Better Tieback Walls with CHANCE® Helical Tieback Anchors
A pre-engineered tieback system for earth retention supplied by the largest manufacturer of anchors in the world simplifies the challenges for contractors. These tieback anchors are installed by rotating the anchors into the ground with common rotary drilling equipment.
Once the minimum depth is obtained the capacity can be determined by reading the installing torque and correlating it to the holding capacity ratio.
Capacities to 200,000 pounds per anchor are obtainable with this system. Proven on hundreds of applications these cost effective tiebacks can be tested immediately. No concrete to wait for curing! This saves time and money plus improves schedules.
Your local CHANCE® Distributor can show you the advantages on specific applications.
Contractors are using the CHANCE anchor tieback system for these reasons:
- Installed anchors can be proof-tested immediately — no waiting for grout to cure
- Install in almost any weather, with conventional drilling equipment. No concrete trucks or grout pumps required
- Predictable holding strength in all soils
The success of the screw anchor tieback system is based on decades of similar use of CHANCE anchors by electric utilities. The proven reliability and engineered predictability of the system’s performance give you tiebacks that are positive, economical and hassle-free.
Typical Construction Applications:
- Building-site preparation
- Retaining walls
- Predictable results
- Cost-effective method
- Easy to store, reusable
- Pre-engineered system
- Labor-saving, keeps crew small
- Screws into place (not predrilled)
- Site-specific to conditions and loads
- Terminations for various threadbars
- Less equipment than grouted tendons
- Bearing device, not friction dependent
- Extendable with bolted joint connection
- Installs in any weather
- Installs in limited access areas
- No excavation or spoils to remove
- Immediate proof testing and loading
- Permanent or temporary (removable)
- Labor saving – as few as four on a crew
- Capacity proportional to installing torque
- No concrete trucks or grout pumps needed
- Install with equipment for grouted tendons
Faster Tieback Walls with all the Practical Advantages of Helical Anchors
Immediate pull testing of helical tieback anchors after installation serves as a check on design procedures and eliminates deflection at working loads.
No delays because there is no grout
- Typical production rate of 30 to 40 per day for installing and testing
- No holes to drill
- Cuts labor and equipment costs
- Can save 30% while obtaining high anchor-load capacities
Solves construction problems
- In cohesive soils, no belled and/or long sockets
- In non-cohesive soils, no casings or grouted sockets
- Bearing mode (not friction mode) anchors
- No de-watering for below-water-table applications
HeliCAP® Helical Capacity Design Software Sample Specs
Design and Build Means Just That with HeliCAP® Software!
HeliCAP® Helical Capacity Design Software helps design professionals quickly derive the proper helical tieback anchor for site- and load-specific data. For a free demo, click here. Then contact your local Distributor or Territory Manager about how to get a copy for your PC.
Site-Specific Basics of Screw Anchor Design
Two typical steps to anchorage design:
- Select helix configuration based on accurate soil characteristics data and tension load.
- Select shaft configuration based on tension load and anticipated installation torque.
- Anchor load capacity equals the sum of all its individual helix bearing capacities. Bearing capacity of each helix equals the product of its projected area and bearing pressure
- Pre-engineered CHANCE® screw anchors optimize helix spacing at three times the next lower helix diameter. This assures more predictable torque-to-capacity relationship
- Holding capacity is proportional to installation torque (recommended 10 lb per ft-lb)
- Monitor torque while installing to ensure a minimum and not to exceed anchor rating
- Sample Specification Guides are available here
Helical Tieback Anchors have shafts in five square sizes (1-1/4”, 1-1/2”, 1-3/4”, 2” and 2-1/4”) with helices in configurations of two to four and diameters from 6” to 14”. All components are available hot-dip galvanized per ASTM A 153 after fabrication.
Plain and helical extensions are used to reach competent load-bearing soil. Plain extensions range from 37” to 124” long. Helical extensions range from 48” to 124” long with 14”-diameter helices in single, double and triple configurations. Forged integral coupling sockets bolt-up quickly and efficiently transfer installing torque.
For job-specific combinations, leading sections range from 30” to 124” long in two-, three- or four-helix configurations usually with increasing diameters from the 6”, 8”, 10”, 12” and 14” range.
Terminations fit threadbar or provide a threaded stud to work with prefabricated or site-made lockoff devices. Other termination fittings also are available. In some cases, the through-hole at the shaft end may be simply crosspinned.
- 1” Threadbar Adapter for 1-1/2”, 1-3/4”and 2” Tieback Anchor Types
- 1-1/4” Threadbar Adapter for 2” and 2-1/4” Tieback Anchor Types
- 1-3/8” Threadbar Adapter for 2-1/4” Tieback Anchor Types
Threaded Stud Socket Adapter for 1-1/4” and 1-1/2” Tieback Anchors
Threaded Stud Clevis Adapter for 1-3/4” Tieback Anchors
* The Ultimate Capacity is based on the Installation Torque-Capacity relationship in soil.
For more detailed design information, contact your local Civil Construction distributor.
Calculate bearing capacities using our exclusive HeliCAP® Helical Capacity Design Software. Click here for a full demo.
Anchoring the World
With both the CHANCE® and ATLAS™ brands, Chance Civil Construction is the international leader in earth anchoring and structural mitigation. CHANCE Helical piles and ATLAS Resistance® piers are used worldwide to secure residential and commercial buildings, tower foundations, heavy equipment foundations and many other deep foundation applications.
Engineered for dependability and long-term stability, our systems feature exclusive anchoring techniques, tools, designs and sizes that make other foundation methods a thing of the past.
Selected by application, our systems are your first line of defense against poor soil conditions, floods and time.
Demand A Better Foundation
With nearly 400 dealers and distributors nationwide and in Canada, we are ready to provide you everything you need to get the job done right. We offer engineering guidance, field supervision, accessibility, warehouses, material traceability, AWCcertified welders, technical support and complete documentation.
Ask a distributor near you for our comprehensive design manual (hardcopy or CD) or download a complete Sample Specification Guide online. Demand a better foundation today. Locate your nearest distributor at our web sites below.
Down. Right. Solid.
Our tagline is our promise. Our foundation and anchoring products go down with power into the ground and are accurate, level and right the first time. The result is solid stability.