Trusted Foundation Repair from Residential to
Heavy Commercial
The capacity of helical piers is directly related to the installation torque. The installation torque can be measured by either converting installation pressure to torque or using calibrated monitoring equipment with direct torque readings. The torque heads are calibrated yearly to ensure that each installation meets the minimum torque values specified.
For large scale projects, pre-production verification test may be performed. Pre-production verification test elements are installed to a specified torque value correlating to an ultimate load capacity of 200% of the design load. The elements are loaded either in tension or compression through a test beam and a calibrated center-hole hydraulic jack. The tests are loaded incrementally to 200% of the design load. The movement of the element is measured at each load increment with dial indicators.
The capacity of micropiles is developed through the grout to ground skin friction along the length of the pile. Full scale verification testing is commonly performed on micropiles to verify the grout to ground bond stress values assumed in design.
Like helical pier verification testing; micropiles are tested to 200% of the design load in accordance with NHI-05-039, “Design and Construction of Micropiles”. The verification test is a cyclic test that includes a minimum 10-minute creep test at 130% of design load. After the pile is loaded to 200% of the design load, it is unloaded back to a 5% alignment load, where permanent (residual) movement is determined.
In addition to verification tests, proof tests are also frequently performed on production micropiles. Proof testing is typically performed on approximately 5% of the production micropiles. Proof tests are generally taken to a load corresponding to 160% of the design load.
Compressive strength testing is typically performed on micropile grout by a 3rd party. Straight Line Construction also uses a Baroid Mud Balance to verify the specific gravity of each hopper of grout batched. The specific gravity for structural grout is typically between 1.80 and 1.90 which correlates to a water to cement ratio of 0.45 to 0.40.
Similar to micropiles, pre-production verification testing is generally performed on soil nails to verify the grout to ground bond stress values assumed in design. Proof tests are also typically performed on 5% of the production nails. Soil nail grout is also typically tested for compressive strength by a 3rd party. Test panels of the shotcrete may also be sprayed to facilitate taking cores of the shotcrete for compressive strength testing.
Preproduction verification tests are typically run to 133% of anchor design load, unless the bond length is in material that is susceptible to creep, where the anchor would be tested to 150% of design load. The preproduction verification test is a cyclic test with a minimum 10-minute creep test at the maximum test load. If the creep does not exceed 0.040” in 10 minutes, it is discontinued; if it exceeds 0.040” in 10 minutes the test is extended another 50 minutes. The total creep cannot exceed 0.080” for the entire 60-minute hold or else the anchor is considered unacceptable. After the creep test, the anchor is unloaded back to the initial alignment load and a permanent movement reading is taken. The difference between the total movement at maximum test load and the permanent movement at alignment load yields the total elastic movement the anchor experienced during the test. The elastic movement can be used to determine the apparent free length of the tieback anchor. The anchor must de-bond 80% of the unbonded length, but no more than the unbonded length plus 50% of the bond length to be considered acceptable.
Performance tests are cyclic load test identical to the pre-production verification test, except they are performed on production anchors. All the same acceptance criteria apply to the performance test that apply to the verification test. Typically, 5% of the production anchors are subjected to performance testing on a project. After a performance test is deemed acceptable, the anchor is typically loaded to 70% of ultimate and locked off at that load. The typical design load of an anchor does not exceed 60% of the anchor ultimate strength and locking off 10% higher allows for some losses in prestress force.
The balance of the anchors that are not subject to performance testing are proof tested. The proof test is not a cyclic loading schedule, as the load is advanced directly to the creep load at 133% or 150% of design load, is held for the creep portion of the test and unloaded to the initial alignment load for the permanent movement reading. The anchor is then loaded to70% of ultimate load and locked off.
Tieback Anchor grout is also tested for compressive strength in accordance with ASTM C109, typically by a 3rd party testing laboratory. Straight Line Construction/Ram Jack Companies utilize a mud balance to verify the specific gravity of each hopper of grout batched. Ideally, the specific gravity for structural grout is between 1.80 and 1.90. Since the grout typically used for tieback anchors is a simple water and cement grout, the specific gravity of the grout relates directly to the water/cement ratio and corresponding compressive strength of the grout. A study was conducted with CTL Thompson-Pueblo, Printz Engineering Services, LLC and Straight Line Construction during the micropile installation at the CSU Pueblo Academic Resources Center. Mud balance testing was performed on each batch of grout and the results were compared to the compressive strength test results from the grout cubes. Samples with specific gravities of 1.80 to 1.90 consistently yielded compressive strengths in excess of 3,000 psi in three days (data is available upon request). Performing mud balance testing of each grout batch helps to immediately ensure that quality structural grout is consistently being used, prior to receiving compressive strength results.
