Micropiles
Micropiles provide tested deep support where low overhead, restricted access, existing structures, or difficult ground limit larger foundation systems.
Pacific plans drilling method, casing, bond zone, grout placement, testing, access, and installation sequence around the constraints that made micropiles necessary.
How Micropiles Work
Micropiles are small-diameter drilled and grouted foundation elements reinforced with steel casing, threadbar, reinforcing bar, or other approved reinforcement.
They are often selected where access, clearance, existing structures, difficult ground, or retrofit requirements limit the use of conventional drilled shafts, driven piles, or shallow foundations.
For contractors, the value is the ability to install a tested foundation element in locations where the work face, structure, or ground conditions limit the available options.
When to Use Micropiles
Micropiles are most useful when the project needs deep foundation capacity but the site does not allow a conventional foundation approach.
Limited access sites
Installed with compact drill rigs where larger foundation equipment cannot reasonably access the work.
Low overhead conditions
Useful inside structures, below bridges, near utilities, or where vertical clearance controls equipment selection.
Existing structures and underpinning
Supports retrofit, strengthening, settlement repair, and load transfer around existing construction.
Bridge and seismic retrofit work
Used for bridge foundations, footing anchors, pier strengthening, seismic upgrades, and transportation retrofits.
Difficult ground
Casing, rotary-percussive drilling, DTH systems, and tooling options help through gravel, cobbles, weathered rock, basalt, and obstructions.
Battered or vertical elements
Installed vertically or battered when the design requires axial, uplift, lateral, or combined load resistance.
Equipment and Tooling
Equipment selection starts with access, overhead clearance, working-platform conditions, casing and grout requirements, ground conditions, and the testing setup. We match the drill rig, tooling, grout support, and test equipment to those project constraints.
Klemm KR 806-3D
The Klemm KR 806-3D is a small-diameter crawler drill rig for anchor, micropile, and related specialty foundation work.
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Hutte HBR 202 E
The Hutte HBR 202 E is a compact crawler drill rig for limited-access small-diameter drilling.
View equipmentFinal equipment selection depends on access, overhead clearance, pile geometry, ground conditions, casing requirements, grout support, and testing requirements.
Project Experience
These projects show how micropiles support bridge, retrofit, repair, and limited-access work where drilling and testing must fit the site.
Salem, OR / Civic & Institutional CAMS III – Oregon Capitol
Pacific Foundation installed low-clearance micropiles and steel jacking towers to support structural jacking and the base-isolation sequence beneath the existing Capitol.
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Pullman, WA / Electric Power Lower Granite Dam
Pacific Foundation installed 32 drilled shafts, each 54 inches in diameter, with 48-inch-diameter rock sockets. The shafts were installed over water through overburden and hard bedrock.
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Bingen, WA / Bridges & Transportation BNSF 66.4 White Salmon Bridge
Pacific Foundation supported the BNSF 66.4 White Salmon Bridge project with battered and vertical 12-5/8-inch micropiles installed in saturated river-adjacent ground.
View projectAdditional micropile examples are available during estimating when project type, access, and ground conditions match the scope.
Pacific Capabilities
Pacific coordinates drilling, casing, grout, access, testing, and the existing work around the pile location. That planning helps contractors turn a difficult foundation detail into a controlled field sequence.
Micropile FAQs
What are micropiles?
Micropiles are small-diameter drilled and grouted foundation elements reinforced with steel casing, threadbar, reinforcing bar, or other approved reinforcement. They can transfer load through bond with the surrounding ground or rock.
When are micropiles a good fit?
Micropiles are often a good fit where access, overhead clearance, existing structures, difficult ground, uplift loads, or retrofit requirements limit the use of larger foundation systems.
Can micropiles be installed inside or near existing structures?
Yes. Micropiles are commonly used for underpinning, retrofit work, interior foundation support, bridge strengthening, and other areas where compact equipment is required.
Can micropiles be installed in rock or cobbles?
Yes, depending on the conditions. Casing, rotary-percussive drilling, down-hole hammer systems, and other tooling can be used where gravel, cobbles, weathered rock, or basalt affect drilling.
How are micropiles tested?
Micropiles may require verification testing, proof testing, or both, depending on the design and specifications. Testing setup, cure time, test loads, and reaction systems should be planned before production begins.
What should we send Pacific for review?
Send the plans, geotechnical report, pile layout, design loads, access constraints, overhead clearance, existing structure information, testing requirements, and schedule assumptions.
Discuss Your Micropile Scope
Send the plans, geotechnical report, pile layout, design loads, access constraints, overhead clearance, testing requirements, and schedule. Pacific will review drilling method, casing, grout, testing, and sequence.