 2006 The 5-ft pour strip along the perimeter wall is sloped an avaage of I ·inch. Once the soil under the slab is stabilized, this area can be leveled This involves removal of the tile or carpet, cleaning and etchi!lg the concrete surface, and application of a cementicious .. leveling compound. The to1al area involved is 400 .. ft by 5 .. ft in Width, for a total of 2,000-sq ft. The job will have to be done in sections that cause minimum conflict with the continuing operation of the stores. Most work will have to be done during the night. co:NCLUSIONS The roof parapet measurements indicated a maximum of 2-inch elevation variation in the south, east, and west walls. The variations, when compared to slab elevation variations, do not indicate subsidence of the outer wall, but a lifting of the main slab and pour strip. Since the pour strip j~ not free to move upward at the outer wall, it mnains stationary at the outer wall and pivots upward following 1he main slab. This results in an imagined subsidence of the outer wall. If the soil under the pour strip and edge of the main ~lab had been stabilized, or if moisture; content had been unchqed, no slab movement would have occurred. The same condition exists on the east back of the Ross Department Store, which is lower than the Ooode store. The water that affected the south upper face was absorbed into the lower soil at the Ross store. Little affect was found in the lower stores to the north, possibly because the water moved from south to northe8$t Wet, subsided exterior~ along the east back of the Ross store indicate the possibility of accumulation of water behind the retainer wall In order to control the water migrating under the slab from the south, it will be necessary to divert the water before h passes under the slab. This can be accomplished by collecting the water in an underground drain on the south end and around the east back. This should be sufficient to stop movement of the interior slab, which has likely reached its maximum heave. The soil expartsion due to water adsorption bas a maximum value. Ortte ~tumtion of the soil is reached. further expansion is impossible. If~ can be restricted, the main slab should move llP no further, and possibly subside. Pq:c3 ofS TRIPLDET RECOMMENDATIONS .. Trip~ Net Propertle!i Wotf~ Pia!!! June 6, 2006 It is recommended that a drain system be installed on the south end of the building and down the . east back to the south end of the Goode loading dock. The tot.al distance is approximately 28()..ft. The ncminal procedure shall proceed as follows; Ex:cavate a trench centered as close es practical to the south and el1st walls. Tue trench will cut through the asphalt, base, and sub-soil a depth of 4-112 ft, and should be a minimum of 30 .. inches wide. A loose medium gravel bed, 6-inches deep. shall be laid in the bottom of the trench. A 6 .. inch diameter perforated pipe shall be covered with a fiber sock and laid into the trench. Medium gravel shall be laid 12-inches wide on both sides of the pipe and a minimum of 18- inches above the pipe. At the tenn.ination of the perforated pipe drain, a 24 x 24-inch catch basin with traffic grate rover shall be installed and a 6~inch drain run to the mmn drain system. Compacted soil and a 3-inch thick concrete sidewalk shall be installed aaainst the building a width of 5-feet, sloped away from the wall. The remaining area shall be compacted and covered with Type D asphalt to match the surrounding drive area. All of the asphalt to the south of the building shall be sealed with 5tandard asphalt sealant to reduce water perm.en.don. The second phase of the project involves installing a total of folD' 12 x 12-inch catch basins to tie in roof downspouts located behind Goode and Ross storea. From tbeso boxes, open, grated drains should be set from the lowest points on the east back outward to the east. to points low enough to provide positive drainage away from the building. In the lowest points behind Ross store, four 4·ineh bores should be made at the low, w~ points at ~-1-1 ___ 1 _c .... ,_. " t _ -____ ,.,. . . • • -... ... --.. -· LJ . . . ...... -. _"""""".,, •• ,,.,..,. remove water trapped behind the retainer wall at the lo~ j,oints, preventing buildup of water during wet periods. Pagc4of5 FRU'M :BEE LI NE SERV ICES FRX NO. :972 429 6643 06/19./2006 16:28 9720500G05 TRIPLEl'£T Jun. 20 2006 09:33RM P5 PAGE 06/06 Triple Net PropenleS WoJf Per'! Plaza lune 6, 2006 A quote shell be submitted for leveling of the interior slab a distance of 5-ft back from the exterior wall. This involm; clearin& leveling and replacement of the carpeting or tile. This must be done one area at a time to minimi7.C downtime and disruption of customers. Specific . areas, such as the women's restroom must be done at night, and open for use during open hours. The mes to be leveled include all of the south wall area, and approximately 100-ft of the east back. An additional run of approximately 100-ft shall also be leveled along the east back of Ross store. The leveling material should be fast set. Hot air fans may be needed to speed the operation. Variations to this procedure. which may involve better procedure, may be submitted. Such variations shall be accompanied by explanation for the change. Pase 5of5