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3.6 In some cases, GCL rolls will be stacked in three pyramids on flatbed trucks. If slings are not used, <br />rolls will require unloading with a stinger bar and extendible boom fork lift. Spreader bars will not <br />work in this situation because of the limited access between the stacks of GCL. Three types of <br />stingers are available from CETCO (Figures 2-4). To unload, guide the stinger through the core tube <br />before lifting the GCL roll and removing from the truck. <br />3.7 An extendible boom fork lift with a stinger bar is required for unloading vans. Rolls in the <br />nose and center of van should first be carefully pulled toward the door using the slings <br />provided on the rolls. <br />3.8 Rolls should be stored at the job site away from high-traffic areas but sufficiently close to <br />the active work area to minimize handling. The designated storage area should be flat, <br />dry and stable. Moisture protection of the GCL is provided by its packaging; however, an <br />additional tarpaulin or plastic sheet is recommended. <br />3.9 Rolls should be stacked in a manner that prevents them from sliding or rolling. This can <br />be accomplished by chocking the bottom layer of rolls. Rolls should be stacked no higher <br />than the height at which they caridbe safely handled by laborers (typically no higher than <br />four Layers of rolls). Rolls should never be stacked on end. <br />SUBGRADE PREPARATION ~ <br />4.1 subgrade surfaces consisting of granular soils or gravel may not be acceptable due to their <br />large void fraction and puncture potential. In high-head (greater than one foot or 30 cm) <br />applications, subgrade soils should possess a particle size distribution such that at least 80 <br />percent of the soil is finer than a #60 sieve (0.250 mm) unless amembrane-laminated GCL <br />(Bentomat CL or Bentomat CLT) is used. <br />4.2 When the GCL is placed over an earthen subgrade, the subgrade surface must be prepared in <br />accordance with the project specifications. The engineer's approval of the subgrade must be <br />obtained prior to installation. The finished surface should be firm and unyielding, without abrupt <br />elevation changes, voids, cracks, ice, or standing water. <br />4.3 The subgrade surface must be smooth and free of vegetation, sharp-edged rocks, stones, <br />sticks, construction debris, and other foreign matter that could contact the GCL. The <br />subgrade should be rolled with asmooth-drum compactor to remove any wheel ruts, <br />footprints, or other abrupt grade changes. Furthermore, all protrusions extending more than <br />1 inch (25 mm) from the subgrade surface shall be removed, crushed, or pushed into the <br />surface with asmooth-drum compactor. The GCL may be installed on a frozen subgrade, but <br />the subgrade soil in the unfrozen state should meet the above requirements. <br />0 <br />BENTOMAT/CLAYMAX Installation Guidelines <br />6of15 <br />