Micropiles are small diameter (2” to 15”) drilled and grouted in-place piles. They typically have full depth steel reinforcing placed in the center to carry structural loadings. The reinforcing consists of a single bar or multiple bars bundled together. Micropiles can be installed by using relatively small drilling equipment, single piles or in pile groups. They are well suited for use in limited access applications especially those with low headroom. Advantages of micropiles, is that they can be installed in almost any type of ground condition with minimal vibration and disturbance to existing structures.
H-pile and Lagging
H-pile and lagging is probably the most common shoring system for urban construction and is commonly called Soldier pile and lagging. Steel sections are driven vertically and spaced at 6’-10’ on center. Timber lagging is then placed between the flanges of adjacent piles as excavation proceeds downward. Water is able to pass between the gaps between lagging boards so that water pressure doesn’t build up behind the wall. This type of system is normally cantilevered but wales and tiebacks can be added to increase the excavation depths.
Steel Sheet Piling and Cofferdams
Sheet piling is generally used in open water situations or to retain soils which are below the water table and would flow if excavated. The sheet sheets are fabricated so that each sheet interlocks with the adjacent sheets in an attempt to limit the flow of water and/or soil particles through the wall. Sheet piling can be used for temporary or permanent retention applications. Sheet piling is often cantilevered but can be combined with wales and tiebacks to increase the excavation depths. A major advantage of steel sheet piling is that it can be driven quickly and then removed and reused on another project.
Auger Cast Piles
Auger Cast piles are a type of drilled foundation which are drilled to the final depth in one continuous process. They are also called “continuous flight augered” piles. Once the pile is drilled to the desired depth grout is pumped through the hollow center of the auger pipe. This fills the pile with grout from the bottom up as the auger is retracted. By filling the hole with grout as the auger is being retracted the sides of the hole are continuously supported. After grouting a reinforcing cage can be placed into the pile to the designed depth. Auger cast piles can be designed to carry vertical and lateral loads as well as uplift. Auger cast piles are advantageous because of the speed of installation and can be a very cost effective piling solution.
A soil nail wall is a method of earth retention that utilizes a reinforced block of soil which is large enough to resist the overturning and sliding forces applied to it by lateral earth pressures. The wall is constructed from the top down by installing either helical or grouted tiebacks (nails). A shotcrete facing is designed to span between the nails and retain the soil. This facing is reinforced by welded wire mesh and/or reinforcing steel. Soil nail walls are well suited for applications where rock prohibits the driving of soldier piles that must extend below the proposed excavation. Soil nailing can also be used as a method of slope stabilization.
Helical Piers, Helical Tiebacks and Helical Pulldown Microplies©
Helical piers are a deep foundation system that utilize steel helical plates welded to a central steel shaft in order to support vertical loads either in tension or compression. These piles are advanced into the ground by using small hydraulic equipment and can be installed for either new construction or for repair of existing structures. Helical products can also be used as tiebacks in earth retention applications. The A.B. Chance Company of Centralia, Missouri also offers a Helical Pulldown Micropile© products which combines a helical pier with a grout column to increase the structural properties of the system.
Structural Engineering Concepts, PLC has a wide
variety of bridge design experience. We have
designed structures for State Departments of
Transportation as well as for private landowners.
These bridges can be concrete or timber decks
supported by steel or concrete beams.
Our experience includes bridges of varying lengths
(multi-span continuous, short single spans, etc.)
and materials like concrete and timber decks
supported by steel and/or concrete beams.
In cases where the bridge has already been
designed we provide miscellaneous design for
items like: temporary sheeting, formwork,
falsework, demolition plans and erection plans.
Our experience also includes design-build projects.
Structural Engineering Concepts, PLC - Service List
Structural Engineering Concepts, PLC offers a wide variety of services to our clients: