LOCK+LOAD Engineering LOCK+LOAD is comprised of two pieces; a panel,and a counterfort that are assembled into a"Modular Cantilever". The assembled LOCK+LOADmodule has a face area of 3.5 sf (0.32sm) andweighs some 130lbs or < 40lbs/sf (59kg) 185kg/smmaking it the largest manually installed retainingwall facing on the market.LOCK+LOAD is used by itself for retaining walls inthe five foot high range. For taller retaining walls, LOCK+LOAD becomes a facing element for varioustypes of retaining structures.LOCK+LOAD has been utilized extensively in mechanically stabilized earth walls. These MSE walls can bedesigned by any code-approved procedure (AASHTO, NCMA etc.). All design procedures consider theparticulars of the facing elements used for the wall. These facing element design considerations include;component strength, durability, and connection mechanism.LOCK+LOAD elements are wet cast from 5500psi (42mpa) polyfiber reinforced concrete. Both elementshave steel reinforcement. The panel reinforcement is made of corrosion resistant steel that extends out ofthe panel back to provide a connecting loop for attachment to the counterfort.Engineering Considerations for LOCK+LOAD (assembled unit, panel hooked over the counterfort)Strength of PanelLOCK+LOAD tests the product by pulling the panel into the soil mass using the counterfort to test loopembedment strength. The steel connection loops pull out of the concrete panel at a value of ~6000 lbs(2727 kg) and provide a 75 year or 100 years design life, using standard AASHTO corrosion criteria for theconnecting steel. Standard LOCK+LOAD products have been tested and certified lab test reports areavailable upon request.Strength of Counterfort (panel soil reinforcement)The counterfort is embedded into the compacted fill, immediately behind the face panel. LOCK+LOAD hastested the embedment of the counterfort with various different confining stresses. The fill in the counterfortzone is currently specified as clean crushed rock compacted to a specific performance specification. Testsshow that the counterfort pullout resistance develops over 6 times faster than the driving forces thusensuring a large safety factor for counterfort connection to the soil mass. These tests are also availableupon request.Connection Strength of Primary Soil ReinforcementThe final connection consideration is the connection of the primary soil reinforcement (grid, wire mat, etc.)into the zone of backfill overlapping the counterfort. Since this is the crushed rock zone these connectionvalues can be easily calculated from the Ci (coefficient of interaction) values provided by reinforcementmanufactures. To verify these calculated values LOCK+LOAD has test data from several combinations ofprimary soil reinforcement types and manufacturers. In all cases the tested capacities exceed the calculated connection capacities.Since the strength of the counterfort and panel are never critical and pullout capacity increases rapidly withrising "overburden" stresses in retaining walls, "Connection" strength is rarely a critical design considerationfor LOCK+LOAD fascias. Current computer programs calculate the connection of the LOCK+LOAD modulesto the soil reinforcement as the pullout capacity generated by the primary soil reinforcement from the“crushed stone” zone overlapping the counterfort in their design.While LOCK+LOAD can be used on walls designed by numerous methods the MSEW3 & ReSSA3 softwareavailable from Adama Engineering (www.Geoprograms.com) are most often used with the test dataprovided.For specific questions regarding the design of a LOCK+LOAD facing for retaining walls or for test reportsplease contact: Technical Support