Grout volumes are measured at each injection location throughout the treatment depth to determine the appropriate cut-off criteria. Cut-off criteria for compaction grouting generally involves reaching one of three criteria; a specified grout volume per foot is achieved, a maximum injection pressure is reached, or, unwanted ground movement or grout return at the surface occurs. The slump of the grout may be measured in the field to help verify the appropriate grout consistency is being achieved. Compressive strength specimens may also be taken on the grout. Elevations are also typically monitored during compaction grouting to monitor and minimize unwanted movement.
Mudjacking, or slabjacking, involves drilling 1 ¾” holes into the concrete and injecting a cementitious grout slurry consisting of water, sand and cement under the slab. The injected grout first fills the voids under the slab and once filled, additional grout is injected creating enough pressure to recover the slab up to its original elevation as much as the slab will allow. Mudjacking/Slabjacking is an effective technique for raising lightly loaded concrete flatwork (sidewalks, driveways, garage floors, patios, porches, etc.). Elevations are monitored with a Ziplevel during the repair to determine when the appropriate recovery has been achieved.
Polyurethane Foam Injection takes the original concept of Mudjacking/Slabjacking with cementitious material and combines it with the use of high-density, low-weight, expansive polyurethane foam to recover slabs back to a desired elevation. Small diameter holes are drilled into the concrete slab and structural grade polyurethane foam is injected into the void below the slab. After the void is filled, the expanding properties of the polyurethane foam creates pressure resulting in recovery of the concrete slab. Elevations are monitored during treatment with a Ziplevel to determine when appropriate lift has been achieved.
ROC# 269692 / ROC# 291336 / ROC # 312650
Straight Line & RamJack Corporate Office
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Northern Colorado: (303) 716-7437 Southern Colorado: (719) 545-9942
Arizona: (480) 941-3448 New Mexico: (505) 771-8890
Straight Line Construction has changed a great deal over the last 30+ years in the industry, but one thing remains the same: our commitment to quality and to designing and installing permanent solutions to foundation settlement issues. Beginning with small residential jobs more than 30 years ago when the family-owned company was founded by Tim Davis, Sr., Straight Line Construction today repairs cracking residential and commercial foundations through its Ram Jack product toolkit and designs solutions for large infrastructure and industrial projects. We specialize in matching the right solution to each type of foundation repair issue.
Are you building a new home and want to ensure it has a solid foundation? Or is your house experiencing unwanted sagging or a cracking foundation? Are your walls cracked or your doors and windows sticking? As a bonded, licensed, and fully insured foundation repair company, we are proud to serve Colorado homeowners, builders, and commercial contractors. Our technical certifications enable us to offer the highest quality services and the best American-made, environmentally safe products available for foundation repair. Regardless of how your building is shifting or sinking, we can help you stop it. Our 30 years in the business and our designation as a Ram Jack certified dealer means you get the most technologically savvy solution to fix your foundation.
From the factory to the field, we strive to ensure the quality of our products and workmanship meet the highest industry standards. We work with other vetted professionals in the industry. All of our helical piers, push piers, and mounting brackets are manufactured by Ram Jack in Ada, OK, at an ISO-certified facility with American-made steel. Williams Form Engineering in Golden, CO, manufactures our reinforcing bar for ground anchor systems and shares our commitment to quality control and quality assurance.
Ram Jack is a family-owned business that began operations in 1968, in Ada, OK, where we currently source our piers and brackets. Back then, concrete piering was the original repair method used simply because it was the only technology available at the time. Over time, it became evident that concrete piers did not provide long-term stabilization of foundations and only provided a short-term warranty period. To guarantee the highest grade of customer satisfaction, a greater solution needed to be found.
The Ram Jack owners embarked on a research program to develop a foundation repair system to stand the test of time. The U.S. Patent and Trademark Office first issued a patent to Ram Jack for its foundation repair system in 1985. Over the next few years, additional refinements and patents have followed, resulting in the strongest patented system in the industry. Ram Jack driven pilings are ICC-ES recognized (International Construction Code—Evaluation Services). Ram Jack is one of only two ICC-ES recognized foundation repair companies in the industry. Ram Jack’s products meet or exceed code requirements set down by ICC-ES for both commercial and residential properties.
CO: (303) 716-7437 AZ: (480) 941-3448 NM: (505) 771-8890
